Android: 从图库加载的位图在 ImageView 中旋转

当我把媒体库中的图片加载到 Bitmap 中时，一切都很正常，除了那些用相机垂直拿着手机拍摄的图片，它们会旋转，所以我总是得到一张水平的图片，即使它在图库中看起来是垂直的。 为什么会这样，我怎样才能正确加载它？

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最佳答案

你看过图像的 EXIF 数据了吗？它可能知道照片拍摄时相机的方向。

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举个例子。

首先，您需要创建一个 ExifInterface:

ExifInterface exif = new ExifInterface(filename);

然后你可以获取图像的方向:

orientation = exif.getAttributeInt(ExifInterface.TAG_ORIENTATION, 1);

以下是方向值的含义: 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(6) ，你可以像这样旋转图像:

Matrix matrix = new Matrix();
matrix.postRotate(90);
rotatedBitmap = Bitmap.createBitmap(sourceBitmap, 0, 0, sourceBitmap.getWidth(), sourceBitmap.getHeight(), matrix, true);

不过这只是个简单的例子。我相信还有其他方法可以实现真正的旋转。但是您也可以在 StackOverflow 上找到这些内容。

小开

我用下面的变通方法解决了这个问题。注意，我还在缩放图像，这是避免 OutOfMemory 异常所必需的。

请注意，这个解决方案将不能正常工作的肖像图像或反向向下的图像(谢谢你提到)。如果需要的话，提姆的上述解决方案可能是更好的选择，它看起来也更优雅: https://stackoverflow.com/a/8914291/449918

File path = // ... location of your bitmap file
int w = 512; int h = 384; // size that does not lead to OutOfMemoryException on Nexus One
Bitmap b = BitmapFactory.decodeFile(path);




// Hack to determine whether the image is rotated
boolean rotated = b.getWidth() > b.getHeight();


Bitmap resultBmp = null;


// If not rotated, just scale it
if (!rotated) {
resultBmp = Bitmap.createScaledBitmap(b, w, h, true);
b.recycle();
b = null;


// If rotated, scale it by switching width and height and then rotated it
} else {
Bitmap scaledBmp = Bitmap.createScaledBitmap(b, h, w, true);
b.recycle();
b = null;


Matrix mat = new Matrix();
mat.postRotate(90);
resultBmp = Bitmap.createBitmap(scaledBmp, 0, 0, h, w, mat, true);


// Release image resources
scaledBmp.recycle();
scaledBmp = null;
}


// resultBmp now contains the scaled and rotated image

干杯

小开

这是一个完整的解决方案(可以在 Facebook SDK 的 Hackbook 示例中找到)。它的优点是不需要访问文件本身。如果你正在从内容解析器装载一个图像，这是非常有用的(例如，如果你的应用程序正在响应一个共享照片意图)。

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);
}

然后你可以得到一个旋转的位图，如下所示。这段代码还将图像(很不幸地)缩放到 MAX _ IMAGE _ DIMENION。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;
}
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对上面的解决方案进行了改进，添加了一些额外的缩放，以确保图像符合界限:

public static Bitmap loadBitmap(String path, int orientation, final int targetWidth, final int targetHeight) {
Bitmap bitmap = null;
try {
// First decode with inJustDecodeBounds=true to check dimensions
final BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeFile(path, options);


// Adjust extents
int sourceWidth, sourceHeight;
if (orientation == 90 || orientation == 270) {
sourceWidth = options.outHeight;
sourceHeight = options.outWidth;
} else {
sourceWidth = options.outWidth;
sourceHeight = options.outHeight;
}


// Calculate the maximum required scaling ratio if required and load the bitmap
if (sourceWidth > targetWidth || sourceHeight > targetHeight) {
float widthRatio = (float)sourceWidth / (float)targetWidth;
float heightRatio = (float)sourceHeight / (float)targetHeight;
float maxRatio = Math.max(widthRatio, heightRatio);
options.inJustDecodeBounds = false;
options.inSampleSize = (int)maxRatio;
bitmap = BitmapFactory.decodeFile(path, options);
} else {
bitmap = BitmapFactory.decodeFile(path);
}


// Rotate the bitmap if required
if (orientation > 0) {
Matrix matrix = new Matrix();
matrix.postRotate(orientation);
bitmap = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, true);
}


// Re-scale the bitmap if necessary
sourceWidth = bitmap.getWidth();
sourceHeight = bitmap.getHeight();
if (sourceWidth != targetWidth || sourceHeight != targetHeight) {
float widthRatio = (float)sourceWidth / (float)targetWidth;
float heightRatio = (float)sourceHeight / (float)targetHeight;
float maxRatio = Math.max(widthRatio, heightRatio);
sourceWidth = (int)((float)sourceWidth / maxRatio);
sourceHeight = (int)((float)sourceHeight / maxRatio);
bitmap = Bitmap.createScaledBitmap(bitmap, sourceWidth, sourceHeight, true);
}
} catch (Exception e) {
}
return bitmap;
}
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您可以只读取路径从 sd 卡，并做以下代码... 它将替换现有的照片后，旋转它。.

