检查应用程序是否正在运行（后台或前台）Android

Question

I have created a BroadCastReceiver for SMS and I want it to work only when the application is running (either in forgeground or background) . The current code im using is :

public class BroadCastReceiver extends BroadcastReceiver 
{

    public void onReceive(Context context, Intent intent)
    {

        ActivityManager am = (ActivityManager) context
                .getSystemService(Activity.ACTIVITY_SERVICE);
        String packageName = am.getRunningTasks(1).get(0).topActivity
                .getPackageName();

    if(packageName.contains("com.example.sms") )
     {
        abortBroadcast();

     }else
     {

      }

     }
    }

But the problem is this code only works in foreground , so when the user hits back button or home button the application will work in background but the BroadCastReceiver will not work . So is there's any method to solve this issue ?? &Thanks in advance

Answer 1

If you only want to run a broadcast when your app is running, then you only have to register the broadcast when the app is running.

public class BroadCastReceiver extends BroadcastReceiver {
    public void onReceive(Context context, Intent intent) {
        /** SMS received while app was running. Do whatever */
    }
}

public class MainActivity extends Activity {

  private BroadCastReceiver mBroadcastReceiver = new BroadCastReceiver();

  @Override
  public void onStart() {
    super.onStart();
    registerReceiver(myBroadcastReciever, new IntentFilter(Telephony.Sms.Intents.SMS_RECEIVED_ACTION);
  }

  @Override
  public void onStop() {
    super.onStop();
    unregisterReceiver(myBroadcastReceiver);
  }
}

The broadcast receiver will only receive broadcasts when your app is running. No need to check running processes. You can move them to onResume()/onPause() if you only want to receive broadcasts when the app is visible to users. You can (un)register in onCreate()/onDestroy() if you want to start receiving broadcasts as soon as possible. You can do the same thing in a Service with its respective callbacks.

Answer 2

You can run ps and check output for your package name

try {
    Process process = Runtime.getRuntime().exec("ps | grep \""+myPackageName+"\"");

    BufferedReader reader = new BufferedReader(new InputStreamReader(process.getInputStream()));
    int bytes;
    char[] buffer = new char[4096];
    StringBuffer output = new StringBuffer();
    while ((bytes = reader.read(buffer)) > 0) {
        output.append(buffer, 0, bytes);
    }
    reader.close();
    process.waitFor();

    return output.toString().length()>1;
} catch (Exception e) {
}