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Android Launcher源码研究(二) 加载app流程1
今天主要分析Android Launcher源码中的一些重要类之间的关系，基本的加载流程。先来看一个类图
Launcher.java 是主Activity 在onCreate方法里面初始化了LauncherMode实例.
LauncherApplication app = ((LauncherApplication)getApplication());
mModel = app.setLauncher(this);
直接进入LauncherApplication.java的方法
LauncherModel setLauncher(Launcher launcher) {
mModel.initialize(launcher);
return mModel;
}这里的mModel就是LauncherModel类了，LauncherModel扮演者重要的角色，实际上是个广播,监控app的安装，改变，和卸载另外就是加载所有app信息
这里Launcher实现了Callbacks接口，直接加入到callbacks列表中，后面的很多功能都要靠它回调处理
public void initialize(Callbacks callbacks) {
synchronized (mLock) {
mCallbacks = new WeakReference<Callbacks>(callbacks);
}
}在Launcher.java onCreate的代码中看下面的一段代码.
if (!mRestoring) {
if (sPausedFromUserAction) {
// If the user leaves launcher, then we should just load items asynchronously when
// they return.
mModel.startLoader(true, -1);
} else {
// We only load the page synchronously if the user rotates (or triggers a
// configuration change) while launcher is in the foreground
mModel.startLoader(true, mWorkspace.getCurrentPage());
}
}源码中注释也显示了2中情况，一种是当前用户的界面不是桌面可能是某个应用程序界面 这样我们通过后台异步加载。
另外一种情况是 刷新当前页面的app信息数据.
现在定位到LauncherMode.java源码中startLoader方法 部分代码如下.
if (synchronousBindPage > -1 && mAllAppsLoaded && mWorkspaceLoaded) {
mLoaderTask.runBindSynchronousPage(synchronousBindPage);//同步加载当前页
} else {
sWorkerThread.setPriority(Thread.NORM_PRIORITY);
sWorker.post(mLoaderTask);//异步加载
}和上面讲的一样，加载当前页面信息还是更新所有信息. synchronousBindPage就是当前用户滑动到第几个屏幕，一共是5个屏幕.我们用到了LoaderTask这个类是一个Runnable实现. 这个地方用的是HandlerThread (这个类我以前没用过，一直是自己获取Looper再处理的
)
这个类就是具体载入appinfo，appwidget， folder的信息了。
我们看看LoaderTask run方法实现. 注意 LoaderTask 是LauncherMode的内部类.
keep_running: {
// Elevate priority when Home launches for the first time to avoid
// starving at boot time. Staring at a blank home is not cool.
synchronized (mLock) {
if (DEBUG_LOADERS) Log.d(TAG, "Setting thread priority to " +
(mIsLaunching ? "DEFAULT" : "BACKGROUND"));
android.os.Process.setThreadPriority(mIsLaunching
? Process.THREAD_PRIORITY_DEFAULT : Process.THREAD_PRIORITY_BACKGROUND);
}
if (loadWorkspaceFirst) {
if (DEBUG_LOADERS) Log.d(TAG, "step 1: loading workspace");
loadAndBindWorkspace();//第一次载入
} else {
if (DEBUG_LOADERS) Log.d(TAG, "step 1: special: loading all apps");
loadAndBindAllApps(); //更新数据
}
if (mStopped) {
break keep_running;
}
// Whew! Hard work done. Slow us down, and wait until the UI thread has
// settled down.
synchronized (mLock) {
if (mIsLaunching) {
if (DEBUG_LOADERS) Log.d(TAG, "Setting thread priority to BACKGROUND");
android.os.Process.setThreadPriority(Process.THREAD_PRIORITY_BACKGROUND);
}
}
waitForIdle();
// second step
if (loadWorkspaceFirst) {
if (DEBUG_LOADERS) Log.d(TAG, "step 2: loading all apps");
loadAndBindAllApps();
} else {
if (DEBUG_LOADERS) Log.d(TAG, "step 2: special: loading workspace");
loadAndBindWorkspace();
}
// Restore the default thread priority after we are done loading items
synchronized (mLock) {
android.os.Process.setThreadPriority(Process.THREAD_PRIORITY_DEFAULT);
}
}按照源码的注释 是第一次加载workspace , 第二次加载所有的app 信息，你会发现 loadAndBindAllApps方法和loadAndBindWorkspace 2次调用是倒着的。
我的理解就是 先执行加载workspace 再执行加载all apps.
我们定位到 loadAndBindWorkspace方法中，
if (!mWorkspaceLoaded) {
loadWorkspace();
synchronized (LoaderTask.this) {
if (mStopped) {
return;
}
mWorkspaceLoaded = true;
}
}如果workspace还没加载就调用loadWorkspace方法. 定位到这个方法里面，一目了然发现 都是直接获取应用程序信息了包括widget.
直接调用了 PackageManager，AppWidgetManager，ContentResolver 获取信息.
