本文记录了用自定义Camera实现的简单拍照功能。
Camera类在5.0以后不推荐使用了，取而代之的是android.hardware.camera2包下的类，本文使用Camera。
我们首先自定义一个View去继承SurfaceView:
public class CameraSurfaceView extends SurfaceView implements SurfaceHolder.Callback, Camera.AutoFocusCallback {
private SurfaceHolder mHolder;
private Camera mCamera;
private static final int ORIENTATION = 90;
private int mScreenWidth;
private int mScreenHeight;
private boolean isOpen;
public CameraSurfaceView(Context context, AttributeSet attrs) {
super(context, attrs);
getScreenMatrix(context);
mHolder = getHolder();
mHolder.addCallback(this);
mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
private void getScreenMatrix(Context context) {
WindowManager WM = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
DisplayMetrics outMetrics = new DisplayMetrics();
WM.getDefaultDisplay().getMetrics(outMetrics);
mScreenWidth = outMetrics.widthPixels;
mScreenHeight = outMetrics.heightPixels;
}
public void takePicture(Camera.ShutterCallback mShutterCallback, Camera.PictureCallback rawPictureCallback, Camera.PictureCallback jpegPictureCallback) {
if (mCamera != null)
mCamera.takePicture(mShutterCallback, rawPictureCallback, jpegPictureCallback);
}
public void startPreview() {
mCamera.startPreview();
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
if (!checkCameraHardware(getContext()))
return;
if (mCamera == null) {
isOpen = safeCameraOpen(Camera.CameraInfo.CAMERA_FACING_BACK);
}
if (!isOpen) {
return;
}
mCamera.setDisplayOrientation(ORIENTATION);
try {
mCamera.setPreviewDisplay(holder);
} catch (IOException e) {
e.printStackTrace();
}
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
if (mCamera != null) {
setCameraParams(mScreenWidth, mScreenHeight);
mCamera.startPreview();
}
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
releaseCameraAndPreview();
}
private boolean safeCameraOpen(int id) {
boolean qOpened = false;
try {
releaseCameraAndPreview();
mCamera = Camera.open(id);
qOpened = (mCamera != null);
} catch (Exception e) {
e.printStackTrace();
}
return qOpened;
}
private void releaseCameraAndPreview() {
if (mCamera != null) {
mCamera.stopPreview();
mCamera.release();
mCamera = null;
}
}
private boolean checkCameraHardware(Context context) {
if (context.getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA)) {
return true;
} else {
return false;
}
}
@Override
public void onAutoFocus(boolean success, Camera camera) {
}
private void setCameraParams(int width, int height) {
Camera.Parameters parameters = mCamera.getParameters();
// 获取摄像头支持的PictureSize列表
List<Camera.Size> pictureSizeList = parameters.getSupportedPictureSizes();
/**从列表中选取合适的分辨率*/
Camera.Size picSize = getProperSize(pictureSizeList, ((float) height / width));
if (null == picSize) {
picSize = parameters.getPictureSize();
}
// 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) {
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
}
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);
}
/**
* 选取合适的分辨率
*/
private Camera.Size getProperSize(List<Camera.Size> pictureSizeList, float 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;
}
}
代码没什么难度，在View创建的时候完成Camera的初始化，然后对Camera进行参数的设置（图片尺寸，质量之类的），最后别忘了在View销毁的时候对资源进行释放。
控件定义完了之后我们就要去使用它，在布局文件中添加就OK：
<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/activity_main" android:layout_width="match_parent" android:layout_height="match_parent" > <com.padoon.cameratest.CameraSurfaceView android:id="@+id/sv_camera" android:layout_width="match_parent" android:layout_height="match_parent" android:layout_weight="4"/> <ImageView android:id="@+id/img_take_photo" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignParentBottom="true" android:layout_alignParentRight="true" android:layout_gravity="bottom" android:layout_marginBottom="10dp" android:layout_marginRight="10dp" android:src="@mipmap/icon_camera"/> </RelativeLayout>
然后在Activity中去完成拍照功能：
public class CameraActivity extends AppCompatActivity {
private boolean isClick = true;
private static final String PATH_IMAGES = Environment.getExternalStorageDirectory().getAbsolutePath() + File.separator + "easy_check";
private CameraSurfaceView mCameraSurfaceView;
//拍照快门的回调
private Camera.ShutterCallback mShutterCallback = new Camera.ShutterCallback() {
@Override
public void onShutter() {
}
};
//拍照完成之后返回原始数据的回调
private Camera.PictureCallback rawPictureCallback = new Camera.PictureCallback() {
@Override
public void onPictureTaken(byte[] data, Camera camera) {
}
};
//拍照完成之后返回压缩数据的回调
private Camera.PictureCallback jpegPictureCallback = new Camera.PictureCallback() {
@Override
public void onPictureTaken(byte[] data, Camera camera) {
mCameraSurfaceView.startPreview();
saveFile(data);
Toast.makeText(CameraActivity.this, "拍照成功", Toast.LENGTH_SHORT).show();
isClick = true;
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ImageView img_take_photo = (ImageView) findViewById(R.id.img_take_photo);
mCameraSurfaceView = (CameraSurfaceView) findViewById(R.id.sv_camera);
img_take_photo.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
takePhoto();
}
});
}
public void takePhoto() {
if (isClick) {
isClick = false;
mCameraSurfaceView.takePicture(mShutterCallback, rawPictureCallback, jpegPictureCallback);
}
}
//保存图片到硬盘
public void saveFile(byte[] data) {
String fileName = UUID.randomUUID().toString() + ".jpg";
FileOutputStream outputStream = null;
try {
File file = new File(PATH_IMAGES);
if (!file.exists()) {
file.mkdirs();
}
outputStream = new FileOutputStream(PATH_IMAGES + File.separator + fileName);
BufferedOutputStream bufferedOutputStream = new BufferedOutputStream(outputStream);
bufferedOutputStream.write(data, 0, data.length);
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
outputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
最后记得添加拍照跟磁盘操作权限：
<uses-permission android:name="android.permission.CAMERA"/> <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
到这一个非常简单的拍照Demo就完成了，只能当做Demo使用，离开发正式使用还有一段的距离，再次特地记录一下。
下载：源码
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