摘要: 基本上所有应用都会用到相机功能,上周尝试了下自定义的相机功能实现。下面记录下在学习尝试中的一些心得。
相机的启动方式有两种:
1、利用隐式跳转跳转到系统的相机应用
Intent intent = new Intent();
intent.setAction(MediaStore.ACTION_IMAGE_CAPTURE);
startActivity(intent);
2、利用camera类自定义相机界面
自定义相机的一般步骤:
1. 创建显示相机画面的布局，Android已经为我们选定好SurfaceView
2. 通过SurfaceView#getHolder()获得链接Camera和SurfaceView的SurfaceHolder
3. Camame.open()打开相机
4. 通过SurfaceHolder链接Camera和SurfaceView实现预览
5. 进行拍照或录制
3、代码演示
private void init() {
TypedArray a = context.obtainStyledAttributes(attrs,
R.styleable.MovieRecorderView, defStyle, 0);
mWidth = a.getInteger(R.styleable.MovieRecorderView_width, 320);// 默认320
mHeight = a.getInteger(R.styleable.MovieRecorderView_height, 240);// 默认240
isOpenCamera = a.getBoolean(
R.styleable.MovieRecorderView_is_open_camera, true);// 默认打开
mSurfaceView = (SurfaceView) findViewById(R.id.surfaceview);
mSurfaceHolder = mSurfaceView.getHolder();
mSurfaceHolder.addCallback(new CustomCallBack());
mSurfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
private class CustomCallBack implements Callback {
@Override
public void surfaceCreated(SurfaceHolder holder) {
if (!isOpenCamera)
return;
try {
initCamera();
} catch (IOException e) {
e.printStackTrace();
}
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width,
int height) {
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
if (!isOpenCamera)
return;
freeCameraResource();
}
}
/**
* 初始化摄像头同时开启预览
*/
private void initCamera() throws IOException {
if (mCamera != null) {
freeCameraResource();
}
try {
mCamera = Camera.open();
} catch (Exception e) {
e.printStackTrace();
freeCameraResource();
}
if (mCamera == null)
return;
// setCameraParams();
mCamera.setDisplayOrientation(90);
mCamera.setPreviewDisplay(mSurfaceHolder);
DisplayMetrics dm = new DisplayMetrics();
dm = getResources().getDisplayMetrics();
setCameraParams(mCamera,dm.widthPixels,dm.heightPixels);
mCamera.startPreview();
mCamera.unlock();
}
/**
* 释放摄像头资源
*/
private void freeCameraResource() {
if (mCamera != null) {
mCamera.setPreviewCallback(null);
mCamera.stopPreview();
// mCamera.lock();
mCamera.release();
mCamera = null;
isOpenCamera = false;
}
}
/**
* 释放资源
*/
private void releaseRecord() {
if (mMediaRecorder != null) {
mMediaRecorder.setOnErrorListener(null);
try {
mMediaRecorder.release();
} catch (IllegalStateException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
}
mMediaRecorder = null;
}
接下来时设置照片尺寸放置预览时的图像变形
private void setCameraParams(Camera camera, int width, int height) {
Log.i(TAG,"setCameraParams width="+width+" height="+height);
Camera.Parameters parameters = mCamera.getParameters();
// 获取摄像头支持的PictureSize列表
List<Camera.Size> pictureSizeList = parameters.getSupportedPictureSizes();
// for (Camera.Size size : pictureSizeList) {
// Log.i(TAG, "pictureSizeList size.width=" + size.width + " size.height=" + size.height);
// }
/**从列表中选取合适的分辨率*/
Camera.Size picSize = getProperSize(pictureSizeList, ((float) height / width));
if (null == picSize) {
Log.i(TAG, "null == picSize");
picSize = parameters.getPictureSize();
}
Log.i(TAG, "picSize.width=" + picSize.width + " picSize.height=" + picSize.height);
// 根据选出的PictureSize重新设置SurfaceView大小
float w = picSize.width;
float h = picSize.height;
parameters.setPictureSize(picSize.width,picSize.height);
this.setLayoutParams(new RelativeLayout.LayoutParams((int) (height*(h/w)), height));
// 获取摄像头支持的PreviewSize列表
