Transparent Activity opening independently - android

I want to create a activity with transparent background that I can start by clicking on a Notification.
I created the notification and the activity with no problem, but now, I want to open this particular TransparentActivity independently i.e. without showing the other activities on the background.
I tried to put some flags on the intent:
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_SINGLE_TOP | Intent.FLAG_ACTIVITY_CLEAR_WHEN_TASK_RESET);
and on the AndroidManifest file, on my TransparentActivity tag, I put:
<activity
android:name=".TransparentActivity"
android:launchMode="singleTask"
android:theme="#style/Theme.Transparent">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
It works as expected, but now I have two icons for my app, which is something I don't want.
Is there a way to make it work?

Easiest way to do this is to change the taskAffinity for this Activity in the manifest. Add:
android:taskAffinity=""
to the <activity> declaration for this oneActivity`.
This one Activity will then be launched into a new task, and not into the task that runs the rest of your application.

Related

Difference between launching app from recents and home screen

I have ActivityA as launcher activity.
From ActivityA I open -> ActivityB. I put the app in background.
When I open the app from recents the app is resumed with ActivityB.
When I open the app from homescreen, the app is resumed with ActivityA without calling onCreate(), just onResume().
Why is ActivityB cleared from stack when I open the app from homescreen, even if onCreate() from ActivityA is never called, and how to fix this?
Manifest file looks like this:
ActivityA:
<activity-alias
android:name=".Launcher"
android:label="#string/app_name"
android:targetActivity="path.ActivityA">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity-alias>
<activity
android:name=".path.ActivityA"
android:launchMode="singleTask"
android:screenOrientation="sensorPortrait"
android:theme="#style/BlackIntroTheme"
android:windowSoftInputMode="adjustPan">
<nav-graph android:value="#navigation/graph1" />
<nav-graph android:value="#navigation/graph2" />
<nav-graph android:value="#navigation/graph3" />
<nav-graph android:value="#navigation/graph4" />
</activity>
ActivityB:
<activity
android:name=".path.ActivityB"
android:launchMode="singleTask"
android:screenOrientation="sensorPortrait"
android:windowSoftInputMode="adjustPan" />
this is how Activity stacking works, some nice example of all launchModes in HERE, more complex info in DOCs
in short - Activity with singleTask started (again) will clear all on-top-of-it Activities. you have your first MAIN Activity declared with this launchMode, so every icon click on devices launcher will clear your Activities stack. you can track this by overriding onNewIntent method. picking from recents just brings all your Activities stack to front, with last opened on top ofc.
consider removing launchMode (is this necessary line for you?) or set it as standard (default)
android:launchMode="standard"

Setting navigation drawer activity as main activity when app start

I have made a navigation drawer with six activities but the thing is i want to make one of these six activities as my main activity so that everytime i open the app it will be shown as my main activity
You have to use intent filter in your manifest file to add your preferred activity as a launcher activity.
Open your manifest file and use intent filter in that activity which you want to make as a launcher activity
<activity android:name=".Your_Activity_Name">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>

Android launchMode="singleTask" and Intent-filters

So I have an Activity A that is defined in the AndroidManifest.xml as defined below:
<activity
android:name=".activity.A"
android:screenOrientation="landscape"
android:windowSoftInputMode="stateAlwaysHidden"
android:launchMode="singleTask">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
This Activity launches a welcome Screen which we will call Activity B.
If you launch the application the Welcome screen is displayed and then once the user is done with it Activity A comes back.
The issue I am having is when I push the "Home" button from the welcome screen I go back to the Home Screen as expected. Now when I reclick on the Application Icon the application won't launch. Instead both my Activity A & B get destroyed. If I click on the icon again then the application relaunches as expected.
Now if I'm on the welcome screen and push the back arrow and reclick on the App icon it launches the application as expected. I don't have to push it twice.
Unfortunately I have to use the launchMode="singleTask" since it is a requirement for integration with another team. I have read the Android API's for Tasks and Back Stacks numerous times. Any pointers or suggestions would be greatly appreciated.
I came across a blog indicating there is an undocumented bug with using singleTask and intent-filters together but didn't find any official documentation on this.
Thanks
EDIT
Launching Activity B like this:
Intent intent = new Intent(context, B.class);
startActivityForResult(intent, CONST_VAR);
I tried making two activities which launches ActivityB from Activity A. I see no such problem as described in the question. PFB my manifest. Also, when you say home button, is it Phone home button or your app specific home button. PFB my manifest
<activity
android:name="com.android.testsingletask.MainActivity"
android:launchMode="singleTask"
android:screenOrientation="landscape"
android:windowSoftInputMode="stateAlwaysHidden"
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:name="com.android.testsingletask.WelcomeActivity"
android:screenOrientation="landscape"
android:windowSoftInputMode="stateAlwaysHidden"
android:label="#string/app_name" >
</activity>