不: Exif 不能在大多数设备上工作，它提供了错误的数据，所以在保存到任何程度之前硬编码旋转是好的，你只需要改变后旋转的角度值到任何你想要的。

    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();
}


}
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通过这篇文章的帮助，我用下面的代码解决了这个问题:

            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);

希望能节省一些人的时间！

小开

这种方法可行，但可能不是最好的方法，但可能对某些人有帮助。

String imagepath = someUri.getAbsolutePath();
imageview = (ImageView)findViewById(R.id.imageview);
imageview.setImageBitmap(setImage(imagepath, 120, 120));


public Bitmap setImage(String path, final int targetWidth, final int targetHeight) {
Bitmap bitmap = null;
// Get exif orientation
try {
ExifInterface exif = new ExifInterface(path);
int orientation = exif.getAttributeInt(ExifInterface.TAG_ORIENTATION, 1);
if (orientation == 6) {
orientation_val = 90;
}
else if (orientation == 3) {
orientation_val = 180;
}
else if (orientation == 8) {
orientation_val = 270;
}
}
catch (Exception e) {
}


try {
// First decode with inJustDecodeBounds=true to check dimensions
final BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeFile(path, options);


// Adjust extents
int sourceWidth, sourceHeight;
if (orientation_val == 90 || orientation_val == 270) {
sourceWidth = options.outHeight;
sourceHeight = options.outWidth;
} else {
sourceWidth = options.outWidth;
sourceHeight = options.outHeight;
}


// Calculate the maximum required scaling ratio if required and load the bitmap
if (sourceWidth > targetWidth || sourceHeight > targetHeight) {
float widthRatio = (float)sourceWidth / (float)targetWidth;
float heightRatio = (float)sourceHeight / (float)targetHeight;
float maxRatio = Math.max(widthRatio, heightRatio);
options.inJustDecodeBounds = false;
options.inSampleSize = (int)maxRatio;
bitmap = BitmapFactory.decodeFile(path, options);
} else {
bitmap = BitmapFactory.decodeFile(path);
}


// Rotate the bitmap if required
if (orientation_val > 0) {
Matrix matrix = new Matrix();
matrix.postRotate(orientation_val);
bitmap = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, true);
}


// Re-scale the bitmap if necessary
sourceWidth = bitmap.getWidth();
sourceHeight = bitmap.getHeight();
if (sourceWidth != targetWidth || sourceHeight != targetHeight) {
float widthRatio = (float)sourceWidth / (float)targetWidth;
float heightRatio = (float)sourceHeight / (float)targetHeight;
float maxRatio = Math.max(widthRatio, heightRatio);
sourceWidth = (int)((float)sourceWidth / maxRatio);
sourceHeight = (int)((float)sourceHeight / maxRatio);
bitmap = Bitmap.createScaledBitmap(bitmap, sourceWidth,     sourceHeight, true);
}
} catch (Exception e) {
}
return bitmap;
}
小开

使用以下代码可以正确旋转图像:

private Bitmap rotateImage(Bitmap bitmap, String filePath)
{
Bitmap resultBitmap = bitmap;


try
{
ExifInterface exifInterface = new ExifInterface(filePath);
int orientation = exifInterface.getAttributeInt(ExifInterface.TAG_ORIENTATION, 1);


Matrix matrix = new Matrix();


if (orientation == ExifInterface.ORIENTATION_ROTATE_90)
{
matrix.postRotate(ExifInterface.ORIENTATION_ROTATE_90);
}
else if (orientation == ExifInterface.ORIENTATION_ROTATE_180)
{
matrix.postRotate(ExifInterface.ORIENTATION_ROTATE_180);
}
else if (orientation == ExifInterface.ORIENTATION_ROTATE_270)
{
matrix.postRotate(ExifInterface.ORIENTATION_ROTATE_270);
}


// Rotate the bitmap
resultBitmap = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, true);
}
catch (Exception exception)
{
Logger.d("Could not rotate the image");
}
return resultBitmap;
}
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下面的方法缩放和旋转位图根据方向:

public Bitmap scaleAndRotateImage(String path, int orientation, final int targetWidth, final int targetHeight)
{
Bitmap bitmap = null;


try
{
// Check the dimensions of the Image
final BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeFile(path, options);


