Android---->Allapps加载流程详解【AndroidICS4.0——>Launcher系列五】

 工作需要总结，这样就能保证地基牢固，就能爬得更高；                              

                                                                          ----2013-01-07题记

        转载请标明出处：http://blog.csdn.net/wdaming1986/article/details/8478533

        前段时间研究了Launcher的AllApps的加载流程，对这个进行了一点修改，呵呵，其实也不算太难，只要把Launcher的代码都能看个80%，基本就是想怎么改就怎么改！AllApps是什么，就是在Android的IDEL界面（主界面）点击MainMenu键进入后的界面，也就是所有应用程序界面；

        先来看看它是怎么被手机加载上来的？

        Step1：手机第一次开机，首先加载LauncherApplication,注册一些监听，共享数据，比如：LauncherModel对象，通过((LauncherApplication)getApplication());可以获取到LauncherApplication的对象；然后再加载Launcher.java这个类，先走onCreate（）方法；里面调用如下方法：

if (!mRestoring) {            mModel.startLoader(this, true);        }

       

        Step2：在Step1中这个方法调到了LauncheModel.java的类里面了，在这个方法里面主要的工作就是启动一个线程，下面我们来看看在线程的run（）方法做了哪些操作；

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;                }            }        }

其实主要的操作就是加载workspace和AllApps；loadAndBindAllApps（）这个方法就是加载AllApps的；

 

        Step3：在这个loadAndBindAllApps（）里面，会调用loadAllAppsByBatch（），批量加载AllApps；

先根据：

final Intent mainIntent = new Intent(Intent.ACTION_MAIN, null);            mainIntent.addCategory(Intent.CATEGORY_LAUNCHER);

创建一个带有CATEGORY_LAUNCHER这种类型的mainIntent，然后再通过

List<ResolveInfo> apps=packageManager.queryIntentActivities(mainIntent, 0);

过滤出所有的apps，通过sort对apps进行排序：

Collections.sort(apps,new LauncherModel.ShortcutNameComparator(packageManager, mLabelCache));

排序完成后，然后把这些apps逐个添加到ArrayList中去：代码如下：

for (int j=0; i<N && j<batchSize; j++) {                    // This builds the icon bitmaps.                    mAllAppsList.add(new ApplicationInfo(packageManager, apps.get(i),                            mIconCache, mLabelCache));                    i++;                }

调到AllAppsList.java中的add方法：

public void add(ApplicationInfo info) {        if (findActivity(data, info.componentName)) {            return;        }        data.add(info);        added.add(info);    }

这个added的定义就是：

public ArrayList<ApplicationInfo> added =            new ArrayList<ApplicationInfo>(DEFAULT_APPLICATIONS_NUMBER);

然后通过开启线程callback回调到Launcher.java的bindAllApplications（）方法中：

final ArrayList<ApplicationInfo> added = mAllAppsList.added;                mAllAppsList.added = new ArrayList<ApplicationInfo>();                mHandler.post(new Runnable() {                    public void run() {                        final long t = SystemClock.uptimeMillis();                        if (callbacks != null) {                            if (first) {                                callbacks.bindAllApplications(added);                            } else {                                callbacks.bindAppsAdded(added);                            }                            if (DEBUG_LOADERS) {                                Log.d(TAG, "bound " + added.size() + " apps in "                                    + (SystemClock.uptimeMillis() - t) + "ms");                            }                        } else {                            Log.i(TAG, "not binding apps: no Launcher activity");                        }                    }                });

        

        Step4：在Launcher.java中bindAllApplications（）方法中做的事：如果有对话框存在，就remove对话框，主要是

mAppsCustomizeContent.setApps(apps);

       

          Step5:在AppsCustomizePagedView.java中的setApps()中主要做的事就是，赋值给mApps，再次对apps进行排序，计算apps的页数和widget占用的页数；代码如下：

public void setApps(ArrayList<ApplicationInfo> list) {        mApps = list;        Collections.sort(mApps, LauncherModel.APP_NAME_COMPARATOR);        updatePageCounts();        // The next layout pass will trigger data-ready if both widgets and apps are set, so         // request a layout to do this test and invalidate the page data when ready.        if (testDataReady()) requestLayout();    }

updatePageCounts()就是计算apps的页数和widget的页数；

 

