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Catch onTouch event by parent, handle it and pass to children?
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/* | |
* Copyright (C) 2006 The Android Open Source Project | |
* | |
* Licensed under the Apache License, Version 2.0 (the "License"); | |
* you may not use this file except in compliance with the License. | |
* You may obtain a copy of the License at | |
* | |
* http://www.apache.org/licenses/LICENSE-2.0 | |
* | |
* Unless required by applicable law or agreed to in writing, software | |
* distributed under the License is distributed on an "AS IS" BASIS, | |
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
* See the License for the specific language governing permissions and | |
* limitations under the License. | |
*/ | |
/* | |
* Revised 5/19/2010 by GORGES | |
* Now supports two-dimensional view scrolling | |
* http://GORGES.us | |
*/ | |
import java.util.List; | |
import android.content.Context; | |
import android.graphics.Rect; | |
import android.util.AttributeSet; | |
import android.view.FocusFinder; | |
import android.view.GestureDetector; | |
import android.view.GestureDetector.SimpleOnGestureListener; | |
import android.view.KeyEvent; | |
import android.view.MotionEvent; | |
import android.view.VelocityTracker; | |
import android.view.View; | |
import android.view.ViewConfiguration; | |
import android.view.ViewGroup; | |
import android.view.ViewParent; | |
import android.view.animation.AnimationUtils; | |
import android.widget.FrameLayout; | |
import android.widget.LinearLayout; | |
import android.widget.Scroller; | |
import android.widget.TextView; | |
/** | |
* Layout container for a view hierarchy that can be scrolled by the user, | |
* allowing it to be larger than the physical display. A TwoDScrollView | |
* is a {@link FrameLayout}, meaning you should place one child in it | |
* containing the entire contents to scroll; this child may itself be a layout | |
* manager with a complex hierarchy of objects. A child that is often used | |
* is a {@link LinearLayout} in a vertical orientation, presenting a vertical | |
* array of top-level items that the user can scroll through. | |
* | |
* <p>The {@link TextView} class also | |
* takes care of its own scrolling, so does not require a TwoDScrollView, but | |
* using the two together is possible to achieve the effect of a text view | |
* within a larger container. | |
*/ | |
public class TwoDScrollView extends FrameLayout { | |
static final int ANIMATED_SCROLL_GAP = 250; | |
static final float MAX_SCROLL_FACTOR = 0.5f; | |
private long mLastScroll; | |
private final Rect mTempRect = new Rect(); | |
private Scroller mScroller; | |
GestureDetector gestureDetector; | |
/** | |
* Flag to indicate that we are moving focus ourselves. This is so the | |
* code that watches for focus changes initiated outside this TwoDScrollView | |
* knows that it does not have to do anything. | |
*/ | |
private boolean mTwoDScrollViewMovedFocus; | |
/** | |
* Position of the last motion event. | |
*/ | |
private float mLastMotionY; | |
private float mLastMotionX; | |
/** | |
* True when the layout has changed but the traversal has not come through yet. | |
* Ideally the view hierarchy would keep track of this for us. | |
*/ | |
private boolean mIsLayoutDirty = true; | |
/** | |
* The child to give focus to in the event that a child has requested focus while the | |
* layout is dirty. This prevents the scroll from being wrong if the child has not been | |
* laid out before requesting focus. | |
*/ | |
private View mChildToScrollTo = null; | |
/** | |
* True if the user is currently dragging this TwoDScrollView around. This is | |
* not the same as 'is being flinged', which can be checked by | |
* mScroller.isFinished() (flinging begins when the user lifts his finger). | |
*/ | |
private boolean mIsBeingDragged = false; | |
/** | |
* Determines speed during touch scrolling | |
*/ | |
private VelocityTracker mVelocityTracker; | |
/** | |
* Whether arrow scrolling is animated. | |
*/ | |
private int mTouchSlop; | |
private int mMinimumVelocity; | |
private int mMaximumVelocity; | |
public TwoDScrollView(Context context) { | |
super(context); | |
initTwoDScrollView(); | |
} | |
public TwoDScrollView(Context context, AttributeSet attrs) { | |
super(context, attrs); | |
initTwoDScrollView(); | |
} | |
public TwoDScrollView(Context context, AttributeSet attrs, int defStyle) { | |
super(context, attrs, defStyle); | |
initTwoDScrollView(); | |
} | |
@Override | |
protected float getTopFadingEdgeStrength() { | |
if (getChildCount() == 0) { | |
return 0.0f; | |
} | |
final int length = getVerticalFadingEdgeLength(); | |
if (getScrollY() < length) { | |
return getScrollY() / (float) length; | |
} | |
return 1.0f; | |
} | |
@Override | |
protected float getBottomFadingEdgeStrength() { | |
if (getChildCount() == 0) { | |
return 0.0f; | |
} | |
final int length = getVerticalFadingEdgeLength(); | |
final int bottomEdge = getHeight() - getPaddingBottom(); | |
