Question

旋转位图时遇到了很多麻烦。下面的代码有效，但它比Galaxy Note 2手机附带的Gallery应用程序慢4-6倍。

代码：

    File DirectoryFile = new File(Image_Path); 
    Bitmap bitmap = BitmapFactory.decodeFile(DirectoryFile.getAbsolutePath()); 



    String imagePATH = FileLocation + "test.jpg";
    final File newfile = new File(imagePATH);           

    FileOutputStream mFileOutputStream = null;
    try {                   
           mFileOutputStream = new FileOutputStream(newfile);
       } catch (FileNotFoundException e1) { }

        try {
        Bitmap RotatedBitmap =  RotateImage(imagePATH, bitmap);
        RotatedBitmap.compress(Bitmap.CompressFormat.JPEG, 100, mFileOutputStream);
        bitmap.recycle(); 
        RotatedBitmap.recycle();

        mFileOutputStream.flush();
        mFileOutputStream.close();

    } catch (IOException e) {
        e.printStackTrace();
    }

private Bitmap RotateImage(String filePath, Bitmap bitmap) throws IOException {
    ExifInterface exif = new ExifInterface(filePath);
    int exifOrientation = exif.getAttributeInt(ExifInterface.TAG_ORIENTATION, ExifInterface.ORIENTATION_NORMAL);
    int rotate = 0;
    switch (exifOrientation) {
    case ExifInterface.ORIENTATION_NORMAL: rotate = 0; break;               
    case ExifInterface.ORIENTATION_UNDEFINED: rotate = 90; break;                               
    case ExifInterface.ORIENTATION_ROTATE_90: rotate = 90; break; 
    case ExifInterface.ORIENTATION_ROTATE_180: rotate = 180; break;
    case ExifInterface.ORIENTATION_ROTATE_270: rotate = 270; break;
    }                 

    Matrix matrix = new Matrix();
    matrix.postRotate(rotate);
    //matrix.setRotate(rotate); is no difference ???
    return bitmap = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, false);
}

请有人请指导我吗？

如何让它像Gallery应用程序一样工作？

Answer 1

Picasso库是处理位图或图像旋转的最佳工具。在build.gradle中添加此依赖项'com.squareup.picasso：picasso：2.5.2'

请参阅以下代码段以供参考

Picasso.with(context)
                                .load(new File(path))
                                .resize(width, height)                             // optional
                                .rotate(getAngleOfRotation(path))                  // optional
                                .into(imageview);


    private float getAngleOfRotation(String path) {
            ExifInterface exif = null;
            try {
                exif = new ExifInterface(path);
            } catch (IOException e) {
                e.printStackTrace();
            }
            try {
                switch (exif
                        .getAttributeInt(ExifInterface.TAG_ORIENTATION, 1)) {
                    case ExifInterface.ORIENTATION_ROTATE_180:
                        return 180;
                    case ExifInterface.ORIENTATION_ROTATE_90:
                        return 90;
                    case ExifInterface.ORIENTATION_ROTATE_270:
                        return 270;
                    case ExifInterface.ORIENTATION_NORMAL:
                        return 0;
                    default:
                        return 0;
                }
            } catch (NullPointerException e) {
                e.printStackTrace();
            }
            return 0;
        }

如何正确旋转位图？

1 个答案: