android cameraview如何实现拍照和录像功能

要实现拍照和录像功能，可以使用Android的Camera类和MediaRecorder类来实现。

1. 首先，在AndroidManifest.xml文件中添加相机和录像权限：

<uses-permission android:name="android.permission.CAMERA" />
<uses-permission android:name="android.permission.RECORD_AUDIO" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

2. 在布局文件中添加CameraView：

<FrameLayout
    android:id="@+id/camera_preview"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
</FrameLayout>

3. 在Activity中初始化Camera和MediaRecorder对象，并在拍照和录像按钮的点击事件中调用相应的方法：

public class CameraActivity extends Activity {

    private Camera mCamera;
    private CameraPreview mPreview;
    private MediaRecorder mMediaRecorder;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        mCamera = getCameraInstance();
        mPreview = new CameraPreview(this, mCamera);
        
        FrameLayout preview = (FrameLayout) findViewById(R.id.camera_preview);
        preview.addView(mPreview);
        
        Button captureButton = (Button) findViewById(R.id.button_capture);
        captureButton.setOnClickListener(
            new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    mCamera.takePicture(null, null, mPicture);
                }
            }
        );

        Button recordButton = (Button) findViewById(R.id.button_record);
        recordButton.setOnClickListener(
            new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    if (isRecording) {
                        stopRecording();
                    } else {
                        startRecording();
                    }
                }
            }
        );
    }

    private Camera getCameraInstance(){
        Camera c = null;
        try {
            c = Camera.open();
        }
        catch (Exception e){
            Log.e(TAG, "Failed to open camera: " + e.getMessage());
        }
        return c;
    }

    private void startRecording(){
        mCamera.unlock();

        mMediaRecorder = new MediaRecorder();

        mMediaRecorder.setCamera(mCamera);
        mMediaRecorder.setAudioSource(MediaRecorder.AudioSource.CAMCORDER);
        mMediaRecorder.setVideoSource(MediaRecorder.VideoSource.CAMERA);
        mMediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);
        mMediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
        mMediaRecorder.setVideoEncoder(MediaRecorder.VideoEncoder.MPEG_4_SP);
        mMediaRecorder.setOutputFile(getOutputMediaFile(MEDIA_TYPE_VIDEO).toString());

        mMediaRecorder.setPreviewDisplay(mPreview.getHolder().getSurface());

        try {
            mMediaRecorder.prepare();
            mMediaRecorder.start();
        } catch (IOException e) {
            Log.e(TAG, "Failed to start recording: " + e.getMessage());
        }
    }

    private void stopRecording(){
        mMediaRecorder.stop();
        mMediaRecorder.reset();
        mMediaRecorder.release();
        mMediaRecorder = null;
        mCamera.lock();
    }

    private PictureCallback mPicture = new PictureCallback() {
        @Override
        public void onPictureTaken(byte[] data, Camera camera) {
            //保存拍照图片的逻辑
        }
    };
}

在以上代码中，需要自定义CameraPreview类来显示相机预览，具体实现可以参考Android官方文档。同时，需要实现获取输出文件路径的方法getOutputMediaFile()来保存拍照和录像的文件。