Possible to use/layout a compose view in and Activity written in Java?

user_1281501 0
Viewed 2443

Google gives the following example of how to use a ComposeView in XML and inflate it in a fragment.

class ExampleFragment : Fragment() {

    override fun onCreateView(
        inflater: LayoutInflater,
        container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View {
        // Inflate the layout for this fragment
        return inflater.inflate(
            R.layout.fragment_example, container, false
        ).apply {
            findViewById<ComposeView>(R.id.compose_view).setContent {
                // In Compose world
                MaterialTheme {
                    Text("Hello Compose!")
                }
            }
        }
    }
}

I have an activity written in java, not kotlin. Is it possible to use setContent from a Java activity? If so I am struggling with the syntax.

android-jetpack-compose kotlin android java
2 Answers

Yes, it's possible.

First you should create a subclass of AbstractComposeView:

class MyComposeView
@JvmOverloads constructor(context: Context, attrs: AttributeSet? = null) :
    AbstractComposeView(context, attrs) {
    @Composable
    override fun Content() {
        YourComposableFunction()
    }
}

and then set this view as Activity content...

public class MyJavaActivity extends AppCompatActivity {
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(new MyComposeView(this));
    }
}

You can also declare your view in any layout file...

<com.example.MyComposeView
    android:layout_width="match_parent"
    android:layout_height="match_parent"/>

and call setContentView(R.layout.your_layout_file) as usual.

user_10943330

Instead of creating an AbstractComposeView , you can simply wrap up a kotlin function and pass on the activity instance and set the content. For example:

object ComposeContent {
    fun setContentFromJavaActivity(activity: AppCompatActivity) {
        activity.setContent {
            // Your composable content goes here
        }
    }
}

Activity onCreate(..) :-

public class MyJavaActivity extends AppCompatActivity {
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        ComposeContent.INSTANCE.setContentFromJavaActivity(this);
    }
}

(Creating instance of AbstractComposeView or ComposeView comes handy only when we want to render a section of an Activity with a compose UI (or in a Fragment))

user_72583320
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