Created
December 8, 2015 23:23
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Horizontal Snapping RecyclerView with Page Indication
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import android.content.Context; | |
import android.graphics.PointF; | |
import android.support.v7.widget.LinearSmoothScroller; | |
import android.support.v7.widget.RecyclerView; | |
import android.util.AttributeSet; | |
import android.util.DisplayMetrics; | |
import android.util.TypedValue; | |
import android.view.MotionEvent; | |
/** | |
* Created by mgarner on 11/2/2015. | |
*/ | |
public class PagingRecyclerView extends RecyclerView { | |
private LayoutManager mLayout; | |
private boolean mHorizontalScroll = false; | |
private Adapter mAdapter; | |
private boolean mScrollingFurther = false; | |
private float mTouchDownX = 0; | |
private float mTouchDownY = 0; | |
private boolean mTouchHandled = true; | |
public PagingRecyclerView(Context context) { | |
super(context); | |
} | |
public PagingRecyclerView(Context context, AttributeSet attrs) { | |
super(context, attrs); | |
} | |
public PagingRecyclerView(Context context, AttributeSet attrs, int defStyle) { | |
super(context, attrs, defStyle); | |
} | |
private void init() { | |
mLayout = getLayoutManager(); | |
mAdapter = getAdapter(); | |
if (mLayout != null) { | |
mHorizontalScroll = mLayout.canScrollHorizontally(); | |
} | |
} | |
@Override | |
public void setLayoutManager(LayoutManager layout) { | |
super.setLayoutManager(layout); | |
init(); | |
} | |
@Override | |
public boolean fling(int velocityX, int velocityY) { | |
boolean scrollFurther; | |
if (mHorizontalScroll) { | |
scrollFurther = velocityX > 0; | |
} else { | |
scrollFurther = velocityY > 0; | |
} | |
if (scrollFurther) { | |
if (mAdapter != null) { | |
pageMore(); | |
} | |
} else { | |
pageLess(); | |
} | |
return super.fling(0, 0); | |
} | |
private void pageLess() { | |
int newPosition = getCurrentPosition() - 1; | |
//Ensure the next position is >= 0 | |
smoothScrollToPosition(newPosition < 0 ? 0 : newPosition); | |
} | |
private void pageMore() { | |
int newPosition = getCurrentPosition() + 1; | |
//Ensure the next position is not greater than the adapter's count. | |
smoothScrollToPosition(newPosition <= mAdapter.getItemCount() ? newPosition : mAdapter.getItemCount()); | |
} | |
private int getCurrentPosition() { | |
//Assumes full-width / full-height children in recycler view adapter. | |
int currentPosition; | |
if (mHorizontalScroll) { | |
currentPosition = Math.round((computeHorizontalScrollOffset() * 1.0f) / (getWidth() * 1.0f)); | |
} else { | |
currentPosition = Math.round((computeVerticalScrollOffset() * 1.0f) / (getHeight() * 1.0f)); | |
} | |
return currentPosition; | |
} | |
@Override | |
public void onScrollStateChanged(int newState) { | |
// Make sure scrolling has stopped before scrolling to correct position. | |
if (newState == RecyclerView.SCROLL_STATE_IDLE) { | |
int currentRoundedPosition = getCurrentPosition(); | |
smoothScrollToPosition(currentRoundedPosition); | |
} | |
super.onScrollStateChanged(newState); | |
} | |
@Override | |
public boolean onTouchEvent(MotionEvent e) { | |
float currX = e.getX(); | |
float currY = e.getY(); | |
switch (e.getAction()) { | |
case MotionEvent.ACTION_DOWN: | |
mTouchHandled = false; | |
mTouchDownX = e.getX(); | |
mTouchDownY = e.getY(); | |
break; | |
case MotionEvent.ACTION_UP: | |
if (!mTouchHandled) { | |
mTouchHandled = true; | |
if (mHorizontalScroll) { | |
if (mTouchDownX < currX) { | |
//right swipe for left scroll | |
pageLess(); | |
return false; | |
} else if (currX < mTouchDownX) { | |
