从相机拍摄全尺寸照片

要拍照，首先我们需要在 AndroidManifest.xml 中声明所需的权限。我们需要两个权限：

• Camera - 打开相机应用程序。如果属性 required 设置为 true，如果你没有硬件摄像头，则无法安装此应用程序。
• WRITE_EXTERNAL_STORAGE - 创建新文件需要此权限，其中将保存捕获的照片。

AndroidManifest.xml 中

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

从相机拍摄全尺寸照片的主要想法是，在打开相机应用程序和拍摄照片之前，我们需要为照片创建新文件。

private void dispatchTakePictureIntent() {
    Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
    // Ensure that there's a camera activity to handle the intent
    if (takePictureIntent.resolveActivity(getPackageManager()) != null) {
        // Create the File where the photo should go
        File photoFile = null;
        try {
            photoFile = createImageFile();
        } catch (IOException ex) {
            Log.e("DEBUG_TAG", "createFile", ex);
        }
        // Continue only if the File was successfully created
        if (photoFile != null) {
            takePictureIntent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(photoFile));
            startActivityForResult(takePictureIntent, REQUEST_IMAGE_CAPTURE);
        }
    }
}

private File createImageFile() throws IOException {
    // Create an image file name
    String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss", Locale.getDefault()).format(new Date());
    String imageFileName = "JPEG_" + timeStamp + "_";
    File storageDir = getAlbumDir();
    File image = File.createTempFile(
            imageFileName,  /* prefix */
            ".jpg",         /* suffix */
            storageDir      /* directory */
    );

    // Save a file: path for use with ACTION_VIEW intents
    mCurrentPhotoPath = image.getAbsolutePath();
    return image;
}

private File getAlbumDir() {
    File storageDir = null;

    if (Environment.MEDIA_MOUNTED.equals(Environment.getExternalStorageState())) {

        storageDir = new File(Environment.getExternalStorageDirectory()
                + "/dcim/"
                + "MyRecipes");

        if (!storageDir.mkdirs()) {
            if (!storageDir.exists()) {
                Log.d("CameraSample", "failed to create directory");
                return null;
            }
        }

    } else {
        Log.v(getString(R.string.app_name), "External storage is not mounted READ/WRITE.");
    }

    return storageDir;
}

private void setPic() {

    /* There isn't enough memory to open up more than a couple camera photos */
    /* So pre-scale the target bitmap into which the file is decoded */

    /* Get the size of the ImageView */
    int targetW = recipeImage.getWidth();
    int targetH = recipeImage.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 = 2;
    if ((targetW > 0) && (targetH > 0)) {
        scaleFactor = Math.max(photoW / targetW, photoH / targetH);
    }

    /* Set bitmap options to scale the image decode target */
    bmOptions.inJustDecodeBounds = false;
    bmOptions.inSampleSize = scaleFactor;
    bmOptions.inPurgeable = true;

    Matrix matrix = new Matrix();
    matrix.postRotate(getRotation());

    /* Decode the JPEG file into a Bitmap */
    Bitmap bitmap = BitmapFactory.decodeFile(mCurrentPhotoPath, bmOptions);
    bitmap = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, false);

    /* Associate the Bitmap to the ImageView */
    recipeImage.setImageBitmap(bitmap);
}

private float getRotation() {
    try {
        ExifInterface ei = new ExifInterface(mCurrentPhotoPath);
        int orientation = ei.getAttributeInt(ExifInterface.TAG_ORIENTATION, ExifInterface.ORIENTATION_NORMAL);

        switch (orientation) {
            case ExifInterface.ORIENTATION_ROTATE_90:
                return 90f;
            case ExifInterface.ORIENTATION_ROTATE_180:
                return 180f;
            case ExifInterface.ORIENTATION_ROTATE_270:
                return 270f;
            default:
                return 0f;
        }
    } catch (Exception e) {
        Log.e("Add Recipe", "getRotation", e);
        return 0f;
    }
}

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);
    sendBroadcast(mediaScanIntent);
}

private void handleBigCameraPhoto() {

    if (mCurrentPhotoPath != null) {
        setPic();
        galleryAddPic();
    }
}

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    if (requestCode == REQUEST_IMAGE_CAPTURE && resultCode == Activity.RESULT_OK) {
        handleBigCameraPhoto();
    }
}