Android Launcher源码研究(三) 加载app流程2

接上次的。

首先Launcher实现了LauncherModel.Callbacks接口，APP信息数据加载成功后 ，回调接口把app信息显示到Launcher的 workspace界面上，这个过程代码里面称为bind。

下面是个类调用过程的时序图，不是很标准，不过能表达基本调用顺序帮助我们理解。

首先就是Launcher OnCreate中调用LauncherMode startLoader方法，这里只看异步的方式 就是当前的页面下标为-1，加载所有app信息

mWorkspace.getCurrentPage()为-1的情况。
 mModel.startLoader(true, -1); 

 在LauncherMode类的startLoader方法里面，我们需要实例化线程类 LoaderTask，大部分工作都在这里面完成.

run方法的代码：

            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);
                }
            }

        private void loadAndBindWorkspace() {
            mIsLoadingAndBindingWorkspace = true;

            // Load the workspace
            if (DEBUG_LOADERS) {
                Log.d(TAG, "loadAndBindWorkspace mWorkspaceLoaded=" + mWorkspaceLoaded);
            }

            if (!mWorkspaceLoaded) { //第一次加载
                loadWorkspace(); //加载
                synchronized (LoaderTask.this) {
                    if (mStopped) {
                        return;
                    }
                    mWorkspaceLoaded = true;
                }
            }

            // Bind the workspace
            bindWorkspace(-1);//绑定数据到UI
        }

</pre><p></p><p>loadWorkspace方法就是加载手机里面的所有app信息，包括app widget, folder 并且存储到ArrayList中，后面显示这些东西到UI上。</p><p>数据我们存储好以后调用bindWorkspace(-1)开始显示数据到workspace，里面包含了很多调用方法，主要是数据排序，清除以前绑定的UI数据。</p><p>在bindWorkspace方法里面，调用了一些filter方法，这个地方主要是排序和过滤，分别判断需要加载到那个屏幕里面.</p><p></p><pre code_snippet_id="533506" snippet_file_name="blog_20141126_4_7063071" name="code" class="java">            r = new Runnable() {
                public void run() {
                    Callbacks callbacks = tryGetCallbacks(oldCallbacks);
                    if (callbacks != null) {
                        callbacks.startBinding();//绑定之前，清理之前的数据，简单就这么理解
                    }
                }
            };
            runOnMainThread(r);//UI更新需要在主线程中

            bindWorkspaceItems(oldCallbacks, currentWorkspaceItems, currentAppWidgets,
                    currentFolders, null);

      private void bindWorkspaceItems(final Callbacks oldCallbacks,
                final ArrayList<ItemInfo> workspaceItems,
                final ArrayList<LauncherAppWidgetInfo> appWidgets,
                final HashMap<Long, FolderInfo> folders,
                ArrayList<Runnable> deferredBindRunnables) {

            final boolean postOnMainThread = (deferredBindRunnables != null);

            // Bind the workspace items
            int N = workspaceItems.size();
            for (int i = 0; i < N; i += ITEMS_CHUNK) {
                final int start = i;
                final int chunkSize = (i+ITEMS_CHUNK <= N) ? ITEMS_CHUNK : (N-i);
                final Runnable r = new Runnable() {
                    @Override
                    public void run() {
                        Callbacks callbacks = tryGetCallbacks(oldCallbacks);
                        if (callbacks != null) {
                            callbacks.bindItems(workspaceItems, start, start+chunkSize);//显示app信息到UI上
                        }
                    }
                };
                if (postOnMainThread) {
                    deferredBindRunnables.add(r);
                } else {
                    runOnMainThread(r);
                }
            }

            // Bind the folders
            if (!folders.isEmpty()) {
                final Runnable r = new Runnable() {
                    public void run() {
                        Callbacks callbacks = tryGetCallbacks(oldCallbacks);
                        if (callbacks != null) {
                            callbacks.bindFolders(folders);//显示folders
                        }
                    }
                };
                if (postOnMainThread) {
                    deferredBindRunnables.add(r);
                } else {
                    runOnMainThread(r);
                }
            }

