How to implement an app without activity? [duplicate] - android

This question already has answers here:
Closed 10 years ago.
Possible Duplicate:
Start android application without activity
I want to do a download tool for other apps. It would always run in background. All code in service. So no need for a UI. How do I do this?

You can still have an Activity just don't declare an intent-filter in your manifest, that way the user can never start your app from the menu and therefore never see the Activity unless you choose to show it. Going further you could make the Activity theme Transparent as well so that if it is brought to the front it doesn't show anything.
The kind of examples to look at would be a Live Wallpaper app.
http://developer.android.com/resources/samples/CubeLiveWallpaper/index.html
^ Ignore the actually wallpaper bits but notice that the app doesn't have an Activity

You can create a BroadcastReceiver that will start your Service and remove the Activity from the Manifest file.

<activity android:name=".StarterActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
The action MAIN and category LAUNCHER start the application, so remove <intent-filter> of StarterActivity from the <application>. Then your application will not visible into the applications list.

Related

Two Instances opened When opening application from dynamicaLink and from launcher icon?

I ran into an issue in my Android Application where whenever I open my app through a dynamic link shared on Whatsapp, it will open in the same Whatsapp Application. I can see by going to the recent task that there is only one Application in a recent task which is Whatsapp and I can see my application inside it.
If I open my app from launcher icon then it will also create a new Application and there will be two application in recent tasks. My Splashscreen looks like this -
<activity
android:name=".SplashScreen"
android:screenOrientation="portrait"
android:theme="#style/SplashTheme"
android:windowSoftInputMode="stateAlwaysHidden">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
You should added attribute in your activity
android:launchMode="singleTask"
In general it is better to use a dedicated Activity for sharing from other applications. Another app should not launch your main (root) Activity to share, it should launch a different Activity. That Activity can then launch your main (root) Activity in a new task (if necessary). You need to consider the user's behaviour and make sure that you don't confuse the user with multiple tasks.

Need to Hide information in an activity or a fragment when app running in background

i am using one app, for example chrome with some confidential information and i am switching it to background & i am trying to kill the app.
i uploaded the example image when trying to kill the app. even the session the expired it won't close the information in the killing stage when app comes foreground then only it closes the information. i want the info should be closed or hided when it goes background (In killing stage).
i searched in google i am not getting anything related to this and i don't know whether my search phrase is correct. can anyone pleas help me.
I think ur asking this:
Just add this in manifest file:
android:excludeFromRecents="true"
Example:
<activity
android:name=".MainActivity"
android:excludeFromRecents="true"
android:taskAffinity=".OnInviteActivity"
android:noHistory="true"
android:label="#string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
then your app will not show in background or recent app or in menu like that
UPDATE:
for ur app name only u need to add this in Main Activity:
getWindow().addFlags(WindowManager.LayoutParams.FLAG_SECURE);

Change Android App starting activity

I'm trying to change the start up activity.
I created an activity when the app loads but I want to add a screen before that, I'm not sure where to change the Android manifest to load a certain layout/activity when the app starts.
The startup activity [Launcher Activity] is declared in the projects' AndroidManifest.xml file
Look for that activity tag in the manifest which looks like this
<activity android:name=".Main"
android:label="#string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
Look at the attribute android:name. Main is the class which is launched when the app starts. Currently your calendar activity name should be there. Change that to the .classpath of your activity that you want to launch.
That should do it. You may also want to do the hello world application in the tutorials and go through the docs a little to see how Android Applications work.
From here
Just create another activity and set it as Launcher Activity and after a timer (if that's your achieve) just call the other activity!

How could I set an activity to be the one to be resumed (by multitask)

I am experiencing a little pain on Android. I have two activities, one is a Splash Screen, launched when you click on the app icon, and an other one which can wake up when a specific event occurred (a NFC event, but it is not the problem).
There is the declaration in the manifest :
<activity android:label="#string/general.appName" android:name=".activity.SplashActivity" android:screenOrientation="portrait">
<intent-filter>
<action android:name="android.intent.action.MAIN"/>
<category android:name="android.intent.category.LAUNCHER"/>
</intent-filter>
</activity>
<activity android:excludeFromRecents="true" android:label="#string/general.appName" android:name=".EventReceiver" android:noHistory="true" android:screenOrientation="portrait">
<intent-filter>
<action android:name="android.nfc.action.TRANSACTION_DETECTED">
</action>
<category android:name="android.intent.category.DEFAULT">
</category>
<data android:host="secure" android:path="/aXXXXX" android:port="0" android:scheme="nfc"/>
</intent-filter>
</activity>
All works fine, it means that the EventReceiver is launched when it received a specific event, the Splash Screen is functional etc...
But, when the application is launched by an event, so it is the EventReceiver which is launched first. If I pause the app by clicking on the home button of the phone, and by long clicking on it again, it makes appear the multitask table, with all the recent opened apps. There, is I click on my application, it resumed the application on the EventReceiver, just like if an event had occurred. So do you know a way to resume an application on one selected activity only (in my case the SplashScreen).
Or do you know a way to recognize that the application was resumed by a multitask function ? (I could open the good activity at the onCreate of my EventReceiver too if I get this information).
For the moment, the only solution I found is to put a android:excludeFromRecents="true" flag on my EventReceiver activity. This will result that the application will not appear in the multitask table if the application was launched by an event. But this is a little bit tricky and I do not like that very much.
Do you have any ideas ?
Thank you very much beforehand for your answers ! (and sorry for my scholar English ^^)
If you really have to detect when the application is lauched from the "recents" you can use intent flags.
if (getIntent().getFlags() & Intent.FLAG_ACTIVITY_LAUNCHED_FROM_HISTORY) {
// Lauched from recent apps.
}
Do NOT use a splash screen. It only slows down your app experience and has no value what so ever.
In addition... Android apps are a lose set of activities... There is no concrete entry point that would need a splash screen.
That said... the app switcher returns you to the previously active activity. In your case the .EventReceiver. You could change your structure by using a second activity that shows your ui so that the EventReceiver lets you forward to that.
Correct me if i am mistaken... But can't you intercept the nfc event with an receiver? From there you should open your ui activity.

Help with first Android Activity

When my app first opens my first activity that is presented to the user can vary based on configuration options. I only know how to hard code the first activity that runs when the app is running by adding something like this in the Manifest
<activity android:label="#string/app_name" android:name=".MyFirstActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
Where MyFirstActivity is the class name of the first activity class to be run. How can I dynamically select which activity to run first when the app is first launched rather than hard code it in the manifest?
Thanks!
Option #1: In onCreate() of MyFirstActivity, call startActivity() for the right activity, then finish().
Option #2: Define several activities with the LAUNCHER <intent-filter>, all but one disabled. On first run (or as needed), enable the right activity and disable the others. Downside: may require a phone reboot to update the launcher, since not all home screen launchers will detect your change.
Option #3: Redesign your GUI such that this is not an issue.

Categories

Resources