// Adjust the Width and Height
int sourceWidth, sourceHeight;
if (orientation == 90 || orientation == 270)
{
sourceWidth = options.outHeight;
sourceHeight = options.outWidth;
}
else
{
sourceWidth = options.outWidth;
sourceHeight = options.outHeight;
}


// Calculate the maximum required scaling ratio if required and load the bitmap
if (sourceWidth > targetWidth || sourceHeight > targetHeight)
{
float widthRatio = (float)sourceWidth / (float)targetWidth;
float heightRatio = (float)sourceHeight / (float)targetHeight;
float maxRatio = Math.max(widthRatio, heightRatio);
options.inJustDecodeBounds = false;
options.inSampleSize = (int)maxRatio;
bitmap = BitmapFactory.decodeFile(path, options);
}
else
{
bitmap = BitmapFactory.decodeFile(path);
}


// We need to rotate the bitmap (if required)
int orientationInDegrees = exifToDegrees(orientation);
if (orientation > 0)
{
Matrix matrix = new Matrix();
if (orientation != 0f)
{
matrix.preRotate(orientationInDegrees);
};


bitmap = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, true);
}


// Re-scale the bitmap if necessary
sourceWidth = bitmap.getWidth();
sourceHeight = bitmap.getHeight();


if (sourceWidth != targetWidth || sourceHeight != targetHeight)
{
float widthRatio = (float)sourceWidth / (float)targetWidth;
float heightRatio = (float)sourceHeight / (float)targetHeight;
float maxRatio = Math.max(widthRatio, heightRatio);
sourceWidth = (int)((float)sourceWidth / maxRatio);
sourceHeight = (int)((float)sourceHeight / maxRatio);
bitmap = Bitmap.createScaledBitmap(bitmap, sourceWidth, sourceHeight, true);
}
}
catch (Exception e)
{
Logger.d("Could not rotate the image");
Logger.d(e.getMessage());
}
return bitmap;
}

例如:

public void getPictureFromDevice(Uri Uri,ImageView imageView)
{
try
{
ExifInterface exifInterface = new ExifInterface(Uri.getPath());
int orientation = exifInterface.getAttributeInt(ExifInterface.TAG_ORIENTATION, ExifInterface.ORIENTATION_NORMAL);


Bitmap bitmap = scaleAndRotateImage(Uri.getPath(), orientation, imageView.getWidth(), imageView.getHeight());
imageView.setImageBitmap(bitmap);
}
catch (OutOfMemoryError outOfMemoryError)
{
Logger.d(outOfMemoryError.getLocalizedMessage());
Logger.d("Failed to load image from filePath (out of memory)");
Logger.d(Uri.toString());
}
catch (Exception e)
{
Logger.d("Failed to load image from filePath");
Logger.d(Uri.toString());
}
}
小开

也许这会有帮助(旋转90度)(这为我工作)

private Bitmap rotateBitmap(Bitmap image){
int width=image.getHeight();
int height=image.getWidth();


Bitmap srcBitmap=Bitmap.createBitmap(width, height, image.getConfig());


for (int y=width-1;y>=0;y--)
for(int x=0;x<height;x++)
srcBitmap.setPixel(width-y-1, x,image.getPixel(x, y));
return srcBitmap;


}
小开

我改进了 Teo Inke 的答案。它不再旋转图像，除非它实际上是必要的。它也更容易阅读，应该运行得更快。

// 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);
小开

使用一个实用工具来完成重物搬运。

9re 创建了一个简单的工具来处理处理 EXIF 数据和将图像旋转到正确方向的繁重工作。

你可以在这里找到实用代码: https://gist.github.com/9re/1990019

只需下载这个文件，将其添加到项目的 src目录，并使用 ExifUtil.rotateBitmap()获得正确的方向，如下所示:

String imagePath = photoFile.getAbsolutePath();             // photoFile is a File class.
Bitmap myBitmap  = BitmapFactory.decodeFile(imagePath);


Bitmap orientedBitmap = ExifUtil.rotateBitmap(imagePath, myBitmap);
小开

其原因是画廊正确显示旋转的图像，而不是 ImageView 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);
}

你需要这个:

