<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-feature
  android:name="android.hardware.camera2"
  android:required="false" />

private String mCurrentPhotoPath;
/**
* 拍照flag
*/
private static final int REQUEST_IMAGE_CAPTURE_O = 2;

 /**
* 创建拍摄的图片的存储路径及文件名
* @return
* @throws IOException
*/
private File createImageFile() throws IOException{
  String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
  String imageFileName = "JPEG_" + timeStamp + "_";
  File storageDir = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES);
  Log.d("TrainingFirstActivity", "storageDir:" + storageDir);
  File image = File.createTempFile(imageFileName, ".jpg", storageDir);
  mCurrentPhotoPath = image.getAbsolutePath();
  Log.d("image.getAbsolutePath()", image.getAbsolutePath() + "");
  return image;
}

Intent takePictureOintent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
if (takePictureOintent.resolveActivity(getPackageManager()) != null){
 File photoFile = null;
 try {
  photoFile = createImageFile();
 } catch (IOException e) {
  e.printStackTrace();
 }
 if (photoFile != null){
  takePictureOintent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(photoFile));
  startActivityForResult(takePictureOintent, REQUEST_IMAGE_CAPTURE_O);
 }
}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
  if (requestCode == REQUEST_IMAGE_CAPTURE_O && resultCode == RESULT_OK){
   int targetW = takePhotoThenToShowImg.getWidth();
   int targetH = takePhotoThenToShowImg.getHeight();
  /* Get the size of the image */
   BitmapFactory.Options bmOptions = new BitmapFactory.Options();
   bmOptions.inJustDecodeBounds = true;
   BitmapFactory.decodeFile(mCurrentPhotoPath, bmOptions);
   int photoW = bmOptions.outWidth;
   int photoH = bmOptions.outHeight;
  /* Figure out which way needs to be reduced less */
   int scaleFactor = 1;
   if ((targetW > 0) || (targetH > 0)) {
    scaleFactor = Math.min(photoW/targetW, photoH/targetH);
   }
  /* Set bitmap options to scale the image decode target */
   bmOptions.inJustDecodeBounds = false;
   bmOptions.inSampleSize = scaleFactor;
   bmOptions.inPurgeable = true;
  /* Decode the JPEG file into a Bitmap */
   Bitmap bitmap = BitmapFactory.decodeFile(mCurrentPhotoPath, bmOptions);
  /* Associate the Bitmap to the ImageView */
   takePhotoThenToShowImg.setImageBitmap(bitmap);
   galleryAddPic();
  }
}

/**
* 将拍摄到的照片添加到Media Provider的数据库中
*/
private void galleryAddPic(){
  Intent mediaScanIntent = new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE);
  File f = new File(mCurrentPhotoPath);
  Uri contentUri = Uri.fromFile(f);
  mediaScanIntent.setData(contentUri);
  this.sendBroadcast(mediaScanIntent);
}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
 if (requestCode == REQUEST_IMAGE_CAPTURE && resultCode == RESULT_OK){//展示图片
   Bundle extras = data.getExtras();
   Bitmap imageBitmap = (Bitmap) extras.get("data");
   takePhotoThenToShowImg.setImageBitmap(imageBitmap);
  }
}