Android 4.0 Launher分析

一.整个Launcher应用的构成.

要看一个app的构成和入口,首先得了解它的AndroidManifest.xml.application标签包含以下内容：

1.Launcher 整个桌面的载体,整个应用真正的入口 .

2.wallpaperChooser 选择壁纸界面

3. RocketLauncher 好像没有用到.

4.installShorcutReceiver/uninstallShorcutReceiver接受添加/删除快捷方式的广播接收器

5.LauncherProvider 操作数据库,保存home的数据，比如桌面有那些小部件,快捷方式等.

二.Launcher 架构：

从MVC模式分析,Launcher处于controller层,LauncherMode 处于mode层,而view层是DragLayer,它是整个lanuncher布局的根.

通过launcher.xml可以看到整个布局的层次结构:

从左图可以看出Draglayer是launcher布局的根节点.

前两个imageview是divider和page_indicator.

Workspace作为子view,默认包含五个cellLayout（每屏）

Hotseat就是桌面底部应用快捷栏,与Android2.3不同的是它也是个cellLayout,可以自定义里面的快捷方式.

SearchDropTargetBar 就是桌面固定不动的搜索框,以及删除图标时的删除区。

Android使用向导

应用程序界面.

三.启动流程分析.

启动LauncherActivity 进入onCreate（）

执行LauncherApplicationapp = ((LauncherApplication)getApplication());

mModel = app.setLauncher(this);

初始化LauncherMode对象.

---->整个应用真正的入口,LaucherApplicationonCreate();

创建mModel =new LauncherModel(this,mIconCache);LauncherMode继承自 BroadcastReceiver.注册监听应用应用程序的安装，卸载等等。

LauncherApplication 注册ContentResolver监听favorites表的变化。

     private static final HandlerThread sWorkerThread = new HandlerThread("launcher-loader");
    static {
        sWorkerThread.start();
    }
    private static final Handler sWorker = new Handler(sWorkerThread.getLooper());

mLoaderTask = new LoaderTask(mApp, isLaunching);
sWorkerThread.setPriority(Thread.NORM_PRIORITY);
sWorker.post(mLoaderTask);

private class LoaderTask implements Runnable {

------>launcher.java 初始化Widget框架相关类

mAppWidgetManager = AppWidgetManager.getInstance(this);

mAppWidgetHost =new LauncherAppWidgetHost(this,APPWIDGET_HOST_ID);

mAppWidgetHost.startListening();作为Appwidget Service和 app交互的桥梁。

------>setupViews()初始化所有view对象

mDragLayer.setup(this,dragController);配置DragController对象，DrayLayer的一些事件处理，会调用DragController中的方法处理。如：onInterceptTouchEvent,onTouchEvent.

mWorkspace.setHapticFeedbackEnabled(false);

mWorkspace.setOnLongClickListener(this);

mWorkspace.setup(dragController);

dragController.addDragListener(mWorkspace)；

初始化workspace信息，实现DragListener，赋给 dragController，workspace中view拖动到不同状态的具体处理，会调用workspace中的方法。如onStartDrag，onDrop等。

mAppsCustomizeContent.setup(this,dragController);初始化应用主界面。

初始化dragController信息，如：dragController.setDragScoller(mWorkspace);

初始化桌面搜索和删除view。mSearchDropTargetBar.setup(this,dragController);

-------->mModel.startLoader(this, true);开始加载launcher数据。

进入LauncherModel中 startLoader，加载默认的AllAppsList.loadTopPackage(context);

mLoaderTask= new LoaderTask(context, isLaunching);sWorker.post(mLoaderTask);

通过Task加载Launcher的内容。其run中会调用一下方法加载和绑定workpace和AllApp内容 onlyLoadWorkspace();onlyLoadAllApps();bindWorkspace();onlyBindAllApps();

------>LoadWorkspace()加载桌面上的内容。

sWorkspaceItems.clear();

sAppWidgets.clear();

sFolders.clear();

sItemsIdMap.clear();

sDbIconCache.clear();

清空各个list，每个放的信息显而易见，如AppWidgets 小部件信息。 contentResolver.query(LauncherSettings.Favorites.CONTENT_URI,...);

