Prevent new activity instance after clicking on no

问题:

application (non-wanted) behavior -

1. application is started, some text is put into text-box and notification is created through button action.
2. user "clicks" the home button, application is "minimized", notification is available in bar
3. user selects the notification and the application is "maximized"

BUT - instead of the original instance, new instance is started (e.g. in the newest instance is missing the original text; when the latest instance is closed there is still the original instance with original text ) .

the code of the notification method

Context context = getApplicationContext();
    CharSequence contentTitle = "someText1";
    CharSequence contentText = "someText2";
    Intent notifyIntent = new Intent(Intent.ACTION_MAIN);
    notifyIntent.setClass(getApplicationContext(), RadioStream.class);
    PendingIntent intent = 
       PendingIntent.getActivity(RadioStream.this, 0, notifyIntent, 0);

    notifyDetails.setLatestEventInfo(context, contentTitle, contentText, intent);
    mNotificationManager.notify(SIMPLE_NOTFICATION_ID, notifyDetails);

i have also in the manifest xml file following tag

android:launchMode="singleTask"

but it is still the same... The main problem is double/triple initialization of the application, i know that there are other means to preserve the values in resumed applications. Also it is needed that the applications stays running in background as the main functionality is the streaming of internet radio.

What is missing in the code ? What kind of information from my side is missing for to troubleshoot the issue ?

Thanks!

Dav

回答1:

What you refer as "application" is most probably an Activity. To avoid re-crating it when bringing up to front, use

android:launchMode="singleTop"

To have some code running background, you need to realize it as Service

回答2:

Another option is to use setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_SINGLE_TOP) on your Intent.

回答3:

add this flag to your activity properties.

android:launchMode="singleInstance"

回答4:

You can set PendingIntent.FLAG_CANCEL_CURRENT on the PendingIntent:

PendingIntent pIntent = PendingIntent.getActivity(this, 0, intent,
            PendingIntent.FLAG_CANCEL_CURRENT);

If the activity already exists,The new one will cancel and not update the old one! This works for me!

回答5:

reimplemented as service - everything works as expected

回答6:

This will bring the app back to its MainActivity even if it has opened child activities. Child activities are also cleared.

AndroidManifest:

android:launchMode="singleTop"

Code:

val intent = Intent(context, MainActivity::class.java)
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP or Intent.FLAG_ACTIVITY_SINGLE_TOP)
val pendingIntent = PendingIntent.getActivity(context, 0, intent, PendingIntent.FLAG_CANCEL_CURRENT)

回答7:

I used GCM example as base code for a personal project and I faced the same issue described on top. GCM Example: https://github.com/googlesamples/google-services/tree/master/android/gcm/app/src/main/java/gcm/play

I found a solution by combining to answers:

1) From @ognian answer, by adding to App Manifest on application section:

android:launchMode="singleTop"

<application
    android:allowBackup="true"
    android:icon="@mipmap/logo"
    android:label="@string/app_name"
    android:supportsRtl="true"
    android:theme="@style/AppTheme"
    **android:launchMode="singleInstance">**

2) From @CommonsWare by setting setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_SINGLE_TOP)

private void sendNotification(String message) {
    Intent intent = new Intent(this, MainActivity.class);
    intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP| Intent.FLAG_ACTIVITY_SINGLE_TOP);
    PendingIntent pendingIntent = PendingIntent.getActivity(this, 0 /* Request code */, intent,
            PendingIntent.FLAG_ONE_SHOT);

回答8:

It is working for me by using below combination.

1) add launch mode in Manifest file android:launchMode="singleInstance"

2) set setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_SINGLE_TOP) while creating intent.

intent = new Intent(this, StartUpActivity.class); intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP| Intent.FLAG_ACTIVITY_SINGLE_TOP);

回答9:

instead of :

notifyIntent.setClass(getApplicationContext(), RadioStream.class);
PendingIntent intent =   PendingIntent.getActivity(RadioStream.this, 0, notifyIntent, 0);

simply use these lines,it will helps you,

notifyIntent = new Intent();
PendingIntent intent= PendingIntent.getActivity(RadioStream.this, 0, notifyIntent, 0);