In my application there is a behavior that I don't understand. I have the MainActivity A as SingleTask.
It calls an Activity B that is SingleTask too.
When I press the Home button in the second activity to open another application, and after that I try to go to my application mantaining Home button pressed i always go to Main Activity, and I want second activity to be opened mantaining the state that had when i press Home button.
I've tried setting then second activity to singleTop and it doesn't work.
Any help?
The behaviour of activity back stack becomes quit weird when define main activity with singleTask at the same time:
<activity android:name=".MainActivity"
android:launchMode="singleTask">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
What even worse is there is no clear explanation in the official dev guide regarding to this special use case. Some sections related to this topic are even self-contradictory.
Try using launchMode="standard" on your MainActivity A, and launchMode="singleTask" on your Activity B, which will give the expect behaviour you described.
Related
The following situation:
app is started from a deep link (sms) and launches the MainActivity
user presses the start button in the app which opens SecondActivity
app goes into background
user presses on app icon again in launcher => HERE I EXPECT the SecondActivity be still active. But instead, MainActivity is relaunched.
Tried with "singleTop" activity mode - no difference.
SecondActivity is launched from MainActivity without any special intent flags, plain startActivity()
<activity
android:name=".MainActivity"
android:label="#string/app_name"
android:screenOrientation="portrait"
android:alwaysRetainTaskState="true"
android:launchMode="singleTop"
android:windowSoftInputMode="adjustResize">
<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”/>
It turned out there are two reasons:
Starting app from deep link created separate instance of the app => solved by specifying "singleTask"
The SecondActivity was destroyed at some point, which explains why starting the app again from icon will bring MainActivity screen
Thanks all commenters for helpful hints!
When starting the secondActivity you can just call finish() in the firstActivity (for example in onPause() or buttonClick() firstActivity). In this way, your app is still running (i.e secondActivity). When you launch the app the secondActivity should run directly (if the app is not totally destroyed yet).
I have an app that acts as a Launcher. This app has 3 activities:
SplashActivity: shows a splash screen while loading, then launches LauncherActivity and finishes. This is the Activity marked as launcher in the manifest.
startActivity(Intent(this, LauncherActivity::class.java))
finish()
<activity
android:name=".SplashActivity"
android:label="#string/app_name"
android:screenOrientation="landscape"
android:theme="#style/SplashTheme">
<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>
LauncherActivity: main activity for Launcher. Has a menu button that launches DashboardActivity.
startActivity(Intent(this#LauncherActivity, DashboardActivity::class.java))
<activity
android:name=".LauncherActivity"
android:launchMode="singleTask"
android:screenOrientation="landscape" />
DashboardActivity: shows a list of apps and launches them through their launch intent.
private val DEFAULT_FLAGS_APP_LAUNCH = Intent.FLAG_ACTIVITY_CLEAR_TOP or Intent.FLAG_ACTIVITY_NEW_TASK or Intent.FLAG_ACTIVITY_CLEAR_TASK
startActivity(packageManager.getLaunchIntentForPackage(packageInfo.packageName).apply {
flags = DEFAULT_FLAGS_APP_LAUNCH
})
<activity
android:label="#string/apps"
android:theme="#style/TNA"
android:name=".DashboardActivity"
android:launchMode="singleTask"
android:screenOrientation="landscape" />
All activities are launched through startActivity, including the apps.
I want the standard Android Launcher behavior, that is: when entering an app through DashboardActivity, if I click home button, go to the main Launcher activity (LauncherActivity), and when clicking back, go to the dashboard (DashboardActivity).
The problem I have is that when clicking home, it goes back to DashboardActivity, not to LauncherActivity. If I finish DashboardActivity, then when clicking back on an app, it goes back to LauncherActivity.
Any ideas on how to solve this?
This is definitely back/task stack related. See this link for more information about the task stack.
When you go from LauncherActivity to DashboardActivity, the dashboard is placed on to the task stack. When the LauncherActivity is requested again via the HOME button, the task stack is restored back to the last Activity which was in use after launching the LauncherActivity, which was DashboardActivity.