查询Favorites表中的信息，其中存放的信息包括桌面上的小部件,快捷方式，文件夹等，分类初始化后，放入list中以备后用。

------>loadApps加载应用程序界面信息

packageManager.queryIntentActivities(mainIntent,0);查询所有app信息，每个app对应一个ResolveInfo对象。

mAllAppsList.add(newApplicationInfo(packageManager, apps.get(i),

mIconCache,mLabelCache));

根据app的信息创建ApplicationInfo对象，并放入mAllAppsList中以备后用。

------>bindWorkspace()绑定桌面上的小部件，快捷方式等。

首先通过post一Runnable()调用为callbacks.startBinding();callbacks其实是Launcher

在launcherApplication调用mModel.initialize(launcher);

创建多个new Runnable(),通过Handler的post执行callbacks.bindItems， callbacks.bindFolders，callbacks.bindAppWidget，调用Launcher中对应的方法。

Launcher中绑定内容以bindAppWidget(...)为例,根据widget的信息

mAppWidgetHost.createView(this,appWidgetId, appWidgetInfo)；创建view，通过

workspace.addInScreen添加到workpace中。

和2.3不同的是addInScreen中加入了一下判断，

if(container == LauncherSettings.Favorites.CONTAINER_HOTSEAT) {

layout= mLauncher.getHotseat().getLayout();

child.setOnKeyListener(null);

//Hide folder title in the hotseat

if (child instanceof FolderIcon) {

((FolderIcon)child).setTextVisible(false);

}

if(screen < 0) {

screen= mLauncher.getHotseat().getOrderInHotseat(x, y);

} else{

x= mLauncher.getHotseat().getCellXFromOrder(screen);

y= mLauncher.getHotseat().getCellYFromOrder(screen);

}

这是由于,4.0的hostseat可以自己定制,把app快捷方式突入即可。

------>接下来Launcher调用onResume()

if(mRestoring || mOnResumeNeedsLoad) {//如果Launcher回到前台,需要重新加载,执行

mWorkspaceLoading= true;

mModel.startLoader(this,true);

mRestoring= false;

mOnResumeNeedsLoad= false;

}

mAppsCustomizeTabHost.onResume();唤醒应用程序界面。

四.功能能点分析

1.托放功能分析

Luancher有一个相对比较复杂的功能就是拖放功能，要深入了解launcher,深入理解拖放功能是有必要的.
　　1.首先直观感受什么时候开始拖放?我们长按桌面一个应用图标或者控件的时候拖放就开始了，包括在应用程序界面中长按应用图标,下面就是我截取的拖放开始的代码调用堆栈

2. at com.android.launcher2.DragController.startDrag

3. at com.android.launcher2.Workspace.startDrag

4. at com.android.launcher2.Launcher.onLongClick

5. at android.view.View.performLongClick

6. at android.widget.TextView.performLongClick

7. at android.view.View$CheckForLongPress.run

8. at android.os.Handler.handleCallback

9. at android.os.Handler.dispatchMessage

10. at android.os.Looper.loop

桌面应用图标由Launcher.onLongClick负责监听处理，插入断点debug进入onLongclick函数

if (!(vinstanceof CellLayout)) {

v = (View)v.getParent().getParent();

}

CellLayout.CellInfolongClickCellInfo = (CellLayout.CellInfo) v.getTag();

//获得长按的item的tag

...

else {

if (!(itemUnderLongClickinstanceof Folder)) {

…

// User long pressed on an item

mWorkspace.startDrag(longClickCellInfo);

首先是获取被拖动的对象v.getTag()( v : worksapce.celllayout,hotseat)，Tag什么时候被设置进去的了.相应onTouch之前,

onInterceptTouchEvent的处理从DargLayer,到workspace,再到CellLayout中的onInterceptTouchEven t.
@Override

publicbooleanonInterceptTouchEvent(MotionEvent ev) {

// First we clear the tag toensure that on every touch down we start with a fresh slate,

// even in the case where wereturn early. Not clearing here was causing bugs whereby on

// long-press we'd end up pickingup an item from a previous drag operation.

