Develop Reference

How to open a specific activity from an external link clicking

I know this question is not new, but its a bit different from already asked questions. I have a website that provides links to my app. The links direct users to specific data on my app. This is the layout of my app: I have 4 activities as Activity1.class, Activity2.class, Activity3.class, and of course the MainActivity.class which is the launcher activity.
My worry is this: On my website, I have 3 buttons: button 1 goes to open directly Activity1 on my app (assuming the app is already installed on the device), Button 2 on website opens Activity2 in my app.
Note: the app and the website are not by any means linked.
My question is: how to get a URL link to specific activity on my app. I need 3 URLs that open different 3 activities. I need these links for external use, such that they open a specified activity whey clicked.
Something like: http://myapppackage/ACTIVITY1.
This is just an example.

In you AndroidManifest.xml add intent-filters to the activities like this
<activity android:name=".ACTIVITY1">
<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="http"
android:host="myapppackage"
android:pathPattern="/ACTIVITY1" />
</intent-filter>
</activity>
<activity android:name=".ACTIVITY2">
<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="http"
android:host="myapppackage"
android:pathPattern="/ACTIVITY2" />
</intent-filter>
</activity>
<activity android:name=".ACTIVITY3">
<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="http"
android:host="myapppackage"
android:pathPattern="/ACTIVITY3" />
</intent-filter>
</activity>
For more info check this out
Deep Linking In Android

Add own app to the whatsapp audio selection

How can I add my own app to the whatsapp audio selection like this application in android (with java)?
I know, I asked this question already but I didn't get a useful answer. I didn't think that it could work, but I found this app and it works on my android phone (Huawei VNC-L31/Huawei P9 Lite, Android 7.0). (Screenshot)
I tried it with the one-to-one intent filter from the manifest of this app but it didn't work.
Thanks for grammar correction ;)

in whatsapp(like app) do like this on audio selection
Intent intent = new Intent();
intent.setType("audio/*");
intent.setAction(Intent.ACTION_PICK);
startActivityForResult(Intent.createChooser(intent,"Select Audio "), reqCode);
and in your application create an activity which contains list of audio.
add code like this in AndroidManifest.xml
<activity
android:name=".activity.AudioListActivity"
android:windowSoftInputMode="stateAlwaysHidden">
<intent-filter>
<action android:name="android.intent.action.PICK" />
<category android:name="android.intent.category.DEFAULT" />
<data android:mimeType="audio/*" />
</intent-filter>
</activity>
and in your AudioListActivity return result to other app on selection of audio or as you required.

<intent-filter>
<action android:name="android.intent.action.VIEW" />
<category android:name="android.intent.category.DEFAULT" />
<data android:scheme="content"/>
<data android:host="media"/>
<data android:mimeType="audio/*"/>
<data android:mimeType="application/ogg"/>
<data android:mimeType="application/x-ogg"/>
<data android:mimeType="application/itunes"/>
</intent-filter>

Open Application in App Link outside of receiver

When using App Links, the receiver app (EX. Whatsapp) is paused, and your application's activity is opened on top of the receiver app.
For example, if you open your link from a WhatsApp's chat page, the new activity isn't opened from your app (The WhatsApp's task in recent apps includes your app), while your app isn't in the recent task.
But what if I want to open my application in a new task? Separate from the receiver app?
This is my Manifest file of the activity opened from the App Link:
<activity
android:name=".Activitys.MainActivity"
android:screenOrientation="portrait">
<intent-filter>
<action android:name="android.intent.action.VIEW" />
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
<intent-filter
android:autoVerify="true"
android:label="#string/app_name">
<action android:name="android.intent.action.VIEW" />
<category android:name="android.intent.category.DEFAULT" />
<category android:name="android.intent.category.BROWSABLE" />
<data
android:host="eventtk.uae-dc.com"
android:pathPrefix="/product/"
android:scheme="https" />
</intent-filter>
</activity>
Is there a thing I should add to the IntentFilter?

Not sure if I understood correctly what you would like to achieve, but you can try
to add
android:launchMode="singleTask"
to your activity definition.
More information here:
https://inthecheesefactory.com/blog/understand-android-activity-launchmode/en

Adding 3rd party application into Settings.apk

Recently I'm building a AOSP ROM from source. What I wanted to do is, add a 3rd party application into Settings app and It should be launched only from Settings and it should be invisible from Launcher.
Here's what I did, It fails everytime.
Removed these lines from apps AndroidManifest.xml
android:name="android.intent.category.LAUNCHER" />
and added below lines in SettingsActivity.java from Settings app.
if (KA_FRAGMENT.equals(fragmentName)) {
Intent kaIntent = new Intent();
kaIntent.setClassName("com.cyborg.manager", "com.cyborg.manager.activities.MainActivity");
startActivity(kaIntent);
finish();
return null;
}
Also added below lines in AndroidManifest.xml of Settings
<activity android:name="Settings$KActivity"
android:label="#string/hit_perform"
android:icon="#drawable/hit_performance_icon"
android:taskAffinity="" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.DEFAULT" />
<category android:name="com.android.settings.SHORTCUT" />
</intent-filter>
<intent-filter android:priority="1">
<action android:name="com.android.settings.action.SETTINGS" />
</intent-filter>
<meta-data android:name="com.android.settings.category"
android:value="com.android.settings.category.urom" />
<meta-data android:name="com.android.settings.FRAGMENT_CLASS"
android:value="com.android.settings.ka" />
</activity>
Although, it works fine when 3rd party app is visible in launcher

If you want to play with custom ROM I'd recommend getting familiar with Android fundamentals first.
What makes you activity shown by launcher is this <intent-filter>
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.DEFAULT" />
<category android:name="com.android.settings.SHORTCUT" />
</intent-filter>
especially these two lines:
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.DEFAULT" />
so remove them and you are done.

Associate email addresses for my android application

I am an absolute beginner in android development. I am making a small email application. What I want to do is: when I click on any email in web browser, My application should be used to open this email. Now My phone shows only gmail, Drive, and Email only. How can I add my application too to the list.
Thanks

You have to use intent-filters.
<intent-filter>
<action android:name="android.intent.action.VIEW" />
<action android:name="android.intent.action.SENDTO" />
<data android:scheme="mailto" />
<category android:name="android.intent.category.DEFAULT" />
<category android:name="android.intent.category.BROWSABLE" />
</intent-filter>
https://github.com/android/platform_packages_apps_email/blob/master/AndroidManifest.xml