final int span = getChildAt(0).getBottom() - getScrollY() - bottomEdge; | |
if (span < length) { | |
return span / (float) length; | |
} | |
return 1.0f; | |
} | |
@Override | |
protected float getLeftFadingEdgeStrength() { | |
if (getChildCount() == 0) { | |
return 0.0f; | |
} | |
final int length = getHorizontalFadingEdgeLength(); | |
if (getScrollX() < length) { | |
return getScrollX() / (float) length; | |
} | |
return 1.0f; | |
} | |
@Override | |
protected float getRightFadingEdgeStrength() { | |
if (getChildCount() == 0) { | |
return 0.0f; | |
} | |
final int length = getHorizontalFadingEdgeLength(); | |
final int rightEdge = getWidth() - getPaddingRight(); | |
final int span = getChildAt(0).getRight() - getScrollX() - rightEdge; | |
if (span < length) { | |
return span / (float) length; | |
} | |
return 1.0f; | |
} | |
/** | |
* @return The maximum amount this scroll view will scroll in response to | |
* an arrow event. | |
*/ | |
public int getMaxScrollAmountVertical() { | |
return (int) (MAX_SCROLL_FACTOR * getHeight()); | |
} | |
public int getMaxScrollAmountHorizontal() { | |
return (int) (MAX_SCROLL_FACTOR * getWidth()); | |
} | |
private void initTwoDScrollView() { | |
gestureDetector = new GestureDetector(new YScrollDetector());// | |
mScroller = new Scroller(getContext()); | |
setFocusable(true); | |
setDescendantFocusability(FOCUS_AFTER_DESCENDANTS); | |
setWillNotDraw(false); | |
final ViewConfiguration configuration = ViewConfiguration.get(getContext()); | |
mTouchSlop = configuration.getScaledTouchSlop(); | |
mMinimumVelocity = configuration.getScaledMinimumFlingVelocity(); | |
mMaximumVelocity = configuration.getScaledMaximumFlingVelocity(); | |
} | |
@Override | |
public void addView(View child) { | |
if (getChildCount() > 0) { | |
throw new IllegalStateException("TwoDScrollView can host only one direct child"); | |
} | |
super.addView(child); | |
} | |
@Override | |
public void addView(View child, int index) { | |
if (getChildCount() > 0) { | |
throw new IllegalStateException("TwoDScrollView can host only one direct child"); | |
} | |
super.addView(child, index); | |
} | |
@Override | |
public void addView(View child, ViewGroup.LayoutParams params) { | |
if (getChildCount() > 0) { | |
throw new IllegalStateException("TwoDScrollView can host only one direct child"); | |
} | |
super.addView(child, params); | |
} | |
@Override | |
public void addView(View child, int index, ViewGroup.LayoutParams params) { | |
if (getChildCount() > 0) { | |
throw new IllegalStateException("TwoDScrollView can host only one direct child"); | |
} | |
super.addView(child, index, params); | |
} | |
/** | |
* @return Returns true this TwoDScrollView can be scrolled | |
*/ | |
private boolean canScroll() { | |
View child = getChildAt(0); | |
if (child != null) { | |
int childHeight = child.getHeight(); | |
int childWidth = child.getWidth(); | |
return (getHeight() < childHeight + getPaddingTop() + getPaddingBottom()) || | |
(getWidth() < childWidth + getPaddingLeft() + getPaddingRight()); | |
} | |
return false; | |
} | |
@Override | |
public boolean dispatchKeyEvent(KeyEvent event) { | |
// Let the focused view and/or our descendants get the key first | |
boolean handled = super.dispatchKeyEvent(event); | |
if (handled) { | |
return true; | |
} | |
return executeKeyEvent(event); | |
} | |
/** | |
* You can call this function yourself to have the scroll view perform | |
* scrolling from a key event, just as if the event had been dispatched to | |
* it by the view hierarchy. | |
* | |
* @param event The key event to execute. | |
* @return Return true if the event was handled, else false. | |
*/ | |
public boolean executeKeyEvent(KeyEvent event) { | |
mTempRect.setEmpty(); | |
if (!canScroll()) { | |
if (isFocused()) { | |
View currentFocused = findFocus(); | |
if (currentFocused == this) currentFocused = null; | |
View nextFocused = FocusFinder.getInstance().findNextFocus(this, currentFocused, View.FOCUS_DOWN); | |
return nextFocused != null && nextFocused != this && nextFocused.requestFocus(View.FOCUS_DOWN); | |
} | |
return false; | |
} | |
boolean handled = false; | |
if (event.getAction() == KeyEvent.ACTION_DOWN) { | |
switch (event.getKeyCode()) { | |
case KeyEvent.KEYCODE_DPAD_UP: | |
if (!event.isAltPressed()) { | |
handled = arrowScroll(View.FOCUS_UP, false); | |
} else { | |
handled = fullScroll(View.FOCUS_UP, false); | |
} | |
break; | |
case KeyEvent.KEYCODE_DPAD_DOWN: | |
if (!event.isAltPressed()) { | |
handled = arrowScroll(View.FOCUS_DOWN, false); | |
} else { | |
handled = fullScroll(View.FOCUS_DOWN, false); | |
} | |
break; | |
case KeyEvent.KEYCODE_DPAD_LEFT: | |
if (!event.isAltPressed()) { | |
handled = arrowScroll(View.FOCUS_UP, true); | |
} else { | |
handled = fullScroll(View.FOCUS_UP, true); | |
} | |
break; | |
case KeyEvent.KEYCODE_DPAD_RIGHT: | |
if (!event.isAltPressed()) { | |
handled = arrowScroll(View.FOCUS_DOWN, true); | |
} else { | |
handled = fullScroll(View.FOCUS_DOWN, true); | |
} | |
break; | |
} | |
} | |
return handled; | |
} | |