...

if (action == MotionEvent.ACTION_DOWN) {

clearTagCellInfo();

}

if (mInterceptTouchListener !=null &&mInterceptTouchListener.onTouch(this, ev)) {

//mInterceptTouchListener是workspace中的。

returntrue;

}

if (action == MotionEvent.ACTION_DOWN) {

setTagToCellInfoForPoint((int) ev.getX(), (int) ev.getY());

}

returnfalse;

}

clearTagCellInfo------》初始化tag信息。

privatevoid clearTagCellInfo() {

final CellInfo cellInfo =mCellInfo;

cellInfo.cell =null;

cellInfo.cellX = -1;

cellInfo.cellY = -1;

cellInfo.spanX = 0;

cellInfo.spanY = 0;

setTag(cellInfo);

}

setTagToCellInfoForPoint-------》

final nt count =mChildren.getChildCount();

...

boolean found =false;

for (int i = count - 1; i >= 0; i--) {

final View child = mShortcutsAndWidgets.getChildAt(i);

child.getHitRect(frame);

…

// The child hitrectis relative to the CellLayoutChildren parent, so we need to

// offset that by thisCellLayout's padding to test an (x,y) point that is relative

// to this view.

frame.offset(mPaddingLeft, mPaddingTop);

if (frame.contains(x, y)) {

cellInfo.cell = child;

cellInfo.cellX = lp.cellX;

cellInfo.cellY = lp.cellY;

cellInfo.spanX = lp.cellHSpan;

cellInfo.spanY = lp.cellVSpan;

found = true;

break;

}

...

if (!found) {

finalint cellXY[] =mTmpXY;

pointToCellExact(x, y, cellXY);

cellInfo.cell =null;

cellInfo.cellX = cellXY[0];

cellInfo.cellY = cellXY[1];

cellInfo.spanX = 1;

cellInfo.spanY = 1;

}

setTag(cellInfo);

看了上面代码知道，当开始点击桌面时，celllayout会先清楚tag,然后调用就会根据点击区域去查找在该区域是否有child存在，若有把它设置为tag.cell,后面在开始拖放时launcher.onlongclick中对tag进行处理.
　　这个理顺了，再深入到workspace.startDrag函数.

child.setVisibility(GONE);//隐藏真是item.

// The outline is usedto visualize where the item will land if dropped

mDragOutline =createDragOutline(child, canvas, bitmapPadding);

//创建拖动桌面item时，item下面可放置位置的轮廓。

workspace.startDrag调用DragController.startDrag去处理拖放
mDragController.startDrag(child, this,child.getTag(), DragController.DRAG_ACTION_MOVE);
　　再分析一下上面调用的几个参数
　　child = tag.cell ->the longclick icon
　　this = workspace

child.getTag()是什么呢?在什么时候被设置?再仔细回顾原来launcher加载过程代码，在launcher.createShortcut中它被设置了：注意下面我代码中的注释
View createShortcut(int layoutResId, ViewGroupparent, ShortcutInfo info) {

BubbleTextView favorite =(BubbleTextView)mInflater.inflate(layoutResId, parent,false);

favorite.applyFromShortcutInfo(info, mIconCache);

favorite.setOnClickListener(this);

return favorite;

}

进入 applyFromShortcutInfo我们会看到：

publicvoid applyFromShortcutInfo(ShortcutInfo info, IconCacheiconCache) {

Bitmap b =info.getIcon(iconCache);

setCompoundDrawablesWithIntrinsicBounds(null,new FastBitmapDrawable(b),//图标

null,null);

setText(info.title);//图标下的字

setTag(info);//设置item信息

}

继续深入解读DragController.startDrag函数

publicvoid startDrag(Bitmap b,int dragLayerX,int dragLayerY,

DragSource source, Object dragInfo, int dragAction, Point dragOffset, RectdragRegion) {

// Hide soft keyboard, if visible

if (mInputMethodManager ==null) {

mInputMethodManager = (InputMethodManager)

mLauncher.getSystemService(Context.INPUT_METHOD_SERVICE);

