Android: Unable to find explicit activity class... startActivity from a PreferenceActivity

Question

I'm trying to start a new Activity from a PreferenceActivity. However, it fails with "Unable to find explicit activity class. Have you declared this activity in your AndroidManifest.xml?"

Well, yeah, I declared it:

<application [......] android:debuggable="true">
    <activity android:name=".AlarmSettings"
              android:label="@string/app_name">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>

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

    <receiver
        android:name="AlarmReceiver"
        android:process=":remote" >
    </receiver>
</application>

AlarmSettings is my PreferenceActivity. AlarmSettings calls FlashLightActivity this way:

Intent i = new Intent(AlarmSettings.this, FlashLightActivity.class);
startActivity(i);

And this is FlashLightActivity:

public class FlashLightActivity extends Activity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.flashlight);
   }    
}

... I don't know what to do. Any ideas?

That's strange. Try to remove the beginning dot from `.FlashLightActivity` and test with a bare `FlashLightActivity` name or try to provide the full package name of your activity like `com.example.FlashLightActivity`. — Renaud, Oct 30 '11 at 17:03
Damn! Does the FlashLightActivity class is in the same package? You surely know http://developer.android.com/guide/topics/manifest/activity-element.html#nm but else it can help… Tried fully qualified name on both side (AndroidManifest and startActivity)? — Renaud, Oct 30 '11 at 17:10
Tried every combination... it doesn't work. Yes, the fully qualified name is the same. So, if the code is ok... I can only think about some strange Eclipse problem — danieleds, Oct 30 '11 at 17:22
Can you show what do you have in `android:package` field (in element? And what's the package of `FlashLightActivity` class? — Kocus, Oct 30 '11 at 17:22

score 6 · Answer 1 · answered May 30 '12 at 12:02

6

I had this problem too. If you read carefully the error on the logcat, you will know what to do.

You have to declare the activity in the AndroidManifest.xml

    <activity
        android:name=".TheNameOfMyActivity"
        android:label="@string/app_name" >
        <intent-filter>
            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>

answered May 30 '12 at 12:02

Mirey

117
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if you read carefully the question, he had already declared it in the manifest! – X.X_Mass_Developer Aug 08 '13 at 09:27

score 2 · Answer 2 · answered Dec 18 '13 at 15:51

2

For me this error occurred because I had moved my activity class file to a different package and for some reason Eclipse didn't refactor it correctly. Always use a fully qualified name for your activity and double-check that it is accurate.

answered Dec 18 '13 at 15:51

tpbapp

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score 2 · Answer 3 · answered May 26 '14 at 06:58

When starting an activity from inside another you need to provide your AndroidManifest file the parent child relationship, to ensure that the started activity will return its result to you requires parent activity. example,

<activity
            android:name="ACTIVITY TO BE STARTED"
            android:label="@string/TITLE"
            android:screenOrientation="landscape" >
             <meta-data
                android:name="android.support.PARENT_ACTIVITY"
                android:value="ACTIVITY STARTED FROM?RETURNING TO" />
        </activity>

score 0 · Answer 4 · answered Jul 04 '16 at 14:30

0

I had the same problem, what I did is wrote the Intent declaration inside the onCreate function of the Service or the Layout. actually that is what said 'could not access Explicity'

answered Jul 04 '16 at 14:30

Madhan Mafiya

1

score 0 · Answer 5 · edited Apr 11 '20 at 00:34

0

In my case, i just had to rename the class, because that was a word reserved from android studio or have another reference, So:

Could find this with crl+space and check the route of your suggest
Check out the imports in the class and delete which are not necessary
Don't use default names

So don't use FlashLightActivity for example.

Maybe its work for others

edited Apr 11 '20 at 00:34

X-Black...

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answered Apr 10 '20 at 19:45

mFos

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score 0 · Accepted Answer · answered Mar 04 '12 at 03:57

0

Copying poster's solution into the answer section, in order to remove this from the "Unanswered" filter:

It wasn't a problem with my code, but with Eclipse and the Android SDK. After some research, I did "Help -> Check for updates" in Eclipse and everything is working now.

answered Mar 04 '12 at 03:57

DreadPirateShawn

8,164
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I had this problem too. Everything was OK until I switch to Android ADT Bundle Package (Eclipse + Android SDK) from developer.android.com :(. But your way did not work for me :( – vanloi999 Jul 15 '13 at 04:58
I seem to be having the same problem. My code seems to check out, unfortunately I have the Android ADT Bundle and it is not working for me. Any ideas? – GothamNite Sep 20 '13 at 02:38

Android: Unable to find explicit activity class... startActivity from a PreferenceActivity

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