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;
}
小开

光标打开后应关闭。

这里有一个例子。

 public static int getOrientation(Context context, Uri selectedImage)
{
int orientation = -1;
Cursor cursor = context.getContentResolver().query(selectedImage,
new String[] { MediaStore.Images.ImageColumns.ORIENTATION }, null, null, null);
if (cursor.getCount() != 1)
return orientation;


cursor.moveToFirst();
orientation = cursor.getInt(0);
cursor.close(); // ADD THIS LINE
return orientation;
}
小开

首先需要的是真正的 File 路径 如果你有它的伟大，如果你使用 URI 然后使用这个方法 得到真正的路径:

 public static String getRealPathFromURI(Uri contentURI,Context context) {
String path= contentURI.getPath();
try {
Cursor cursor = context.getContentResolver().query(contentURI, null, null, null, null);
cursor.moveToFirst();
String document_id = cursor.getString(0);
document_id = document_id.substring(document_id.lastIndexOf(":") + 1);
cursor.close();


cursor = context.getContentResolver().query(
android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI,
null, MediaStore.Images.Media._ID + " = ? ", new String[]{document_id}, null);
cursor.moveToFirst();
path = cursor.getString(cursor.getColumnIndex(MediaStore.Images.Media.DATA));
cursor.close();
}
catch(Exception e)
{
return path;
}
return path;
}

例如，提取你的位图:

  try {
Bitmap bitmap = MediaStore.Images.Media.getBitmap(this.getContentResolver(), selectedImage);


}
catch (IOException e)
{
Log.e("IOException",e.toString());
}

如果愿意，您可以使用 decdeFile ()来代替。

现在你有了位图和真正的路径，得到了图像的方向:

 private static int getExifOrientation(String src) throws IOException {
int orientation = 1;


ExifInterface exif = new ExifInterface(src);
String orientationString=exif.getAttribute(ExifInterface.TAG_ORIENTATION);
try {
orientation = Integer.parseInt(orientationString);
}
catch(NumberFormatException e){}


return orientation;
}

最后像这样把它旋转到正确的位置:

public static Bitmap rotateBitmap(String src, Bitmap bitmap) {
try {
int orientation = getExifOrientation(src);


if (orientation == 1) {
return bitmap;
}


Matrix matrix = new Matrix();
switch (orientation) {
case 2:
matrix.setScale(-1, 1);
break;
case 3:
matrix.setRotate(180);
break;
case 4:
matrix.setRotate(180);
matrix.postScale(-1, 1);
break;
case 5:
matrix.setRotate(90);
matrix.postScale(-1, 1);
break;
case 6:
matrix.setRotate(90);
break;
case 7:
matrix.setRotate(-90);
matrix.postScale(-1, 1);
break;
case 8:
matrix.setRotate(-90);
break;
default:
return bitmap;
}


try {
Bitmap oriented = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, true);
bitmap.recycle();
return oriented;
} catch (OutOfMemoryError e) {
e.printStackTrace();
return bitmap;
}
} catch (IOException e) {
e.printStackTrace();
}


return bitmap;
}

就是这样，您现在已经将位图旋转到了正确的位置。

干杯。

小开

我已经融化了“提姆答案”和“曼纽尔”。如果执行此解决方案，则不会出现内存不足异常。

此方法检索图像方向:

private static final int ROTATION_DEGREES = 90;
// This means 512 px
private static final Integer MAX_IMAGE_DIMENSION = 512;


public static int getOrientation(Uri photoUri) throws IOException {


ExifInterface exif = new ExifInterface(photoUri.getPath());
int orientation = exif.getAttributeInt(ExifInterface.TAG_ORIENTATION, 1);


switch (orientation) {
case ExifInterface.ORIENTATION_ROTATE_90:
orientation = ROTATION_DEGREES;
break;
case ExifInterface.ORIENTATION_ROTATE_180:
orientation = ROTATION_DEGREES * 2;
break;
case ExifInterface.ORIENTATION_ROTATE_270:
orientation = ROTATION_DEGREES * 3;
break;
default:
// Default case, image is not rotated
orientation = 0;
}


return orientation;
}

因此，在将图像加载到内存之前，可以使用此方法调整图像的大小。这样，就不会出现内存异常。

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(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, 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;
}

这对我很有用，我希望这能帮到别人

小开

经过多次尝试，终于让它工作了，这要归功于一个我再也找不到的帖子:

Exif 似乎总是能够工作，难点在于获取文件路径。我发现的代码在4.4以后的 API 和4.4以后的 API 之间有所不同。基本上，4.4 + 的图片 URI 包含“ com.android.provider”。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，而对于较旧的 SDK，代码直接使用 ContentResolver 查询 URI。

下面是代码(很抱歉我不能相信是谁发布的) :

/**
* 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);
}
}
小开

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)
}

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