//=========================================================================== | |
@Override | |
public boolean onInterceptTouchEvent(MotionEvent ev) { | |
/* | |
* This method JUST determines whether we want to intercept the motion. | |
* If we return true, onMotionEvent will be called and we do the actual | |
* scrolling there. | |
* | |
* Shortcut the most recurring case: the user is in the dragging | |
* state and he is moving his finger. We want to intercept this | |
* motion. | |
*/ | |
// boolean result = super.onInterceptTouchEvent(ev); | |
// //Now see if we are scrolling vertically with the custom gesture detector | |
// if (gestureDetector.onTouchEvent(ev)) { | |
// return result; | |
// } | |
// //If not scrolling vertically (more y than x), don't hijack the event. | |
// else { | |
// return false; | |
// } | |
final int action = ev.getAction(); | |
if ((action == MotionEvent.ACTION_MOVE) && (mIsBeingDragged)) { | |
return true; | |
} | |
if (!canScroll()) { | |
mIsBeingDragged = false; | |
return false; | |
} | |
final float y = ev.getY(); | |
final float x = ev.getX(); | |
switch (action) { | |
case MotionEvent.ACTION_MOVE: | |
/* | |
* mIsBeingDragged == false, otherwise the shortcut would have caught it. Check | |
* whether the user has moved far enough from his original down touch. | |
*/ | |
/* | |
* Locally do absolute value. mLastMotionY is set to the y value | |
* of the down event. | |
*/ | |
final int yDiff = (int) Math.abs(y - mLastMotionY); | |
final int xDiff = (int) Math.abs(x - mLastMotionX); | |
if (yDiff > mTouchSlop || xDiff > mTouchSlop) { | |
mIsBeingDragged = true; | |
} | |
break; | |
case MotionEvent.ACTION_DOWN: | |
/* Remember location of down touch */ | |
mLastMotionY = y; | |
mLastMotionX = x; | |
/* | |
* If being flinged and user touches the screen, initiate drag; | |
* otherwise don't. mScroller.isFinished should be false when | |
* being flinged. | |
*/ | |
mIsBeingDragged = !mScroller.isFinished(); | |
break; | |
case MotionEvent.ACTION_CANCEL: | |
case MotionEvent.ACTION_UP: | |
/* Release the drag */ | |
mIsBeingDragged = false; | |
break; | |
} | |
/* | |
* The only time we want to intercept motion events is if we are in the | |
* drag mode. | |
*/ | |
return mIsBeingDragged; | |
} | |
@Override | |
public boolean onTouchEvent(MotionEvent ev) { | |
/* boolean result = super.onInterceptTouchEvent(ev); | |
//Now see if we are scrolling vertically with the custom gesture detector | |
GestureDetector gestureDetector = new GestureDetector(new YScrollDetector()); | |
if (gestureDetector.onTouchEvent(ev)) { | |
return result; | |
} | |
//If not scrolling vertically (more y than x), don't hijack the event. | |
else { | |
return false; | |
}*/ | |
if (ev.getAction() == MotionEvent.ACTION_DOWN && ev.getEdgeFlags() != 0) { | |
// Don't handle edge touches immediately -- they may actually belong to one of our | |
// descendants. | |
return false; | |
} | |
if (!canScroll()) { | |
return false; | |
} | |
if (mVelocityTracker == null) { | |
mVelocityTracker = VelocityTracker.obtain(); | |
} | |
mVelocityTracker.addMovement(ev); | |
final int action = ev.getAction(); | |
final float y = ev.getY(); | |
final float x = ev.getX(); | |
switch (action) { | |
// case MotionEvent.ACTION_: | |
// | |
// return true; | |
case MotionEvent.ACTION_DOWN: | |
/* | |
* If being flinged and user touches, stop the fling. isFinished | |
* will be false if being flinged. | |
*/ | |
if (!mScroller.isFinished()) { | |
mScroller.abortAnimation(); | |
} | |
// Remember where the motion event started | |
mLastMotionY = y; | |
mLastMotionX = x; | |
break; | |
case MotionEvent.ACTION_MOVE: | |
// Scroll to follow the motion event | |
int deltaX = (int) (mLastMotionX - x); | |
int deltaY = (int) (mLastMotionY - y); | |
mLastMotionX = x; | |
mLastMotionY = y; | |
if (deltaX < 0) { | |
if (getScrollX() < 0) { | |
deltaX = 0; | |
} | |
} else if (deltaX > 0) { | |
final int rightEdge = getWidth() - getPaddingRight(); | |
final int availableToScroll = getChildAt(0).getRight() - getScrollX() - rightEdge; | |
if (availableToScroll > 0) { | |
deltaX = Math.min(availableToScroll, deltaX); | |
} else { | |
deltaX = 0; | |
} | |
} | |
if (deltaY < 0) { | |
if (getScrollY() < 0) { | |
deltaY = 0; | |
} | |
} else if (deltaY > 0) { | |
final int bottomEdge = getHeight() - getPaddingBottom(); | |
final int availableToScroll = getChildAt(0).getBottom() - getScrollY() - bottomEdge; | |
if (availableToScroll > 0) { | |
deltaY = Math.min(availableToScroll, deltaY); | |
} else { | |
deltaY = 0; | |
} | |
} | |
if (deltaY != 0 || deltaX != 0) | |
scrollBy(deltaX, deltaY); | |
break; | |
case MotionEvent.ACTION_UP: | |
final VelocityTracker velocityTracker = mVelocityTracker; | |
velocityTracker.computeCurrentVelocity(1000, mMaximumVelocity); | |
int initialXVelocity = (int) velocityTracker.getXVelocity(); | |
int initialYVelocity = (int) velocityTracker.getYVelocity(); | |
if ((Math.abs(initialXVelocity) + Math.abs(initialYVelocity) > mMinimumVelocity) && getChildCount() > 0) { | |
