android中相机的简单调用
1.生命周期方法中初始化和释放Camera
@TargetApi(Build.VERSION_CODES.GINGERBREAD)
@Override
public void onResume() {
super.onResume();
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.GINGERBREAD) {
mCamera = Camera.open(0);
} else {
mCamera = Camera.open();
}
}
@Override
public void onPause() {
super.onPause();
if (mCamera != null) {
mCamera.release();
mCamera = null;
}
}
2. 设置SurfaceView
mSurfaceView = (SurfaceView) view
.findViewById(R.id.crime_camera_surfaceView);
SurfaceHolder holder = mSurfaceView.getHolder();
holder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
holder.addCallback(new SurfaceHolder.Callback() {
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
if (mCamera != null) {
mCamera.stopPreview();
}
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
if (mCamera != null) {
try {
mCamera.setPreviewDisplay(holder);
} catch (IOException e) {
e.printStackTrace();
}
}
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format,
int width, int height) {
Camera.Parameters parameters = mCamera.getParameters();
//设置预览图片大小
Size size = getBestSupportSize(
parameters.getSupportedPreviewSizes(), width, height);
parameters.setPreviewSize(size.width, size.height);
//设置实际生成的图片大小
size = getBestSupportSize(parameters.getSupportedPictureSizes(),
width, height);
parameters.setPictureSize(size.width, size.height);
mCamera.setParameters(parameters);
try {
mCamera.startPreview();
} catch (Exception e) {
mCamera.release();
mCamera = null;
}
}
});
//获得最佳的支持尺寸
private Size getBestSupportSize(List<Size> sizes, int width, int height) {
Size bestSize = sizes.get(0);
int largestArea = bestSize.width * bestSize.height;
for (Size size : sizes) {
int area = size.width * size.height;
if (area > largestArea) {
bestSize = size;
largestArea = area;
}
}
return bestSize;
}
3. 点击按钮时调用takePicture API，与在回调中保存图和片
.takePicture(mShutterCallback shutter, PictureCallback raw, PictureCallback jpg); 方法
ShutterCallback回调方法会在相机捕获图像时调用，但此时，图像数据还未处理完成。
第
一个PictureCallback回调方法是在原始图像数据可用时调用，通常来说，是在加工处理原始图
像数据且没有存储之前。
第二个PictureCallback回调方法是在JPEG版本的图像可用时调用
Button takePicbButton = (Button) view
.findViewById(R.id.crime_camera_takePictureButton);
takePicbButton.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
//getActivity().finish();
if (mCamera != null) {
mCamera.takePicture(mShutterCallback, null, mPictureCallback);
}
}
});
// 相机的回调
private Camera.ShutterCallback mShutterCallback = new Camera.ShutterCallback() {
@Override
public void onShutter() {
mProgressContainer.setVisibility(View.VISIBLE);
}
};
private Camera.PictureCallback mPictureCallback = new Camera.PictureCallback() {
@Override
public void onPictureTaken(byte[] data, Camera camera) {
String fileName = UUID.randomUUID().toString() + ".jpg";
FileOutputStream fos = null;
boolean success = true;
try {
fos = getActivity().openFileOutput(fileName,
Context.MODE_PRIVATE);
fos.write(data);
} catch (Exception e) {
e.printStackTrace();
success = false;
} finally {
if (fos != null) {
try {
fos.close();
} catch (IOException e) {
e.printStackTrace();
success = false;
}
if (success) {
Log.i(TAG, "JPEG save at " + fileName);
//把路径返回给CrimeActivity
Intent intent = new Intent();
intent.putExtra(EXTRAL_PHOTO_FILENAME, fileName);
getActivity().setResult(Activity.RESULT_OK, intent);
} else {
getActivity().setResult(Activity.RESULT_CANCELED);
}
}
getActivity().finish();
}
}
};
4. 设置图片缩放显示
public static BitmapDrawable getScaledDrawable(Activity activity,
String path) {
Display display = activity.getWindowManager().getDefaultDisplay();
int destWidth = display.getWidth();
int destHeight = display.getHeight();
BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeFile(path, options);
float srcWidth = options.outWidth;
float srcHeight = options.outHeight;
int inSampleSize = 1;
if (srcWidth > destWidth || srcHeight > destHeight) {
if (srcWidth > srcHeight) {
inSampleSize = Math.round(srcHeight / destHeight);
} else {
inSampleSize = Math.round(srcWidth / destWidth);
}
}
options = new BitmapFactory.Options();
options.inSampleSize = inSampleSize;
Bitmap bitmap = BitmapFactory.decodeFile(path, options);
return new BitmapDrawable(activity.getResources(), bitmap);
}