navutils

Android Navigation Utils examples

todo: Make a library that allows full dynamic control for custom intents

Android System way using manifest tags

Web Intents

Define PARENT_ACTIVITY in manifest as described here

Web Intent to test with https://applinktest.appspot.com/app-link.html?url=android-app%3A%2F%2Fca.nickadams.navutils%2Fexample%2Ftest

<activity
    android:name=".ChildActivity"
    android:label="@string/title_activity_child"
    android:parentActivityName=".MainActivity" >
    <meta-data
        android:name="android.support.PARENT_ACTIVITY"
        android:value="ca.nickadams.navutils.MainActivity" />

    <intent-filter android:label="view child">
        <action android:name="android.intent.action.VIEW" />
        <category android:name="android.intent.category.DEFAULT" />
        <category android:name="android.intent.category.BROWSABLE" />
        <!-- Accepts URIs that begin with "example://test" -->
        <data android:scheme="example"
            android:host="test" />
    </intent-filter>
</activity>

Then Override getSupportParentActivityIntent to change the intent

@Nullable
@Override
public Intent getSupportParentActivityIntent() {
    Intent intent = super.getSupportParentActivityIntent();
    if (intent != null) {
        // add clear top flag so it doesn't create new instance of parent.
        intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
    }
    return intent;
}

The Parent activity could also be defined as SingleTop and then you wouldn't need to clear top as it would be done automatically.

Note: Parent navigation does not work when starting from adb ex: adb shell am start -a android.intent.action.VIEW -d "example://test" ca.nickadams.navutils

Push Notifications

Intent for push notification handling taken from guide here

Intent activityIntent = new Intent(this, ChildActivity.class);

TaskStackBuilder stackBuilder = TaskStackBuilder.create(this);
// Adds the back stack for the Intent (but not the Intent itself)
stackBuilder.addParentStack(ChildActivity.class);
// Adds the Intent that starts the Activity to the top of the stack
stackBuilder.addNextIntent(activityIntent);

PendingIntent pendingIntent = stackBuilder.getPendingIntent(0, PendingIntent.FLAG_CANCEL_CURRENT);

How it all works

We could use finish() instead of NavUtils.NavigateUpTo(Activity sourceActivity, Intent upIntent) but that would require us to be 100% certain that the parent activity is already running. If possible it is advised to use the default impl.

The TaskStackBuilder does context.startActivities() which allows us to be able to build the correct parent stack. We could build these manually if we desired instead of using the ancestral parent navigation.

For Activities that can have multiple parents a default should be implemented as the parent in the manifest and it can be overridden in the Activity as required.