在将媒体库中的图像加载到位图中时,一切都正常,但是使用手机竖直拍摄的照片会被旋转,导致即使在媒体库中它看起来是竖直的,但我得到的却是横向的图片。
为什么会这样,我应该如何正确地加载它?
所以,举个例子...
首先,您需要创建一个ExifInterface:
ExifInterface exif = new ExifInterface(filename);
接下来,您可以获取图像的方向:
orientation = exif.getAttributeInt(ExifInterface.TAG_ORIENTATION, 1);
这是方向值的意思:
http://sylvana.net/jpegcrop/exif_orientation.html
因此,最重要的值是3、6和8。
例如,如果方向是ExifInterface.ORIENTATION_ROTATE_90
(即6),则可以这样旋转图像:Matrix matrix = new Matrix();
matrix.postRotate(90);
rotatedBitmap = Bitmap.createBitmap(sourceBitmap, 0, 0, sourceBitmap.getWidth(), sourceBitmap.getHeight(), matrix, true);
那只是一个快速的例子,我相信还有其他的方法来执行实际的旋转。但是您也可以在StackOverflow上找到这些方法。
OutOfMemoryError
,因为它需要同时在内存中保存两个位图。请注意避免。 - Alex Bonel通过参考这篇文章,我用以下代码解决了我的问题:
Bitmap myBitmap = getBitmap(imgFile.getAbsolutePath());
try {
ExifInterface exif = new ExifInterface(imgFile.getAbsolutePath());
int orientation = exif.getAttributeInt(ExifInterface.TAG_ORIENTATION, 1);
Log.d("EXIF", "Exif: " + orientation);
Matrix matrix = new Matrix();
if (orientation == 6) {
matrix.postRotate(90);
}
else if (orientation == 3) {
matrix.postRotate(180);
}
else if (orientation == 8) {
matrix.postRotate(270);
}
myBitmap = Bitmap.createBitmap(myBitmap, 0, 0, myBitmap.getWidth(), myBitmap.getHeight(), matrix, true); // rotating bitmap
}
catch (Exception e) {
}
ImageView img = (ImageView) findViewById(R.id.imgTakingPic);
img.setImageBitmap(myBitmap);
希望它能为某人节省时间!
这是一个完整的解决方案(在Facebook SDK的Hackbook示例中找到)。它不需要访问文件本身,这是非常有用的,特别是当你从内容解析器加载图像时(例如,如果你的应用响应于共享照片意图)。
public static int getOrientation(Context context, Uri photoUri) {
/* it's on the external media. */
Cursor cursor = context.getContentResolver().query(photoUri,
new String[] { MediaStore.Images.ImageColumns.ORIENTATION }, null, null, null);
if (cursor.getCount() != 1) {
return -1;
}
cursor.moveToFirst();
return cursor.getInt(0);
}
然后,您可以按以下方式获得旋转的位图。该代码还将图像缩小(不幸的是效果很差),以MAX_IMAGE_DIMENSION为最大尺寸。否则,您可能会耗尽内存。
public static Bitmap getCorrectlyOrientedImage(Context context, Uri photoUri) throws IOException {
InputStream is = context.getContentResolver().openInputStream(photoUri);
BitmapFactory.Options dbo = new BitmapFactory.Options();
dbo.inJustDecodeBounds = true;
BitmapFactory.decodeStream(is, null, dbo);
is.close();
int rotatedWidth, rotatedHeight;
int orientation = getOrientation(context, photoUri);
if (orientation == 90 || orientation == 270) {
rotatedWidth = dbo.outHeight;
rotatedHeight = dbo.outWidth;
} else {
rotatedWidth = dbo.outWidth;
rotatedHeight = dbo.outHeight;
}
Bitmap srcBitmap;
is = context.getContentResolver().openInputStream(photoUri);
if (rotatedWidth > MAX_IMAGE_DIMENSION || rotatedHeight > MAX_IMAGE_DIMENSION) {
float widthRatio = ((float) rotatedWidth) / ((float) MAX_IMAGE_DIMENSION);
float heightRatio = ((float) rotatedHeight) / ((float) MAX_IMAGE_DIMENSION);
float maxRatio = Math.max(widthRatio, heightRatio);
// Create the bitmap from file
BitmapFactory.Options options = new BitmapFactory.Options();
options.inSampleSize = (int) maxRatio;
srcBitmap = BitmapFactory.decodeStream(is, null, options);
} else {
srcBitmap = BitmapFactory.decodeStream(is);
}
is.close();
/*
* if the orientation is not 0 (or -1, which means we don't know), we
* have to do a rotation.