读取信息保存后 我们需要与workspace汇合，这个地方是调用bindWorkspace
在这个方面里面我们会发现使用前面说的callbacks进行回调完整数据与View的绑定显示.
/**
* Binds all loaded data to actual views on the main thread.
*/
private void bindWorkspace(int synchronizeBindPage) {
final long t = SystemClock.uptimeMillis();
Runnable r;
// Don't use these two variables in any of the callback runnables.
// Otherwise we hold a reference to them.
final Callbacks oldCallbacks = mCallbacks.get();
if (oldCallbacks == null) {
// This launcher has exited and nobody bothered to tell us. Just bail.
Log.w(TAG, "LoaderTask running with no launcher");
return;
}
final boolean isLoadingSynchronously = (synchronizeBindPage > -1);
final int currentScreen = isLoadingSynchronously ? synchronizeBindPage :
oldCallbacks.getCurrentWorkspaceScreen();
// Load all the items that are on the current page first (and in the process, unbind
// all the existing workspace items before we call startBinding() below.
unbindWorkspaceItemsOnMainThread();
ArrayList<ItemInfo> workspaceItems = new ArrayList<ItemInfo>();
ArrayList<LauncherAppWidgetInfo> appWidgets =
new ArrayList<LauncherAppWidgetInfo>();
HashMap<Long, FolderInfo> folders = new HashMap<Long, FolderInfo>();
HashMap<Long, ItemInfo> itemsIdMap = new HashMap<Long, ItemInfo>();
synchronized (sBgLock) {
workspaceItems.addAll(sBgWorkspaceItems);
appWidgets.addAll(sBgAppWidgets);
folders.putAll(sBgFolders);
itemsIdMap.putAll(sBgItemsIdMap);
}
ArrayList<ItemInfo> currentWorkspaceItems = new ArrayList<ItemInfo>();
ArrayList<ItemInfo> otherWorkspaceItems = new ArrayList<ItemInfo>();
ArrayList<LauncherAppWidgetInfo> currentAppWidgets =
new ArrayList<LauncherAppWidgetInfo>();
ArrayList<LauncherAppWidgetInfo> otherAppWidgets =
new ArrayList<LauncherAppWidgetInfo>();
HashMap<Long, FolderInfo> currentFolders = new HashMap<Long, FolderInfo>();
HashMap<Long, FolderInfo> otherFolders = new HashMap<Long, FolderInfo>();
// Separate the items that are on the current screen, and all the other remaining items
filterCurrentWorkspaceItems(currentScreen, workspaceItems, currentWorkspaceItems,
otherWorkspaceItems);
filterCurrentAppWidgets(currentScreen, appWidgets, currentAppWidgets,
otherAppWidgets);
filterCurrentFolders(currentScreen, itemsIdMap, folders, currentFolders,
otherFolders);
sortWorkspaceItemsSpatially(currentWorkspaceItems);
sortWorkspaceItemsSpatially(otherWorkspaceItems);
// Tell the workspace that we're about to start binding items
r = new Runnable() {
public void run() {
Callbacks callbacks = tryGetCallbacks(oldCallbacks);
if (callbacks != null) {
callbacks.startBinding();
}
}
};
runOnMainThread(r);
// Load items on the current page
bindWorkspaceItems(oldCallbacks, currentWorkspaceItems, currentAppWidgets,
currentFolders, null);
if (isLoadingSynchronously) {
r = new Runnable() {
public void run() {
Callbacks callbacks = tryGetCallbacks(oldCallbacks);
if (callbacks != null) {
callbacks.onPageBoundSynchronously(currentScreen);
}
}
};
runOnMainThread(r);
}
// Load all the remaining pages (if we are loading synchronously, we want to defer this
// work until after the first render)
mDeferredBindRunnables.clear();
bindWorkspaceItems(oldCallbacks, otherWorkspaceItems, otherAppWidgets, otherFolders,
(isLoadingSynchronously ? mDeferredBindRunnables : null));
// Tell the workspace that we're done binding items
r = new Runnable() {
public void run() {
Callbacks callbacks = tryGetCallbacks(oldCallbacks);
if (callbacks != null) {
callbacks.finishBindingItems();
}
// If we're profiling, ensure this is the last thing in the queue.
if (DEBUG_LOADERS) {
Log.d(TAG, "bound workspace in "
+ (SystemClock.uptimeMillis()-t) + "ms");
}
mIsLoadingAndBindingWorkspace = false;
}
};
if (isLoadingSynchronously) {
mDeferredBindRunnables.add(r);
} else {
runOnMainThread(r);
}
}这段代码有很多需要解释的，本质就是app，widgets, folders获取并传给主界面。今天就分析到这里。后面还有很多，这次就分析到这里，
如有问题 ，欢迎指出 谢谢。O(∩_∩)O~
Android Launcher源码研究(二) 加载app流程1
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