fling(-initialXVelocity, -initialYVelocity); | |
} | |
if (mVelocityTracker != null) { | |
mVelocityTracker.recycle(); | |
mVelocityTracker = null; | |
} | |
} | |
return true; | |
} | |
//=================================================================== | |
@Override | |
public boolean dispatchTouchEvent (MotionEvent ev) { | |
// Do your calcluations | |
// return super.dispatchTouchEvent(ev); | |
boolean result = super.dispatchTouchEvent(ev); | |
if (gestureDetector.onTouchEvent(ev)) { | |
return result; | |
} | |
//If not scrolling vertically (more y than x), don't hijack the event. | |
else { | |
return false; | |
} | |
} | |
//=================================================================== | |
/** | |
* Finds the next focusable component that fits in this View's bounds | |
* (excluding fading edges) pretending that this View's top is located at | |
* the parameter top. | |
* | |
* @param topFocus look for a candidate is the one at the top of the bounds | |
* if topFocus is true, or at the bottom of the bounds if topFocus is | |
* false | |
* @param top the top offset of the bounds in which a focusable must be | |
* found (the fading edge is assumed to start at this position) | |
* @param preferredFocusable the View that has highest priority and will be | |
* returned if it is within my bounds (null is valid) | |
* @return the next focusable component in the bounds or null if none can be | |
* found | |
*/ | |
private View findFocusableViewInMyBounds(final boolean topFocus, final int top, final boolean leftFocus, final int left, View preferredFocusable) { | |
/* | |
* The fading edge's transparent side should be considered for focus | |
* since it's mostly visible, so we divide the actual fading edge length | |
* by 2. | |
*/ | |
final int verticalFadingEdgeLength = getVerticalFadingEdgeLength() / 2; | |
final int topWithoutFadingEdge = top + verticalFadingEdgeLength; | |
final int bottomWithoutFadingEdge = top + getHeight() - verticalFadingEdgeLength; | |
final int horizontalFadingEdgeLength = getHorizontalFadingEdgeLength() / 2; | |
final int leftWithoutFadingEdge = left + horizontalFadingEdgeLength; | |
final int rightWithoutFadingEdge = left + getWidth() - horizontalFadingEdgeLength; | |
if ((preferredFocusable != null) | |
&& (preferredFocusable.getTop() < bottomWithoutFadingEdge) | |
&& (preferredFocusable.getBottom() > topWithoutFadingEdge) | |
&& (preferredFocusable.getLeft() < rightWithoutFadingEdge) | |
&& (preferredFocusable.getRight() > leftWithoutFadingEdge)) { | |
return preferredFocusable; | |
} | |
return findFocusableViewInBounds(topFocus, topWithoutFadingEdge, bottomWithoutFadingEdge, leftFocus, leftWithoutFadingEdge, rightWithoutFadingEdge); | |
} | |
/** | |
* Finds the next focusable component that fits in the specified bounds. | |
* </p> | |
* | |
* @param topFocus look for a candidate is the one at the top of the bounds | |
* if topFocus is true, or at the bottom of the bounds if topFocus is | |
* false | |
* @param top the top offset of the bounds in which a focusable must be | |
* found | |
* @param bottom the bottom offset of the bounds in which a focusable must | |
* be found | |
* @return the next focusable component in the bounds or null if none can | |
* be found | |
*/ | |
private View findFocusableViewInBounds(boolean topFocus, int top, int bottom, boolean leftFocus, int left, int right) { | |
List<View> focusables = getFocusables(View.FOCUS_FORWARD); | |
View focusCandidate = null; | |
/* | |
* A fully contained focusable is one where its top is below the bound's | |
* top, and its bottom is above the bound's bottom. A partially | |
* contained focusable is one where some part of it is within the | |
* bounds, but it also has some part that is not within bounds. A fully contained | |
* focusable is preferred to a partially contained focusable. | |
*/ | |
boolean foundFullyContainedFocusable = false; | |
int count = focusables.size(); | |
for (int i = 0; i < count; i++) { | |
View view = focusables.get(i); | |
int viewTop = view.getTop(); | |
int viewBottom = view.getBottom(); | |
int viewLeft = view.getLeft(); | |
int viewRight = view.getRight(); | |
if (top < viewBottom && viewTop < bottom && left < viewRight && viewLeft < right) { | |
/* | |
* the focusable is in the target area, it is a candidate for | |
* focusing | |
*/ | |
final boolean viewIsFullyContained = (top < viewTop) && (viewBottom < bottom) && (left < viewLeft) && (viewRight < right); | |
if (focusCandidate == null) { | |
/* No candidate, take this one */ | |
focusCandidate = view; | |
foundFullyContainedFocusable = viewIsFullyContained; | |
} else { | |
final boolean viewIsCloserToVerticalBoundary = | |
(topFocus && viewTop < focusCandidate.getTop()) || | |
(!topFocus && viewBottom > focusCandidate.getBottom()); | |
final boolean viewIsCloserToHorizontalBoundary = | |
(leftFocus && viewLeft < focusCandidate.getLeft()) || | |
(!leftFocus && viewRight > focusCandidate.getRight()); | |
if (foundFullyContainedFocusable) { | |
