这可能是不言而喻的，但请始终记住，您可以在服务器上处理其中一些映像处理问题。我使用类似于这个线程中包含的响应来处理图像的即时显示。然而，我的应用程序要求图像存储在服务器上(这可能是一个常见的要求，如果你希望图像在用户切换手机时保持不变)。

关于这个主题的许多讨论中包含的解决方案没有讨论EXIF数据缺乏持久性的问题，这种数据无法在位图的图像压缩中幸存下来，这意味着您需要在服务器每次加载图像时旋转图像。或者，您可以将EXIF方向数据发送到服务器，然后根据需要旋转图像。

对我来说，在服务器上创建一个永久的解决方案更容易，因为我不必担心Android的秘密文件路径。

大多数手机摄像头都是横拍的，也就是说如果你用竖拍，拍出来的照片会旋转90度。在这种情况下，相机软件应该填充Exif数据，以显示照片的方向。

请注意，下面的解决方案取决于填充Exif数据的相机软件/设备制造商，因此它在大多数情况下都可以工作，但它不是100%可靠的解决方案。

ExifInterface ei = new ExifInterface(photoPath);
int orientation = ei.getAttributeInt(ExifInterface.TAG_ORIENTATION,
                                     ExifInterface.ORIENTATION_UNDEFINED);

Bitmap rotatedBitmap = null;
switch(orientation) {

    case ExifInterface.ORIENTATION_ROTATE_90:
        rotatedBitmap = rotateImage(bitmap, 90);
        break;

    case ExifInterface.ORIENTATION_ROTATE_180:
        rotatedBitmap = rotateImage(bitmap, 180);
        break;

    case ExifInterface.ORIENTATION_ROTATE_270:
        rotatedBitmap = rotateImage(bitmap, 270);
        break;

    case ExifInterface.ORIENTATION_NORMAL:
    default:
        rotatedBitmap = bitmap;
}

下面是rotateImage方法:

public static Bitmap rotateImage(Bitmap source, float angle) {
    Matrix matrix = new Matrix();
    matrix.postRotate(angle);
    return Bitmap.createBitmap(source, 0, 0, source.getWidth(), source.getHeight(),
                               matrix, true);
}

// Try this way,hope this will help you to solve your problem...

activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1"
        android:gravity="center">
        <ImageView
            android:id="@+id/imgFromCameraOrGallery"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:adjustViewBounds="true"
            android:src="@drawable/ic_launcher"/>
    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content">
        <Button
            android:id="@+id/btnCamera"
            android:layout_width="0dp"
            android:layout_weight="1"
            android:layout_height="wrap_content"
            android:text="Camera"/>
        <Button
            android:id="@+id/btnGallery"
            android:layout_width="0dp"
            android:layout_weight="1"
            android:layout_marginLeft="5dp"
            android:layout_height="wrap_content"
            android:text="Gallery"/>

    </LinearLayout>
</LinearLayout>

MainActivity.java

    public class MainActivity extends Activity {

    private ImageView imgFromCameraOrGallery;
    private Button btnCamera;
    private Button btnGallery;

    private String imgPath;
    final private int PICK_IMAGE = 1;
    final private int CAPTURE_IMAGE = 2;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        imgFromCameraOrGallery = (ImageView) findViewById(R.id.imgFromCameraOrGallery);
        btnCamera = (Button) findViewById(R.id.btnCamera);
        btnGallery = (Button) findViewById(R.id.btnGallery);

        btnCamera.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                final Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
                intent.putExtra(MediaStore.EXTRA_OUTPUT, setImageUri());
                startActivityForResult(intent, CAPTURE_IMAGE);
            }
        });

        btnGallery.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent();
                intent.setType("image/*");
                intent.setAction(Intent.ACTION_GET_CONTENT);
                startActivityForResult(Intent.createChooser(intent, ""), PICK_IMAGE);
            }
        });

    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (resultCode == Activity.RESULT_OK) {
            if (requestCode == CAPTURE_IMAGE) {
                setCapturedImage(getImagePath());
            } else if (requestCode == PICK_IMAGE) {
                imgFromCameraOrGallery.setImageBitmap(BitmapFactory.decodeFile(getAbsolutePath(data.getData())));
            }
        }

    }

    private String getRightAngleImage(String photoPath) {

        try {
            ExifInterface ei = new ExifInterface(photoPath);
            int orientation = ei.getAttributeInt(ExifInterface.TAG_ORIENTATION, ExifInterface.ORIENTATION_NORMAL);
            int degree = 0;

            switch (orientation) {
                case ExifInterface.ORIENTATION_NORMAL:
                    degree = 0;
                    break;
                case ExifInterface.ORIENTATION_ROTATE_90:
                    degree = 90;
                    break;
                case ExifInterface.ORIENTATION_ROTATE_180:
                    degree = 180;
                    break;
                case ExifInterface.ORIENTATION_ROTATE_270:
                    degree = 270;
                    break;
                case ExifInterface.ORIENTATION_UNDEFINED:
                    degree = 0;
                    break;
                default:
                    degree = 90;
            }

            return rotateImage(degree,photoPath);

