最近研究ICS4.0的Launcher,發現4.0和2.3有稍微點區別,但是區別不是特別大,所以我就先整理一下Launcher啓動的大致流程。Launcher其實是貫徹於手機的整個系統的,時時刻刻都在運行,要是Launcher不運行了,手機就得黑屏了。Launcher的LauncherMode=singletask,所以說不管Launcher啓動了哪個應用,總有個Launcher的實例在堆棧中,並且位於棧底。點擊Home鍵進入到Launcher,上篇Android的全局鍵(home鍵/長按耳機鍵)詳解【android源碼解析八】 中有詳細的介紹。大致思路其實就是啓動launcher的時候,新啓動一個task。大致先說這麼多,先看截圖: 大明原創,轉載請標明出處:http://blog.csdn.net/wdaming1986/article/details/7585649
圖(1)
上圖是4.0的Launcher界面,下面我們分步來解析一下Launcher的啓動過程。
Step 0:首先要給大家介紹一下Launcher的數據庫,這個數據庫中存放着待機界面的圖標,主屏底部的應用程序圖標和桌面folder中各應用程序的圖標,ICS4.0的folder中只能放應用程序的快捷方式,shortcut不能放到這個folder中,先看截圖:
圖(2)
說說各字段的含義:
title:表示桌面應用程序的名字,有的title爲空,表示是widget的快捷方式;
intent:表示啓動這個圖標的intent放到數據庫中,當click的時候就會調用這個字段,啓動相應的應用程序;
container:表示應用程序的容器,folder的容器爲整數,-100:表示在桌面的程序,-101:表示是主屏底部的程序;
screen:表示在第幾個屏,folder的screen都是0, container=-101的爲0,1,3,4;2爲allapp的按鈕;
cellX:表示在屏幕X軸的位置,(0,1,2,3),左上角爲0點,往右依次增加;
cellY:表示在屏幕Y軸的位置,(0,1,2,3),左上角爲0點,往下依次增加;
spallX:表示佔X軸幾個格;
spallY:表示佔Y軸幾個格;
itemType:應用程序用0表示,shortcut用1表示,folder用2表示,widget用4表示;
appWidgetId:-1表示不是widget,數字大於0表示纔是widget;
isShortCut:值爲0表示不是應用程序的ShortCut,值爲1表示是應用程序的ShortCut;
iconType:值爲0表示圖標的名字被定義爲包名的資源id,值爲1表示圖標用bitmap保存;
icon:表示應用程序的圖標,二進制的;顯示爲一張圖片;
說明:folder中的應用快捷方式綁定folder---->是用container的值綁定folder的id的;
詳細的講解請參考LauncherSettings.java這個類,有數據庫字段的詳細講解;
手機是在第一次燒機完成後,數據庫的值還沒有,這時候launcher解析default_workspace.xml把這個值存到數據庫中;所以說想定製什麼樣的開機桌面就在default_workspace.xml中做相應的配置,具體參照我前面的博客:
Android中源碼Launcher主屏幕程序排列詳解【安卓Launcher進化一】中有詳細的介紹:
i f (!convertDatabase(db)) {
// Populate favorites table with initial favorites
loadFavorites(db, R.xml.default_workspace);
}
Step 1:開機後先啓動LauncherApplication.java這個類的onCreate()方法,下面看代碼:
@Override
public void onCreate() {
super.onCreate();
// set sIsScreenXLarge and sScreenDensity *before* creating icon cache
// 在創建圖標緩存之前先設置sIsScreenXLarge和屏幕設備的分辨率
final int screenSize = getResources().getConfiguration().screenLayout &
Configuration.SCREENLAYOUT_SIZE_MASK;
sIsScreenLarge = screenSize == Configuration.SCREENLAYOUT_SIZE_LARGE ||
screenSize == Configuration.SCREENLAYOUT_SIZE_XLARGE;
sScreenDensity = getResources().getDisplayMetrics().density;
// 實例化圖標緩存區的對象
mIconCache = new IconCache(this);
// 實例化一個LauncherModel對象,這個類是保存Launcher的內存啓動狀態,更新Launcher的數據庫的作用
mModel = new LauncherModel(this, mIconCache);
// Register intent receivers
// 註冊監聽,應用package增加,刪除,改變的監聽。
IntentFilter filter = new IntentFilter(Intent.ACTION_PACKAGE_ADDED);
filter.addAction(Intent.ACTION_PACKAGE_REMOVED);
filter.addAction(Intent.ACTION_PACKAGE_CHANGED);
filter.addDataScheme("package");
registerReceiver(mModel, filter);
filter = new IntentFilter();
// 註冊application是否可用,語言改變,方向改變的監聽。4.0支持橫豎屏
filter.addAction(Intent.ACTION_EXTERNAL_APPLICATIONS_AVAILABLE);
filter.addAction(Intent.ACTION_EXTERNAL_APPLICATIONS_UNAVAILABLE);
filter.addAction(Intent.ACTION_LOCALE_CHANGED);
filter.addAction(Intent.ACTION_CONFIGURATION_CHANGED);
registerReceiver(mModel, filter);
filter = new IntentFilter();
filter.addAction(SearchManager.INTENT_GLOBAL_SEARCH_ACTIVITY_CHANGED);
registerReceiver(mModel, filter);
filter = new IntentFilter();
filter.addAction(SearchManager.INTENT_ACTION_SEARCHABLES_CHANGED);
registerReceiver(mModel, filter);
// Register for changes to the favorites
// 註冊favorites應用程序數據庫改變的監聽
ContentResolver resolver = getContentResolver();
resolver.registerContentObserver(LauncherSettings.Favorites.CONTENT_URI, true,
mFavoritesObserver);
}
Step 2:在LauncherApplication.java中onTerminate()的方法,解除監聽的綁定;
Step 3:Step1中的數據庫mFavoritesObserver監聽內部類如下:
/**
* Receives notifications whenever the user favorites have changed.
