Develop Reference

Android Lollipop App Notification Settings

In Android Lollipop, when you long press a Notification, it gives you access to settings for that Notification's app, such as priority, or simply blocking it. Is there an intent that I can use to access those settings?

Found the answer here - https://plus.google.com/+CyrilMottier/posts/YY6tbJrJMra
You need to add this to the activity you want to be attached to that settings icon
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.NOTIFICATION_PREFERENCES" />
</intent-filter>

In addition to the correct answer from #shmuel :
In case you want this "App settings" system button to jump to one specific fragment of your app's Settings activity deriving from PreferenceActivity, you can create a dummy intermediary activity to handle the intent-filter as details above, and then in this activity you simply do:
public class DeepSettingsFragmentDummyActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Intent settingsIntent = new Intent(this, SettingsActivity.class);
// Standard mechanism for a PreferenceActivity intent to indicate
// which fragment to activate automatically.
settingsIntent.putExtra( PreferenceActivity.EXTRA_SHOW_FRAGMENT,
YourTargetPreferenceFragment.class.getName());
startActivity(settingsIntent);
finish();
}
}
This code automatically launches the YourTargetPreferenceFragment fragment, and then dismisses itself (finish()) so as to not remain in the activity stack when the user hits Back.
Your Manifest must contain:
<activity
android:name=".DeepSettingsFragmentDummyActivity"
android:label="...">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.NOTIFICATION_PREFERENCES" />
</intent-filter>
</activity>

Android library project custom redirect

I’ve an android app and checked as library let it be Mainapp. Now I have created two separate app using that library viz. subapp1 and subapp2. Individual apps are running fine. I’ve login activity in the library package. On successful login user will be redirected to dashboard activity.
Written simply in loginactivity page of the library pack
Intent i = new Intent();
i.setClass(getApplicationContext(), UserhomeActivity.class);
startActivity(i);
Now I need to specify to which activity the user will be redirected based on the sub app. So how I can manage this without replicating the pages. Thanks.

you could provide the class and package name as an argument and start a new intent:
Intent sccuess = new Intent();
sccuess.setClassName(packageName, className);
startActivity(sccuess);

I am not sure I understand you correctly but If I understand you correct, you need to derive your activities from SecureActivity which user is supposed to be logged in to access there.
After you extend your classes from SecureActivity, you can check it in onResume() method.
Here is an example:
public class SecureActivity extends Activity
{
#Override
public void onResume()
{
// Check if user logged in or not.
}
}
public class YourActivity extends SecureActivity
{
// ...
}

In the Mainifest of your Library, your should define like that
<activity
android:name="com.gmail.app.activities.A_Activity"
android:label="#string/app_name"
android:screenOrientation="portrait"
android:theme="#style/NoActionBar" >
<intent-filter>
<action android:name="com.gmail.app.A.Fire_Activity" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
<activity
android:name="com.gmail.app.activities.B_Activity"
android:label="#string/app_name"
android:screenOrientation="portrait"
android:theme="#style/NoActionBar" >
<intent-filter>
<action android:name="com.gmail.app.B.Fire_Activity" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
In library code where to fire the intent:
Intent i = new Intent(_context.getPackageName() + ".Fire_Activity");
//Action will be like com.gmail.app.A.Fire_Activity or com.gmail.app.B.Fire_Activity
startActivity(i);
PS:
Your Sub-Apps have package-names:
com.gmail.app.A
com.gmail.app.B

How to export an activity so other apps can call it?

Well I searched a lot, but I didn't find a precise answer how to export an Activity, so an app can start it with startActivityforResult.
How do I achieve that? Do I have to change the Manifest in some ways?

As an alternate to Dalmas' answer, you can actually export an Activity without creating an <intent-filter> (along with the hassle of coming up with a custom action).
In the Manifest edit your Activity tag like so:
<activity
android:name=".SomeActivity"
....
android:exported="true" />
The important part is android:exported="true", this export tag determines "whether or not the activity can be launched by components of other applications". If your <activity> contains an <intent-filter> then this tag is set to true automatically, if it does not then it is set to false by default.
Then to launch the Activity do this:
Intent i = new Intent();
i.setComponent(new ComponentName("package name", "fully-qualified name of activity"));
startActivity(i);
Of course with this method you will need to know the exact name of the Activity you are trying to launch.

You need to declare an intent-filter in your Manifest (I took the following example from Barcode Scanner) :
<activity android:name="...">
<intent-filter>
<action android:name="com.google.zxing.client.android.SCAN" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
Then create an intent with the same action string :
Intent intent = new Intent("com.google.zxing.client.android.SCAN");
startActivityForResult(intent, code);
Android should start your activity (or it will show a drop-down box if there are multiple apps sharing the same action string).