List<Camera.Size> previewSizeList = parameters.getSupportedPreviewSizes();
Camera.Size preSize = getProperSize(previewSizeList, ((float) height) / width);
if (null != preSize) {
Log.i(TAG, "preSize.width=" + preSize.width + " preSize.height=" + preSize.height);
parameters.setPreviewSize(preSize.width, preSize.height);
}
parameters.setJpegQuality(100); // 设置照片质量
if (parameters.getSupportedFocusModes().contains(android.hardware.Camera.Parameters.FOCUS_MODE_CONTINUOUS_PICTURE)) {
parameters.setFocusMode(android.hardware.Camera.Parameters.FOCUS_MODE_CONTINUOUS_PICTURE);// 连续对焦模式
}
parameters.set("orientation", "portrait");
mCamera.cancelAutoFocus();//自动对焦。
mCamera.setDisplayOrientation(90);// 设置PreviewDisplay的方向，效果就是将捕获的画面旋转多少度显示
mCamera.setParameters(parameters);
}
/**
* 从列表中选取合适的分辨率
* 默认w:h = 4:3
* <p>注意：这里的w对应屏幕的height
* h对应屏幕的width<p/>
*/
private Camera.Size getProperSize(List<Camera.Size> pictureSizeList, float screenRatio) {
Log.i(TAG, "screenRatio=" + screenRatio);
Camera.Size result = null;
for (Camera.Size size : pictureSizeList) {
float currentRatio = ((float) size.width) / size.height;
if (currentRatio - screenRatio == 0) {
result = size;
break;
}
}
if (null == result) {
for (Camera.Size size : pictureSizeList) {
float curRatio = ((float) size.width) / size.height;
if (curRatio == 4f / 3) {// 默认w:h = 4:3
result = size;
break;
}
}
}
return result;
}
在完成预览设置之后可以根据需求进行拍照或者拍摄的操作:
--首先时拍照操作:
拍照时我们需要设置三个回调函数
// 拍照瞬间调用
private Camera.ShutterCallback shutter = new Camera.ShutterCallback() {
@Override
public void onShutter() {
}
};
// 获得没有压缩过的图片数据
private Camera.PictureCallback raw = new Camera.PictureCallback() {
@Override
public void onPictureTaken(byte[] data, Camera Camera) {
}
};
//图像数据处理完成后的回调函数
private Camera.PictureCallback jpeg = new Camera.PictureCallback() {
@Override
public void onPictureTaken(byte[] data, Camera Camera) {
BufferedOutputStream bos = null;
Bitmap bm = null;
try {
// 获得图片
bm = BitmapFactory.decodeByteArray(data, 0, data.length);
if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
Log.i(TAG, "Environment.getExternalStorageDirectory()="+Environment.getExternalStorageDirectory());
File file = new File(Environment.getExternalStorageDirectory()
+ File.separator + "ysb/image/"+System.currentTimeMillis()+".jpg");//拍摄照片的保存地址
// String filePath = "/sdcard/dyk"+System.currentTimeMillis()+".jpg";//照片保存路径
// File file = new File(filePath);
if (!file.exists()){
file.mkdirs();
}
bos = new BufferedOutputStream(new FileOutputStream(file));
bm.compress(Bitmap.CompressFormat.JPEG, 100, bos);//将图片压缩到流中
}else{
Toast.makeText(getContext(),"没有检测到内存卡", Toast.LENGTH_SHORT).show();
}
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
bos.flush();//输出
bos.close();//关闭
bm.recycle();// 回收bitmap空间
mCamera.stopPreview();// 关闭预览
mCamera.startPreview();// 开启预览
} catch (IOException e) {
e.printStackTrace();
}
}
}
};
然后调用camera.takePicture方法实现拍照
/**
* 拍照方法
* @param onRecordFinishListener 拍照完成后的回调接口
*/
public void takePicture(OnRecordFinishListener onRecordFinishListener) {
this.mOnRecordFinishListener = onRecordFinishListener;
pause();
try {
if (!isOpenCamera)
initCamera();
Log.e(TAG, ""+mCamera);
this.mCamera.autoFocus(new AutoFocusCallback() {
@Override
public void onAutoFocus(boolean flag, Camera camera) {
camera.takePicture(shutter, raw, jpeg);
}
});
// mCamera.takePicture(null, null, jpeg);
if (mOnRecordFinishListener != null)
