android 5.1 壁纸路径,RTFSC – Android5.1 壁纸设置流程简析

Android5.1 壁纸设置流程浅析

Ubuntu14.04 Android5.1 Source Insight3

这里只是简单分析一下5.1里是如何设置壁纸的；这个流程和4.4有一些不同。但基本都是找个地方存放壁纸文件，需要的时候读取，设置的时候更新

这里只看设置的过程。权当参考。

机器使用launcher3，在桌面上长按，底部显示设置壁纸的入口。

进入设置壁纸界面，观察log可知，此界面属于Trebuchet。也是launcher3

点击设置壁纸按钮，发现整个标题栏都有响应。在以下文件中可以找到相关定义：

/*— ↓ — WallpaperPickerActivity.java *********/

//Action bar//Show the custom action bar view

final ActionBar actionBar =getActionBar();

actionBar.setCustomView(R.layout.actionbar_set_wallpaper);

actionBar.getCustomView().setOnClickListener(newView.OnClickListener() {

@Overridepublic voidonClick(View v) {if (mSelectedTile != null) {

WallpaperTileInfo info=(WallpaperTileInfo) mSelectedTile.getTag();

info.onSave(WallpaperPickerActivity.this);

}else{//no tile was selected, so we just finish the activity and go back

setResult(Activity.RESULT_OK);

finish();

}

});

mSetWallpaperButton=findViewById(R.id.set_wallpaper_button);/*— ↑ — (packages/apps/Trebuchet/WallpaperPicker/src/com/android/launcher3/) *********/

整个 actionBar都拿来响应点击。info是 WallpaperTileInfo抽象类的对象，有5个子类。

这样系统能根据图片来选择使用哪一个子类。再调用 onSave方法。以FileWallpaperInfo类为例。

它复写了 onSave方法

/*— ↓ — WallpaperPickerActivity.java *********/@Overridepublic voidonSave(WallpaperPickerActivity a) {

a.setWallpaper(Uri.fromFile(mFile),true);

}/*— ↑ — (packages/apps/Trebuchet/WallpaperPicker/src/com/android/launcher3/) *********/

因为WallpaperPickerActivity 继承自 WallpaperCropActivity

setWallpaper方法在 WallpaperCropActivity中找到；传入了Uri和一个boolean值

/*↓ — WallpaperCropActivity.java *********/

protected void setWallpaper(Uri uri, final booleanfinishActivityWhenDone) {int rotation = getRotationFromExif(this, uri);

BitmapCropTask cropTask= newBitmapCropTask(this, uri, null, rotation, 0, 0, true, false, null);final Point bounds =cropTask.getImageBounds();

Runnable onEndCrop= newRunnable() {public voidrun() {

updateWallpaperDimensions(bounds.x, bounds.y);if(finishActivityWhenDone) {

setResult(Activity.RESULT_OK);

finish();

}

};

cropTask.setOnEndRunnable(onEndCrop);

cropTask.setNoCrop(true);

cropTask.execute();

}/*↑ — (packages/apps/trebuchet/wallpaperpicker/src/com/android/launcher3) *********/

以上代码可以看出，它启动了一个异步任务 BitmapCropTask extends AsyncTask ；把一些列参数都传入了cropTask

启动一个线程onEndCrop，等待任务结束

进入BitmapCropTask看，系统做了什么工作

这是setWallpaper使用的构造方法

/*↓ — WallpaperCropActivity.java *********/

publicBitmapCropTask(Context c, Uri inUri,

RectF cropBounds,int rotation, int outWidth, intoutHeight,boolean setWallpaper, booleansaveCroppedBitmap, Runnable onEndRunnable) {

mContext=c;

mInUri=inUri;

init(cropBounds, rotation,

outWidth, outHeight, setWallpaper, saveCroppedBitmap, onEndRunnable);

}//……

private void init(RectF cropBounds, int rotation, int outWidth, intoutHeight,boolean setWallpaper, booleansaveCroppedBitmap, Runnable onEndRunnable) {

Log.d(“rust”,”init after bitmapcroptask”);

mCropBounds=cropBounds;

mRotation= rotation; //传入各项参数

mOutWidth =outWidth;

mOutHeight=outHeight;

mSetWallpaper=setWallpaper;

mSaveCroppedBitmap=saveCroppedBitmap;

mOnEndRunnable=onEndRunnable;

}//…… 在这里处理任务，启动 cropBitmap()