}

mInputMethodManager.hideSoftInputFromWindow(mWindowToken, 0);

for (DragListener listener :mListeners) {

listener.onDragStart(source,dragInfo, dragAction);

}

finalint registrationX =mMotionDownX – dragLayerX;

//记住手指点击位置与屏幕左上角位置偏差

finalint registrationY =mMotionDownY - dragLayerY;

finalint dragRegionLeft = dragRegion ==null ? 0 : dragRegion.left;

finalint dragRegionTop = dragRegion ==null ? 0 : dragRegion.top;

//手指触点相对draglayer左上角的偏移量。

mDragObject.dragSource = source;

mDragObject.dragInfo = dragInfo;

mVibrator.vibrate(VIBRATE_DURATION);

final DragView dragView =mDragObject.dragView =new DragView(mLauncher, b,registrationX, registrationY, 0, 0, b.getWidth(), b.getHeight());

//用于手指拖动的，一个和这是item大小样式相同的view。

...

dragView.show(mMotionDownX,mMotionDownY);

//显示drayView，并开启弹出到手指触点的动画。

handleMoveEvent(mMotionDownX,mMotionDownY);

}

对于 handleMoveEvent(...):

privatevoid handleMoveEvent(int x, int y) {

//移动到手指点击位置

mDragObject.dragView.move(x, y);

// Drop on someone?

finalint[] coordinates =mCoordinatesTemp;

//查找可放置此view的目标容器。

DropTarget dropTarget =findDropTarget(x, y, coordinates);

…

}

接下进入 findDropTarget(...):

DropTarget findDropTarget(int x,int y,int[] dropCoordinates) {

...

DropTarget target =dropTargets.get(i);

target.getHitRect(r);

// Convert the hitrect toDragLayer coordinates

//target位置

target.getLocationInDragLayer(dropCoordinates);

r.offset(dropCoordinates[0] -target.getLeft(), dropCoordinates[1] - target.getTop());

...

if (r.contains(x, y)) {//手机触点是否在target区域

//一般返回空，是否一个可以吧事件传递给一个object。

DropTarget delegate =target.getDropTargetDelegate(mDragObject);

if (delegate !=null) {...}

// Make dropCoordinates relativeto the DropTarget

//手指触点，相对target位移

dropCoordinates[0] = x -dropCoordinates[0];

dropCoordinates[1] = y -dropCoordinates[1];

return target;

}

通过上边代码，找到目前可放置的target后，

接下来继续handleMoveEvent（...）中的代码：

if (dropTarget !=null) {

//一般返回空，是否一个可以吧事件传递给一个object。

DropTarget delegate =dropTarget.getDropTargetDelegate(mDragObject);

if (delegate !=null) {...}

if (mLastDropTarget != dropTarget) {

if (mLastDropTarget !=null) {

//和上次在不同target，调用 onDragExit,重置上次target数据信息。

mLastDropTarget.onDragExit(mDragObject);

}

//准备当前Target数据，

dropTarget.onDragEnter(mDragObject);

}

dropTarget.onDragOver(mDragObject);

} else {

if (mLastDropTarget !=null) {

mLastDropTarget.onDragExit(mDragObject);

}

接着进入onDragOver:如workspace中的onDragOver

publicvoid onDragOver(DragObject d){

// Skip drag over events while weare dragging over side pages

if (mInScrollArea)return;

if (mIsSwitchingState)return;

// Identify whether we havedragged over a side page

if (isSmall()) {

if (mLauncher.getHotseat() !=null &&!isExternalDragWidget(d)) {

mLauncher.getHotseat().getHitRect(r);

if (r.contains(d.x, d.y)) {

//target是否是launcher上的快捷栏。

layout = mLauncher.getHotseat().getLayout();

}

if (layout ==null) {

//获得view托进的cellayout

layout =findMatchingPageForDragOver(d.dragView, d.x, d.y,false);

}

...

