作者：某人_Valar
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在Android的开发过程中，目前使用相机大概分为两种方式，一种是直接拉起系统的相机进行拍照，另一种就是自定义一个相机界面。
关于自定义相机的使用：
在自定义相机中我们就可以自定义拍照的界面，设置拍照的参数等。
一个自定义的相机界面
主要是一个自定义的Activity，
- 使用CameraPreview 进行预览，
- 然后调用Camera的takePicture方法拍照，
- 之后再对应的回调中保存或者展示即可。
public class CameraActivity extends Activity {
protected static final String TAG = "raycamera";
private Camera mCamera;
private int cameraPosition = 0;//0代表后置摄像头，1代表前置摄像头
private SurfaceHolder mHolder;
static CameraActivity mInstance = null;
private File compressFile;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_camera);
ButterKnife.bind(this);
CameraPreview mPreview = new CameraPreview(this);
FrameLayout preview = (FrameLayout) findViewById(R.id.camera_preview);
preview.addView(mPreview);
mInstance = this;
}
public static Camera getCameraInstance() {
Camera c = null;
try {
c = Camera.open(0);
} catch (Exception e) {
// Camera is notavailable (in use or does not exist)
}
return c;
}
@OnClick(R.id.capture_iv)
void takePic() {
mCamera.takePicture(null, null, mPicture);
tip("拍照中，请保持手机稳定");
}
//点击屏幕进行对焦
@OnClick(R.id.camera_preview)
void autoFocus() {
try {
mCamera.autoFocus(autoFocusCallback);
} catch (Exception e) {
e.printStackTrace();
}
}
@OnClick(R.id.changeCamera_iv)
void changeCamera() {
//切换前后摄像头
Camera.CameraInfo cameraInfo = new Camera.CameraInfo();
int cameraCount = Camera.getNumberOfCameras();//得到摄像头的个数
for (int i = 0; i < cameraCount; i++) {
Camera.getCameraInfo(i, cameraInfo);//得到每一个摄像头的信息
if (cameraPosition == 0) {
//现在是后置，变更为前置
if (cameraInfo.facing == Camera.CameraInfo.CAMERA_FACING_FRONT) {
if (mCamera != null) {
mCamera.stopPreview();//停掉原来摄像头的预览
mCamera.release();//释放资源
mCamera = null;//取消原来摄像头
}
Log.d(TAG, "open front ,i = " + i);
mCamera = Camera.open(i);//打开当前选中的摄像头
try {
mCamera.setPreviewDisplay(mHolder);//通过surfaceview显示取景画面
mCamera.setDisplayOrientation(90);
setCameraParms(mCamera);
} catch (IOException e) {
e.printStackTrace();
}
mCamera.startPreview();//开始预览
cameraPosition = 1;
break;
}
} else {
//现在是前置， 变更为后置
if (cameraInfo.facing == Camera.CameraInfo.CAMERA_FACING_BACK) {
if (mCamera != null) {
mCamera.stopPreview();//停掉原来摄像头的预览
mCamera.release();//释放资源
mCamera = null;//取消原来摄像头
}
Log.d(TAG, "open back ,i = " + i);
mCamera = Camera.open(i);//打开当前选中的摄像头
try {
mCamera.setPreviewDisplay(mHolder);//通过surfaceview显示取景画面
mCamera.setDisplayOrientation(90);
setCameraParms(mCamera);
} catch (IOException e) {
e.printStackTrace();
}
mCamera.startPreview();//开始预览
cameraPosition = 0;
break;
}
}
}
}
public class CameraPreview extends SurfaceView implements
SurfaceHolder.Callback {
// private Camera mCamera;
public CameraPreview(Context context) {
super(context);
//mCamera = camera;
mHolder = getHolder();
mHolder.addCallback(this);
// deprecatedsetting, but required on Android versions prior to 3.0
mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
public void surfaceCreated(SurfaceHolder holder) {
Log.d(TAG, "surfaceCreated: ");
cameraPosition = 0;//创建时设置默认后置摄像头
mCamera = getCameraInstance();
try {
mCamera.setPreviewDisplay(holder);
mCamera.setDisplayOrientation(90);
mCamera.startPreview();
} catch (IOException e) {
Log.d(TAG, "Errorsetting camera preview: " + e.getMessage());
}
}
public void surfaceDestroyed(SurfaceHolder holder) {
Log.d(TAG, "surfaceDestroyed: ");
if (mCamera != null) {
mCamera.release();
mCamera = null;
}
}
public void surfaceChanged(SurfaceHolder holder, int format, int w,
int h) {
// If your preview can change or rotate, take care of those events here.
