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Android：从相册加载的位图在ImageView中旋转

androidbitmaprotationgallery
154

在将媒体库中的图像加载到位图中时，一切都正常，但是使用手机竖直拍摄的照片会被旋转，导致即使在媒体库中它看起来是竖直的，但我得到的却是横向的图片。

为什么会这样，我应该如何正确地加载它？

我有真正的答案 https://dev59.com/7Yrda4cB1Zd3GeqPLFZH#32747566 - A.Sanchez.SD
20个回答
2

首先需要的是真实的文件路径。如果您已经有了它，那很好。如果您正在使用URI，则可以使用以下方法获取真实路径：

 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());
                        }

如果您愿意，可以使用decodeFile()代替。

现在，您已经拥有了位图和真实路径，请获取图像的方向：

 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;
    }

好的，现在位图已经旋转到正确的位置了。

干杯。

1
光标在打开后应该关闭。
这里是一个例子。
 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;
}
1

这个方法可行，但可能不是最佳方式，但它可能会帮助某些人。

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;
    }
1
以下方法可根据方向缩放和旋转位图：
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;
}

例子：

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());
    }
}
1

也许这会有帮助（旋转90度）（这对我起作用了）

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;

    }
Bitmap.createBitmap(…, matrix, …) 是创建旋转位图的更快速的方法。 - Alex Cohn
1
我已经整合了@Timmmm和@Manuel的答案。如果您使用这个解决方案，就不会出现内存不足异常。
这个方法用于获取图像的方向：
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，您需要使用此方法调整其大小。这样，您就不会遇到内存异常问题。
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;
}

这对我来说完美地运作。我希望这能帮助其他人。
1

所有之前的答案都使用已经过时的android.media.ExifInterface。

这个类在某些版本的Android上存在已知问题。建议使用AndroidX ExifInterface库，因为它提供了该类功能的超集，并且更容易更新。

在新的Android版本（AndroidX）中，您可以这样做：

fun loadBitmapFromFile(file: File): Bitmap {
    val bitmap = BitmapFactory.decodeFile(file.path)
    val exif = ExifInterface(file)
    val rotation = exif.rotationDegrees
    if (rotation == 0) return bitmap
    val matrix = Matrix().apply { postRotate(rotation.toFloat()) }
    return Bitmap.createBitmap(bitmap, 0, 0, bitmap.width, bitmap.height, matrix, true)
}

您还需要将 implementation 'androidx.exifinterface:exifinterface:1.3.6' 添加到您的 build.gradle 依赖项中。

确保导入的是 androidx.exifinterface.media.ExifInterface 而不是已过时的 android.media.ExifInterface。

0
通过对Timmmm提供的解决方案进行改进，在最后添加一些额外的缩放来确保图像适合边界。
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;
}
0
请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;
}
你可以将所有的if条件合并在一起，以减少代码量。 - Chandranshu
-2

我用以下解决方法解决了这个问题。请注意，我还缩放了图片，这是为了避免OutOfMemoryExceptions。

请注意，这个解决方案对纵向图片或倒置的图片不起作用（感谢Timmmm的提醒）。如果需要处理这种情况，Timmmm在上面提供的解决方案可能更好，而且看起来更优雅：https://dev59.com/XHA65IYBdhLWcg3wxBir#8914291

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

这样做不会正常工作。竖向图像怎么办？倒置的图像呢？使用exif数据更好。 - Timmmm
它在我的一个应用程序中正常工作，但当然我没有测试所有类型的场景。@Timmmm，你能否更具体地说明它不起作用的情况？我也对你投票反对感到困惑。这似乎是对分享潜在解决方案的诚实尝试的相当严厉的回应。 - Martin
我不是故意要严厉的，抱歉！我只是不希望有人复制你的解决方案并期望它能够工作。正如我所说，它对于纵向或倒置的图像是无效的。我会将正确的解决方案添加为答案。 - Timmmm
我明白了。我会添加一条评论，将您的解决方案突出显示为首选方案。 - Martin
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