       Step6：而进入这个allapps的时候，就是进入到AppsCustomizePagedView.java这个类的时候会调用

onMeasure（）这个方法；在这个里面首先会对allapps和widgets进行校验，

protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {        int width = MeasureSpec.getSize(widthMeasureSpec);        int height = MeasureSpec.getSize(heightMeasureSpec);        if (!isDataReady()) {            if (testDataReady()) {                setDataIsReady();                setMeasuredDimension(width, height);                onDataReady(width, height);            }        }        super.onMeasure(widthMeasureSpec, heightMeasureSpec);    }

通过testDataReady（）这个方法来校验是否他们为空！如果为空就不加载他们；代码如下：

/**     * This differs from isDataReady as this is the test done if isDataReady is not set.     */    private boolean testDataReady() {        // We only do this test once, and we default to the Applications page, so we only really        // have to wait for there to be apps.        // TODO: What if one of them is validly empty        return !mApps.isEmpty() && !mWidgets.isEmpty();    }

当allapps和widgets的数据都准备好了的时候，给这个view设置宽和高setMeasuredDimension(width, height);

然后调用onDataReady(width, height);在这个方法中会计算占用的页数，内容的宽度，细胞的数量，强制措施，以更新重新计算差距，存储页面，刷新数据显示上来通过invalidatePageData(Math.max(0, page), hostIsTransitioning);

这个调用到了PageView.java这个类（Launcher的主要精华类，写得相当有水准，看了好几遍，每次看都有收获）在这个方法里面主要做的是

（1）先加载apps和widgets的view，通过方法：

// Update all the pages            syncPages();

public void syncPages() {        removeAllViews();        cancelAllTasks();        Context context = getContext();        for (int j = 0; j < mNumWidgetPages; ++j) {            PagedViewGridLayout layout = new PagedViewGridLayout(context, mWidgetCountX,                    mWidgetCountY);            setupPage(layout);            addView(layout, new PagedViewGridLayout.LayoutParams(LayoutParams.MATCH_PARENT,                    LayoutParams.MATCH_PARENT));        }        for (int i = 0; i < mNumAppsPages; ++i) {            PagedViewCellLayout layout = new PagedViewCellLayout(context);            setupPage(layout);            addView(layout);        }    }

（2）再刷新数据到每页的view界面中，通过方法：

 // Load any pages that are necessary for the current window of views            loadAssociatedPages(mCurrentPage, immediateAndOnly);            requestLayout();

在PageView.java中的loadAssociatedPages（）方法中里面调用的主要的方法syncPageItems(i, (i == page) && immediateAndOnly);这个通过接口调到了AppsCustomizePagedView.java中的syncPageItems（）方法中去了：

@Override    public void syncPageItems(int page, boolean immediate) {        if (page < mNumAppsPages) {            syncAppsPageItems(page, immediate);        } else {            syncWidgetPageItems(page - mNumAppsPages, immediate);        }    }

里面就是刷新apps或者是widget的每一页；
再来看看syncAppsPageItems（）这个方法：

public void syncAppsPageItems(int page, boolean immediate) {        // ensure that we have the right number of items on the pages        int numCells = mCellCountX * mCellCountY;        int startIndex = page * numCells;        int endIndex = Math.min(startIndex + numCells, mApps.size());        PagedViewCellLayout layout = (PagedViewCellLayout) getPageAt(page);        layout.removeAllViewsOnPage();        ArrayList<Object> items = new ArrayList<Object>();        ArrayList<Bitmap> images = new ArrayList<Bitmap>();        for (int i = startIndex; i < endIndex; ++i) {            ApplicationInfo info = mApps.get(i);            PagedViewIcon icon = (PagedViewIcon) mLayoutInflater.inflate(                    R.layout.apps_customize_application, layout, false);            icon.applyFromApplicationInfo(info, true, mHolographicOutlineHelper);            icon.setOnClickListener(this);            icon.setOnLongClickListener(this);            icon.setOnTouchListener(this);            icon.setOnKeyListener(this);            int index = i - startIndex;            int x = index % mCellCountX;            int y = index / mCellCountX;            layout.addViewToCellLayout(icon, -1, i, new PagedViewCellLayout.LayoutParams(x,y, 1,1));            items.add(info);            images.add(info.iconBitmap);        }        layout.createHardwareLayers();        /* TEMPORARILY DISABLE HOLOGRAPHIC ICONS        if (mFadeInAdjacentScreens) {            prepareGenerateHoloOutlinesTask(page, items, images);        }        */    }