// Make sure to stop the preview before resizing or reformatting it.
Log.d(TAG, "surfaceChanged ");
if (mHolder.getSurface() == null) {
return;
}
try {
mCamera.stopPreview();
} catch (Exception e) {
// ignore: triedto stop a non-existent preview
}
try {
mCamera.setPreviewDisplay(mHolder);
mCamera.setDisplayOrientation(90);
mCamera.startPreview();
setCameraParms(mCamera);
} catch (Exception e) {
Log.d(TAG, "Errorstarting camera preview: " + e.getMessage());
}
}
}
private void setCameraParms(Camera camera) {
Camera.Parameters params = camera.getParameters();
//设置相机保存图片的尺寸大小
List supportSizes = params.getSupportedPictureSizes();
Camera.Size bestSize = supportSizes.get(0);
for (int i = 1; i < supportSizes.size(); i++) {
if ((supportSizes.get(i).width * supportSizes.get(i).height) > (bestSize.width * bestSize.height)) {
bestSize = supportSizes.get(i);
}
}
params.setPictureSize(bestSize.width, bestSize.height);
camera.setParameters(params);
}
Camera.AutoFocusCallback autoFocusCallback = new Camera.AutoFocusCallback() {
@Override
public void onAutoFocus(boolean success, Camera camera) {
}
};
//拍照结束后的回调
private PictureCallback mPicture = new PictureCallback() {
@Override
public void onPictureTaken(byte[] data, Camera camera) {
camera.stopPreview();
File file = new File(Environment.getExternalStorageDirectory().getAbsolutePath() + "/songshucang");
boolean isFileCreated = file.exists();
if (!isFileCreated) {
isFileCreated = file.mkdir();
}
if (isFileCreated) {
Bitmap bm = BitmapFactory.decodeByteArray(data, 0, (data != null) ? data.length : 0);
final Matrix matrix = new Matrix();
if (cameraPosition == 0) {
matrix.setRotate(90);
} else {
matrix.setRotate(270);
}
final Bitmap bitmap =
Bitmap.createBitmap(bm, 0, 0, bm.getWidth(), bm.getHeight(), matrix, true);
String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss", Locale.CHINA)
.format(new Date());
String photoPath = file + "/ssc/IMG_" + timeStamp;
try {
saveImageToSD(CameraActivity.this,
photoPath, bitmap, 90);
//拍照完成后用广播通知系统相册更新，否则可能在相册中看不见刚保存的图片
File fileTemp = new File(photoPath);
Uri uri = Uri.fromFile(fileTemp);
Intent intent = new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE);
intent.setData(uri);
CameraActivity.this.sendBroadcast(intent);
} catch (FileNotFoundException e) {
Log.i("cameratest", "File notfound: " + e.getMessage());
} catch (IOException e) {
Log.i("cameratest", "Erroraccessing file: " + e.getMessage());
}
}
}
};
//保存图片
public void saveImageToSD(String filePath,
Bitmap bitmap, int quality) throws IOException {
if (bitmap != null) {
File file = new File(filePath.substring(0,
filePath.lastIndexOf(File.separator)));
if (!file.exists()) {
file.mkdirs();
}
BufferedOutputStream bos = new BufferedOutputStream(
new FileOutputStream(filePath));
bitmap.compress(Bitmap.CompressFormat.JPEG, quality, bos);
bos.flush();
bos.close();
}
}
@Override
public void onPause() {
super.onPause();
if (mCamera != null) {
mCamera.stopPreview();
mCamera.release();
mCamera = null;
}
}
}
布局文件如下：
有时候我们会发现拍照保存的图片在相册中查看不到，这是因为没有通知系统相册更新。
//拍照完成后用广播通知系统相册更新
File fileTemp = new File(photoPath);
Uri uri = Uri.fromFile(fileTemp);
Intent intent = new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE);
intent.setData(uri);
CameraActivity.this.sendBroadcast(intent);