Android 12系统源码_系统壁纸（二）动态壁纸的设置流程

动态壁纸的设置流程

1、通过调用WallpaperManager的setWallpaperComponent方法可以帮我们开启自定义动态壁纸。

frameworks/base/core/java/android/app/WallpaperManager.java

public class WallpaperManager {

    @SystemApi
    @RequiresPermission(android.Manifest.permission.SET_WALLPAPER_COMPONENT)
    public boolean setWallpaperComponent(ComponentName name) {
        return setWallpaperComponent(name, mContext.getUserId());
    }

    @RequiresPermission(android.Manifest.permission.SET_WALLPAPER_COMPONENT)
    @UnsupportedAppUsage
    public boolean setWallpaperComponent(ComponentName name, int userId) {
        if (sGlobals.mService == null) {
            Log.w(TAG, "WallpaperService not running");
            throw new RuntimeException(new DeadSystemException());
        }
        try {
        	//通过binder调用WallpaperManagerService的setWallpaperComponentChecked方法
            sGlobals.mService.setWallpaperComponentChecked(name, mContext.getOpPackageName(),
                    userId);
            return true;
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }
    private static class Globals extends IWallpaperManagerCallback.Stub {
     	private final IWallpaperManager mService;//WallpaperManagerService的binder代理对象
    }
}

类型为Globals的sGlobals对象，内部属性mService是一个代理者，setWallpaperComponent最终会调用WallpaperManagerService的setWallpaperComponentChecked方法。

2、WallpaperManagerService的setWallpaperComponentChecked方法如下所示。

frameworks/base/core/java/android/app/WallpaperManager.java

public class WallpaperManagerService extends IWallpaperManager.Stub
        implements IWallpaperManagerService {
        
    @Override
    public void setWallpaperComponentChecked(ComponentName name, String callingPackage,
            int userId) {
        //权限验证
        if (isWallpaperSupported(callingPackage) && isSetWallpaperAllowed(callingPackage)) {
            setWallpaperComponent(name, userId);
        }
    }
    
    //设置动态壁纸
    private void setWallpaperComponent(ComponentName name, int userId) {
        userId = ActivityManager.handleIncomingUser(getCallingPid(), getCallingUid(), userId,
                false /* all */, true /* full */, "changing live wallpaper", null /* pkg */);
        //权限检测
        checkPermission(android.Manifest.permission.SET_WALLPAPER_COMPONENT);

        int which = FLAG_SYSTEM;
        boolean shouldNotifyColors = false;
        WallpaperData wallpaper;//壁纸数据

        synchronized (mLock) {
            Slog.v(TAG, "setWallpaperComponent name=" + name);
            wallpaper = mWallpaperMap.get(userId);
            if (wallpaper == null) {
                throw new IllegalStateException("Wallpaper not yet initialized for user " + userId);
            }
            final long ident = Binder.clearCallingIdentity();

            // Live wallpapers can't be specified for keyguard.  If we're using a static
            // system+lock image currently, migrate the system wallpaper to be a lock-only
            // image as part of making a different live component active as the system
            // wallpaper.
            if (mImageWallpaper.equals(wallpaper.wallpaperComponent)) {
                if (mLockWallpaperMap.get(userId) == null) {
                    // We're using the static imagery and there is no lock-specific image in place,
                    // therefore it's a shared system+lock image that we need to migrate.
                    Slog.i(TAG, "Migrating current wallpaper to be lock-only before"
                            + "updating system wallpaper");
                    migrateSystemToLockWallpaperLocked(userId);
                }
            }

            // New live wallpaper is also a lock wallpaper if nothing is set
            if (mLockWallpaperMap.get(userId) == null) {
                which |= FLAG_LOCK;
            }

            try {
                wallpaper.imageWallpaperPending = false;
                boolean same = changingToSame(name, wallpaper);
                //启动新壁纸的WallpaperService
                if (bindWallpaperComponentLocked(name, false, true, wallpaper, null)) {
                    if (!same) {
                        wallpaper.primaryColors = null;
                    } else {
                        if (wallpaper.connection != null) {
                            wallpaper.connection.forEachDisplayConnector(displayConnector -> {
                                try {
                                    if (displayConnector.mEngine != null) {
                                        displayConnector.mEngine.dispatchWallpaperCommand(
                                                COMMAND_REAPPLY, 0, 0, 0, null);
                                    }
                                } catch (RemoteException e) {
                                    Slog.w(TAG, "Error sending apply message to wallpaper", e);
                                }
                            });
                        }
                    }
                    wallpaper.wallpaperId = makeWallpaperIdLocked();
                    notifyCallbacksLocked(wallpaper);
                    shouldNotifyColors = true;
                }
            } finally {
                Binder.restoreCallingIdentity(ident);
            }
        }

        if (shouldNotifyColors) {
            notifyWallpaperColorsChanged(wallpaper, which);
            notifyWallpaperColorsChanged(mFallbackWallpaper, FLAG_SYSTEM);
        }
    }
}

参考文章：https://www.kancloud.cn/wizardforcel/deepin-android-vol3/122360
https://www.freesion.com/article/6656482862/