*/
if (orientation > 0) {
Matrix matrix = new Matrix();
matrix.postRotate(orientation);
srcBitmap = Bitmap.createBitmap(srcBitmap, 0, 0, srcBitmap.getWidth(),
srcBitmap.getHeight(), matrix, true);
}
return srcBitmap;
}
ExifInterface exif = new ExifInterface(photoUri.getPath());
然后使用 exif.getAttributeInt(ExifInterface.TAG_ORIENTATION, 1)
来获取方向(例如 ORIENTATION_ROTATE_90
、ORIENTATION_ROTATE_180
)。 - Atul9re创建了一个简单的实用工具,可处理EXIF数据和旋转图像以将其正确方向,轻松解决繁重的问题。
您可以在此处找到实用程序代码:https://gist.github.com/9re/1990019
只需下载它,将其添加到项目的 src
目录中,并使用 ExifUtil.rotateBitmap()
获取正确的方向,如下所示:
String imagePath = photoFile.getAbsolutePath(); // photoFile is a File class.
Bitmap myBitmap = BitmapFactory.decodeFile(imagePath);
Bitmap orientedBitmap = ExifUtil.rotateBitmap(imagePath, myBitmap);
您是否查看过图片的EXIF数据?它可能会知道拍摄照片时相机的方向。
Kotlin 代码:
if (file.exists()){
val bitmap = BitmapFactory.decodeFile(file.absolutePath)
val exif = ExifInterface(file.absoluteFile.toString())
val orientation = exif.getAttributeInt(ExifInterface.TAG_ORIENTATION, ExifInterface.ORIENTATION_NORMAL)
val matrix = Matrix()
when(orientation){
ExifInterface.ORIENTATION_ROTATE_90 -> matrix.postRotate(90F)
ExifInterface.ORIENTATION_ROTATE_180 -> matrix.postRotate(180F)
ExifInterface.ORIENTATION_ROTATE_270 -> matrix.postRotate(270F)
}
val rotatedBitmap = Bitmap.createBitmap(bitmap, 0,0 , bitmap.width, bitmap.height, matrix, true)
bitmap.recycle()
iv_capture.setImageBitmap(rotatedBitmap)
}
这是因为图库正确显示旋转的图片,但 ImageView 却不行。请看这里:
myBitmap = BitmapFactory.decodeFile(imgFile.getAbsolutePath(),optionss);
ExifInterface exif = new ExifInterface(selectedImagePath);
int rotation = exif.getAttributeInt(ExifInterface.TAG_ORIENTATION, ExifInterface.ORIENTATION_NORMAL);
int rotationInDegrees = exifToDegrees(rotation);
deg = rotationInDegrees;
Matrix matrix = new Matrix();
if (rotation != 0f) {
matrix.preRotate(rotationInDegrees);
myBitmap = Bitmap.createBitmap(myBitmap, 0, 0, myBitmap.getWidth(), myBitmap.getHeight(), matrix, true);
}
并且您需要这个:
private static int exifToDegrees(int exifOrientation) {
if (exifOrientation == ExifInterface.ORIENTATION_ROTATE_90) { return 90; }
else if (exifOrientation == ExifInterface.ORIENTATION_ROTATE_180) { return 180; }
else if (exifOrientation == ExifInterface.ORIENTATION_ROTATE_270) { return 270; }
return 0;
}
通过多次尝试,我终于让它工作了,感谢一篇我找不到的帖子 :-(
Exif似乎总是有效的,难点在于获取文件路径。我找到的代码根据API是否早于4.4或之后做出了区分。基本上,4.4+的图片URI包含“com.android.providers”。对于这种类型的URI,代码使用DocumentsContract获取图片ID,然后使用ContentResolver运行查询,而对于旧的SDK,则直接查询ContentResolver中的URI。
以下是代码(抱歉我不能给发帖人以荣誉):
/**
* Handles pre V19 uri's
* @param context
* @param contentUri
* @return
*/
public static String getPathForPreV19(Context context, Uri contentUri) {
String res = null;
String[] proj = { MediaStore.Images.Media.DATA };
