Launcher3--壁纸(5/5)

本篇文章主要介绍了" Launcher3--壁纸"，主要涉及到方面的内容，对于Android开发感兴趣的同学可以参考一下： 在说Launcher上设置壁纸时，首先需要弄清楚的是，壁纸的设置属于系统行为，而不是Launcher的应用特性。在Launcher中，壁纸的设置最终也是...

    public LiveWallpaperListAdapter(Context context) {
        mInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        mPackageManager = context.getPackageManager();

        List list = mPackageManager.queryIntentServices(
                new Intent(WallpaperService.SERVICE_INTERFACE),
                PackageManager.GET_META_DATA);

        mWallpapers = new ArrayList();

        new LiveWallpaperEnumerator(context).execute(list);
    }

    这是构造方法，查询action为"android.service.wallpaper.WallpaperService"的service，这是动态壁纸应用中必须配置的，如果我们自己想做一个动态壁纸也是要添加这个action的。

    public static class LiveWallpaperTile extends WallpaperPickerActivity.WallpaperTileInfo {
        private Drawable mThumbnail;
        private WallpaperInfo mInfo;
        public LiveWallpaperTile(Drawable thumbnail, WallpaperInfo info, Intent intent) {
            mThumbnail = thumbnail;
            mInfo = info;
        }
        @Override
        public void onClick(WallpaperPickerActivity a) {
            Intent preview = new Intent(WallpaperManager.ACTION_CHANGE_LIVE_WALLPAPER);
            preview.putExtra(WallpaperManager.EXTRA_LIVE_WALLPAPER_COMPONENT,
                    mInfo.getComponent());
            a.onLiveWallpaperPickerLaunch(mInfo);
            a.startActivityForResultSafely(preview, WallpaperPickerActivity.PICK_LIVE_WALLPAPER);
        }
    }

     WallpaperTileInfo的子类，然后异步加载信息。

            for (ResolveInfo resolveInfo : list) {
                WallpaperInfo info = null;
                try {
                    info = new WallpaperInfo(mContext, resolveInfo);
                } catch (XmlPullParserException e) {
                    Log.w(LOG_TAG, "Skipping wallpaper " + resolveInfo.serviceInfo, e);
                    continue;
                } catch (IOException e) {
                    Log.w(LOG_TAG, "Skipping wallpaper " + resolveInfo.serviceInfo, e);
                    continue;
                }

                // 获取动态壁纸信息
                Drawable thumb = info.loadThumbnail(packageManager);
                Intent launchIntent = new Intent(WallpaperService.SERVICE_INTERFACE);
                launchIntent.setClassName(info.getPackageName(), info.getServiceName());
                LiveWallpaperTile wallpaper = new LiveWallpaperTile(thumb, info, launchIntent);
                publishProgress(wallpaper);
            }

    4）第三方壁纸

        // Populate the third-party wallpaper pickers
        // 填充第三方壁纸选择器
        final LinearLayout thirdPartyWallpapersView =
                (LinearLayout) findViewById(R.id.third_party_wallpaper_list);
        final ThirdPartyWallpaperPickerListAdapter ta =
                new ThirdPartyWallpaperPickerListAdapter(this);
        populateWallpapersFromAdapter(thirdPartyWallpapersView, ta, false);

    加载第三方壁纸选择器，这个还是很友好的，这样手机中如果装有其他的第三方壁纸设置的应用，也可以在此处显示出来。查询是在ThirdPartyWallpaperPickerListAdapter适配器类中进行的，这个适配器跟刚才说的动态壁纸适配器类类似。

    定义了第三方壁纸对象ThirdPartyWallpaperTile，

    public static class ThirdPartyWallpaperTile extends WallpaperPickerActivity.WallpaperTileInfo {

        private ResolveInfo mResolveInfo;
        public ThirdPartyWallpaperTile(ResolveInfo resolveInfo) {
            mResolveInfo = resolveInfo;
        }

