現在市面上大多數手機的桌面文件夾都是類似ios那樣的風格,將內部包含的app縮略展示在icon圖標上;但是Google原生的文件夾風格是圓形背景,app以45度角向外疊起來的。據說Android早期版本也是ios那樣的,後來被蘋果告侵權才改的。不管怎麼說,我個人還是覺得縮略圖展示是比較好的,方便查看內部包含的app。正好這段時間比較閒,就來改的玩玩。
以下只是對Launcher3中Folder的源碼作了分析,看懂了源碼,想要改風格是非常容易的。
Folder的創建起源於Workspace.java的onDrop回調,每次onDrop都需要判斷是否需要創建文件夾。添加文件夾時,首先要將targetCell位置的app從CellLayout中移除,然後再調用Launcher.java的addFolder,將創建好的FolderIcon添加回targetCell這個位置;最後清除放入文件夾的兩個app的座標(因爲他們被移出了workspace),並將這兩個app添加到FolderIcon中。
boolean createUserFolderIfNecessary(View newView, long container, CellLayout target,
int[] targetCell, float distance, boolean external, DragView dragView,
Runnable postAnimationRunnable) {
…………
target.removeView(v);
FolderIcon fi =
mLauncher.addFolder(target, container, screenId, targetCell[0], targetCell[1]);
destInfo.cellX = -1;
destInfo.cellY = -1;
sourceInfo.cellX = -1;
sourceInfo.cellY = -1;
// If the dragView is null, we can't animate
boolean animate = dragView != null;
if (animate) {
fi.performCreateAnimation(destInfo, v, sourceInfo, dragView, folderLocation, scale,
postAnimationRunnable);
} else {
fi.addItem(destInfo);
fi.addItem(sourceInfo);
}
return true;
}
return false;
}
在Launcher.java的addFolder中創建了2個實例,folderInfo和newFolder,並通過Workspace的addInScreen將foler添加到屏幕上。
FolderIcon addFolder(CellLayout layout, long container, final long screenId, int cellX,
int cellY) {
final FolderInfo folderInfo = new FolderInfo();
folderInfo.title = getText(R.string.folder_name);
// Update the model
LauncherModel.addItemToDatabase(Launcher.this, folderInfo, container, screenId,
cellX, cellY);
sFolders.put(folderInfo.id, folderInfo);
// Create the view
FolderIcon newFolder =
FolderIcon.fromXml(R.layout.folder_icon, this, layout, folderInfo, mIconCache);
mWorkspace.addInScreen(newFolder, container, screenId, cellX, cellY, 1, 1,
isWorkspaceLocked());
// Force measure the new folder icon
CellLayout parent = mWorkspace.getParentCellLayoutForView(newFolder);
parent.getShortcutsAndWidgets().measureChild(newFolder);
return newFolder;
}
FolderIcon實際上是一個自定義View,繼承自FrameLayout,其核心改寫在dispatchDraw。爲什麼不是onDraw?因爲FrameLayout是ViewGroup啊。
@Override
protected void dispatchDraw(Canvas canvas) {
super.dispatchDraw(canvas);
if (mFolder == null) return;
if (mFolder.getItemCount() == 0 && !mAnimating) return;
ArrayList<View> items = mFolder.getItemsInReadingOrder();
Drawable d;
TextView v;
// Update our drawing parameters if necessary
if (mAnimating) {
computePreviewDrawingParams(mAnimParams.drawable);
} else {
v = (TextView) items.get(0);
d = getTopDrawable(v);
computePreviewDrawingParams(d);
}
int nItemsInPreview = Math.min(items.size(), NUM_ITEMS_IN_PREVIEW);
if (!mAnimating) {
for (int i = nItemsInPreview - 1; i >= 0; i--) {
v = (TextView) items.get(i);
if (!mHiddenItems.contains(v.getTag())) {
d = getTopDrawable(v);
mParams = computePreviewItemDrawingParams(i, mParams);
mParams.drawable = d;
drawPreviewItem(canvas, mParams);
}
}
} else {
drawPreviewItem(canvas, mAnimParams);
}
}
DispatchDraw包含三部分:
computePreviewDrawingParams:計算背景參數
computePreviewItemDrawingParams:計算內部Item參數,主要是計算座標,縮放尺寸,透明度。
drawPreviewItem:依據參數繪製Icon內的Item。
因此要修改Folder樣式,主要就是修改computePreviewItemDrawingParams的邏輯,還是挺簡單的。