Java 在android中从后台启动活动或全屏意图

当有人打电话时，我必须从后台启动呼叫活动。我已经尝试过这个代码，但它不起作用。未发出通知，且不存在错误。我犯了多大的错误

Intent fullScreenIntent = new Intent(conn, IncCallActivity.class);
fullScreenIntent.putExtra("name", callerName);
fullScreenIntent.putExtra("out", false);
fullScreenIntent.putExtra("channel_id", channelId);
fullScreenIntent.putExtra("id", callerId);

PendingIntent fullScreenPendingIntent = PendingIntent.getActivity(conn, 112,fullScreenIntent, PendingIntent.FLAG_UPDATE_CURRENT);

Uri sound = Uri.parse(((AppBack) getApplication()).shared().getString("ringU", "no"));

NotificationManager notificationManager =(NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);

NotificationChannel mChannel = notificationManager.getNotificationChannel("VIDEO_CALL");
                                                
AudioAttributes attributes = new AudioAttributes.Builder().setContentType(AudioAttributes.CONTENT_TYPE_SONIFICATION)
                                                        .setUsage(AudioAttributes.USAGE_ALARM)
                                                        .build();
if (mChannel == null) {
         mChannel = new NotificationChannel("VIDEO_CALL", "VIDEO_CALL",NotificationManager.IMPORTANCE_HIGH);
         mChannel.setSound(sound, attributes);
         notificationManager.createNotificationChannel(mChannel);
}

NotificationCompat.Builder builder = new NotificationCompat.Builder(conn, " VIDEO_CALL").setSmallIcon(R.drawable.logo)
                                                        .setContentTitle("Incoming call")
                                                        .setContentText("Call from " + callFrom)
                                                        .setPriority(NotificationCompat.PRIORITY_HIGH)
                                                        .setCategory(NotificationCompat.CATEGORY_CALL)
                                                        .setContentIntent(fullScreenPendingIntent)
                                                        .setFullScreenIntent(fullScreenPendingIntent, true)
                                                        .setAutoCancel(true)
                                                        .setOngoing(true);

Notification notification = builder.build();
notificationManager.notify(120, notification); 

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我认为您应该向

AndroidManifest.xml

添加权限

设备应该被锁定