gibs gibs - 10 days ago 7
Android Question

ActivityNotFoundException when opening another activity with Intent

Before you downvote: I have googled this for hour+ now and still can't understand why this isn't working. I am following the official docs.

I want to open another Activity from my main Activity with an Intent.
This is my main Activity class (

MainActivity.java
):

public class MainActivity extends Activity {

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);

LinearLayout l = new LinearLayout(this);
Button b = new Button(this);
b.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent goToActivity2 = new Intent(MainActivity.this, Activity2.class);
MainActivity.this.startActivity(goToActivity2);
}
});
l.addView(b);

this.setContentView(l);
}
}


And this is
Activity2.java
:

public class Activity2 extends Activity {

}


If I run the app I will see the main activity with a gray button. If I click on the button I get an Exception:

android.content.ActivityNotFoundException: Unable to find explicit activity class {com.testing.kaarelp.androidtest2/com.testing.kaarelp.androidtest2.Activity2}; have you declared this activity in your AndroidManifest.xml?


Why am I getting the Exception? Whats wrong here?

------------- edit1 ---------------

okay I declared the other Activity in the manifest like this:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.testing.kaarelp.androidtest2">

<application>
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name=".Activity2" />
</application>

</manifest>


... and the app works now! Yet I am looking at another working code example right now that has multiple Activity-s that are not declared in the manifest and it still works. What is going on?!

------------- edit2 ---------------

Ahh I figured it out. The code example I was looking at contained multiple
Fragment
-s, not
Activity
-s

Answer

You must declare the Activity in your AndroidManifest.xml file:

<activity android:name=".Activity2"/>