我正在尝试在gridview中显示图库图像,并在图像上单击时,打开图像的全屏视图。奇怪的是,当图像在图库中显示时,它们遵循正确的旋转。但是,当我只是查询自定义图库中的照片时,它们总是逆时针旋转90度。
我已经看到了一些使用exif接口旋转的解决方案,这需要内存来旋转,因为它加载了原始位图和新旋转的位图。
我的问题是:为什么在ImageView中只显示图库中的图像会导致图像被旋转?
感谢。
答案 0 :(得分:1)
首先,您需要创建一个ExifInterface:
ExifInterface exif = new ExifInterface(filename);
然后您可以抓取图像的方向:
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,如果方向为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);
答案 1 :(得分:1)
尝试这样可以避免OOM错误 参考Load Bitmap Effieiently和Whatsapp bitmap loading
public static int calculateInSampleSize(BitmapFactory.Options options,
int reqWidth, int reqHeight) {
// Raw height and width of image
final int height = options.outHeight;
final int width = options.outWidth;
int inSampleSize = 1;
if (height > reqHeight || width > reqWidth) {
final int halfHeight = height / 2;
final int halfWidth = width / 2;
// Calculate the largest inSampleSize value that is a power of 2 and
// keeps both
// height and width larger than the requested height and width.
while ((halfHeight / inSampleSize) > reqHeight
&& (halfWidth / inSampleSize) > reqWidth) {
inSampleSize *= 2;
}
}
return inSampleSize;
}
public static Bitmap decodeSampledBitmapFromResource(Resources res,
int resId, int reqWidth, int reqHeight) {
// First decode with inJustDecodeBounds=true to check dimensions
final BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeResource(res, resId, options);
// Calculate inSampleSize
options.inSampleSize = calculateInSampleSize(options, reqWidth,
reqHeight);
// Decode bitmap with inSampleSize set
options.inJustDecodeBounds = false;
return BitmapFactory.decodeResource(res, resId, options);
}
检查图像的旋转并正确显示...如
scaledBitmap=decodeSampledBitmapFromResource(.....);
ExifInterface exif=null;
try {
exif = new ExifInterface(filePath);
int orientation = exif.getAttributeInt(
ExifInterface.TAG_ORIENTATION, 0);
Log.d("EXIF", "Exif: " + orientation);
Matrix matrix = new Matrix();
if (orientation == 6) {
matrix.postRotate(90);
Log.d("EXIF", "Exif: " + orientation);
} else if (orientation == 3) {
matrix.postRotate(180);
Log.d("EXIF", "Exif: " + orientation);
} else if (orientation == 8) {
matrix.postRotate(270);
Log.d("EXIF", "Exif: " + orientation);
}
scaledBitmap = Bitmap.createBitmap(scaledBitmap, 0, 0,
scaledBitmap.getWidth(), scaledBitmap.getHeight(), matrix,
true);
} catch (IOException e) {
e.printStackTrace();
}