Develop Reference

Always retain a single instance of my MainActivity (launcher app)

I'm currently working on an app that is supposed to replace the devices whole UI. Therefore I'm using <category android:name="android.intent.category.HOME"/> in order to call it whenever I press the home button, replacing the devices launcher.
This app should always have just one instance of its MainActivity running and when the home button is pressed, it shouldn't start a new Activity but resume to the existing one.
I've played with the different launchModes a bit and it looks like singleInstance is by best bet. But for some reason the home button gets rendered useless and I'm unabled to return the launcher. Sporadically sometimes it works and when it works, it works just like I've intended it to be.
standard launchmode starts a new instance of the launcher whenever I press the home button, which leads to several issues, since the launcher is supposed to do some things, like opening other apps and resuming to the launcher, whenever the MainActivity is created. This leads to a loop: launcher starts apps -> resumes to launcher by creating a new Activity -> launcher starts apps...
That behaviour could be fixed somehow, but still it doesn't solve the root of its cause
singleTop does the same.
singleTask does the same.
singleInstance retains the Activity and whenever I press the home button, the launcher just resumes with its last state. BUT for some reason, the home button sometimes doesn't work. Meaning that the App won't come to the foreground. Even closing all apps doesn't return me to the launcher -> the device kind of gets bricked since you can't do anything
Edit:
Couldn't really find a solution. I'm pretty sure it's a bug on googles side. I couldn't find the cause, but I've settled with a workaround.
I've created a new activitiy called "LoadingActivity" which literally only loads the activity:
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_loading);
}
#Override
protected void onResume() {
super.onResume();
startActivity(new Intent(LoadingActivity.this,MainActivity.class));
}
The LoadingActivitys launchMode is "standard" while the "MainActivity" remains "singleInstance". This fixes everything for now. If I find a better solution in the future, I can simply delete the Activity and make the MainActivity the main activity again.
Edit2, per request, here's the manifest prior to the workaround:
<?xml version="1.0" encoding="utf-8"?>
<manifest
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
package="[package]">
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.REQUEST_DELETE_PACKAGES" />
<uses-permission android:name="android.permission.FOREGROUND_SERVICE" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.REQUEST_INSTALL_PACKAGES"/>
<uses-permission android:name="android.permission.READ_LOGS" tools:ignore="ProtectedPermissions" />
<uses-permission android:name="android.permission.PACKAGE_USAGE_STATS" tools:ignore="ProtectedPermissions" />
<application
android:allowBackup="true"
android:icon="#drawable/logo"
android:label="#string/app_name"
android:roundIcon="#drawable/logo"
android:supportsRtl="false"
android:requestLegacyExternalStorage="true"
android:theme="#style/AppTheme">
<activity
android:name="[package].MainActivity"
android:launchMode="singleInstance"
android:excludeFromRecents="true"
android:alwaysRetainTaskState="true"
android:configChanges="uiMode|fontScale">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
<category android:name="android.intent.category.HOME" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
<service android:name=".MediaServiceBrowser">
<intent-filter>
<action android:name="android.intent.action.MEDIA_BUTTON" />
<action android:name="android.media.AUDIO_BECOMING_NOISY" />
<action android:name="android.media.browse.MediaBrowserService" />
</intent-filter>
</service>
<service android:name=".LocationService" />
<service
android:name=".NotificationListener"
android:enabled="true"
android:exported="true" android:permission="android.permission.BIND_NOTIFICATION_LISTENER_SERVICE">
<intent-filter>
<action android:name="android.service.notification.NotificationListenerService" />
</intent-filter>
</service>
<provider
android:name="androidx.core.content.FileProvider"
android:authorities="${applicationId}.provider"
android:exported="false"
android:grantUriPermissions="true">
<meta-data android:name="android.support.FILE_PROVIDER_PATHS"
android:resource="#xml/provider_paths" />
</provider>
</application>
</manifest>

Android Deeplink opens application twice

i used webview to create app and implemented deep linking like this:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.ariagp.myapplication">
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:roundIcon="#mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="#style/AppTheme">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
<intent-filter>
<action android:name="android.intent.action.VIEW" />
<category android:name="android.intent.category.DEFAULT" />
<category android:name="android.intent.category.BROWSABLE" />
<data android:scheme="https" android:host="mysitename.com" />
</intent-filter>
</activity>
</application>
</manifest>
it will asking my for open with my application before open the links, but the problem is:
two applications will open in the phone task manager (the application does not open in the previous application which is running):
what is the solution?

Add android:launchMode="singleTask" in declared activity in AndroidManifest.xml.
And then, in your activity, you should override onNewIntent() method and you will get arguments there.

Ok, so you don't actually have a problem here.
This is just how deep links work. If you open one in a certain app, the deep link will open your app but in the same window the deep link was originally in.
Your app will have two instances in a way.
You could go to you web brower app and click share and any app that pops up. They all open in the web browsing app window. So there is nothing to worry about. I had the same problem myself before I realised that it is just how things work.
Some apps are just verified to open other apps if they implement the browsability.

Add android:launchMode="singleTask" in declared activity in AndroidManifest.xml.
And then, in your activity, you should override onNewIntent() method and call mNavController.handleDeepLink(intent) there.
It is worth mentioning that you are now able to get your arguments using, private val args: XFragmentArgs by navArgs()in your fragment.