if (viewIsFullyContained && viewIsCloserToVerticalBoundary && viewIsCloserToHorizontalBoundary) { | |
/* | |
* We're dealing with only fully contained views, so | |
* it has to be closer to the boundary to beat our | |
* candidate | |
*/ | |
focusCandidate = view; | |
} | |
} else { | |
if (viewIsFullyContained) { | |
/* Any fully contained view beats a partially contained view */ | |
focusCandidate = view; | |
foundFullyContainedFocusable = true; | |
} else if (viewIsCloserToVerticalBoundary && viewIsCloserToHorizontalBoundary) { | |
/* | |
* Partially contained view beats another partially | |
* contained view if it's closer | |
*/ | |
focusCandidate = view; | |
} | |
} | |
} | |
} | |
} | |
return focusCandidate; | |
} | |
/** | |
* <p>Handles scrolling in response to a "home/end" shortcut press. This | |
* method will scroll the view to the top or bottom and give the focus | |
* to the topmost/bottommost component in the new visible area. If no | |
* component is a good candidate for focus, this scrollview reclaims the | |
* focus.</p> | |
* | |
* @param direction the scroll direction: {@link android.view.View#FOCUS_UP} | |
* to go the top of the view or | |
* {@link android.view.View#FOCUS_DOWN} to go the bottom | |
* @return true if the key event is consumed by this method, false otherwise | |
*/ | |
public boolean fullScroll(int direction, boolean horizontal) { | |
if (!horizontal) { | |
boolean down = direction == View.FOCUS_DOWN; | |
int height = getHeight(); | |
mTempRect.top = 0; | |
mTempRect.bottom = height; | |
if (down) { | |
int count = getChildCount(); | |
if (count > 0) { | |
View view = getChildAt(count - 1); | |
mTempRect.bottom = view.getBottom(); | |
mTempRect.top = mTempRect.bottom - height; | |
} | |
} | |
return scrollAndFocus(direction, mTempRect.top, mTempRect.bottom, 0, 0, 0); | |
} else { | |
boolean right = direction == View.FOCUS_DOWN; | |
int width = getWidth(); | |
mTempRect.left = 0; | |
mTempRect.right = width; | |
if (right) { | |
int count = getChildCount(); | |
if (count > 0) { | |
View view = getChildAt(count - 1); | |
mTempRect.right = view.getBottom(); | |
mTempRect.left = mTempRect.right - width; | |
} | |
} | |
return scrollAndFocus(0, 0, 0, direction, mTempRect.top, mTempRect.bottom); | |
} | |
} | |
/** | |
* <p>Scrolls the view to make the area defined by <code>top</code> and | |
* <code>bottom</code> visible. This method attempts to give the focus | |
* to a component visible in this area. If no component can be focused in | |
* the new visible area, the focus is reclaimed by this scrollview.</p> | |
* | |
* @param direction the scroll direction: {@link android.view.View#FOCUS_UP} | |
* to go upward | |
* {@link android.view.View#FOCUS_DOWN} to downward | |
* @param top the top offset of the new area to be made visible | |
* @param bottom the bottom offset of the new area to be made visible | |
* @return true if the key event is consumed by this method, false otherwise | |
*/ | |
private boolean scrollAndFocus(int directionY, int top, int bottom, int directionX, int left, int right) { | |
boolean handled = true; | |
int height = getHeight(); | |
int containerTop = getScrollY(); | |
int containerBottom = containerTop + height; | |
boolean up = directionY == View.FOCUS_UP; | |
int width = getWidth(); | |
int containerLeft = getScrollX(); | |
int containerRight = containerLeft + width; | |
boolean leftwards = directionX == View.FOCUS_UP; | |
View newFocused = findFocusableViewInBounds(up, top, bottom, leftwards, left, right); | |
if (newFocused == null) { | |
newFocused = this; | |
} | |
if ((top >= containerTop && bottom <= containerBottom) || (left >= containerLeft && right <= containerRight)) { | |
handled = false; | |
} else { | |
int deltaY = up ? (top - containerTop) : (bottom - containerBottom); | |
int deltaX = leftwards ? (left - containerLeft) : (right - containerRight); | |
doScroll(deltaX, deltaY); | |
} | |
if (newFocused != findFocus() && newFocused.requestFocus(directionY)) { | |
mTwoDScrollViewMovedFocus = true; | |
mTwoDScrollViewMovedFocus = false; | |
} | |
return handled; | |
} | |
/** | |
* Handle scrolling in response to an up or down arrow click. | |
* | |
* @param direction The direction corresponding to the arrow key that was | |
* pressed | |
* @return True if we consumed the event, false otherwise | |
*/ | |
public boolean arrowScroll(int direction, boolean horizontal) { | |
View currentFocused = findFocus(); | |
if (currentFocused == this) currentFocused = null; | |
View nextFocused = FocusFinder.getInstance().findNextFocus(this, currentFocused, direction); | |
final int maxJump = horizontal ? getMaxScrollAmountHorizontal() : getMaxScrollAmountVertical(); | |
if (!horizontal) { | |
if (nextFocused != null) { | |
nextFocused.getDrawingRect(mTempRect); | |
offsetDescendantRectToMyCoords(nextFocused, mTempRect); | |
int scrollDelta = computeScrollDeltaToGetChildRectOnScreen(mTempRect); | |
doScroll(0, scrollDelta); | |
nextFocused.requestFocus(direction); | |
} else { | |
// no new focus | |
int scrollDelta = maxJump; | |
