res/layout/folder_icon.xml: android:src=”@drawable/icon_bg_6″/> 换个方形的背景
packages\apps\Launcher3\src\com\android\launcher3\FolderIcon.java
private PreviewItemDrawingParams computePreviewItemDrawingParams(int index,
PreviewItemDrawingParams params) {
// add by x
int index_order = index;
final int previewPadding = FolderRingAnimator.sPreviewPadding;
// add end
index = NUM_ITEMS_IN_PREVIEW – index – 1;
float r = (index * 1.0f) / (NUM_ITEMS_IN_PREVIEW – 1);
float scale = (1 – PERSPECTIVE_SCALE_FACTOR * (1 – r));
float offset = (1 – r) * mMaxPerspectiveShift;
float scaledSize = scale * mBaselineIconSize;
float scaleOffsetCorrection = (1 – scale) * mBaselineIconSize;
// We want to imagine our coordinates from the bottom left, growing up and to the
// right. This is natural for the x-axis, but for the y-axis, we have to invert things.
float transY = mAvailableSpaceInPreview – (offset + scaledSize + scaleOffsetCorrection) + getPaddingTop();
float transX = offset + scaleOffsetCorrection;
float totalScale = mBaselineIconScale * scale;
final int overlayAlpha = (int) (80 * (1 – r));
// add by x
if( PERSPECTIVE_SHIFT_FACTOR ==0.24f){
}else{
if(0 <= index_order&&index_order < 3){ // 0 1 2
transX=index_order*mBaselineIconSize + 1*previewPadding;
transY=mAvailableSpaceInPreview – (2*mBaselineIconSize + scaledSize + scaleOffsetCorrection) + getPaddingTop()+0.2f*mBaselineIconSize;
}else if(3 <= index_order&&index_order < 6){ // 3 4 5
transX=(index_order-3)*mBaselineIconSize + 1*previewPadding;
//transY=1*mBaselineIconSize+9*previewPadding;
transY=mAvailableSpaceInPreview – (1*mBaselineIconSize + scaledSize + scaleOffsetCorrection) + getPaddingTop()+0.2f*mBaselineIconSize;
}else if(6 <= index_order&&index_order < 9){ // 6 7 8
transX=(index_order-6)*mBaselineIconSize + 1*previewPadding;
//transY=2*mBaselineIconSize+9*previewPadding;
transY=mAvailableSpaceInPreview – (0*mBaselineIconSize + scaledSize + scaleOffsetCorrection) + getPaddingTop()+0.2f*mBaselineIconSize;
}
totalScale = mBaselineIconScale * 1 – 0.1f;
}
//add end
if (params == null) {
params = new PreviewItemDrawingParams(transX, transY, totalScale, overlayAlpha);
} else {
params.transX = transX;
params.transY = transY;
params.scale = totalScale ;
params.overlayAlpha = overlayAlpha;
}
return params;
}
// The number of icons to display in the
private static final int NUM_ITEMS_IN_PREVIEW = 4; // 显示的个数
// The amount of vertical spread between items in the stack [0…1]
private static final float PERSPECTIVE_SHIFT_FACTOR = 1.59f;//1.59f //0.24f //控制文件夹内的子图标大小，值越大，图标越小
因为这个值关系到 mBaselineIconSize ，如下
private void computePreviewDrawingParams(int drawableSize, int totalSize) {
int unscaledHeight = (int) (mIntrinsicIconSize * (1 + PERSPECTIVE_SHIFT_FACTOR));
mBaselineIconScale = (1.0f * adjustedAvailableSpace / unscaledHeight);
mBaselineIconSize = (int) (mIntrinsicIconSize * mBaselineIconScale);
…
}
@Override
protected void dispatchDraw(Canvas canvas) {
~ // 显示子图标的 顺序
int nItemsInPreview = Math.min(items.size(), NUM_ITEMS_IN_PREVIEW);
if (!mAnimating) {
//for (int i = nItemsInPreview – 1; i >= 0; i–) {
for (int i = 0; i <= nItemsInPreview – 1; i++) {
v = (TextView) items.get(i);
if (!mHiddenItems.contains(v.getTag())) {
d = v.getCompoundDrawables()[1];
mParams = computePreviewItemDrawingParams(i, mParams);
mParams.drawable = d;
drawPreviewItem(canvas, mParams);
}
}
} else {
drawPreviewItem(canvas, mAnimParams);
}
~
}