画廊中的图像自动旋转 - Android

Question

在我的 android 应用程序中，我正在从设备库中加载图像。在这方面，我面临着关于图像方向的问题。当我从画廊加载大分辨率图像时，它们会自动旋转然后显示在我的视图中。我尝试了有关此问题的各种解决方案，但无法获得适当的解决方案。我提到了 getOrientation() 和 this 链接。我已经尝试了这两种解决方案，但都没有得到想要的结果。ExifInterface 返回正确的数据，但它们也没有帮助，因为图像被旋转是因为它们的高分辨率而不是因为相机方向。请帮我解决这个问题。

谢谢。

Answer 1

创建一个名为 ExifUtils

的类

public class ExifUtils {
/**
 * @see http://sylvana.net/jpegcrop/exif_orientation.html
 */
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;
}

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

    try {
        /**
         * if your are targeting only api level >= 5 ExifInterface exif =
         * new ExifInterface(src); orientation =
         * exif.getAttributeInt(ExifInterface.TAG_ORIENTATION, 1);
         */
        if (Build.VERSION.SDK_INT >= 5) {
            Class<?> exifClass = Class
                    .forName("android.media.ExifInterface");
            Constructor<?> exifConstructor = exifClass
                    .getConstructor(new Class[] { String.class });
            Object exifInstance = exifConstructor
                    .newInstance(new Object[] { src });
            Method getAttributeInt = exifClass.getMethod("getAttributeInt",
                    new Class[] { String.class, int.class });
            Field tagOrientationField = exifClass
                    .getField("TAG_ORIENTATION");
            String tagOrientation = (String) tagOrientationField.get(null);
            orientation = (Integer) getAttributeInt.invoke(exifInstance,
                    new Object[] { tagOrientation, 1 });
        }
    } catch (ClassNotFoundException e) {
        e.printStackTrace();
    } catch (SecurityException e) {
        e.printStackTrace();
    } catch (NoSuchMethodException e) {
        e.printStackTrace();
    } catch (IllegalArgumentException e) {
        e.printStackTrace();
    } catch (InstantiationException e) {
        e.printStackTrace();
    } catch (IllegalAccessException e) {
        e.printStackTrace();
    } catch (InvocationTargetException e) {
        e.printStackTrace();
    } catch (NoSuchFieldException e) {
        e.printStackTrace();
    }

    return orientation;
}

现在您可以通过以下方式在 Activity 中调用它：

  ExifUtils.rotateBitmap("your Image path here", "your bitmap object here");

编辑：

 public void decodeFile(String filePath) {

    // Decode image size
    BitmapFactory.Options o = new BitmapFactory.Options();
    o.inJustDecodeBounds = true;
    BitmapFactory.decodeFile(filePath, o);

    // The new size we want to scale to
    final int REQUIRED_SIZE = 1024;

    // Find the correct scale value. It should be the power of 2.
    int width_tmp = o.outWidth, height_tmp = o.outHeight;
    int scale = 1;
    while (true) {
        if (width_tmp < REQUIRED_SIZE && height_tmp < REQUIRED_SIZE)
            break;
        width_tmp /= 2;
        height_tmp /= 2;
        scale *= 2;
    }

    // Decode with inSampleSize
    BitmapFactory.Options o2 = new BitmapFactory.Options();
    o2.inSampleSize = scale;
    Bitmap b1 = BitmapFactory.decodeFile(filePath, o2);
    Bitmap b= ExifUtils.rotateBitmap(filePath, b1);

    // image.setImageBitmap(bitmap);
}

现在调用这个方法

  decodeFile(imagepath);

谢谢！

Answer 2

这很好用；

public class ExifUtils {

public static Bitmap getRotatedBitmap(Context context, Uri uri) {
    try {
        Bitmap bitmap = MediaStore.Images.Media.getBitmap(context.getContentResolver(), uri);
        float width = (float) bitmap.getWidth();
        float height = (float) bitmap.getHeight();
        float max = Math.max(width / 1280.0f, height / 1280.0f);
        if (max > 1.0f) {
            bitmap = Bitmap.createScaledBitmap(bitmap, (int) (width / max), (int) (height / max), false);
        }
        Bitmap rotateBitmap = rotateBitmap(bitmap,
                new ExifInterface(context.getContentResolver().openInputStream(uri))
                        .getAttributeInt(ExifInterface.TAG_ORIENTATION, 1));
        if (rotateBitmap != bitmap) {
            bitmap.recycle();
        }
        return rotateBitmap;
    } catch (Exception e) {
        e.printStackTrace();
        return null;
    }
}

private static Bitmap rotateBitmap(Bitmap bitmap, int i) {
    Matrix matrix = new Matrix();
    switch (i) {
        case 2:
            matrix.setScale(-1.0f, 1.0f);
            break;
        case 3:
            matrix.setRotate(180.0f);
            break;
        case 4:
            matrix.setRotate(180.0f);
            matrix.postScale(-1.0f, 1.0f);
            break;
        case 5:
            matrix.setRotate(90.0f);
            matrix.postScale(-1.0f, 1.0f);
            break;
        case 6:
            matrix.setRotate(90.0f);
            break;
        case 7:
            matrix.setRotate(-90.0f);
            matrix.postScale(-1.0f, 1.0f);
            break;
        case 8:
            matrix.setRotate(-90.0f);
            break;
        default:
            return bitmap;
    }
    try {
        Bitmap createBitmap = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, false);
        bitmap.recycle();
        return createBitmap;
    } catch (OutOfMemoryError e) {
        e.printStackTrace();
        return null;
    }
  }
}