if (direction == View.FOCUS_UP && getScrollY() < scrollDelta) { | |
scrollDelta = getScrollY(); | |
} else if (direction == View.FOCUS_DOWN) { | |
if (getChildCount() > 0) { | |
int daBottom = getChildAt(0).getBottom(); | |
int screenBottom = getScrollY() + getHeight(); | |
if (daBottom - screenBottom < maxJump) { | |
scrollDelta = daBottom - screenBottom; | |
} | |
} | |
} | |
if (scrollDelta == 0) { | |
return false; | |
} | |
doScroll(0, direction == View.FOCUS_DOWN ? scrollDelta : -scrollDelta); | |
} | |
} else { | |
if (nextFocused != null) { | |
nextFocused.getDrawingRect(mTempRect); | |
offsetDescendantRectToMyCoords(nextFocused, mTempRect); | |
int scrollDelta = computeScrollDeltaToGetChildRectOnScreen(mTempRect); | |
doScroll(scrollDelta, 0); | |
nextFocused.requestFocus(direction); | |
} else { | |
// no new focus | |
int scrollDelta = maxJump; | |
if (direction == View.FOCUS_UP && getScrollY() < scrollDelta) { | |
scrollDelta = getScrollY(); | |
} else if (direction == View.FOCUS_DOWN) { | |
if (getChildCount() > 0) { | |
int daBottom = getChildAt(0).getBottom(); | |
int screenBottom = getScrollY() + getHeight(); | |
if (daBottom - screenBottom < maxJump) { | |
scrollDelta = daBottom - screenBottom; | |
} | |
} | |
} | |
if (scrollDelta == 0) { | |
return false; | |
} | |
doScroll(direction == View.FOCUS_DOWN ? scrollDelta : -scrollDelta, 0); | |
} | |
} | |
return true; | |
} | |
/** | |
* Smooth scroll by a Y delta | |
* | |
* @param delta the number of pixels to scroll by on the Y axis | |
*/ | |
private void doScroll(int deltaX, int deltaY) { | |
if (deltaX != 0 || deltaY != 0) { | |
smoothScrollBy(deltaX, deltaY); | |
} | |
} | |
/** | |
* Like {@link View#scrollBy}, but scroll smoothly instead of immediately. | |
* | |
* @param dx the number of pixels to scroll by on the X axis | |
* @param dy the number of pixels to scroll by on the Y axis | |
*/ | |
public final void smoothScrollBy(int dx, int dy) { | |
long duration = AnimationUtils.currentAnimationTimeMillis() - mLastScroll; | |
if (duration > ANIMATED_SCROLL_GAP) { | |
mScroller.startScroll(getScrollX(), getScrollY(), dx, dy); | |
awakenScrollBars(mScroller.getDuration()); | |
invalidate(); | |
} else { | |
if (!mScroller.isFinished()) { | |
mScroller.abortAnimation(); | |
} | |
scrollBy(dx, dy); | |
} | |
mLastScroll = AnimationUtils.currentAnimationTimeMillis(); | |
} | |
/** | |
* Like {@link #scrollTo}, but scroll smoothly instead of immediately. | |
* | |
* @param x the position where to scroll on the X axis | |
* @param y the position where to scroll on the Y axis | |
*/ | |
public final void smoothScrollTo(int x, int y) { | |
smoothScrollBy(x - getScrollX(), y - getScrollY()); | |
} | |
/** | |
* <p>The scroll range of a scroll view is the overall height of all of its | |
* children.</p> | |
*/ | |
@Override | |
protected int computeVerticalScrollRange() { | |
int count = getChildCount(); | |
return count == 0 ? getHeight() : (getChildAt(0)).getBottom(); | |
} | |
@Override | |
protected int computeHorizontalScrollRange() { | |
int count = getChildCount(); | |
return count == 0 ? getWidth() : (getChildAt(0)).getRight(); | |
} | |
@Override | |
protected void measureChild(View child, int parentWidthMeasureSpec, int parentHeightMeasureSpec) { | |
ViewGroup.LayoutParams lp = child.getLayoutParams(); | |
int childWidthMeasureSpec; | |
int childHeightMeasureSpec; | |
childWidthMeasureSpec = getChildMeasureSpec(parentWidthMeasureSpec, getPaddingLeft() + getPaddingRight(), lp.width); | |
childHeightMeasureSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); | |
child.measure(childWidthMeasureSpec, childHeightMeasureSpec); | |
} | |
@Override | |
protected void measureChildWithMargins(View child, int parentWidthMeasureSpec, int widthUsed, int parentHeightMeasureSpec, int heightUsed) { | |
final MarginLayoutParams lp = (MarginLayoutParams) child.getLayoutParams(); | |
final int childWidthMeasureSpec = MeasureSpec.makeMeasureSpec(lp.leftMargin + lp.rightMargin, MeasureSpec.UNSPECIFIED); | |
final int childHeightMeasureSpec = MeasureSpec.makeMeasureSpec(lp.topMargin + lp.bottomMargin, MeasureSpec.UNSPECIFIED); | |
child.measure(childWidthMeasureSpec, childHeightMeasureSpec); | |
} | |
@Override | |
public void computeScroll() { | |
if (mScroller.computeScrollOffset()) { | |
// This is called at drawing time by ViewGroup. We don't want to | |
// re-show the scrollbars at this point, which scrollTo will do, | |
// so we replicate most of scrollTo here. | |
// | |
// It's a little odd to call onScrollChanged from inside the drawing. | |
// | |
// It is, except when you remember that computeScroll() is used to | |
// animate scrolling. So unless we want to defer the onScrollChanged() | |
// until the end of the animated scrolling, we don't really have a | |
// choice here. | |
// | |
// I agree. The alternative, which I think would be worse, is to post | |
// something and tell the subclasses later. This is bad because there | |
// will be a window where mScrollX/Y is different from what the app | |