Forwarding intents in Android

I am trying to capture audio/* mimetype action.View intents and forward them to another application (chosen by the user). The problem is that, while I am able, from a file manager, to select my Activity on file opening (through the app chosen dialog), I am not able to forward the intent to another activity (not the same one).
This is the manifest part about the activity:
<activity
android:label="#string/app_name"
android:name=".TestMimeActivity" >
<intent-filter >
<action android:name="android.intent.action.VIEW" />
<data android:mimeType="audio/*" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
This is the onStart code in the activity:
#Override
protected void onStart() {
super.onStart();
setContentView(R.layout.main);
Intent intent = getIntent();
startActivity(intent);
}
I obtain only an infinite loop. I would like to open on the activity che app chosen dialog (preferably without my app listed but I can also tolerate the whole list). Is it possible? How can I achieve this?
Thanks
Tobia Loschiavo

From your comments above I think you are looking for createChooser. You should modify your code to look like this:
Intent intent = getIntent();
startActivity(Intent.createChooser(intent, "Select application"));

ActivityNotFoundException?

I am getting an ActivityNotFoundException in the following code:
Main.java
Intent intent = new Intent();
intent.setAction("com.test.app.TEST");
startActivity(intent); // ActivityNotFoundException
Manifest.xml
<activity android:name=".MainActivity" android:theme="#android:style/Theme.Dialog">
<intent-filter>
<action android:name="com.test.app.TEST" />
</intent-filter>
</activity>

I've had this issue too, as perfectly concisely described by jpahn.
the period at the front did not give any help to me.
even with exactly this (a copy of the original question including edits), I would still get ActivityNotFoundException.
Main.java
Intent intent = new Intent();
intent.setAction("com.test.app.TEST");
startActivity(intent); // ActivityNotFoundException
Manifest.xml
<activity android:name=".MainActivity" android:theme="#android:style/Theme.Dialog">
<intent-filter>
<action android:name="com.test.app.TEST" />
</intent-filter>
</activity>
This was resolved, after much trial-and-error, by simply adding this to the intent-filter in the manifest:
<category android:name="android.intent.category.DEFAULT" />
So the final manifest file contained:
<activity android:name=".MainActivity" android:theme="#android:style/Theme.Dialog">
<intent-filter>
<action android:name="com.test.app.TEST" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>

I got this error after moving an activity class from one package to another.
Clean build solved it (Project -> Clean).

Be sure to declare your activity in the manifest.xml within the aplication:
<application>
<activity android:name=".YourNewActivity"/>
</application>
To start the new Activity:
Intent intent = new Intent(main.this, YourNewActivity.class);
startActivity(intent);
Where main stands for the current activity,

Add a . (dot) before your activity name in Android Manifest. So it should be android:name=".WordsToSpeakMainActivity"

I have some addition to the #Tom Pace answer. The answer is completely right, but to make it more clear:
ActivityNotFoundException occurs because of absence of
<category android:name="android.intent.category.DEFAULT" />
Because when Android OS see this in the manifest file, understands that this activity can receive intent.
The point ActivityNotFoundException thrown is that, when activity(intent-creator-activity) tries to create intent for other activity(intent-receiver-activity), Android OS sees there is intent for receiver activity but receiver activity does not receive anyone. Then Android OS returns null or empty intent to intent-creator-activity. And startActivity throws that exception.
I have found a code from android developers to avoid this exception:
// Verify the original intent will resolve to at least one activity
if (sendIntent.resolveActivity(getPackageManager()) != null) {
startActivity(chooser);
}
Android Developers: Intent Filters

To be safe you can also call your new activity like this:
Intent intent = new Intent();
intent.setClass(this, THECLASSNAME);
startActivity(intent); //
However, you must add the activity to the androidmanifest - and write a . in front of it, e.g.
<activity android:name=".YOURACTIVITYNAME"></activity>

There two types of intents in android framework,
1-Implicit intents that you are using,
<activity android:name=".MainActivity" android:theme="#android:style/Theme.Dialog">
<intent-filter>
<action android:name="com.test.app.TEST" />
</intent-filter>
</activity>
just add one line in intent filter
<intent-filter>
<action android:name="com.test.app.TEST" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
2- Explicit Intents
Intent i=new Intent(CurrentActivity.this,WhereWeWantToGoActivity.class);
startActivity(i);

To launch an activity by a string definition, use:
Intent intent = new Intent();
intent.setComponent(
new ComponentName("com.app", "com.app.activity.TheActivity"));
startActivity(intent);

At the very top of your AndroidManifest.xml, you'll see the package attribute
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.android.example"
and then, in the activity tag, you'll see the name attribute:
<activity
android:name=".Something"
Make sure that the package name and activity name, when joined together, make the full package specification of your Activity i.e.
com.android.example + .Something = com.android.example.Something
Otherwise, you'll get a ActivityNotFoundException.

I found a solution to this problem... I´m using 2 modules in a android studio project, the thing here is that I needed to add the activity to the main manifest file
<activity android:name="com.HeadApp.ARTry.UnityPlayerActivity"
android:clearTaskOnLaunch="false" android:label="#string/app_name"
android:screenOrientation="portrait"
android:configChanges="fontScale|keyboard|keyboardHidden|locale|mnc|mcc|navigation|orientation|screenLayout|screenSize|smallestScreenSize|uiMode|touchscreen"
/>
I had that in the unity activity manifest, I just copied the activity and paste it in the main manifest and that was it, hope it helps, eve been struggling a lot with this for the past 3 weeks