//left swipe for right scroll | |
pageMore(); | |
return false; | |
} | |
} else { | |
if (mTouchDownY < currY) { | |
//down swipe for up scroll | |
pageLess(); | |
return false; | |
} else if (currY < mTouchDownY) { | |
//up swipe for down scroll | |
pageMore(); | |
return false; | |
} | |
} | |
} | |
} | |
return super.onTouchEvent(e); | |
} | |
//As seen here: http://stackoverflow.com/questions/26370289/snappy-scrolling-in-recyclerview | |
public void smoothScrollToPosition(int position) { | |
// A good idea would be to create this instance in some initialization method, and just set the target position in this method. | |
LinearSmoothScroller smoothScroller = new LinearSmoothScroller(getContext()) { | |
@Override | |
public PointF computeScrollVectorForPosition(int targetPosition) { | |
int yDelta = calculateCurrentDistanceToPosition(targetPosition); | |
return new PointF(0, yDelta); | |
} | |
private int calculateCurrentDistanceToPosition(int targetPosition) { | |
if (mScrollingFurther) { | |
return getWidth() * (getCurrentPosition() + targetPosition); | |
} else { | |
return getWidth() * (getCurrentPosition() - targetPosition); | |
} | |
} | |
// This is the important method. This code will return the amount of time it takes to scroll 1 pixel. | |
// This code will request X milliseconds for every Y DP units. | |
@Override | |
protected float calculateSpeedPerPixel(DisplayMetrics displayMetrics) { | |
return 1.0f / TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 1, displayMetrics); | |
} | |
}; | |
smoothScroller.setTargetPosition(position); | |
mLayout.startSmoothScroll(smoothScroller); | |
} | |
} |
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import android.content.Context; | |
import android.content.res.Resources; | |
import android.content.res.TypedArray; | |
import android.graphics.Canvas; | |
import android.graphics.Paint; | |
import android.os.Parcel; | |
import android.os.Parcelable; | |
import android.support.v7.widget.RecyclerView; | |
import android.util.AttributeSet; | |
import android.view.View; | |
/** | |
* Created by mgarner on 10/30/2015. | |
* RecyclerViewPositionIndicator based on WideCirclePageIndicator based on Jake Wharton's CirclePageIndicator. | |
*/ | |
public class RecyclerViewPositionIndicator extends View { | |
private RecyclerView mRecyclerView; | |
private Paint mCircleStrokePaint = new Paint(Paint.ANTI_ALIAS_FLAG); | |
private Paint mCircleFillPaint = new Paint(Paint.ANTI_ALIAS_FLAG); | |
private float mRadius; | |
private RecyclerView.Adapter mAdapter = null; | |
private int mCurrentPosition; | |
private float mSpacing; | |
private int mSpacingFactor; | |
public RecyclerViewPositionIndicator(Context context) { | |
super(context); | |
} | |
public RecyclerViewPositionIndicator(Context context, AttributeSet attrs) { | |
this(context, attrs, R.attr.vpiCirclePageIndicatorStyle); | |
} | |
public RecyclerViewPositionIndicator(Context context, AttributeSet attrs, int defStyleAttr) { | |
super(context, attrs, defStyleAttr); | |
init(context, attrs, defStyleAttr); | |
} | |
public void init(Context context, AttributeSet attrs, int defStyle) { | |
final Resources res = getResources(); | |
final int defaultFillColor = res.getColor(R.color.default_circle_indicator_fill_color); | |
final int defaultStrokeColor = res.getColor(R.color.default_circle_indicator_stroke_color); | |
final float defaultStrokeWidth = res.getDimension(R.dimen.default_circle_indicator_stroke_width); | |
final float defaultRadius = res.getDimension(R.dimen.default_circle_indicator_radius); | |