// thinks it is. | |
// | |
int oldX = getScrollX(); | |
int oldY = getScrollY(); | |
int x = mScroller.getCurrX(); | |
int y = mScroller.getCurrY(); | |
if (getChildCount() > 0) { | |
View child = getChildAt(0); | |
scrollTo(clamp(x, getWidth() - getPaddingRight() - getPaddingLeft(), child.getWidth()), | |
clamp(y, getHeight() - getPaddingBottom() - getPaddingTop(), child.getHeight())); | |
} else { | |
scrollTo(x, y); | |
} | |
if (oldX != getScrollX() || oldY != getScrollY()) { | |
onScrollChanged(getScrollX(), getScrollY(), oldX, oldY); | |
} | |
// Keep on drawing until the animation has finished. | |
postInvalidate(); | |
} | |
} | |
/** | |
* Scrolls the view to the given child. | |
* | |
* @param child the View to scroll to | |
*/ | |
private void scrollToChild(View child) { | |
child.getDrawingRect(mTempRect); | |
/* Offset from child's local coordinates to TwoDScrollView coordinates */ | |
offsetDescendantRectToMyCoords(child, mTempRect); | |
int scrollDelta = computeScrollDeltaToGetChildRectOnScreen(mTempRect); | |
if (scrollDelta != 0) { | |
scrollBy(0, scrollDelta); | |
} | |
} | |
/** | |
* If rect is off screen, scroll just enough to get it (or at least the | |
* first screen size chunk of it) on screen. | |
* | |
* @param rect The rectangle. | |
* @param immediate True to scroll immediately without animation | |
* @return true if scrolling was performed | |
*/ | |
private boolean scrollToChildRect(Rect rect, boolean immediate) { | |
final int delta = computeScrollDeltaToGetChildRectOnScreen(rect); | |
final boolean scroll = delta != 0; | |
if (scroll) { | |
if (immediate) { | |
scrollBy(0, delta); | |
} else { | |
smoothScrollBy(0, delta); | |
} | |
} | |
return scroll; | |
} | |
/** | |
* Compute the amount to scroll in the Y direction in order to get | |
* a rectangle completely on the screen (or, if taller than the screen, | |
* at least the first screen size chunk of it). | |
* | |
* @param rect The rect. | |
* @return The scroll delta. | |
*/ | |
protected int computeScrollDeltaToGetChildRectOnScreen(Rect rect) { | |
if (getChildCount() == 0) return 0; | |
int height = getHeight(); | |
int screenTop = getScrollY(); | |
int screenBottom = screenTop + height; | |
int fadingEdge = getVerticalFadingEdgeLength(); | |
// leave room for top fading edge as long as rect isn't at very top | |
if (rect.top > 0) { | |
screenTop += fadingEdge; | |
} | |
// leave room for bottom fading edge as long as rect isn't at very bottom | |
if (rect.bottom < getChildAt(0).getHeight()) { | |
screenBottom -= fadingEdge; | |
} | |
int scrollYDelta = 0; | |
if (rect.bottom > screenBottom && rect.top > screenTop) { | |
// need to move down to get it in view: move down just enough so | |
// that the entire rectangle is in view (or at least the first | |
// screen size chunk). | |
if (rect.height() > height) { | |
// just enough to get screen size chunk on | |
scrollYDelta += (rect.top - screenTop); | |
} else { | |
// get entire rect at bottom of screen | |
scrollYDelta += (rect.bottom - screenBottom); | |
} | |
// make sure we aren't scrolling beyond the end of our content | |
int bottom = getChildAt(0).getBottom(); | |
int distanceToBottom = bottom - screenBottom; | |
scrollYDelta = Math.min(scrollYDelta, distanceToBottom); | |
} else if (rect.top < screenTop && rect.bottom < screenBottom) { | |
// need to move up to get it in view: move up just enough so that | |
// entire rectangle is in view (or at least the first screen | |
// size chunk of it). | |
if (rect.height() > height) { | |
// screen size chunk | |
scrollYDelta -= (screenBottom - rect.bottom); | |
} else { | |
// entire rect at top | |
scrollYDelta -= (screenTop - rect.top); | |
} | |
// make sure we aren't scrolling any further than the top our content | |
scrollYDelta = Math.max(scrollYDelta, -getScrollY()); | |
} | |
return scrollYDelta; | |
} | |
@Override | |
public void requestChildFocus(View child, View focused) { | |
if (!mTwoDScrollViewMovedFocus) { | |
if (!mIsLayoutDirty) { | |
scrollToChild(focused); | |
} else { | |
// The child may not be laid out yet, we can't compute the scroll yet | |
mChildToScrollTo = focused; | |
} | |
} | |
super.requestChildFocus(child, focused); | |
} | |
/** | |
* When looking for focus in children of a scroll view, need to be a little | |
* more careful not to give focus to something that is scrolled off screen. | |
* | |
* This is more expensive than the default {@link android.view.ViewGroup} | |
* implementation, otherwise this behavior might have been made the default. | |
*/ | |
@Override | |
protected boolean onRequestFocusInDescendants(int direction, Rect previouslyFocusedRect) { | |
// convert from forward / backward notation to up / down / left / right | |
// (ugh). | |
if (direction == View.FOCUS_FORWARD) { | |
direction = View.FOCUS_DOWN; | |
} else if (direction == View.FOCUS_BACKWARD) { | |
direction = View.FOCUS_UP; | |
} | |
final View nextFocus = previouslyFocusedRect == null ? | |
FocusFinder.getInstance().findNextFocus(this, null, direction) : | |