        @Override
        public void onClick(WallpaperPickerActivity a) {
            final ComponentName itemComponentName = new ComponentName(
                    mResolveInfo.activityInfo.packageName, mResolveInfo.activityInfo.name);
            Intent launchIntent = new Intent(Intent.ACTION_SET_WALLPAPER);
            launchIntent.setComponent(itemComponentName);
            a.startActivityForResultSafely(launchIntent, WallpaperPickerActivity.PICK_WALLPAPER_THIRD_PARTY_ACTIVITY);// 启动第三方壁纸选择器
        }
    }

    在构造方法中查询第三方壁纸应用，

    public ThirdPartyWallpaperPickerListAdapter(Context context) {
        mInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        mPackageManager = context.getPackageManager();
        mIconSize = context.getResources().getDimensionPixelSize(R.dimen.wallpaperItemIconSize);
        final PackageManager pm = mPackageManager;

        final Intent pickWallpaperIntent = new Intent(Intent.ACTION_SET_WALLPAPER);
        final List apps = pm.queryIntentActivities(pickWallpaperIntent, 0);

        // Get list of image picker intents
        Intent pickImageIntent = new Intent(Intent.ACTION_GET_CONTENT);
        pickImageIntent.setType("image/*");
        final List imagePickerActivities =
                pm.queryIntentActivities(pickImageIntent, 0);
        final ComponentName[] imageActivities = new ComponentName[imagePickerActivities.size()];
        for (int i = 0; i < imagePickerActivities.size(); i++) {
            ActivityInfo activityInfo = imagePickerActivities.get(i).activityInfo;
            imageActivities[i] = new ComponentName(activityInfo.packageName, activityInfo.name);
        }

        outerLoop:
        for (ResolveInfo info : apps) {
            final ComponentName itemComponentName =
                    new ComponentName(info.activityInfo.packageName, info.activityInfo.name);
            final String itemPackageName = itemComponentName.getPackageName();
            // Exclude anything from our own package, and the old Launcher,
            // and live wallpaper picker
            if (itemPackageName.equals(context.getPackageName()) ||
                    itemPackageName.equals("com.android.launcher") ||
                    itemPackageName.equals("com.android.wallpaper.livepicker")) {
                continue;
            }
            // Exclude any package that already responds to the image picker intent
            for (ResolveInfo imagePickerActivityInfo : imagePickerActivities) {
                if (itemPackageName.equals(
                        imagePickerActivityInfo.activityInfo.packageName)) {
                    continue outerLoop;
                }
            }
            mThirdPartyWallpaperPickers.add(new ThirdPartyWallpaperTile(info));
        }
    }

    根据"android.intent.action.SET_WALLPAPER"来查找的，然后做一些过滤，添加到列表中。
    5）添加图库

        // Add a tile for the Gallery
        // 列表开头放置图库选择器
        LinearLayout masterWallpaperList = (LinearLayout) findViewById(R.id.master_wallpaper_list);
        FrameLayout pickImageTile = (FrameLayout) getLayoutInflater().
                inflate(R.layout.wallpaper_picker_image_picker_item, masterWallpaperList, false);
        setWallpaperItemPaddingToZero(pickImageTile);
        masterWallpaperList.addView(pickImageTile, 0);

        // Make its background the last photo taken on external storage
        Bitmap lastPhoto = getThumbnailOfLastPhoto();
        if (lastPhoto != null) {
            ImageView galleryThumbnailBg =
                    (ImageView) pickImageTile.findViewById(R.id.wallpaper_image);
            galleryThumbnailBg.setImageBitmap(getThumbnailOfLastPhoto());
            int colorOverlay = getResources().getColor(R.color.wallpaper_picker_translucent_gray);
            galleryThumbnailBg.setColorFilter(colorOverlay, PorterDuff.Mode.SRC_ATOP);

        }

        PickImageInfo pickImageInfo = new PickImageInfo();
        pickImageTile.setTag(pickImageInfo);
        pickImageInfo.setView(pickImageTile);
        pickImageTile.setOnClickListener(mThumbnailOnClickListener);