final int defaultSpacingFactor = res.getInteger(R.integer.default_circle_indicator_spacing_factor); | |
TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.RecyclerViewPositionIndicator, defStyle, 0); | |
try { | |
mCircleStrokePaint = new Paint(Paint.ANTI_ALIAS_FLAG); | |
mCircleStrokePaint.setColor(a.getColor(R.styleable.RecyclerViewPositionIndicator_rvpi_stroke_color, defaultStrokeColor)); | |
mCircleStrokePaint.setStyle(Paint.Style.STROKE); | |
mCircleStrokePaint.setStrokeWidth(a.getDimension(R.styleable.RecyclerViewPositionIndicator_rvpi_stroke_width, defaultStrokeWidth)); | |
mCircleFillPaint = new Paint(Paint.ANTI_ALIAS_FLAG); | |
mCircleFillPaint.setColor(a.getColor(R.styleable.RecyclerViewPositionIndicator_rvpi_fill_color, defaultFillColor)); | |
mCircleFillPaint.setStyle(Paint.Style.FILL); | |
mRadius = a.getDimension(R.styleable.RecyclerViewPositionIndicator_rvpi_radius, defaultRadius); | |
mSpacingFactor = a.getInteger(R.styleable.RecyclerViewPositionIndicator_rvpi_spacing_factor, defaultSpacingFactor); | |
mSpacing = mRadius * mSpacingFactor;//4x the radius of circles between each circle. (2 circles) | |
} finally { | |
a.recycle(); | |
} | |
} | |
public void setRecyclerView(RecyclerView recyclerView) { | |
mRecyclerView = recyclerView; | |
if (mRecyclerView.getAdapter() != null) { | |
mAdapter = mRecyclerView.getAdapter(); | |
initRecylerViewListeners(); | |
invalidate(); | |
} | |
} | |
private void initRecylerViewListeners() { | |
mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() { | |
@Override | |
public void onScrollStateChanged(RecyclerView recyclerView, int newState) { | |
super.onScrollStateChanged(recyclerView, newState); | |
if (newState == RecyclerView.SCROLL_STATE_IDLE) { | |
mCurrentPosition = Math.round((recyclerView.computeHorizontalScrollOffset() * 1.0f) / (recyclerView.getWidth() * 1.0f)); | |
setCurrentIndicatorPosition(mCurrentPosition); | |
} | |
} | |
}); | |
} | |
public RecyclerView getRecyclerView() { | |
return mRecyclerView; | |
} | |
@Override | |
protected void onDraw(Canvas canvas) { | |
super.onDraw(canvas); | |
if (mRecyclerView == null || mAdapter == null) { | |
return; | |
} | |
final int totalPageCount = mAdapter.getItemCount(); | |
if (mCurrentPosition >= totalPageCount) { | |
setCurrentIndicatorPosition(totalPageCount - 1); | |
return; | |
} | |
float shortOffset = getPaddingTop() + mRadius; //Add radius to get to middle of circle | |
float longOffset = getPaddingLeft() + mRadius; //Add radius to get to middle of circle | |
float dX; | |
float dY; | |
for (int pageCounter = 0; pageCounter < totalPageCount; pageCounter++) { | |
if (pageCounter > 0) { | |
//get X distance with padding, radius, and all prev circles. | |
float prevCirclesWidth = (pageCounter * mRadius * 2) + pageCounter * mSpacing; | |
dX = longOffset + prevCirclesWidth; | |
} else { | |
//get X distance with padding and radius. | |
dX = longOffset; | |
} | |
dY = shortOffset; | |
// Only paint fill if not completely transparent | |
if (mCircleStrokePaint.getAlpha() > 0) { | |
canvas.drawCircle(dX, dY, mRadius, mCircleStrokePaint); | |
} | |
} | |
//Draw the filled circle according to the current position | |
float cx; | |
if (mCurrentPosition > 0) { | |
float circlesWidth = (mCurrentPosition * mRadius * 2); | |
float spacingBetweenCirclesWidth = mCurrentPosition * mSpacing; | |
cx = circlesWidth + spacingBetweenCirclesWidth; | |
} else { | |
cx = 0; | |
} | |
dX = longOffset + cx; | |
dY = shortOffset; | |
canvas.drawCircle(dX, dY, mRadius, mCircleFillPaint); | |
} | |
public void notifyDataSetChanged() { | |
invalidate(); | |
} | |
public void setCurrentIndicatorPosition(int position) { | |