Cursor cursor = context.getContentResolver().query(contentUri, proj, null, null, null);
if(cursor.moveToFirst()){;
int column_index = cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
res = cursor.getString(column_index);
}
cursor.close();
return res;
}
/**
* Handles V19 and up uri's
* @param context
* @param contentUri
* @return path
*/
@TargetApi(Build.VERSION_CODES.KITKAT)
public static String getPathForV19AndUp(Context context, Uri contentUri) {
String wholeID = DocumentsContract.getDocumentId(contentUri);
// Split at colon, use second item in the array
String id = wholeID.split(":")[1];
String[] column = { MediaStore.Images.Media.DATA };
// where id is equal to
String sel = MediaStore.Images.Media._ID + "=?";
Cursor cursor = context.getContentResolver().
query(MediaStore.Images.Media.EXTERNAL_CONTENT_URI,
column, sel, new String[]{ id }, null);
String filePath = "";
int columnIndex = cursor.getColumnIndex(column[0]);
if (cursor.moveToFirst()) {
filePath = cursor.getString(columnIndex);
}
cursor.close();
return filePath;
}
public static String getRealPathFromURI(Context context,
Uri contentUri) {
String uriString = String.valueOf(contentUri);
boolean goForKitKat= uriString.contains("com.android.providers");
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT && goForKitKat) {
Log.i("KIKAT","YES");
return getPathForV19AndUp(context, contentUri);
} else {
return getPathForPreV19(context, contentUri);
}
}
String photopath = tempphoto.getPath().toString();
Bitmap bmp = BitmapFactory.decodeFile(photopath);
Matrix matrix = new Matrix();
matrix.postRotate(90);
bmp = Bitmap.createBitmap(bmp, 0, 0, bmp.getWidth(), bmp.getHeight(), matrix, true);
FileOutputStream fOut;
try {
fOut = new FileOutputStream(tempphoto);
bmp.compress(Bitmap.CompressFormat.JPEG, 85, fOut);
fOut.flush();
fOut.close();
} catch (FileNotFoundException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
// Load Image
Bitmap bitmap = BitmapFactory.decodeFile(filePath);
// Rotate Image if Needed
try
{
// Determine Orientation
ExifInterface exif = new ExifInterface(filePath);
int orientation = exif.getAttributeInt(ExifInterface.TAG_ORIENTATION, 1);
// Determine Rotation
int rotation = 0;
if (orientation == 6) rotation = 90;
else if (orientation == 3) rotation = 180;
else if (orientation == 8) rotation = 270;
// Rotate Image if Necessary
if (rotation != 0)
{
// Create Matrix
Matrix matrix = new Matrix();
matrix.postRotate(rotation);
// Rotate Bitmap
Bitmap rotated = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, true);
// Pretend none of this ever happened!
bitmap.recycle();
bitmap = rotated;
rotated = null;
}
}
catch (Exception e)
{
// TODO: Log Error Messages Here
}
// TODO: Use Result Here
xxx.setBitmap(bitmap);