OneSignal Android not launching app with custom onNotificationOpened handler

I am attempting to migrate an app from Parse to OneSignal. Things have been running fairly smooth except for one issue. If the app has not already been started, clicking (opening) the notification does not launch the app and bring it to the foreground.
I am using a custom onNotificationOpenedHandler:
Main Activity, onCreate
// Init OneSignal
OneSignal.startInit(this).setNotificationOpenedHandler(new NotificationOpenHandler()).init();
NotificationOpenedHandler, also in the launcher Main Activity:
class NotificationOpenHandler implements OneSignal.NotificationOpenedHandler {
// This fires when a notification is opened by tapping on it.
#Override
public void notificationOpened(OSNotificationOpenResult result) {
JSONObject data = result.notification.payload.additionalData;
String stationName = data.optString("stationName");
String timestamp = data.optString("timestamp");
String filename = data.optString("filename");
String url = getString(R.string.callResourceUrl) + filename;
Log.d("APP", "Notification clicked");
Intent intent = new Intent(getApplicationContext(), CallActivity.class);
intent.putExtra("stationName", stationName);
intent.putExtra("time", timestamp);
intent.putExtra("url", url);
intent.setFlags(Intent.FLAG_ACTIVITY_REORDER_TO_FRONT | Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent);
}
}
Here is my Android Manifest file:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.opheliadesign.tevfd">
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.WAKE_LOCK" />
<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
<application
android:supportsRtl="true"
android:allowBackup="true"
android:icon="#drawable/icon"
android:label="#string/app_name"
android:logo="#drawable/ic_launcher"
android:launchMode="singleInstance"
android:theme="#style/Theme.Tevfd">
<activity android:name="com.example.app.MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name=".CallActivity"
android:label="#string/title_activity_call"
android:parentActivityName=".MainActivity"
android:screenOrientation="portrait" >
<meta-data
android:name="android.support.PARENT_ACTIVITY"
android:value="com.example.app.MainActivity" />
</activity>
<meta-data android:name="com.onesignal.NotificationOpened.DEFAULT" android:value="DISABLE" />
</application>
</manifest>
Any ideas?
UPDATE
Previously, using Parse, I utilized a BroadcastReceiver with a PendingIntent. It seems a bit unclear how to accomplish this with OneSignal as so much seems to be configured automatically.
If I remove the custom Intent, the application comes to the foreground.
Any help would be greatly appreciated.

Linking Activities Using Intents (Android Beginner)

I'm beginning to learn Android and have been reading the "Beginning Android 4 Application Development." (As well as downloading the relevant source code)..
However; I have been trying to create a very simple slideshow with a button labelled "Gallery" which will take me to a new Activity that will show a grid like layout for my photos. However, my application does not do this. When the button is pressed it either crashes the app or refuses to do anything at all.
Manifest
<uses-sdk
android:minSdkVersion="14"
android:targetSdkVersion="21" />
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name=".MainActivity"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:label="Viwer"
android:name=".Viwer" >
<intent-filter >
<action android:name="com.example.viwer.Gallery" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
</application>
</manifest>
Any help would be greatly appreciated, I assume it's something simple but after looking at it for three hours I can't see what it is.

You need to add the Gallery activity to the Android Manifest
<activity
android:name=".Gallery"
android:label="Gallery"></activity>

In your manifest you register viewer activity in an intent-filter yet is not declare as a broadcast receiver.
Second event if it was a broadcast receiver it will never launch as you do not send any broadcast by calling startActivity
i think that what your trying to achieve is this:
Please try this:
ebutton.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
Intent intent = new Intent(MainActivity.this,Viwer.calss )
startActivity(intent);
}
});

GCM Android Client Not Firing WakefulService?

I have literally followed the examples for implementing GCM inside an android app and the app is receiving the messages using the following code:
public class GcmBroadcastReceiver extends WakefulBroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
// Explicitly specify that GcmIntentService will handle the intent.
ComponentName comp;
comp = new ComponentName(context.getPackageName(), GcmIntentService.class.getName());
// Start the service, keeping the device awake while it is launching.
startWakefulService(context, (intent.setComponent(comp)));
setResultCode(Activity.RESULT_OK);
}
}
The problem is that the GcmIntentService (public class GcmIntentService extends IntentService) is never being run? Am I missing something or should it usually fire the onHandleIntent method?
In case in any way related the Manifest file is below, thanks in advance:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.diversivi.test"
android:versionCode="1"
android:versionName="1.0">
<uses-sdk
android:minSdkVersion="16"
android:targetSdkVersion="19"/>
<application
android:label="#string/app_name"
android:icon="#drawable/ic_launcher">
<meta-data android:name="com.google.android.gms.version" android:value="#integer/google_play_services_version" />
<activity
android:name=".DemoActivity"
android:label="#string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN"/>
<category android:name="android.intent.category.LAUNCHER"/>
</intent-filter>
</activity>
<receiver
android:name=".GcmBroadcastReceiver"
android:permission="com.google.android.c2dm.permission.SEND" >
<intent-filter>
<action android:name="com.google.android.c2dm.intent.RECEIVE" />
<category android:name="com.diversivi.test" />
</intent-filter>
</receiver>
</application>
<uses-permission android:name="android.permission.SEND_SMS"/>
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.GET_ACCOUNTS" />
<uses-permission android:name="android.permission.WAKE_LOCK" />
<uses-permission android:name="com.google.android.c2dm.permission.RECEIVE" />
<permission android:name="com.diversivi.test.permission.C2D_MESSAGE" android:protectionLevel="signature" />
<uses-permission android:name="com.diversivi.test.permission.C2D_MESSAGE" />
</manifest>

I don't see your GcmIntentService service declared in the manifest. That could be the problem.
In addition, the following line
comp = new ComponentName(context.getPackageName(), GcmIntentService.class.getName());
assumes that the GcmIntentService class is in the main package of your app (i.e. its full name is com.diversivi.test.GcmIntentService). If that's not the case, the broadcast receiver can't find the service class.