}

// Handle the drag over

if (mDragTargetLayout !=null) {

// We want the point to be mappedto the dragTarget.

if (mLauncher.isHotseatLayout(mDragTargetLayout)) {

mapPointFromSelfToSibling(mLauncher.getHotseat(),mDragViewVisualCenter);

} else {

mapPointFromSelfToChild(mDragTargetLayout,mDragViewVisualCenter,null);

}

ItemInfo info = (ItemInfo) d.dragInfo;

//找到view放置的离当前最近的cell位置信息。

mTargetCell = findNearestArea((int)mDragViewVisualCenter[0],

(int)mDragViewVisualCenter[1], 1, 1,mDragTargetLayout,mTargetCell);

final View dragOverView =mDragTargetLayout.getChildAt(mTargetCell[0],

mTargetCell[1]);//可放置的target view

我们继续handleMoveEvent（...）中剩余代码。

mLastDropTarget = dropTarget;

//After a scroll, the touch point will still be in the scroll region.

//Rather than scrolling immediately, require a bit oftwiddling to scroll again

finalint slop =ViewConfiguration.get(mLauncher).getScaledWindowTouchSlop();

mDistanceSinceScroll +=

Math.sqrt(Math.pow(mLastTouch[0] - x, 2) + Math.pow(mLastTouch[1] - y, 2));

mLastTouch[0] = x;

mLastTouch[1] = y;

...

mScrollRunnable.setDirection(SCROLL_LEFT);

mHandler.postDelayed(mScrollRunnable,SCROLL_DELAY);

-------->最后拖动的出口是在DragController中onTouchEvent的MotionEvent.ACTION_UP。

privatevoid drop(float x, float y) {

finalint[] coordinates =mCoordinatesTemp;

//查找可放置的target

final DropTarget dropTarget =findDropTarget((int) x, (int) y, coordinates);

mDragObject.x = coordinates[0];

mDragObject.y = coordinates[1];

boolean accepted =false;

if (dropTarget !=null) {

mDragObject.dragComplete =true;

dropTarget.onDragExit(mDragObject);

if (dropTarget.acceptDrop(mDragObject)) {

//判断target是否可以放置view

dropTarget.onDrop(mDragObject);

accepted = true;

}

mDragObject.dragSource.onDropCompleted((View) dropTarget,mDragObject, accepted);

}

publicvoid onDrop(DragObject d) {// workspace.ondrop

…

//Reparent the view

getParentCellLayoutForView(cell).removeView(cell);

addInScreen(cell, container, screen,mTargetCell[0],mTargetCell[1],

mDragInfo.spanX,mDragInfo.spanY);

…

if (container != LauncherSettings.Favorites.CONTAINER_HOTSEAT &&

cell instanceofLauncherAppWidgetHostView) {

final CellLayout cellLayout =dropTargetLayout;

// We post this call sothat the widget has a chance to be placed

// in its finallocation

//4.0支持resize widget，以下是显示resize把手。

finalLauncherAppWidgetHostView hostView = (LauncherAppWidgetHostView) cell;

AppWidgetProviderInfopinfo = hostView.getAppWidgetInfo();

if (pinfo.resizeMode != AppWidgetProviderInfo.RESIZE_NONE){

final Runnable resizeRunnable=new Runnable() {

publicvoid run() {

DragLayer dragLayer=mLauncher.getDragLayer();

dragLayer.addResizeFrame(info,hostView, cellLayout);

}

};

post(new Runnable() {

publicvoid run() {

if (!isPageMoving()) {

//设置resize frame大小位置。

resizeRunnable.run();

} else {

mDelayedResizeRunnable = resizeRunnable;

}

});

：：：

DragLayer = 》

    @Override
    public boolean onTouchEvent(MotionEvent ev) {
        boolean handled = false;
        int action = ev.getAction();

        int x = (int) ev.getX();
        int y = (int) ev.getY();

        if (ev.getAction() == MotionEvent.ACTION_DOWN) {
            if (ev.getAction() == MotionEvent.ACTION_DOWN) {
                if (handleTouchDown(ev, false)) {
                    return true;
                }
            }
        }

        if (mCurrentResizeFrame != null) {
            handled = true;
            switch (action) {
                case MotionEvent.ACTION_MOVE:
                    mCurrentResizeFrame.visualizeResizeForDelta(x - mXDown, y - mYDown);
                    break;
                case MotionEvent.ACTION_CANCEL:
                case MotionEvent.ACTION_UP:
                    mCurrentResizeFrame.visualizeResizeForDelta(x - mXDown, y - mYDown);
                    mCurrentResizeFrame.onTouchUp();
                    mCurrentResizeFrame = null;
            }
        }
        if (handled) return true;
        return mDragController.onTouchEvent(ev);
    }

