使用安卓相机应用拍照时，它会检测手机的方向并据此保存照片。因此，如果我拍摄一幢建筑的照片，无论我是竖屏还是横屏拍摄，屋顶都会在顶部。
但是，当我使用
Intent imageCaptureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
在获取图片时，相机应用程序不会响应方向。
如果我将手机竖直（纵向）握持，拍摄的照片将被旋转，建筑物的屋顶位于屏幕左侧。
如何设置意图以使相机考虑方向？
或者我可以通过某种方式推断出拍摄照片时的方向并自行旋转它吗？
还是有其他方法吗？
我找到了答案。这张图片的 Exif 中有方向指示器。如果需要，在Android中可以像这样查看Exif：
ExifInterface exif = new ExifInterface("filepath");
exif.getAttribute(ExifInterface.TAG_ORIENTATION);
public static int getImageOrientation(Context context, String imagePath) {
int orientation = getOrientationFromExif(imagePath);
if(orientation <= 0) {
orientation = getOrientationFromMediaStore(context, imagePath);
}
return orientation;
}
private static int getOrientationFromExif(String imagePath) {
int orientation = -1;
try {
ExifInterface exif = new ExifInterface(imagePath);
int exifOrientation = exif.getAttributeInt(ExifInterface.TAG_ORIENTATION,
ExifInterface.ORIENTATION_NORMAL);
switch (exifOrientation) {
case ExifInterface.ORIENTATION_ROTATE_270:
orientation = 270;
break;
case ExifInterface.ORIENTATION_ROTATE_180:
orientation = 180;
break;
case ExifInterface.ORIENTATION_ROTATE_90:
orientation = 90;
break;
case ExifInterface.ORIENTATION_NORMAL:
orientation = 0;
break;
default:
break;
}
} catch (IOException e) {
Log.e(LOG_TAG, "Unable to get image exif orientation", e);
}
return orientation;
}
private static int getOrientationFromMediaStore(Context context, String imagePath) {
Uri imageUri = getImageContentUri(context, imagePath);
if(imageUri == null) {
return -1;
}
String[] projection = {MediaStore.Images.ImageColumns.ORIENTATION};
Cursor cursor = context.getContentResolver().query(imageUri, projection, null, null, null);
int orientation = -1;
if (cursor != null && cursor.moveToFirst()) {
orientation = cursor.getInt(0);
cursor.close();
}
return orientation;
}
private static Uri getImageContentUri(Context context, String imagePath) {
String[] projection = new String[] {MediaStore.Images.Media._ID};
String selection = MediaStore.Images.Media.DATA + "=? ";
String[] selectionArgs = new String[] {imagePath};
Cursor cursor = context.getContentResolver().query(IMAGE_PROVIDER_URI, projection,
selection, selectionArgs, null);
if (cursor != null && cursor.moveToFirst()) {
int imageId = cursor.getInt(0);
cursor.close();
return Uri.withAppendedPath(IMAGE_PROVIDER_URI, Integer.toString(imageId));
}
if (new File(imagePath).exists()) {
ContentValues values = new ContentValues();
values.put(MediaStore.Images.Media.DATA, imagePath);
return context.getContentResolver().insert(
MediaStore.Images.Media.EXTERNAL_CONTENT_URI, values);
}
return null;
}
快速解决方法是，检查图像的宽度是否大于图像的高度。如果宽度大于高度，则表示该图像为横向图像，您可以将其更改为竖向图像。
private Bitmap fromGallery(final Uri selectedImageUri) {
try {
Bitmap bm = MediaStore.Images.Media.getBitmap(this.getContentResolver(), selectedImageUri);
ExifInterface exif = new ExifInterface(selectedImageUri.getPath());
int orientation = exif.getAttributeInt(ExifInterface.TAG_ORIENTATION, ExifInterface.ORIENTATION_NORMAL);
int angle = 0;
switch (orientation) {
case ExifInterface.ORIENTATION_ROTATE_90:
angle = 90;
break;
case ExifInterface.ORIENTATION_ROTATE_180:
angle = 180;
break;
case ExifInterface.ORIENTATION_ROTATE_270:
angle = 270;
break;
default:
angle = 0;
break;
}
Matrix mat = new Matrix();
if (angle == 0 && bm.getWidth() > bm.getHeight())
mat.postRotate(90);
else
mat.postRotate(angle);
return Bitmap.createBitmap(bm, 0, 0, bm.getWidth(), bm.getHeight(), mat, true);
}
catch (IOException e) {
Log.e("", "-- Error in setting image");
}
catch (OutOfMemoryError oom) {
Log.e("", "-- OOM Error in setting image");
}
return null;
}
我使用了一个文件提供程序，除了制作临时副本并从中读取数据外，什么都没有起作用。
public static int getOrientation(Context context, Uri uri) {
int rotate = 0;
try {
ParcelFileDescriptor parcelFileDescriptor =
context.getContentResolver().openFileDescriptor(uri, "r");
FileDescriptor fileDescriptor = parcelFileDescriptor.getFileDescriptor();
FileInputStream input = new FileInputStream(fileDescriptor);
File tempFile = File.createTempFile("exif", "tmp");
String tempFilename = tempFile.getPath();
FileOutputStream output = new FileOutputStream(tempFile.getPath());
int read;
byte[] bytes = new byte[4096];
while ((read = input.read(bytes)) != -1) {
output.write(bytes, 0, read);
}
input.close();
output.close();
ExifInterface exif = new ExifInterface(tempFile.getAbsolutePath());
int orientation = exif.getAttributeInt(ExifInterface.TAG_ORIENTATION, ExifInterface.ORIENTATION_NORMAL);
switch (orientation) {
case ExifInterface.ORIENTATION_ROTATE_270:
rotate = 270;
break;
case ExifInterface.ORIENTATION_ROTATE_180:
rotate = 180;
break;
case ExifInterface.ORIENTATION_ROTATE_90:
rotate = 90;
break;
}
} catch (Exception e) {
Log.i(TAG, e.getLocalizedMessage());
}
return rotate;
}
奖励旋转功能
public static Bitmap rotateImage(Context context, Uri uri, int orientation) throws IOException {
ParcelFileDescriptor parcelFileDescriptor =
context.getContentResolver().openFileDescriptor(uri, "r");
FileDescriptor fileDescriptor = parcelFileDescriptor.getFileDescriptor();
Bitmap bitmap = BitmapFactory.decodeFileDescriptor(fileDescriptor);
parcelFileDescriptor.close();
if (orientation > 0) {
Matrix matrix = new Matrix();
matrix.postRotate(orientation);
return Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, true);
}
return bitmap;
}