Using an Android library project Activity within a

问题:

I have an Android library project that I would like to use from within another Android project.

The library has a Activity declared in its AndroidManifest. When I try the following within the second project:

        Intent intent = new Intent(this, ReaderActivity.class);
        startActivity(intent);

I get the following exception:

 java.lang.RuntimeException: Unable to start activity ComponentInfo{br.com.digitalpages.reader.demo/br.com.digitalpages.reader.demo.ReaderDemoActivity}: android.content.ActivityNotFoundException: Unable to find explicit activity class {br.com.digitalpages.reader.demo/br.com.digitalpages.reader.ReaderActivity}; have you declared this activity in your AndroidManifest.xml?
     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
...
 Caused by: android.content.ActivityNotFoundException: Unable to find explicit activity class {br.com.digitalpages.reader.demo/br.com.digitalpages.reader.ReaderActivity}; have you declared this activity in your AndroidManifest.xml?
     at android.app.Instrumentation.checkStartActivityResult(Instrumentation.java:1404)
     at android.app.Instrumentation.execStartActivity(Instrumentation.java:1378)
...

How can I open the Activity from the another project?

EDIT: By users answers I added the following line into my second project

<uses-library android:name="br.com.digitalpages.reader" android:required="true" />

But it's still doesn't works

回答1:

I believe you must include the <activity> in your own AndroidManifest.xml -- I don't think it gets picked up from a library. I don't have my reference for that handy.

Update: It's official solution. From the doc:

Declaring library components in the manifest file

In the manifest file of the application project, you must add declarations of all components that the application will use that are imported from a library project. For example, you must declare any <activity>, <service>, <receiver>, <provider>, and so on, as well as <permission>, <uses-library>, and similar elements.

Declarations should reference the library components by their fully-qualified package names, where appropriate.

回答2:

Intent intent = new Intent(android.content.Intent.ACTION_VIEW);
intent.setComponent(new ComponentName("packagename//ex-com.hello", 
                                     "classname//ex-com.hello.ExampleActivity"));
startActivity(intent);

And make sure in library you have declared the activities. You don't need to declare the library activities in your current project's manifest.

回答3:

This works:

In your library, put your custom Activity:

public class MyLibraryActivity extends ListActivity { ... }

No need to put it into a manifest. In your calling Android project, create an empty (dummy) wrapper:

public class MyActivity extends MyLibraryActivity { } 

and add reference to this class to your manifest:

<activity android:name="my_package.MyActivity" ... />

回答4:

did you add to the manifest?

http://developer.android.com/guide/topics/manifest/uses-library-element.html

回答5:

you should import just the code of the activity ( not the manifest too ) , and then , declare your Activity ( of the library ) , in the manifest of your second project

回答6:

I am aware that the question is quite old but I think this might help people like me that came up with the same problem.

Using Eclipse, the best way to share code and activities among libraries is probably the one that can be found in the android documentation here:

Managing Projects from Eclipse with ADT

回答7:

You don't need to explicitly add activity in your main project's manifest if you have already added the activity in your library's manifest by using the following code when starting library's activity.

For Kotlin

   val myIntent = Intent(activityContext, ActivityToLaunch::class.java)
    // Needed to set component to remove explicit activity entry in application's manifest
    myIntent.component = ComponentName(activityContext, PickerActivity::class.java)
    activityContext.startActivity(myIntent, PICKER_REQUEST_CODE)

For Java

    Intent myIntent = new Intent(activityContext, PickerActivity.class);
    // Needed to set component to remove explicit activity entry in application's manifest
    final ComponentName component = new ComponentName(activityContext, PickerActivity.class);
    myIntent.setComponent(component);
    activityContext.startActivity(myIntent, REQUEST_CODE);