*/
private final ContentObserver mFavoritesObserver = new ContentObserver(new Handler()) {
@Override
public void onChange(boolean selfChange) {
mModel.startLoader(LauncherApplication.this, false);
}
};
說明:mModel.startLoader(。。,。。)是開啓一個線程,設置線程的優先級NORM_PRIORITY,開始load桌面圖標對應的數據庫,這個過程是和Launcher.onCreate()同時進行的;
Step 4: 接着我們來看看mModel.startLoader(LauncherApplication.this, false)的方法:
public void startLoader(Context context, boolean isLaunching) {
synchronized (mLock) {
if (DEBUG_LOADERS) {
Log.d(TAG, "startLoader isLaunching=" + isLaunching);
}
// Don't bother to start the thread if we know it's not going to do anything
if (mCallbacks != null && mCallbacks.get() != null) {
// If there is already one running, tell it to stop.
// also, don't downgrade isLaunching if we're already running
isLaunching = isLaunching || stopLoaderLocked();
mLoaderTask = new LoaderTask(context, isLaunching);
sWorkerThread.setPriority(Thread.NORM_PRIORITY);
sWorker.post(mLoaderTask);
}
}
}
Step 5:接着我們來看看LoaderTask.java的run()方法:
public void run() {
// Optimize for end-user experience: if the Launcher is up and // running with the
// All Apps interface in the foreground, load All Apps first. Otherwise, load the
// workspace first (default).
final Callbacks cbk = mCallbacks.get();
final boolean loadWorkspaceFirst = cbk != null ? (!cbk.isAllAppsVisible()) : true;
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();
} else {
if (DEBUG_LOADERS) Log.d(TAG, "step 1: special: loading all apps");
loadAndBindAllApps();
}
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);
}
}
// Update the saved icons if necessary
if (DEBUG_LOADERS) Log.d(TAG, "Comparing loaded icons to database icons");
for (Object key : sDbIconCache.keySet()) {
updateSavedIcon(mContext, (ShortcutInfo) key, sDbIconCache.get(key));
}
sDbIconCache.clear();
// Clear out this reference, otherwise we end up holding it until all of the
// callback runnables are done.
mContext = null;
synchronized (mLock) {
// If we are still the last one to be scheduled, remove ourselves.
if (mLoaderTask == this) {
mLoaderTask = null;
}
}
}
public void stopLocked() {
synchronized (LoaderTask.this) {
mStopped = true;
this.notify();
}
}
加載桌面圖標對應的數據庫的值,這些值能把這些圖標顯示在屏幕上。
Step 6:LauncherApplication.onCreate()方法啓動完成後,接着開始調用Launcher.java的onCreate()方法。代碼如下:
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// 得到LauncherApplication的對象app
LauncherApplication app = ((LauncherApplication)getApplication());
// 得到LauncherModel對象mModel,設置一個mCallbacks = new WeakReference<Callbacks>(callbacks)的
// 回調callbacks
mModel = app.setLauncher(this);
// 得到圖標緩存的對象mIconCache
mIconCache = app.getIconCache();
// 得到拖拽控制類DragController的對象
mDragController = new DragController(this);
// 得到一個LayoutInflater佈局的對象
mInflater = getLayoutInflater();
// 得到一個AppWidgetManager的對象
mAppWidgetManager = AppWidgetManager.getInstance(this);
// 得到LauncherAppWidgetHost的一個對象
mAppWidgetHost = new LauncherAppWidgetHost(this, APPWIDGET_HOST_ID);
// Start receiving onAppWidgetChanged calls for your AppWidgets.
