android - 如何设置相机RelativeLayout的背景？

Question

在我的应用程序中，我有这样的布局

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:background="#ff0000"
    android:orientation="vertical">

    <fragment xmlns:tools="http://schemas.android.com/tools"
        android:id="@+id/map"
        android:name="com.google.android.gms.maps.SupportMapFragment"
        android:layout_width="200dp"
        android:layout_height="200dp"
        android:layout_alignParentBottom="true"
        android:layout_alignParentEnd="true"
        tools:context=".MapsActivity" />

</RelativeLayout>

如何将基本 RelativeLayout 布局的背景设置为相机 View ？

Answer 1

让你的 Root View 成为 SurfaceView:

<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <SurfaceView
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/surfaceView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>

    <fragment
        android:layout_alignParentBottom="true"
        android:layout_alignParentRight="true"
        android:layout_alignParentEnd="true"
        android:id="@+id/map"
        android:layout_width="300dp"
        android:layout_height="300dp"
        android:name="com.google.android.gms.maps.MapFragment"/>
</RelativeLayout>

然后在您的代码中，打开相机并将预览输出到您的 SurfaceView:

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    SurfaceView surfaceView = (SurfaceView) findViewById(R.id.surfaceView);
    SurfaceHolder surfaceHolder = surfaceView.getHolder();

    surfaceHolder.addCallback(new SurfaceHolder.Callback() {
        private Camera mCamera;
        @Override
        public void surfaceDestroyed(SurfaceHolder holder) {
            mCamera.stopPreview();
            mCamera.release();
            mCamera = null;
        }

        @Override
        public void surfaceCreated(SurfaceHolder holder) {
            mCamera = Camera.open();

            try {
                mCamera.setPreviewDisplay(holder);
            } catch (IOException exception) {
                mCamera.release();
                mCamera = null;
            }
        }

        @Override
        public void surfaceChanged(SurfaceHolder holder, int format, int width,
                                   int height) {
            mCamera.startPreview();
        }
    });
}