mOnRecordFinishListener.onRecordFinish();
} catch (IOException e) {
e.printStackTrace();
}
}
--或者进行拍摄操作
在拍照之前我们需要先初始化MediaRecorder:
/**
* 初始化
* @throws IOException
*/
@SuppressLint("NewApi")
private void initRecord() throws IOException {
mMediaRecorder = new MediaRecorder();
mMediaRecorder.reset();
if (mCamera != null)
mMediaRecorder.setCamera(mCamera);
mMediaRecorder.setOnErrorListener(this);
mMediaRecorder.setPreviewDisplay(mSurfaceHolder.getSurface());
mMediaRecorder.setVideoSource(VideoSource.CAMERA);// 视频源
mMediaRecorder.setAudioSource(AudioSource.MIC);// 音频源
mMediaRecorder.setOutputFormat(OutputFormat.MPEG_4);// 视频输出格式
mMediaRecorder.setAudioEncoder(AudioEncoder.AMR_NB);// 音频格式
mMediaRecorder.setVideoSize(mWidth, mHeight);// 设置分辨率：
// mMediaRecorder.setVideoFrameRate(16);// 这个我把它去掉了，感觉没什么用
mMediaRecorder.setVideoEncodingBitRate(1 * 1024 * 1024 * 100);// 设置帧频率，然后就清晰了
mMediaRecorder.setOrientationHint(90);// 输出旋转90度，保持竖屏录制
mMediaRecorder.setVideoEncoder(VideoEncoder.MPEG_4_SP);// 视频录制格式
// mediaRecorder.setMaxDuration(Constant.MAXVEDIOTIME * 1000);
mMediaRecorder.setOutputFile(mVecordFile.getAbsolutePath());
mMediaRecorder.prepare();
try {
mMediaRecorder.start();//开始录制
} catch (IllegalStateException e) {
e.printStackTrace();
} catch (RuntimeException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
}
这里的录制是限制了事件的长按录制
/**
* 开始录制视频
* @param fileName
* 视频储存位置
* @param onRecordFinishListener
* 达到指定时间之后回调接口
*/
public void record(final OnRecordFinishListener onRecordFinishListener) {
this.mOnRecordFinishListener = onRecordFinishListener;
createRecordDir();
try {
if (!isOpenCamera)// 如果未打开摄像头，则打开
initCamera();
mTimeCount = 0;// 时间计数器重新赋值
initRecord();
mTimer = new Timer();
mTimer.schedule(new TimerTask() {
@Override
public void run() {
mTimeCount++;
mProgressBar.setProgress(mTimeCount);// 设置进度条
if ((mTimeCount-1) == mRecordMaxTime) {// 达到指定时间，停止拍摄
stop();
if (mOnRecordFinishListener != null)
mOnRecordFinishListener.onRecordFinish();
}
}
// }
}, 0, 1000);
} catch (IOException e) {
e.printStackTrace();
}
}
在拍摄完成后要记住关闭摄像头释放资源
/**
* 停止拍摄
*/
public void stop() {
stopRecord();
releaseRecord();
freeCameraResource();
}
/**
* 停止录制
*/
public void stopRecord() {
mProgressBar.setProgress(0);
if (mTimer != null)
mTimer.cancel();
if (mMediaRecorder != null) {
// 设置后不会崩
mMediaRecorder.setOnErrorListener(null);
mMediaRecorder.setPreviewDisplay(null);
try {
mMediaRecorder.stop();
} catch (IllegalStateException e) {
e.printStackTrace();
} catch (RuntimeException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
}
}
/**
* 释放资源
*/
private void releaseRecord() {
if (mMediaRecorder != null) {
mMediaRecorder.setOnErrorListener(null);
try {
mMediaRecorder.release();
} catch (IllegalStateException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
}
mMediaRecorder = null;
}
/**
* 释放摄像头资源
*/
private void freeCameraResource() {
if (mCamera != null) {
mCamera.setPreviewCallback(null);
mCamera.stopPreview();
// mCamera.lock();
mCamera.release();
mCamera = null;
isOpenCamera = false;
}
}
最后要记得添加权限
<uses-permission android:name="android.permission.CAMERA" /><!-- 调用相机权限 -->
<uses-feature android:name="android.hardware.camera.autofocus" /><!-- 自动聚焦权限 -->
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" /><!-- SD卡写权限 -->
总结
Android自定义相机实现的主要问题在于实现预览时图像会旋转不同的方向,我们需要根据不同的手机方向设置预览图像旋转角度。
这里因为设置不可旋转,所以只需要设置
mCamera.setDisplayOrientation(90);