当你看到这个addViewToCellLayout（）方法的时候，我相信你就会有“山穷水复疑无路，柳暗花明又一村”的感觉了！这就是加载每个icon到view的那个位置；
syncWidgetPageItems（）这个也是同理，代码我相信大家自己都能看明白了吧！

 

            Step7：而这个widgets的数据是怎么加载上来的呢？？？这个是在Launcher.java中的onCreate（）方法中一步一步加载的：

（1）在Launcher.java中的onCreate（）方法中：

// Update customization drawer _after_ restoring the states        if (mAppsCustomizeContent != null) {            mAppsCustomizeContent.onPackagesUpdated();        }

（2）调用到AppsCustomizePagedView.java中的onPackagesUpdated（）的方法，这个里面主要做的是启动一个延迟的线程来加载widgets

public void onPackagesUpdated() {        // TODO: this isn't ideal, but we actually need to delay here. This call is triggered        // by a broadcast receiver, and in order for it to work correctly, we need to know that        // the AppWidgetService has already received and processed the same broadcast. Since there        // is no guarantee about ordering of broadcast receipt, we just delay here. Ideally,        // we should have a more precise way of ensuring the AppWidgetService is up to date.        postDelayed(new Runnable() {           public void run() {               updatePackages();           }        }, 500);    }

（3）通过updatePackages（）这个方法来实现的加载widgets的下面来看看代码：

public void updatePackages() {        // Get the list of widgets and shortcuts        boolean wasEmpty = mWidgets.isEmpty();        mWidgets.clear();        List<AppWidgetProviderInfo> widgets =            AppWidgetManager.getInstance(mLauncher).getInstalledProviders();        Intent shortcutsIntent = new Intent(Intent.ACTION_CREATE_SHORTCUT);        List<ResolveInfo> shortcuts = mPackageManager.queryIntentActivities(shortcutsIntent, 0);        for (AppWidgetProviderInfo widget : widgets) {            if (widget.minWidth > 0 && widget.minHeight > 0) {                mWidgets.add(widget);            } else {                Log.e(LOG_TAG, "Widget " + widget.provider + " has invalid dimensions (" +                        widget.minWidth + ", " + widget.minHeight + ")");            }        }        mWidgets.addAll(shortcuts);        Collections.sort(mWidgets,                new LauncherModel.WidgetAndShortcutNameComparator(mPackageManager));        updatePageCounts();        if (wasEmpty) {            // The next layout pass will trigger data-ready if both widgets and apps are set, so request            // a layout to do this test and invalidate the page data when ready.            if (testDataReady()) requestLayout();        } else {            cancelAllTasks();            invalidatePageData();        }    }

相信大家看到这里，根据上面的分析，就应该明白了mWidgets数据的加载过程了吧！

 

        Step8：置于里面的click事件就查看onClick（）方法；

                      长按是调用到父类的PagedViewWithDraggableItems.java的onLongClick()事件：    

@Override    public boolean onLongClick(View v) {        // Return early if this is not initiated from a touch        if (!v.isInTouchMode()) return false;        // Return early if we are still animating the pages        if (mNextPage != INVALID_PAGE) return false;        // When we have exited all apps or are in transition, disregard long clicks        if (!mLauncher.isAllAppsCustomizeOpen() ||                mLauncher.getWorkspace().isSwitchingState()) return false;        return beginDragging(v);    }

然后回调子类的AppsCustomizePagedView.java的beginDragging（）方法的：

private void beginDraggingApplication(View v) {        mLauncher.getWorkspace().onDragStartedWithItem(v);        mLauncher.getWorkspace().beginDragShared(v, this);    }

以后的流程大家可以自己跟跟，就明白拖拽事件的传递了，其实和Folder的拖拽是类似的原理；

今天就总结到这里吧！

                                                                                2013年1月7日22:35于北京