Launcher应用图标显示流程

基于Android U

时序图如下：

1. 初始化

packages/apps/Launcher3/src/com/android/launcher3/Launcher.java
protected void onCreate(Bundle savedInstanceState) {
    ...
    LauncherAppState app = LauncherAppState.getInstance(this);  // 获取LauncherAppState的实例
    mModel = app.getModel();  // 获取LauncherModel的实例
    ...    
    if (!mModel.addCallbacksAndLoad(this)) {  // 加载，CallBacks指向Launcher
        ...
    }
    ...
}

• LauncherAppState的构造方法中初始化了一个InvariantDeviceProfile类，该类的构造方法中进行了一系列的配置，如：桌面的行、列、Hotseat（桌面底部固定的应用栏）的个数、Hotseat所有应用的位置、布局id、文件夹的行列、图标的大小等。此外，还会解析device_profiles.xml文件，加载默认页的资源文件。
• mModel.addCallbacksAndLoad()会进行数据加载。

2. 加载

packages/apps/Launcher3/src/com/android/launcher3/LauncherModel.java
public boolean addCallbacksAndLoad(@NonNull final Callbacks callbacks) {
    synchronized (mLock) {
        addCallbacks(callbacks);
        return startLoader(new Callbacks[] { callbacks });
    }
}

private boolean startLoader(@NonNull final Callbacks[] newCallbacks) {
    ...
    synchronized (mLock) {
        ...
        if (callbacksList.length > 0) {
            ...
            if (bindDirectly) {
                // Divide the set of loaded items into those that we are binding synchronously,
                // and everything else that is to be bound normally (asynchronously).
                launcherBinder.bindWorkspace(bindAllCallbacks, /* isBindSync= */ true);

                // For now, continue posting the binding of AllApps as there are other
                // issues that arise from that.
                launcherBinder.bindAllApps();
                launcherBinder.bindDeepShortcuts();
                launcherBinder.bindWidgets();
                if (FeatureFlags.CHANGE_MODEL_DELEGATE_LOADING_ORDER.get()) {
                    mModelDelegate.bindAllModelExtras(callbacksList);
                }
                return true;
            } else {
                // Always post the loader task, instead of running directly
                // (even on same thread) so that we exit any nested synchronized blocks
                MODEL_EXECUTOR.post(mLoaderTask);
            }
        }
    }
    return false;
}

bindWorkspace()：创建CellLayout，并添加到WorkSpace容器中；

bindAllApps()：绑定所有icon图标到CellLayout对应的recyclerView中，即app图标加载；

bindDeepShortcuts()：加载快捷方式；

bindWidgets()：加载桌面widget。

3. 加载应用程序信息

packages/apps/Launcher3/src/com/android/launcher3/model/BaseLauncherBinder.java
public void bindAllApps() {
    ...
    executeCallbacksTask(c -> c.bindAllApplications(apps, flags, packageUserKeytoUidMap),
            mUiExecutor);
}

调用callbacks的bindAllApplications()，这个callbacks实际指向Launcher。

4. 加载应用图标

packages/apps/Launcher3/src/com/android/launcher3/Launcher.java
public void bindAllApplications(AppInfo[] apps, int flags,
        Map<PackageUserKey, Integer> packageUserKeytoUidMap) {
    ...
    AllAppsStore appsStore = mAppsView.getAppsStore();
    appsStore.setApps(apps, flags, packageUserKeytoUidMap);
    ...
}

调用AllAppsStore的setApps()方法，并将包含应用信息的列表apps传进去。

packages/apps/Launcher3/src/com/android/launcher3/allapps/AllAppsStore.java
public void setApps(AppInfo[] apps, int flags, Map<PackageUserKey, Integer> map) {
    mApps = apps;
    mModelFlags = flags;
    notifyUpdate();
    mPackageUserKeytoUidMap = map;
}

private void notifyUpdate() {
    ...
    for (OnUpdateListener listener : mUpdateListeners) {
        ...
        listener.onAppsUpdated();
    }
}

setApps()会将包含应用信息的列表apps设置给mApps，然后通知View刷新界面。

5. 刷新界面

packages/apps/Launcher3/src/com/android/launcher3/allapps/AlphabeticalAppsList.java
public void onAppsUpdated() {
    if (mAllAppsStore == null) {
        return;
    }
    // Sort the list of apps
    mApps.clear();

    Stream<AppInfo> appSteam = Stream.of(mAllAppsStore.getApps());
    if (!hasSearchResults() && mItemFilter != null) {
        appSteam = appSteam.filter(mItemFilter);
    }
    appSteam = appSteam.sorted(mAppNameComparator);

    // As a special case for some languages (currently only Simplified Chinese), we may need to
    // coalesce sections
    Locale curLocale = mActivityContext.getResources().getConfiguration().locale;
    boolean localeRequiresSectionSorting = curLocale.equals(Locale.SIMPLIFIED_CHINESE);
    if (localeRequiresSectionSorting) {
        // Compute the section headers. We use a TreeMap with the section name comparator to
        // ensure that the sections are ordered when we iterate over it later
        appSteam = appSteam.collect(Collectors.groupingBy(
                info -> info.sectionName,
                () -> new TreeMap<>(new LabelComparator()),
                Collectors.toCollection(ArrayList::new)))
                .values()
                .stream()
                .flatMap(ArrayList::stream);
    }

    appSteam.forEachOrdered(mApps::add);
    // Recompose the set of adapter items from the current set of apps
    if (mSearchResults.isEmpty()) {
        updateAdapterItems();
    }
}

AlphabeticalAppsList实现了OnUpdateListener接口。