if (mRecyclerView == null) { | |
throw new IllegalStateException("ViewPager has not been bound."); | |
} | |
//mRecyclerView.scrollToPosition(position); | |
mCurrentPosition = position; | |
invalidate(); | |
} | |
public void remeasure() { | |
requestLayout(); | |
} | |
/* | |
* (non-Javadoc) | |
* | |
* @see android.view.View#onMeasure(int, int) | |
*/ | |
@Override | |
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { | |
setMeasuredDimension(measureLong(widthMeasureSpec), measureShort(heightMeasureSpec)); | |
} | |
/** | |
* Determines the width of this view | |
* | |
* @param measureSpec A measureSpec packed into an int | |
* @return The width of the view, honoring constraints from measureSpec | |
*/ | |
private int measureLong(int measureSpec) { | |
int result; | |
int specMode = MeasureSpec.getMode(measureSpec); | |
int specSize = MeasureSpec.getSize(measureSpec); | |
if ((specMode == MeasureSpec.EXACTLY) || (mRecyclerView == null)) { | |
//We were told how big to be | |
return specSize; | |
} else { | |
//Calculate the width according the views count | |
final int count = mAdapter.getItemCount(); | |
result = (int) (getPaddingLeft() + getPaddingRight() + (count * 2 * mRadius) + (count - 1) * mSpacing); | |
//Respect AT_MOST value if that was what is called for by measureSpec | |
if (specMode == MeasureSpec.AT_MOST) { | |
return Math.min(result, specSize); | |
} | |
if (result > specSize) { | |
return specSize; | |
} | |
} | |
return result; | |
} | |
/** | |
* Determines the height of this view | |
* | |
* @param measureSpec A measureSpec packed into an int | |
* @return The height of the view, honoring constraints from measureSpec | |
*/ | |
private int measureShort(int measureSpec) { | |
int result; | |
int specMode = MeasureSpec.getMode(measureSpec); | |
int specSize = MeasureSpec.getSize(measureSpec); | |
if (specMode == MeasureSpec.EXACTLY) { | |
//We were told how big to be | |
result = specSize; | |
} else { | |
//Measure the height | |
result = (int) (2 * mRadius + getPaddingTop() + getPaddingBottom() + 1); | |
//Respect AT_MOST value if that was what is called for by measureSpec | |
if (specMode == MeasureSpec.AT_MOST) { | |
result = Math.min(result, specSize); | |
} | |
} | |
return result; | |
} | |
@Override | |
public void onRestoreInstanceState(Parcelable state) { | |
SavedState savedState = (SavedState) state; | |
super.onRestoreInstanceState(savedState.getSuperState()); | |
mCurrentPosition = savedState.currentPage; | |
requestLayout(); | |
} | |
@Override | |
public Parcelable onSaveInstanceState() { | |
Parcelable superState = super.onSaveInstanceState(); | |
SavedState savedState = new SavedState(superState); | |
savedState.currentPage = mCurrentPosition; | |
return savedState; | |
} | |
static class SavedState extends BaseSavedState { | |
int currentPage; | |
public SavedState(Parcelable superState) { | |
super(superState); | |
} | |
private SavedState(Parcel in) { | |
super(in); | |
currentPage = in.readInt(); | |
} | |
@Override | |
public void writeToParcel(Parcel dest, int flags) { | |
super.writeToParcel(dest, flags); | |
dest.writeInt(currentPage); | |
} | |
@SuppressWarnings("UnusedDeclaration") | |
public static final Parcelable.Creator<SavedState> CREATOR = new Parcelable.Creator<SavedState>() { | |
@Override | |
public SavedState createFromParcel(Parcel in) { | |
return new SavedState(in); | |
} | |
@Override | |
public SavedState[] newArray(int size) { | |
return new SavedState[size]; | |
} | |
}; | |
} | |
} |
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Can anybody please provide attr file?