    在列表开头添加图库入口，这样用户就可以选择任一图片了。
    

    其他的初始化设置就不一一赘述了。

三、壁纸预览和设置

    之前说到不同类型的壁纸对象时，会重写父类的方法，实现具体的功能，这里我们已ResourceWallpaperInfo为例，来说明壁纸的预览和设置的。

        @Override
        public void onClick(WallpaperPickerActivity a) {
            Log.d("dingfeng","ResourceWallpaperInfo onClick...");
            BitmapRegionTileSource.ResourceBitmapSource bitmapSource =
                    new BitmapRegionTileSource.ResourceBitmapSource(
                            mResources, mResId, BitmapRegionTileSource.MAX_PREVIEW_SIZE);
            bitmapSource.loadInBackground();
            BitmapRegionTileSource source = new BitmapRegionTileSource(a, bitmapSource);
            CropView v = a.getCropView();
            v.setTileSource(source, null);
            Point wallpaperSize = WallpaperCropActivity.getDefaultWallpaperSize(
                    a.getResources(), a.getWindowManager());
            RectF crop = WallpaperCropActivity.getMaxCropRect(
                    source.getImageWidth(), source.getImageHeight(),
                    wallpaperSize.x, wallpaperSize.y, false);
            v.setScale(wallpaperSize.x / crop.width());
            v.setTouchEnabled(false);
            a.setSystemWallpaperVisiblity(false);
        }
        @Override
        public void onSave(WallpaperPickerActivity a) {
            Log.d("dingfeng","ResourceWallpaperInfo onSave...");
            boolean finishActivityWhenDone = true;
            a.cropImageAndSetWallpaper(mResources, mResId, finishActivityWhenDone);
        }
        @Override
        public boolean isSelectable() {
            return true;
        }
        @Override
        public boolean isNamelessWallpaper() {
            return true;
        }

    实现了四个方法，后面两个返回bool值得含义之前已经说过，我们不细说。先看onClick，这个方法在点击缩略图列表是触发，看看它究竟做了什么。

    这面用到了BitmapRegionTileSource及其内部类对象，这些类定义在src\main\java\com\android\photos\目录下，自定义了图片对象，实现了滚动、缩放等功能，这里就不展开了，可以自己查看代码 。

     生成BitmapRegionTileSource对象后，设置到CropView上，然后做合适的缩放，再将系统壁纸设为不可见，这样就可以达到壁纸预览的目的。

     再看onSave方法，这个方法在点击ActionBar时调用，该方法中调用WallpaperCropActivity的cropImageAndSetWallpaper来裁剪和设置壁纸，

    protected void cropImageAndSetWallpaper(
            Resources res, int resId, final boolean finishActivityWhenDone) {
        // crop this image and scale it down to the default wallpaper size for
        // this device
        int rotation = getRotationFromExif(res, resId);
        Point inSize = mCropView.getSourceDimensions();
        Point outSize = getDefaultWallpaperSize(getResources(), getWindowManager());
        RectF crop = getMaxCropRect(inSize.x, inSize.y, outSize.x, outSize.y, false);
        Runnable onEndCrop = new Runnable() {
            public void run() {
                // Passing 0, 0 will cause launcher to revert to using the
                // default wallpaper size
                updateWallpaperDimensions(0, 0);
                if (finishActivityWhenDone) {
                    setResult(Activity.RESULT_OK);
                    finish();
                }
            }
        };
        BitmapCropTask cropTask = new BitmapCropTask(this, res, resId,
                crop, rotation, outSize.x, outSize.y, true, false, onEndCrop);
        cropTask.execute();
    }

    设置裁剪大小，将其作为参数传递给异步任务执行，

        @Override
        protected Boolean doInBackground(Void... params) {
            return cropBitmap();
        }

    最终就是cropBitmap方法来做最后的裁剪和壁纸设置操作。

    其他几种类型的壁纸也是类似的，根据壁纸来源做出相应的操作，比如第三方壁纸时，点击缩略图就是打开第三方应用；如果是图库，就打开图库，总之都是在这几个重写方法中实现的。如果以后有什么不同于目前几种类型的，也可以依此来扩展。

    

以上就介绍了 Launcher3--壁纸，包括了方面的内容，希望对Android开发有兴趣的朋友有所帮助。

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