menudrawer源码摘记

android.R.id.content

 /**
     * Attaches the menu drawer to the content view.
     */
    private static void attachToContent(Activity activity, MenuDrawer menuDrawer) {
        /**
         * Do not call mActivity#setContentView.
         * E.g. if using with a ListActivity, Activity#setContentView is overridden and dispatched to
         * MenuDrawer#setContentView, which then again would call Activity#setContentView.
         */
        ViewGroup content = (ViewGroup) activity.findViewById(android.R.id.content);
        content.removeAllViews();
        content.addView(menuDrawer, LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);
    }
    
    
    //android.R.id.content:代表一个内容布局视图层级的根元素

DecorView

/**
     * Attaches the menu drawer to the window.
     */
    private static void attachToDecor(Activity activity, MenuDrawer menuDrawer) {
        ViewGroup decorView = (ViewGroup) activity.getWindow().getDecorView();
        ViewGroup decorChild = (ViewGroup) decorView.getChildAt(0);

        decorView.removeAllViews();
        decorView.addView(menuDrawer, LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);

        menuDrawer.mContentContainer.addView(decorChild, decorChild.getLayoutParams());
    }
    
    
//DecorView为整个Window界面的最顶层View。

dptopx

 protected int dpToPx(int dp) {
        return (int) (getResources().getDisplayMetrics().density * dp + 0.5f);
    }

StaticDrawer中的measure和layout方法

    @Override
    protected void onLayout(boolean changed, int l, int t, int r, int b) {
        final int width = r - l;
        final int height = b - t;

        switch (getPosition()) {
            case LEFT:
                mMenuContainer.layout(0, 0, mMenuSize, height);
                mContentContainer.layout(mMenuSize, 0, width, height);
                break;

            case RIGHT:
                mMenuContainer.layout(width - mMenuSize, 0, width, height);
                mContentContainer.layout(0, 0, width - mMenuSize, height);
                break;

            case TOP:
                mMenuContainer.layout(0, 0, width, mMenuSize);
                mContentContainer.layout(0, mMenuSize, width, height);
                break;

            case BOTTOM:
                mMenuContainer.layout(0, height - mMenuSize, width, height);
                mContentContainer.layout(0, 0, width, height - mMenuSize);
                break;
        }
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        final int widthMode = MeasureSpec.getMode(widthMeasureSpec);
        final int heightMode = MeasureSpec.getMode(heightMeasureSpec);

        if (widthMode == MeasureSpec.UNSPECIFIED || heightMode == MeasureSpec.UNSPECIFIED) {
            throw new IllegalStateException("Must measure with an exact size");
        }

        final int width = MeasureSpec.getSize(widthMeasureSpec);
        final int height = MeasureSpec.getSize(heightMeasureSpec);

        switch (getPosition()) {
            case LEFT:
            case RIGHT: {
                final int childHeightMeasureSpec = MeasureSpec.makeMeasureSpec(height, MeasureSpec.EXACTLY);

                final int menuWidth = mMenuSize;
                final int menuWidthMeasureSpec = MeasureSpec.makeMeasureSpec(menuWidth, MeasureSpec.EXACTLY);

                final int contentWidth = width - menuWidth;
                final int contentWidthMeasureSpec = MeasureSpec.makeMeasureSpec(contentWidth, MeasureSpec.EXACTLY);

                mContentContainer.measure(contentWidthMeasureSpec, childHeightMeasureSpec);
                mMenuContainer.measure(menuWidthMeasureSpec, childHeightMeasureSpec);
                break;
            }

            case TOP:
            case BOTTOM: {
                final int childWidthMeasureSpec = MeasureSpec.makeMeasureSpec(width, MeasureSpec.EXACTLY);

                final int menuHeight = mMenuSize;
                final int menuHeightMeasureSpec = MeasureSpec.makeMeasureSpec(menuHeight, MeasureSpec.EXACTLY);

                final int contentHeight = height - menuHeight;
                final int contentHeightMeasureSpec = MeasureSpec.makeMeasureSpec(contentHeight, MeasureSpec.EXACTLY);

                mContentContainer.measure(childWidthMeasureSpec, contentHeightMeasureSpec);
                mMenuContainer.measure(childWidthMeasureSpec, menuHeightMeasureSpec);
                break;
            }
        }

        setMeasuredDimension(width, height);
    }
    
    
    
    /*
    onMeasure方法中确定menuContainer和contentContainer的宽度和高度。
    onLayout方法中确定menuContainer和contentContainer在整个视图中的位置
    */

通过代码触发touch事件

 protected void cancelContentTouch() {
        final long now = SystemClock.uptimeMillis();
        final MotionEvent cancelEvent = MotionEvent.obtain(now, now, MotionEvent.ACTION_CANCEL, 0.0f, 0.0f, 0);
        final int childCount = getChildCount();
        for (int i = 0; i < childCount; i++) {
            getChildAt(i).dispatchTouchEvent(cancelEvent);
        }
        mContentContainer.dispatchTouchEvent(cancelEvent);
        cancelEvent.recycle();
    }
    
    /*
    SystemClock.uptimeMillis()
    Returns milliseconds since boot, not counting time spent in deep sleep.


    */