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

        return photoPath;
    }

    private String rotateImage(int degree, String imagePath){

        if(degree<=0){
            return imagePath;
        }
        try{
            Bitmap b= BitmapFactory.decodeFile(imagePath);

            Matrix matrix = new Matrix();
            if(b.getWidth()>b.getHeight()){
                matrix.setRotate(degree);
                b = Bitmap.createBitmap(b, 0, 0, b.getWidth(), b.getHeight(),
                        matrix, true);
            }

            FileOutputStream fOut = new FileOutputStream(imagePath);
            String imageName = imagePath.substring(imagePath.lastIndexOf("/") + 1);
            String imageType = imageName.substring(imageName.lastIndexOf(".") + 1);

            FileOutputStream out = new FileOutputStream(imagePath);
            if (imageType.equalsIgnoreCase("png")) {
                b.compress(Bitmap.CompressFormat.PNG, 100, out);
            }else if (imageType.equalsIgnoreCase("jpeg")|| imageType.equalsIgnoreCase("jpg")) {
                b.compress(Bitmap.CompressFormat.JPEG, 100, out);
            }
            fOut.flush();
            fOut.close();

            b.recycle();
        }catch (Exception e){
            e.printStackTrace();
        }
        return imagePath;
    }

    private void setCapturedImage(final String imagePath){
        new AsyncTask<Void,Void,String>(){
            @Override
            protected String doInBackground(Void... params) {
                try {
                    return getRightAngleImage(imagePath);
                }catch (Throwable e){
                    e.printStackTrace();
                }
                return imagePath;
            }

            @Override
            protected void onPostExecute(String imagePath) {
                super.onPostExecute(imagePath);
                imgFromCameraOrGallery.setImageBitmap(decodeFile(imagePath));
            }
        }.execute();
    }

    public Bitmap decodeFile(String path) {
        try {
            // Decode deal_image size
            BitmapFactory.Options o = new BitmapFactory.Options();
            o.inJustDecodeBounds = true;
            BitmapFactory.decodeFile(path, 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 scale = 1;
            while (o.outWidth / scale / 2 >= REQUIRED_SIZE && o.outHeight / scale / 2 >= REQUIRED_SIZE)
                scale *= 2;
            // Decode with inSampleSize
            BitmapFactory.Options o2 = new BitmapFactory.Options();
            o2.inSampleSize = scale;
            return BitmapFactory.decodeFile(path, o2);
        } catch (Throwable e) {
            e.printStackTrace();
        }
        return null;
    }

    public String getAbsolutePath(Uri uri) {
        if(Build.VERSION.SDK_INT >= 19){
            String id = "";
            if(uri.getLastPathSegment().split(":").length > 1)
                id = uri.getLastPathSegment().split(":")[1];
            else if(uri.getLastPathSegment().split(":").length > 0)
                id = uri.getLastPathSegment().split(":")[0];
            if(id.length() > 0){
                final String[] imageColumns = {MediaStore.Images.Media.DATA };
                final String imageOrderBy = null;
                Uri tempUri = getUri();
                Cursor imageCursor = getContentResolver().query(tempUri, imageColumns, MediaStore.Images.Media._ID + "=" + id, null, imageOrderBy);
                if (imageCursor.moveToFirst()) {
                    return imageCursor.getString(imageCursor.getColumnIndex(MediaStore.Images.Media.DATA));
                }else{
                    return null;
                }
            }else{
                return null;
            }
        }else{
            String[] projection = { MediaStore.MediaColumns.DATA };
            Cursor cursor = getContentResolver().query(uri, projection, null, null, null);
            if (cursor != null) {
                int column_index = cursor.getColumnIndexOrThrow(MediaStore.MediaColumns.DATA);
                cursor.moveToFirst();
                return cursor.getString(column_index);
            } else
                return null;
        }

    }

    private Uri getUri() {
        String state = Environment.getExternalStorageState();
        if(!state.equalsIgnoreCase(Environment.MEDIA_MOUNTED))
            return MediaStore.Images.Media.INTERNAL_CONTENT_URI;

        return MediaStore.Images.Media.EXTERNAL_CONTENT_URI;
    }

    public Uri setImageUri() {
        Uri imgUri;
        String state = Environment.getExternalStorageState();
        if (Environment.MEDIA_MOUNTED.equals(state)) {
            File file = new File(Environment.getExternalStorageDirectory() + "/DCIM/",getString(R.string.app_name) + Calendar.getInstance().getTimeInMillis() + ".png");
            imgUri = Uri.fromFile(file);
            imgPath = file.getAbsolutePath();
        }else {
            File file = new File(getFilesDir() ,getString(R.string.app_name) + Calendar.getInstance().getTimeInMillis()+ ".png");
            imgUri = Uri.fromFile(file);
            this.imgPath = file.getAbsolutePath();
        }
        return imgUri;
    }

    public String getImagePath() {
        return imgPath;
    }
}

如果有人在Android 4.4 (KitKat)上使用ExifInterface获得方向时遇到问题，这可能是因为从URI获得了错误的路径。在堆栈溢出问题中看到一个解决方案，从URI获得真正的路径，Android奇巧新的存储访问框架

