BroadcastReceiver - 无法从已关闭或后台应用启动 Activity
BroadcastReceiver - Can't start Activity from closed or in-background app
我正在尝试使用 AlarmManager 和 BroadcastReceiver 从关闭的应用程序启动 activity。 "received" 调试消息即使在应用程序关闭或处于后台时也会显示,这意味着 AlarmManager 正在按我希望的方式工作。但 CameraActivity 仅在应用程序处于活动状态时启动。
任何人都知道为什么它不起作用?这是我的(部分)代码:
主要活动:
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
...
Intent intent = new Intent(this, AlarmReceiver.class);
PendingIntent pendingIntent = PendingIntent.getBroadcast(this, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT);
AlarmManager alarmManager = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
alarmManager.setRepeating(
AlarmManager.RTC_WAKEUP,
startTimeStamp,
intervalTime,
pendingIntent);
Log.i("########################DEBUG", "started");
}
}
报警接收器
public class AlarmReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
Log.i("########################DEBUG", "received");
Intent launchIntent = new Intent(context, CameraActivity.class);
launchIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_BROUGHT_TO_FRONT);
context.startActivity(launchIntent);
/* Tried this too, didn't work
PackageManager packageManager = context.getPackageManager();
Intent launchIntent = packageManager.getLaunchIntentForPackage(CameraActivity.class.getName());
context.startActivity(launchIntent);*/
}
}
相机活动
public class CameraActivity extends AppCompatActivity {
private final int CAMERA_REQUEST = 1;
private ImageView image;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_camera);
image = findViewById(R.id.imageview);
Intent cameraIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
//startActivityForResult(cameraIntent, CAMERA_REQUEST);
}
@Override
protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
if (resultCode == RESULT_OK && requestCode == CAMERA_REQUEST) {
Bitmap photo = (Bitmap) data.getExtras().get("data");
image.setImageBitmap(photo);
}
}
}
manifest.xml
<application
...
<activity android:name=".CameraActivity">
</activity>
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<receiver android:name=".AlarmReceiver" />
</application>
提前致谢!
根据 Android 10 中的 documentation,当您的应用在后台处于 运行 时,您无法启动 activity,除非在非常有限的情况下涉及用户交互。
文档指南介绍了通知作为从后台启动活动的替代方法。然后,本指南列出了不适用限制的具体情况。它建议显示 Time-sensitive notification 以向用户提供紧急信息,而不是直接启动 activity 或全屏意图。
我正在尝试使用 AlarmManager 和 BroadcastReceiver 从关闭的应用程序启动 activity。 "received" 调试消息即使在应用程序关闭或处于后台时也会显示,这意味着 AlarmManager 正在按我希望的方式工作。但 CameraActivity 仅在应用程序处于活动状态时启动。 任何人都知道为什么它不起作用?这是我的(部分)代码:
主要活动:
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
...
Intent intent = new Intent(this, AlarmReceiver.class);
PendingIntent pendingIntent = PendingIntent.getBroadcast(this, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT);
AlarmManager alarmManager = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
alarmManager.setRepeating(
AlarmManager.RTC_WAKEUP,
startTimeStamp,
intervalTime,
pendingIntent);
Log.i("########################DEBUG", "started");
}
}
报警接收器
public class AlarmReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
Log.i("########################DEBUG", "received");
Intent launchIntent = new Intent(context, CameraActivity.class);
launchIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_BROUGHT_TO_FRONT);
context.startActivity(launchIntent);
/* Tried this too, didn't work
PackageManager packageManager = context.getPackageManager();
Intent launchIntent = packageManager.getLaunchIntentForPackage(CameraActivity.class.getName());
context.startActivity(launchIntent);*/
}
}
相机活动
public class CameraActivity extends AppCompatActivity {
private final int CAMERA_REQUEST = 1;
private ImageView image;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_camera);
image = findViewById(R.id.imageview);
Intent cameraIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
//startActivityForResult(cameraIntent, CAMERA_REQUEST);
}
@Override
protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
if (resultCode == RESULT_OK && requestCode == CAMERA_REQUEST) {
Bitmap photo = (Bitmap) data.getExtras().get("data");
image.setImageBitmap(photo);
}
}
}
manifest.xml
<application
...
<activity android:name=".CameraActivity">
</activity>
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<receiver android:name=".AlarmReceiver" />
</application>
提前致谢!
根据 Android 10 中的 documentation,当您的应用在后台处于 运行 时,您无法启动 activity,除非在非常有限的情况下涉及用户交互。
文档指南介绍了通知作为从后台启动活动的替代方法。然后,本指南列出了不适用限制的具体情况。它建议显示 Time-sensitive notification 以向用户提供紧急信息,而不是直接启动 activity 或全屏意图。