mAppWidgetHost.startListening();
if (PROFILE_STARTUP) {
android.os.Debug.startMethodTracing(
Environment.getExternalStorageDirectory() + "/launcher");
}
// 檢查Locale的語言級別,mcc, mnc的改變
checkForLocaleChange();
// 加載Launcher.xml佈局文件
setContentView(R.layout.launcher);
// Launcher的佈局的初始化
setupViews();
// 第一次啓動Android的展示設置嚮導,
// 這個SharedPreferences中存在
// <boolean name="cling.workspace.dismissed" value="true" />
// 如果值爲true,則不顯示設置嚮導,爲false,則顯示設置嚮導。
showFirstRunWorkspaceCling();
// 註冊數據庫觀察者
registerContentObservers();
lockAllApps();
mSavedState = savedInstanceState;
restoreState(mSavedState);
// Update customization drawer _after_ restoring the states
if (mAppsCustomizeContent != null) {
mAppsCustomizeContent.onPackagesUpdated();
}
if (PROFILE_STARTUP) {
android.os.Debug.stopMethodTracing();
}
if (!mRestoring) {
mModel.startLoader(this, true);
}
if (!mModel.isAllAppsLoaded()) {
ViewGroup appsCustomizeContentParent = (ViewGroup) mAppsCustomizeContent.getParent();
mInflater.inflate(R.layout.apps_customize_progressbar, appsCustomizeContentParent);
}
// For handling default keys
mDefaultKeySsb = new SpannableStringBuilder();
Selection.setSelection(mDefaultKeySsb, 0);
// 註冊系統對話框消失的監聽
IntentFilter filter = new IntentFilter(Intent.ACTION_CLOSE_SYSTEM_DIALOGS);
registerReceiver(mCloseSystemDialogsReceiver, filter);
boolean searchVisible = false;
boolean voiceVisible = false;
// If we have a saved version of these external icons, we load them up immediately
// 如果我們已經保存了外部圖標的版本,我們立即加載它們
int coi = getCurrentOrientationIndexForGlobalIcons();
if (sGlobalSearchIcon[coi] == null || sVoiceSearchIcon[coi] == null ||
sAppMarketIcon[coi] == null) {
updateAppMarketIcon();
searchVisible = updateGlobalSearchIcon();
voiceVisible = updateVoiceSearchIcon(searchVisible);
}
if (sGlobalSearchIcon[coi] != null) {
updateGlobalSearchIcon(sGlobalSearchIcon[coi]);
searchVisible = true;
}
if (sVoiceSearchIcon[coi] != null) {
updateVoiceSearchIcon(sVoiceSearchIcon[coi]);
voiceVisible = true;
}
if (sAppMarketIcon[coi] != null) {
updateAppMarketIcon(sAppMarketIcon[coi]);
}
mSearchDropTargetBar.onSearchPackagesChanged(searchVisible, voiceVisible);
// On large interfaces, we want the screen to auto-rotate based on the current orientation
if (LauncherApplication.isScreenLarge() || Build.TYPE.contentEquals("eng")) {
setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_UNSPECIFIED);
}
}
Step 7:其中LauncherModel這個類中有個回調接口,具體定義如下:
public interface Callbacks {
public boolean setLoadOnResume();
public int getCurrentWorkspaceScreen();
public void startBinding();
public void bindItems(ArrayList<ItemInfo> shortcuts, int start, int end);
public void bindFolders(HashMap<Long,FolderInfo> folders);
public void finishBindingItems();
public void bindAppWidget(LauncherAppWidgetInfo info);
public void bindAllApplications(ArrayList<ApplicationInfo> apps);
public void bindAppsAdded(ArrayList<ApplicationInfo> apps);
public void bindAppsUpdated(ArrayList<ApplicationInfo> apps);
public void bindAppsRemoved(ArrayList<ApplicationInfo> apps, boolean permanent);
public void bindPackagesUpdated();
public boolean isAllAppsVisible();
public void bindSearchablesChanged();
}
對LauncherModel進行初始化的時候mModel = app.setLauncher(this);---->mModel.initialize(launcher);----->
public void initialize(Callbacks callbacks) {
synchronized (mLock) {
mCallbacks = new WeakReference<Callbacks>(callbacks);
}
}
這個callbacks就是定義的接口回調,具體實現是在Launcher.java中定義的,啓動Launcher的過程中,這些實現是異步來實現的。還有Launcher.java的onResume()方法沒有講解,到這兒基本上Android的Launcher已經啓動起來了,這個onResume()我研究後再更新。
歡迎各界同僚留言指正錯誤和拍磚!歡迎留言!