Answers:
举个例子...
首先，您需要创建一个ExifInterface：
ExifInterface exif = new ExifInterface(filename);然后，您可以获取图像的方向：
orientation = exif.getAttributeInt(ExifInterface.TAG_ORIENTATION, 1);定向值的含义如下：http : //sylvana.net/jpegcrop/exif_orientation.html
因此，最重要的值是3、6和8。ExifInterface.ORIENTATION_ROTATE_90例如，如果方向是（即6），则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，这只是一个简单的例子。我确定还有其他方法可以执行实际旋转。但是您也可以在StackOverflow上找到它们。
OutOfMemoryError当您同时在内存中保存两个位图时，请注意何时使用此方法。
这是一个完整的解决方案（可从Facebook SDK的Hackbook示例中找到）。它的优点是不需要访问文件本身。如果要从内容解析器加载图像，这将非常有用（例如，如果您的应用正在响应共享照片的意图）。
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。这段代码还将图片缩小（不幸的是）到MAX_IMAGE_DIMENSION。否则可能会耗尽内存。
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exif.getAttributeInt(ExifInterface.TAG_ORIENTATION, 1)得到取向（例如ORIENTATION_ROTATE_90，ORIENTATION_ROTATE_180）
在这篇文章中，借助这篇文章帮助解决了我的问题：
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);希望它可以节省别人的时间！
9re创建了一个简单的实用程序来处理处理EXIF数据并将图像旋转到正确方向的繁重工作。
您可以在此处找到实用程序代码：https : //gist.github.com/9re/1990019
只需下载此文件，将其添加到项目的src目录中，然后使用它ExifUtil.rotateBitmap()即可获取正确的方向，如下所示：
String imagePath = photoFile.getAbsolutePath(); // photoFile is a File class.
Bitmap myBitmap = BitmapFactory.decodeFile(imagePath);
Bitmap orientedBitmap = ExifUtil.rotateBitmap(imagePath, myBitmap);这是因为图库可以正确显示旋转的图像，而不是ImageView可以在这里查看：
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);
}并且您需要此：
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;
} 经过多次尝试后，它才能正常工作，这要归功于我找不到的帖子：-(
Exif似乎总是可以正常工作，困难在于获取文件路径。我发现的代码使4.4之前的API和4.4以后的API有所不同。基本上，用于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，而对于较早的SDK，代码直接使用ContentResolver查询URI。
这是代码（对不起，我不能相信谁发布了它）：
/**
* 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);
}
}您只需从sd卡中读取路径并执行以下代码即可...旋转后将替换现有照片。
不行：Exif在大多数设备上不起作用，它提供了错误的数据，因此最好在保存到所需的任何角度之前对旋转进行硬编码，只需将postRotate中的角度值更改为所需的任何角度即可。
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();
}
}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)
}我改进了Teo Inke的答案。除非确实需要，否则它将不再旋转图像。它也更容易阅读，并且应该运行得更快。
// 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);您需要的第一件事是真实的文件路径，如果它很好，如果您使用的是URI，则使用此方法获取真实的路径：
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;
}提取您的位图，例如：
try {
Bitmap bitmap = MediaStore.Images.Media.getBitmap(this.getContentResolver(), selectedImage);
}
catch (IOException e)
{
Log.e("IOException",e.toString());
}如果愿意，可以改用解码文件（）。
现在，您已经有了位图和真实路径，从而获得了图像的方向：
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;
}最后将其旋转到正确的位置，如下所示：
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，您现在将位图旋转到了正确的位置。
干杯。
这可行，但可能不是最好的方法，但可能会对某人有所帮助。
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;
}也许这会有所帮助（旋转90度）（这对我有用）
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;
}打开游标后应将其关闭。
这是一个例子。
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;
}我已经融化了@Timmmm答案和@Manuel。如果执行此解决方案，则不会收到“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，您将不会获得“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;
}这对我来说非常合适。我希望这对其他人有帮助
Timmmm对上述解决方案进行了改进，以在末尾添加一些额外的缩放比例，以确保图像适合边界：
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;
}使用以下代码正确旋转图像：
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;
}以下方法缩放并根据方向旋转位图：
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：
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());
}
}我通过以下解决方法解决了该问题。请注意，我也在缩放图像，这对于避免OutOfMemoryExceptions是必需的。
请注意，此解决方案不适用于人像图像或反面图像（感谢Timmmm注意）。如果需要，上述Timmmm的解决方案可能是更好的选择，并且看起来也更优雅：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