AndroidQ版本官方限制了對屏幕內容的訪問。
爲了保護用戶的屏幕內容,Android 10 更改了 READ_FRAME_BUFFER、CAPTURE_VIDEO_OUTPUT 和 CAPTURE_SECURE_VIDEO_OUTPUT 權限的作用域,從而禁止以靜默方式訪問設備的屏幕內容。從 Android 10 開始,這些權限只能通過簽名訪問。
需要訪問設備屏幕內容的應用應使用 MediaProjection API,此 API 會顯示提示,要求用戶同意訪問。
如果還使用之前的邏輯訪問屏幕內容的話,會報如下錯誤:
java.lang.SecurityException: Media projections require a foreground service of type ServiceInfo.FOREGROUND_SERVICE_TYPE_MEDIA_PROJECTION
那麼如何獲取屏幕內容呢?你需要以下幾步。
1、請求用戶授權
this.projectionManager = (MediaProjectionManager)activity.getSystemService(Context.MEDIA_PROJECTION_SERVICE);
activity.startActivityForResult(this.projectionManager.createScreenCaptureIntent(), 1000);
執行上面的代碼,會彈出系統的提示用戶彈框,選擇“立即開始”或者“取消”後,會在onActivityResult中進行回調。
2、新建一個CaptureScreenService
@RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
public class CaptureScreenService extends Service {
private int mResultCode;
private Intent mResultData;
private MediaProjectionManager projectionManager;
private MediaProjection mMediaProjection;
@Nullable
@Override
public IBinder onBind(Intent intent) {
return null;
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
createNotificationChannel();
mResultCode = intent.getIntExtra("code", -1);
mResultData = intent.getParcelableExtra("data");
this.projectionManager = (MediaProjectionManager)getSystemService(Context.MEDIA_PROJECTION_SERVICE);
mMediaProjection = projectionManager.getMediaProjection(mResultCode, Objects.requireNonNull(mResultData));
ScreenCaptureManager.getInstance().start(mMediaProjection);
return super.onStartCommand(intent, flags, startId);
}
private void createNotificationChannel() {
Notification.Builder builder = new Notification.Builder(this.getApplicationContext()); //獲取一個Notification構造器
Intent nfIntent = new Intent(this, MainActivity.class); //點擊後跳轉的界面,可以設置跳轉數據
builder.setContentIntent(PendingIntent.getActivity(this, 0, nfIntent, 0)) // 設置PendingIntent
.setLargeIcon(BitmapFactory.decodeResource(this.getResources(), R.mipmap.ic_launcher)) // 設置下拉列表中的圖標(大圖標)
//.setContentTitle("SMI InstantView") // 設置下拉列表裏的標題
.setSmallIcon(R.mipmap.ic_launcher) // 設置狀態欄內的小圖標
.setContentText("is running......") // 設置上下文內容
.setWhen(System.currentTimeMillis()); // 設置該通知發生的時間
/*以下是對Android 8.0的適配*/
//普通notification適配
if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
builder.setChannelId("notification_id");
}
//前臺服務notification適配
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
NotificationManager notificationManager = (NotificationManager)getSystemService(NOTIFICATION_SERVICE);
NotificationChannel channel = new NotificationChannel("notification_id", "notification_name", NotificationManager.IMPORTANCE_LOW);
notificationManager.createNotificationChannel(channel);
}
Notification notification = builder.build(); // 獲取構建好的Notification
notification.defaults = Notification.DEFAULT_SOUND; //設置爲默認的聲音
startForeground(110, notification);
}
@Override
public void onDestroy() {
super.onDestroy();
stopForeground(true);
}
}
3、註冊CaptureScreenService,並添加foregroundServiceType屬性。
<service android:name=".CaptureScreenService"
android:enabled="true"
android:foregroundServiceType="mediaProjection"/>
4、在activity的onActivityResult中啓動前臺服務
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if(resultCode == RESULT_OK && requestCode == 1000) {
//判斷系統版本選擇不同處理方法
if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
//啓動前臺服務
service = new Intent(this, CaptureScreenService.class);
service.putExtra("code", resultCode);
service.putExtra("data", data);
startForegroundService(service);
}else {
ScreenCaptureManager.getInstance().start(resultCode, data);
}
}
}
5、在CaptureScreenService的onStartCommand執行訪問屏幕內容的邏輯。
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
createNotificationChannel();
mResultCode = intent.getIntExtra("code", -1);
mResultData = intent.getParcelableExtra("data");
this.projectionManager = (MediaProjectionManager)getSystemService(Context.MEDIA_PROJECTION_SERVICE);
mMediaProjection = projectionManager.getMediaProjection(mResultCode, Objects.requireNonNull(mResultData));
ScreenCaptureManager.getInstance().start(mMediaProjection);
return super.onStartCommand(intent, flags, startId);
}
需要在前臺服務啓動後5s內調用startForeground方法,否則也會報錯。
所以先執行createNotificationChannel(),啓動startForeground。
獲取屏幕內容的邏輯封裝在ScreenCaptureManager內,如下:
public void start(MediaProjection mediaProjection) {
this.mediaProjection = mediaProjection;
if (this.projectionManager != null) {
this.initVirtualDisplay(this.activity);
this.mediaProjection.registerCallback(new ScreenCaptureManager.MediaProjectionStopCallback(), (Handler)null);
}
}
public void initVirtualDisplay(Activity activity) {
DisplayMetrics metrics = activity.getResources().getDisplayMetrics();
int density = metrics.densityDpi;
Point size = new Point();
activity.getWindowManager().getDefaultDisplay().getRealSize(size);
int width = size.x;
int height = size.y;
this.imageReader = ImageReader.newInstance(width, height, 1, 1);
this.imageReader.setOnImageAvailableListener(new ScreenCaptureManager.ImageAvailableListener(), (Handler)null);
String virtualDisplayName = "Screenshot";
int flags = 9;
this.virtualDisplay = this.mediaProjection.createVirtualDisplay(virtualDisplayName, width, height, density, flags, this.imageReader.getSurface(), (VirtualDisplay.Callback)null, (Handler)null);
}
在ScreenCaptureManager.ImageAvailableListener()的onImageAvailable(ImageReader reader)就可以拿到屏幕的bitmap信息了。
6、記得關閉服務。
//這是CaptureScreenService的onDestroy()方法
@Override
public void onDestroy() {
super.onDestroy();
stopForeground(true);
}
stopForeground中的參數表示:是否移除之前的通知。
//這是activity的onDestroy()
@Override
protected void onDestroy() {
super.onDestroy();
//停止獲取屏幕內容
ScreenCaptureManager.getInstance().stop();
//關閉服務
Intent service = new Intent(this, CaptureScreenService.class);
stopService(service);
}
7、記得加上FOREGROUND_SERVICE權限。
<uses-permission android:name="android.permission.FOREGROUND_SERVICE"/>
8、compileSdkVersion設置爲29,否則manifest中沒有foregroundServiceType屬性。
至此你就可以愉快的使用屏幕內容了!
demo地址:限制對屏幕內容的訪問。
參考文章:
MediaProjections in Android Q
Android Foreground Service (前臺服務)
官方文檔