Android Launcher源码分析（二）

今天主要分析创建shortcut、widget流程。

创建ShortCut流程，首先看completeAdd函数。

private boolean completeAdd(PendingAddArguments args) {
boolean result = false;
switch (args.requestCode) {
......
case REQUEST_PICK_SHORTCUT:
processShortcut(args.intent);
break;
......
}
resetAddInfo();
return result;
}

在completeAdd里接收到REQUEST_PICK_SHORTCUT请求，执行processShortcut（）创建shortcut
void processShortcut(Intent intent) {

String applicationName = getResources().getString(R.string.group_applications);//applicationName是apps
String shortcutName = intent.getStringExtra(Intent.EXTRA_SHORTCUT_NAME);

if (applicationName != null && applicationName.equals(shortcutName)) {
Intent mainIntent = new Intent(Intent.ACTION_MAIN, null);
mainIntent.addCategory(Intent.CATEGORY_LAUNCHER);

Intent pickIntent = new Intent(Intent.ACTION_PICK_ACTIVITY);//选择应用
pickIntent.putExtra(Intent.EXTRA_INTENT, mainIntent);
pickIntent.putExtra(Intent.EXTRA_TITLE, getText(R.string.title_select_application));
startActivityForResultSafely(pickIntent, REQUEST_PICK_APPLICATION);
} else {
startActivityForResultSafely(intent, REQUEST_CREATE_SHORTCUT);
}
}

如果 shortcutName是apps，则选择应用，若不是，则创建shortcut。在onActivityResult处理返回结果。

 protected void onActivityResult(
            final int requestCode, final int resultCode, final Intent data) {
        ......
        if (resultCode == RESULT_OK && mPendingAddInfo.container != ItemInfo.NO_ID) {
            ......
            //如果workspace正在被锁住，则加入列表，否则则进行创建
            if (isWorkspaceLocked()) {
                sPendingAddList.add(args);
            } else {
                delayExitSpringLoadedMode = completeAdd(args);
            }
        }
        .......
    }

如果workspace正在被锁住，则加入列表，在finishBindingItems被执行

public void finishBindingItems() {

......

for (int i = 0; i < sPendingAddList.size(); i++) {
completeAdd(sPendingAddList.get(i));
}
sPendingAddList.clear();

.......

}

若workspace没有被锁住，则直接创建，看completeAdd()

private boolean completeAdd(PendingAddArguments args) {
boolean result = false;
switch (args.requestCode) {
......
case REQUEST_CREATE_SHORTCUT:
completeAddShortcut(args.intent, args.container, args.screen, args.cellX,
args.cellY);
result = true;
break;
......
}
resetAddInfo();
return result;
}

completeAddShortcut()，创建shortcut到workspace

private void completeAddShortcut(Intent data, long container, int screen, int cellX,
int cellY) {
.......

ShortcutInfo info = mModel.infoFromShortcutIntent(this, data, null);
......
final View view = createShortcut(info);

// First we check if we already know the exact location where we want to add this item.

//首先判断希望添加的位置是否合适
if (cellX >= 0 && cellY >= 0) {
cellXY[0] = cellX;
cellXY[1] = cellY;
foundCellSpan = true;

// If appropriate, either create a folder or add to an existing folder
if (mWorkspace.createUserFolderIfNecessary(view, container, layout, cellXY, 0,
true, null,null)) {
return;
}
DragObject dragObject = new DragObject();
dragObject.dragInfo = info;
if (mWorkspace.addToExistingFolderIfNecessary(view, layout, cellXY, 0, dragObject,
true)) {
return;
}
} else if (touchXY != null) {
// when dragging and dropping, just find the closest free spot
int[] result = layout.findNearestVacantArea(touchXY[0], touchXY[1], 1, 1, cellXY);
foundCellSpan = (result != null);
} else {
foundCellSpan = layout.findCellForSpan(cellXY, 1, 1);
}

if (!foundCellSpan) {//如果已经没有空余的位置，则显示相应的提示
showOutOfSpaceMessage(isHotseatLayout(layout));
return;
}

LauncherModel.addItemToDatabase(this, info, container, screen, cellXY[0], cellXY[1], false);//将相应的数据添加到数据库

if (!mRestoring) {
mWorkspace.addInScreen(view, container, screen, cellXY[0], cellXY[1], 1, 1,
isWorkspaceLocked());
}
}

在completeAddShortcut里，先创建shortcut视图，判断添加shortcut的位置是否合适， 如果已经没有空余的位置，则显示相应的提示，添加相应的数据到数据库中，最后将shortcut添加到workspace中

创建widget流程与创建shortcut基本一致。