Purpose of using CATEGORY_HOME in android manifest?

What is the alternative to removing the following from AndroidManifest:
<activity
android:name="com.apper.main.UserActivity"
android:label="#string/app_name"
android:launchMode="singleTask"
android:clearTaskOnLaunch="true"
android:stateNotNeeded="true" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.HOME"/>
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
I also found that after removing the above line, there was no impact to my android
application. What's the main use of this category and what's the alternative to it.
If the intent of this category is to launch the home screen then it can be done by the following:
Intent homeIntent= new Intent(Intent.ACTION_MAIN);
homeIntent.addCategory(Intent.CATEGORY_HOME);
homeIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(homeIntent);
This above code will launch the home screen but why the line in the android manifest ?
What's the purpose as removing the line from here does nothing change the application ?
What's the main use of this category
It, coupled with ACTION_MAIN, identifies a replacement home screen.
what's the alternative to it
Not having it. Either you have this category, or you do not.
The category HOME is used to declare your application as a Home launcher. By putting this in the manifest then user will have the option to have your application open upon pressing the home button.
This is typically used when creating an application that will be used in a kiosk mode.
I do not believe there is an alternative to make an application a home launcher.
Documentation

How to add flags to an APPWIDGET_CONFIGURE intent?

I have an activity registered on APPWIDGET_CONFIGURE:
<activity android:name="com.tahanot.activities.NearbyStops">
<intent-filter>
<action android:name="android.appwidget.action.APPWIDGET_CONFIGURE" />
</intent-filter>
</activity>
However this activity does not behave as expected. It opens inside of an existing stack, and when I press the Back button, it takes me to other activities instead of closing the task. Ideally, I would like the APPWIDGET_CONFIGURE intent to include FLAG_ACTIVITY_NEW_TASK and FLAG_ACTIVITY_MULTIPLE_TASK.
Is it possible to specify flags in AndroidManifest.xml, and if not, what workaround would you suggest?
Consider specifying launchMode attribute to the activity element.
<activity android:launchMode="singleTask" android:name="com.tahanot.activities.NearbyStops">
<intent-filter>
<action android:name="android.appwidget.action.APPWIDGET_CONFIGURE" />
</intent-filter>
</activity>
As per the official docs,
FLAG_ACTIVITY_NEW_TASK
Start the activity in a new task. If a task is already running for
the activity you are now starting, that task is brought to the
foreground with its last state restored and the activity receives the
new intent in onNewIntent().
This produces the same behavior as the "singleTask" launchMode value,
discussed in the previous section.
Since you mention you want FLAG_ACTIVITY_NEW_TASK behavior so singleTask launchMode might work for you.
USe this java code when you start your activity
Intent intent = new Intent(this,
activityname.class);
intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent);
Here you can add flag with your intent object like this.
And you can also add multiple flag.
This is the manifest declaration that I used, following appsroxcom's idea for android:launchMode:
<activity
android:name="com.tahanot.activities.NearbyStops"
android:configChanges="orientation"
android:label="#string/title_activity_stops_nearby"
android:launchMode="singleTop"
android:taskAffinity="com.tahanot.tasks.widgetConfiguration" >
<!-- android:launchMode makes sure the Back button doesn't navigate to another NearbyStops activity.
android:taskAffinity makes sure the Back button doesn't navigate to some other activity. -->
<intent-filter>
<action android:name="android.appwidget.action.APPWIDGET_CONFIGURE" />
</intent-filter>
</activity>

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