最好试着以特定的方向照相。

android:screenOrientation="landscape"
android:configChanges="orientation|keyboardHidden"

为了获得最好的结果，在cameraview活动中给出景观方向。

很容易检测图像方向和替换位图使用:

 /**
 * Rotate an image if required.
 * @param img
 * @param selectedImage
 * @return
 */
private static Bitmap rotateImageIfRequired(Context context,Bitmap img, Uri selectedImage) {

    // Detect rotation
    int rotation = getRotation(context, selectedImage);
    if (rotation != 0) {
        Matrix matrix = new Matrix();
        matrix.postRotate(rotation);
        Bitmap rotatedImg = Bitmap.createBitmap(img, 0, 0, img.getWidth(), img.getHeight(), matrix, true);
        img.recycle();
        return rotatedImg;
    }
    else{
        return img;
    }
}

/**
 * Get the rotation of the last image added.
 * @param context
 * @param selectedImage
 * @return
 */
private static int getRotation(Context context,Uri selectedImage) {

    int rotation = 0;
    ContentResolver content = context.getContentResolver();

    Cursor mediaCursor = content.query(MediaStore.Images.Media.EXTERNAL_CONTENT_URI,
                                       new String[] { "orientation", "date_added" },
                                       null, null, "date_added desc");

    if (mediaCursor != null && mediaCursor.getCount() != 0) {
        while(mediaCursor.moveToNext()){
            rotation = mediaCursor.getInt(0);
            break;
        }
    }
    mediaCursor.close();
    return rotation;
}

为了避免大图像的内存不足，我建议您使用以下方法重新缩放图像:

private static final int MAX_HEIGHT = 1024;
private static final int MAX_WIDTH = 1024;
public static Bitmap decodeSampledBitmap(Context context, Uri selectedImage)
    throws IOException {

    // First decode with inJustDecodeBounds=true to check dimensions
    final BitmapFactory.Options options = new BitmapFactory.Options();
    options.inJustDecodeBounds = true;
    InputStream imageStream = context.getContentResolver().openInputStream(selectedImage);
    BitmapFactory.decodeStream(imageStream, null, options);
    imageStream.close();

    // Calculate inSampleSize
    options.inSampleSize = calculateInSampleSize(options, MAX_WIDTH, MAX_HEIGHT);

    // Decode bitmap with inSampleSize set
    options.inJustDecodeBounds = false;
    imageStream = context.getContentResolver().openInputStream(selectedImage);
    Bitmap img = BitmapFactory.decodeStream(imageStream, null, options);

    img = rotateImageIfRequired(img, selectedImage);
    return img;
}

由于Android操作系统的问题，不能使用ExifInterface来获取方向: https://code.google.com/p/android/issues/detail?id=19268

这里是calculateInSampleSize

/**
 * Calculate an inSampleSize for use in a {@link BitmapFactory.Options} object when decoding
 * bitmaps using the decode* methods from {@link BitmapFactory}. This implementation calculates
 * the closest inSampleSize that will result in the final decoded bitmap having a width and
 * height equal to or larger than the requested width and height. This implementation does not
 * ensure a power of 2 is returned for inSampleSize which can be faster when decoding but
 * results in a larger bitmap which isn't as useful for caching purposes.
 *
 * @param options   An options object with out* params already populated (run through a decode*
 *                  method with inJustDecodeBounds==true
 * @param reqWidth  The requested width of the resulting bitmap
 * @param reqHeight The requested height of the resulting bitmap
 * @return The value to be used for inSampleSize
 */
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) {

        // Calculate ratios of height and width to requested height and width
        final int heightRatio = Math.round((float) height / (float) reqHeight);
        final int widthRatio = Math.round((float) width / (float) reqWidth);

        // Choose the smallest ratio as inSampleSize value, this will guarantee a final image
        // with both dimensions larger than or equal to the requested height and width.
        inSampleSize = heightRatio < widthRatio ? heightRatio : widthRatio;

        // This offers some additional logic in case the image has a strange
        // aspect ratio. For example, a panorama may have a much larger
        // width than height. In these cases the total pixels might still
        // end up being too large to fit comfortably in memory, so we should
        // be more aggressive with sample down the image (=larger inSampleSize).

        final float totalPixels = width * height;

        // Anything more than 2x the requested pixels we'll sample down further
        final float totalReqPixelsCap = reqWidth * reqHeight * 2;

        while (totalPixels / (inSampleSize * inSampleSize) > totalReqPixelsCap) {
            inSampleSize++;
        }
    }
    return inSampleSize;
}