static final int REQUEST_IMAGE_CAPTURE = 1; private void dispatchTakePictureIntent() { Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE); try { startActivityForResult(takePictureIntent, REQUEST_IMAGE_CAPTURE); } catch (ActivityNotFoundException e) { // display error state to the user } }怎么用SurfaceView预览

要使用SurfaceView预览相机画面，可以通过Camera API获取相机实例，并在SurfaceView上绘制预览画面。以下是示例代码：

1. 在布局文件中添加SurfaceView

<SurfaceView
    android:id="@+id/surfaceView"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />

2. 在Activity中获取SurfaceView实例，并在SurfaceView的生命周期方法中处理相机预览

public class CameraPreviewActivity extends AppCompatActivity implements SurfaceHolder.Callback {
    private Camera mCamera;
    private SurfaceView mSurfaceView;
    private SurfaceHolder mHolder;

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

        mSurfaceView = findViewById(R.id.surfaceView);
        mHolder = mSurfaceView.getHolder();
        mHolder.addCallback(this);
    }

    @Override
    public void surfaceCreated(SurfaceHolder holder) {
        // 获取相机实例
        mCamera = Camera.open();

        try {
            // 设置预览显示
            mCamera.setPreviewDisplay(holder);
            // 启动预览
            mCamera.startPreview();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    @Override
    public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
        // 相机预览尺寸发生变化时，重新启动预览
        mCamera.stopPreview();
        try {
            mCamera.setPreviewDisplay(holder);
            mCamera.startPreview();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {
        // 释放相机资源
        mCamera.stopPreview();
        mCamera.release();
        mCamera = null;
    }
}

在以上代码中，我们通过SurfaceHolder.Callback接口监听SurfaceView的生命周期方法，并在surfaceCreated方法中获取Camera实例、设置预览显示、启动预览，在surfaceChanged方法中处理预览尺寸变化，在surfaceDestroyed方法中释放相机资源。

需要注意的是，为了保证顺利运行，需要在AndroidManifest.xml文件中添加相应的权限：

<uses-permission android:name="android.permission.CAMERA" />
<uses-feature android:name="android.hardware.camera" />