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。

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" />

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>

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。