实现Launcher默认壁纸、选择壁纸定制化功能

需求功能说明：

    该定制需求为在系统中添加一个新的分区如myimage。用以实现存放定制资源。比如在myimage下新建wallpaper目录用于存放定制的墙纸图片资源，当Launcher载入默认墙纸或者选择设置墙纸时会优先从该路径下读取资源。

第一部分：客制化默认壁纸：

    Launcher默认的壁纸配置是放在framework下res以下配置的，图片也是放在framework以下，对于独立的第三方Launcher要想绕开framework实现默认壁纸则须要自身实现设置默认壁纸的功能。因此要在Launcher第一次执行或者重置时设置默认壁纸。实现方式为在Launcher.java类的onCreate（）方法下的showFirstRunWorkspaceCling（）执行设置默认壁纸的功能代码，例如以下：

  /*封装设置默认壁纸的方法*/

    private void setDefaultWallpaper(){

        WallpaperManager wm = (WallpaperManager)getSystemService(Context.WALLPAPER_SERVICE);

        try{

            wm.setBitmap(getBitmap("/myimage/wallpaper/wallpaper_01.jpg"));

        }catch(Exception e){

            e.printStackTrace();

        }

    }

    /*得到绝对路径下的图片为bitmap类型*/

    public Bitmap getBitmap(String path) {

        Bitmap bitmap = null;

        File file = new File(path);

        if (file.exists())

            bitmap = BitmapFactory.decodeFile(path);

            return bitmap;

        }

    /*第一次启动时显示的指导画面*/

    public void showFirstRunWorkspaceCling() {

        setDefaultWallpaper();

        ......

    }

第二部分 客制化选择壁纸：

    因为在Launcher2中对墙纸资源的引用是通过id引用，可是当前客制化定制的文件路径为绝对路径如/myimage/wallpaper，也就说须要通过路径进行引用，因此改动例如以下：

    第一步：wallpapers.xml

        如：

        <item>wallpaper_01</item>

        <item>wallpaper_02</item>

        <item>wallpaper_04</item>

        <item>wallpaper_05</item>

        <item>wallpaper_06</item>

        <item>wallpaper_07</item>

        <item>wallpaper_08</item>

注：每一项的值应与实际图片名字同样

    第二步：改动WallpaperChooserDialogFragment.java类

 

 

    private ArrayList<String> mThumbs;

    private ArrayList<String> mImages;

    private void selectWallpaper(int position) {

        if (LauncherLog.DEBUG) {

            LauncherLog.d(TAG, "selectWallpaper: position = " + position + ", this = " + this);

        }

        try {

            WallpaperManager wpm = (WallpaperManager) getActivity().getSystemService(

                    Context.WALLPAPER_SERVICE);

            wpm.setBitmap(getBitmap(mImages.get(position)));

            Activity activity = getActivity();

            activity.setResult(Activity.RESULT_OK);

            activity.finish();

        } catch (IOException e) {

            Log.e(TAG, "Failed to set wallpaper: " + e);

        }

    }

 

    public Bitmap getBitmap(String path) {

        Bitmap bitmap = null;

        File file = new File(path);

        if (file.exists())

            bitmap = BitmapFactory.decodeFile(path);

        return bitmap;

    }

    private void findWallpapers() {

        mThumbs = new ArrayList<String>();

        mImages = new ArrayList<String>();

 

        final Resources resources = getResources();

        final String packageName = resources.getResourcePackageName(R.array.wallpapers);

        addWallpapers(resources, packageName, R.array.wallpapers);

        addWallpapers(resources, packageName, R.array.extra_wallpapers);

    }

 

    private void addWallpapers(Resources resources, String packageName, int list) {

        final String[] extras = resources.getStringArray(list);

        for (String extra : extras) {

            String res="/myimage/wallpaper/"+extra+".jpg";

            String thumbRes="/myimage/wallpaper/"+extra+"_small.jpg";

            mThumbs.add(thumbRes);

            mImages.add(res);

        }

    }

 

 

        public View getView(int position, View convertView, ViewGroup parent) {

            View view;

 

            if (convertView == null) {

                view = mLayoutInflater.inflate(R.layout.wallpaper_item, parent, false);

            } else {

                view = convertView;

            }

 

            ImageView image = (ImageView) view.findViewById(R.id.wallpaper_image);

 

            String thumbRes = mThumbs.get(position);

            image.setImageBitmap(getBitmap(thumbRes));

            Drawable thumbDrawable = image.getDrawable();

            if (thumbDrawable != null) {

                thumbDrawable.setDither(true);

            } else {

                Log.e(TAG, "Error decoding thumbnail resId=" + thumbRes + " for wallpaper #"

                        + position);

            }

 

            return view;

        }

    }

        @Override

        protected Bitmap doInBackground(Integer... params) {

            if (isCancelled() || !isAdded()) {

                LauncherLog.d(TAG, "WallpaperLoader doInBackground: canceled = " + isCancelled()

                        + ",isAdded() = " + isAdded() + ",activity = " + getActivity());

                return null;

            }

            try {

                return BitmapFactory.decodeFile(mImages.get(params[0]), mOptions);

            } catch (OutOfMemoryError e) {

                LauncherLog.e(TAG, "WallpaperLoader decode resource out of memory " + e.getMessage());

                return null;

            }

        }

}