            // Bind the widgets, one at a time
            N = appWidgets.size();
            for (int i = 0; i < N; i++) {
                final LauncherAppWidgetInfo widget = appWidgets.get(i);
                final Runnable r = new Runnable() {
                    public void run() {
                        Callbacks callbacks = tryGetCallbacks(oldCallbacks);
                        if (callbacks != null) {
                            callbacks.bindAppWidget(widget);//绑定AppWidget信息
                        }
                    }
                };
                if (postOnMainThread) {
                    deferredBindRunnables.add(r);
                } else {
                    runOnMainThread(r);
                }
            }
        }

我们这里只看第一个绑定shortcut信息代码，其他2个其实道理差不多.

    public void bindItems(ArrayList<ItemInfo> shortcuts, int start, int end) {
        setLoadOnResume();

        // Get the list of added shortcuts and intersect them with the set of shortcuts here
        Set<String> newApps = new HashSet<String>();
        newApps = mSharedPrefs.getStringSet(InstallShortcutReceiver.NEW_APPS_LIST_KEY, newApps);

        Workspace workspace = mWorkspace;
        for (int i = start; i < end; i++) {
            final ItemInfo item = shortcuts.get(i);

            // Short circuit if we are loading dock items for a configuration which has no dock
            if (item.container == LauncherSettings.Favorites.CONTAINER_HOTSEAT &&
                    mHotseat == null) {
                continue;
            }

            switch (item.itemType) {
                case LauncherSettings.Favorites.ITEM_TYPE_APPLICATION:
                case LauncherSettings.Favorites.ITEM_TYPE_SHORTCUT:
                    ShortcutInfo info = (ShortcutInfo) item;
                    String uri = info.intent.toUri(0).toString();
                    View shortcut = createShortcut(info);
                    workspace.addInScreen(shortcut, item.container, item.screen, item.cellX,
                            item.cellY, 1, 1, false);
                    boolean animateIconUp = false;
                    synchronized (newApps) {
                        if (newApps.contains(uri)) {
                            animateIconUp = newApps.remove(uri);
                        }
                    }
                    if (animateIconUp) {
                        // Prepare the view to be animated up
                        shortcut.setAlpha(0f);
                        shortcut.setScaleX(0f);
                        shortcut.setScaleY(0f);
                        mNewShortcutAnimatePage = item.screen;
                        if (!mNewShortcutAnimateViews.contains(shortcut)) {
                            mNewShortcutAnimateViews.add(shortcut);
                        }
                    }
                    break;
                case LauncherSettings.Favorites.ITEM_TYPE_FOLDER:
                    FolderIcon newFolder = FolderIcon.fromXml(R.layout.folder_icon, this,
                            (ViewGroup) workspace.getChildAt(workspace.getCurrentPage()),
                            (FolderInfo) item, mIconCache);
                    workspace.addInScreen(newFolder, item.container, item.screen, item.cellX,
                            item.cellY, 1, 1, false);
                    break;
            }
        }

        workspace.requestLayout();
    }

重点就是下面这个，把数据画到UI上面，坐标信息，APP信息.

                    workspace.addInScreen(shortcut, item.container, item.screen, item.cellX,
                            item.cellY, 1, 1, false);

最后我们调用 finishBindingItems完成调用，这个方法里面还包括了滑动和显示APP动画方法的处理。 

        if (mVisible || mWorkspaceLoading) {
            Runnable newAppsRunnable = new Runnable() {
                @Override
                public void run() {
                    runNewAppsAnimation(false);
                }
            };

            boolean willSnapPage = mNewShortcutAnimatePage > -1 &&
                    mNewShortcutAnimatePage != mWorkspace.getCurrentPage();
            if (canRunNewAppsAnimation()) {
                // If the user has not interacted recently, then either snap to the new page to show
                // the new-apps animation or just run them if they are to appear on the current page
                if (willSnapPage) {
                    mWorkspace.snapToPage(mNewShortcutAnimatePage, newAppsRunnable);
                } else {
                    runNewAppsAnimation(false);
                }
            } else {
                // If the user has interacted recently, then just add the items in place if they
                // are on another page (or just normally if they are added to the current page)
                runNewAppsAnimation(willSnapPage);
            }
        }

详细的我们到后面继续分析。还包括具体Workspace上面的界面格子cell是怎么设计和APP添加位置的计算问题。

若有问题，请指出，谢谢~ O(∩_∩)O~