You have several different options to resolve this:
Don't use a separate Activity for the "dashboard". Consider a drawer or even a Fragment which shows the content and can be popped back to the main LauncherActivity when it is done calling startActivity to launch another app.
After your DashboardActivity calls startActivity, it should call finish() so it will get popped off the current task stack.
Usually launchers are setup to be launched in singleInstance mode, preventing multiple instances of the launcher Activity to run at the same time. Note that you'll need to support onNewIntent in your LauncherActivity.
To prevent odd interactions with the task manager, consider setting FLAG_ACTIVITY_NO_HISTORY when launcher your DashboardActivity.
I want to know what is the differences between the back and up actions.
I've already found online how they work, but I didn't find what different happens when I trigger them.
When I intent another activity and go back with up action, it seems to just show again my last activity without executing any method (my images show like it was cached).
When I intent another activity and go back with back action, it seems to reconstruct the entire layout (my images reloads).
What really happens?
Thanks.
First you must understand the concept of Up and Back navigation, you should read this link about Navigation with UP and Back
When pressed back button the actual screen is removed but when pressed up button relaunch the parent-activity.
In your manifest need to add propert launchMode of activity, something like this
<activity
android:name="com.example.client.app.MainActivity"
android:label="#string/app_name"
android:launchMode="singleInstance"
android:screenOrientation="portrait" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
I hope you serve.
I have created an app widget which, when clicked, launches an Activity in my application.
The activity it launches is NOT the main launcher activity (as set in the application manifest).
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
The activity I'm launching has launchMode="singleTop" (may be relevant)
If I launch the app from the app launcher, then press home and then the recent apps button, the app is there.
I then remove the app from recent activities list or force close it.
If I then click on my widget, the activity launches fine.
I then press Home and then the app does not appear in the list of recent apps.
Any ideas?
My activity was defined with flag android:excludeFromRecents="true" in the Manifest.
Silly me, should've spotted that earlier.
Removing that flag fixes the problem.
I have the following problem:
When I press the Android HOME key, I can see the "Desktop" and my app icon. Then I press my app icon and my application launches twice. I don't want open my app twice.
How my program works:
I have 4 Activities (A, B, C, D).
A - The Main Activity: It is the first to open. It opens the other activity that has a lot of buttons. It's like a Java's main() method. I show a SplashScreen and I call another Activity. Then I finish my activity "A".
B - The Menu Screen: In this activity, I have some buttons, like a menu. I have a configuration button, update button, and Login Button. When I click the login button, I finish this activity and open the Login Screen (Activity "C").
C - The Login Screen: The user writes the Login and Password. If the login is successful, I finish this activity and open the Activity "D".
D - The application main screen: It stays opened all the time and launches another Activities. I finish this when I want close my application.
P.S.: I tried change the launchMode flag (androidManifest.xml), but didn't work.
My AndroidManifest.xml bellow:
<application android:label="#string/app_name" android:icon="#drawable/icon" android:name="MyApplication">
<activity android:name="A"
android:label="#string/app_name"
android:configChanges="orientation">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name="br.com.site.B" android:label="#string/app_name" />
<activity android:name="br.com.site.C" android:label="#string/app_name" />
<activity android:name="br.com.site.D" android:label="#string/app_name" />
</application>
And this is my Activity "A.java" source:
public class A extends Activity {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
finish();
startActivity(new Intent(this, AtualizaDadosFrame.class));
}
}
I don't want open my app twice.
Thanks in advance!
I'm going to assume that you started the app initially (the first time) from an IDE (like Eclipse or IntelliJ). If so, this is a known bug in Android (see http://code.google.com/p/android/issues/detail?id=26658 ). Many people have struggled for days chasing this problem :-(
Please don't change the launchMode. This is not the correct way to solve this problem. The default (standard) launchMode is the one that works in most cases.
EDIT (Added link to workaround):
A simple workaround for this problem can be found at http://code.google.com/p/android/issues/detail?id=2373#c21
You should set the desired launch mode in your AndroidManifest.xml.
You can restrict this.....
Please go through below link.
Home key press behaviour