@OverrideprotectedBoolean doInBackground(Void… params) {returncropBitmap();

}//……

public booleancropBitmap() {boolean failure = false;

WallpaperManager wallpaperManager= null;if(mSetWallpaper) {

wallpaperManager=WallpaperManager.getInstance(mContext.getApplicationContext());

}if (mSetWallpaper &&mNoCrop) {try{

InputStream is= regenerateInputStream(); //获得InputStream

if (is != null) {

wallpaperManager.setStream(is);//把is写进去，从这里进入到wallpaperManager

Utils.closeSilently(is);

}

}catch(IOException e) {

Log.w(LOGTAG,“cannot write stream to wallpaper”, e);

failure= true;

}return !failure;

}else { //顺利的话不会进入这里//……//Helper to setup input stream

privateInputStream regenerateInputStream() {if (mInUri == null && mInResId == 0 && mInFilePath == null && mInImageBytes == null) {

Log.w(LOGTAG,“cannot read original file, no input URI, resource ID, or ” +

“image byte array given”);

}else{try{

String filepath=mInFilePath;if(mInUri != null){

filepath=DrmHelper.getFilePath(mContext, mInUri);

}if(DrmHelper.isDrmFile(filepath)){byte[] bytes =DrmHelper.getDrmImageBytes(filepath);return new ByteArrayInputStream(bytes); //返回一个ByteArray

}/*↑ — (packages/apps/trebuchet/wallpaperpicker/src/com/android/launcher3) *********/

调用了wallpaperManager.setStream(is);进入 WallpaperManager.java 看看

/*↓ — WallpaperManager.java *********/

public void setStream(InputStream data) throws IOException { //luncher3 里直接调用了这个方法

if (sGlobals.mService == null) { //WallpaperCropActivity 调用

Log.w(TAG, “WallpaperService not running”);return;

}try{

ParcelFileDescriptor fd= sGlobals.mService.setWallpaper(null); //利用service得到fd

if (fd == null) { //这里要去WallpaperManagerService里找到对应方法

return;

}

FileOutputStream fos= null;try{

fos= newParcelFileDescriptor.AutoCloseOutputStream(fd);

setWallpaper(data, fos);//写入壁纸数据

} finally{if (fos != null) {

fos.close();

}

}catch(RemoteException e) {//Ignore

}

}//…… 在这里写入壁纸，写入过程结束，Manager完成任务

private voidsetWallpaper(InputStream data, FileOutputStream fos)throwsIOException {byte[] buffer = new byte[32768];intamt;while ((amt=data.read(buffer)) > 0) {

fos.write(buffer,0, amt);

}

}/*↑ — (framework/base/core/java/android/app) *********/

再来看Globals extends IWallpaperManagerCallback.Stub

包含成员变量 IWallpaperManager mService，通过

Globals(Looper looper) {

IBinder b=ServiceManager.getService(Context.WALLPAPER_SERVICE);

mService=IWallpaperManager.Stub.asInterface(b);

}

调用 WallpaperManagerService.java 里的setWallpaper方法

Service的作用

进入WallpaperManagerService看看，是如何返回ParcelFileDescriptor值的

/*↓ — WallpaperManagerService.java *********/

public ParcelFileDescriptor setWallpaper(String name) { //供 WallpaperManager 调用

checkPermission(android.Manifest.permission.SET_WALLPAPER);synchronized(mLock) {if (DEBUG) Slog.v(TAG, “setWallpaper”);int userId =UserHandle.getCallingUserId();

WallpaperData wallpaper=mWallpaperMap.get(userId);if (wallpaper == null) {throw new IllegalStateException(“Wallpaper not yet initialized for user ” +userId);

}final long ident =Binder.clearCallingIdentity();try{

ParcelFileDescriptor pfd=updateWallpaperBitmapLocked(name, wallpaper);if (pfd != null) {//启动下面的方法

wallpaper.imageWallpaperPending = true;

}return pfd; //返回ParcelFileDescriptor值给WallpaperManager

} finally{

Binder.restoreCallingIdentity(ident);

}

ParcelFileDescriptor updateWallpaperBitmapLocked(String name, WallpaperData wallpaper) {if (name == null) name = “”;try{

File dir= getWallpaperDir(wallpaper.userId); //找到壁纸

if (!dir.exists()) {

dir.mkdir();

FileUtils.setPermissions(