。。。
}

AppWidgetResizeFrame ==》 static void updateWidgetSizeRanges(AppWidgetHostView widgetView, Launcher launcher,
int spanX, int spanY) {

：：：

//保存view的信息到数据库。

LauncherModel.moveItemInDatabase(mLauncher, info, container, screen, lp.cellX,lp.cellY);

…

android4.0支持快捷方式合并：
// If the item being droppedis a shortcut and the nearest drop

// cell also contains a shortcut,then create a folder with the two shortcuts.

if (!mInScrollArea &&createUserFolderIfNecessary(cell, container,

dropTargetLayout, mTargetCell, false, d.dragView,null)) {

return;

}

if(addToExistingFolderIfNecessary(cell, dropTargetLayout,mTargetCell, d, false)) {

return;

}

createUserFolderIfNecessary：

View v = target.getChildAt(targetCell[0],targetCell[1]);

boolean aboveShortcut =(v.getTag()instanceof ShortcutInfo);

boolean willBecomeShortcut =(newView.getTag()instanceof ShortcutInfo);

//如果都是快捷方式，才能进行合并

if (aboveShortcut&& willBecomeShortcut) {

ShortcutInfo sourceInfo =(ShortcutInfo) newView.getTag();

ShortcutInfo destInfo =(ShortcutInfo) v.getTag();

// if the drag started here, weneed to remove it from the workspace

if (!external) {

getParentCellLayoutForView(mDragInfo.cell).removeView(mDragInfo.cell);

}

Rect folderLocation = new Rect();

float scale =mLauncher.getDragLayer().getDescendantRectRelativeToSelf(v,folderLocation);

target.removeView(v);

FolderIcon fi =

mLauncher.addFolder(target, container,screen, targetCell[0], targetCell[1]);

// If the dragView is null, wecan't animate

boolean animate = dragView !=null;

if (animate) {

fi.performCreateAnimation(destInfo,v, sourceInfo, dragView, folderLocation, scale,

postAnimationRunnable);

} else {

fi.addItem(destInfo);

fi.addItem(sourceInfo);

}

returntrue;

}

…

-------------->最后调用endDrag()

privatevoid endDrag() {

if (mDragging) {

mDragging =false;

for (DragListener listener :mListeners) {

listener.onDragEnd();

}

if (mDragObject.dragView != null) {

mDragObject.dragView.remove();

mDragObject.dragView =null;

}

mDragObject =null;

}

到此Launcher 上view的拖动就分析完了。

Launcher开关门切换效果：

Workspace：

screenScrolledStandardUI()

PagedView : screenCenter = mScrollX +halfScreenSize 代表当前页面中心移动到的位置

getScrollProgress(screenCenter, cl, index)获取滑动的距离占最大距离。

int totalDistance = getScaledMeasuredWidth(v)+ mPageSpacing;

int delta = screenCenter -(getChildOffset(page) -

getRelativeChildOffset(page) +halfScreenSize);

float scrollProgress = delta /(totalDistance * 1.0f);

这样我们可以通过scrollProgress这个百分比，计算每个屏幕每个时刻旋转的角度，透明度，然后，根据屏幕位置设置旋转的轴位置，旋转方向。

循环滑动：

由于但scrollX = 0时，viewgroup就不能向左滑动，因此应该设置初始化位置离左边界很远，10万，这样想滑动到边界也要上万次滑动。向右滑动就不停romove第一个view，添加到最后，

然后再reLayout.更新view顺序在computeScrollHelper 的else中去处理。

posted on 2012-12-07 20:51 zyuchao 阅读(888) 评论(0) 收藏举报

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