FocusFinder.getInstance().findNextFocusFromRect(this, | |
previouslyFocusedRect, direction); | |
if (nextFocus == null) { | |
return false; | |
} | |
return nextFocus.requestFocus(direction, previouslyFocusedRect); | |
} | |
@Override | |
public boolean requestChildRectangleOnScreen(View child, Rect rectangle, boolean immediate) { | |
// offset into coordinate space of this scroll view | |
rectangle.offset(child.getLeft() - child.getScrollX(), child.getTop() - child.getScrollY()); | |
return scrollToChildRect(rectangle, immediate); | |
} | |
@Override | |
public void requestLayout() { | |
mIsLayoutDirty = true; | |
super.requestLayout(); | |
} | |
@Override | |
protected void onLayout(boolean changed, int l, int t, int r, int b) { | |
super.onLayout(changed, l, t, r, b); | |
mIsLayoutDirty = false; | |
// Give a child focus if it needs it | |
if (mChildToScrollTo != null && isViewDescendantOf(mChildToScrollTo, this)) { | |
scrollToChild(mChildToScrollTo); | |
} | |
mChildToScrollTo = null; | |
// Calling this with the present values causes it to re-clam them | |
scrollTo(getScrollX(), getScrollY()); | |
} | |
@Override | |
protected void onSizeChanged(int w, int h, int oldw, int oldh) { | |
super.onSizeChanged(w, h, oldw, oldh); | |
View currentFocused = findFocus(); | |
if (null == currentFocused || this == currentFocused) | |
return; | |
// If the currently-focused view was visible on the screen when the | |
// screen was at the old height, then scroll the screen to make that | |
// view visible with the new screen height. | |
currentFocused.getDrawingRect(mTempRect); | |
offsetDescendantRectToMyCoords(currentFocused, mTempRect); | |
int scrollDeltaX = computeScrollDeltaToGetChildRectOnScreen(mTempRect); | |
int scrollDeltaY = computeScrollDeltaToGetChildRectOnScreen(mTempRect); | |
doScroll(scrollDeltaX, scrollDeltaY); | |
} | |
/** | |
* Return true if child is an descendant of parent, (or equal to the parent). | |
*/ | |
private boolean isViewDescendantOf(View child, View parent) { | |
if (child == parent) { | |
return true; | |
} | |
final ViewParent theParent = child.getParent(); | |
return (theParent instanceof ViewGroup) && isViewDescendantOf((View) theParent, parent); | |
} | |
/** | |
* Fling the scroll view | |
* | |
* @param velocityY The initial velocity in the Y direction. Positive | |
* numbers mean that the finger/curor is moving down the screen, | |
* which means we want to scroll towards the top. | |
*/ | |
public void fling(int velocityX, int velocityY) { | |
if (getChildCount() > 0) { | |
int height = getHeight() - getPaddingBottom() - getPaddingTop(); | |
int bottom = getChildAt(0).getHeight(); | |
int width = getWidth() - getPaddingRight() - getPaddingLeft(); | |
int right = getChildAt(0).getWidth(); | |
mScroller.fling(getScrollX(), getScrollY(), velocityX, velocityY, 0, right - width, 0, bottom - height); | |
final boolean movingDown = velocityY > 0; | |
final boolean movingRight = velocityX > 0; | |
View newFocused = findFocusableViewInMyBounds(movingRight, mScroller.getFinalX(), movingDown, mScroller.getFinalY(), findFocus()); | |
if (newFocused == null) { | |
newFocused = this; | |
} | |
if (newFocused != findFocus() && newFocused.requestFocus(movingDown ? View.FOCUS_DOWN : View.FOCUS_UP)) { | |
mTwoDScrollViewMovedFocus = true; | |
mTwoDScrollViewMovedFocus = false; | |
} | |
awakenScrollBars(mScroller.getDuration()); | |
invalidate(); | |
} | |
} | |
/** | |
* {@inheritDoc} | |
* | |
* <p>This version also clamps the scrolling to the bounds of our child. | |
*/ | |
public void scrollTo(int x, int y) { | |
// we rely on the fact the View.scrollBy calls scrollTo. | |
if (getChildCount() > 0) { | |
View child = getChildAt(0); | |
x = clamp(x, getWidth() - getPaddingRight() - getPaddingLeft(), child.getWidth()); | |
y = clamp(y, getHeight() - getPaddingBottom() - getPaddingTop(), child.getHeight()); | |
if (x != getScrollX() || y != getScrollY()) { | |
super.scrollTo(x, y); | |
} | |
} | |
} | |
private int clamp(int n, int my, int child) { | |
if (my >= child || n < 0) { | |
/* my >= child is this case: | |
* |--------------- me ---------------| | |
* |------ child ------| | |
* or | |
* |--------------- me ---------------| | |
* |------ child ------| | |
* or | |
* |--------------- me ---------------| | |
* |------ child ------| | |
* | |
* n < 0 is this case: | |
* |------ me ------| | |
* |-------- child --------| | |
* |-- mScrollX --| | |
*/ | |
return 0; | |
} | |
if ((my+n) > child) { | |
/* this case: | |
* |------ me ------| | |
* |------ child ------| | |
* |-- mScrollX --| | |
*/ | |
return child-my; | |
} | |
return n; | |
} | |
class YScrollDetector extends SimpleOnGestureListener { | |
@Override | |
public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) { | |
try { | |
if (Math.abs(distanceY) > Math.abs(distanceX)) { | |
return true; | |
} else { | |
return false; | |
} | |
} catch (Exception e) { | |
// nothing | |
} | |
return false; | |
} | |
}} |
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