Question

我希望每次单击按钮时将图像旋转90度。这部分效果很好：

public void rotateImage(View view) {

    mCurrRotation %= 360;
    float fromRotation = mCurrRotation;
    float toRotation = mCurrRotation += 90;

    final RotateAnimation rotateAnim = new RotateAnimation(
            fromRotation, toRotation, mImageView.getWidth()/2, mImageView.getHeight()/2);

    rotateAnim.setDuration(1000); // Use 0 ms to rotate instantly
    rotateAnim.setFillAfter(true); // Must be true or the animation will reset

    mImageView.startAnimation(rotateAnim);

这会将图像转换为byteArray，以便将其保存到SQLite数据库中：

    bitmapDrawable = (BitmapDrawable) mImageView.getDrawable();
     Bitmap imageBitmap = bitmapDrawable.getBitmap();
     ByteArrayOutputStream stream = new ByteArrayOutputStream();
     imageBitmap.compress(Bitmap.CompressFormat.PNG, 100, stream);
     byte[] image = stream.toByteArray();

但图像会在旋转前保存。

Answer 1

通过在画布上临时保存Drawable并使用外部方法来实现：

public void rotateImage(View view) {
            try{
                rotateViewto90();
            }catch (Exception e){
                Toast ToastMessage = Toast.makeText(getApplicationContext(), "There is no Image for rotation", Toast.LENGTH_LONG);
                View toastView = ToastMessage.getView();
                toastView.setBackgroundResource(R.drawable.toast_background_color_editor_act);
                ToastMessage.show();
            }

        }

        // This method will rotate an image to 90 degrees each time rotateImage Button is clicked.
        void rotateViewto90(){
            Bitmap bmpOriginal = drawableToBitmap(mImageView.getDrawable());
            Bitmap bmResult = Bitmap.createBitmap(bmpOriginal.getWidth(), bmpOriginal.getHeight(), Bitmap.Config.ARGB_8888);
            Canvas tempCanvas = new Canvas(bmResult);
            tempCanvas.rotate(90, bmpOriginal.getWidth()/2, bmpOriginal.getHeight()/2);
            tempCanvas.drawBitmap(bmpOriginal, 0, 0, null);
            mImageView.setImageBitmap(bmResult);
        }

        //convert Drawable to Bitmap
        public static Bitmap drawableToBitmap (Drawable drawable) {
            Bitmap bitmap = null;

            if (drawable instanceof BitmapDrawable) {
                BitmapDrawable bitmapDrawable = (BitmapDrawable) drawable;
                if(bitmapDrawable.getBitmap() != null) {
                    return bitmapDrawable.getBitmap();
                }
            }

            if(drawable.getIntrinsicWidth() <= 0 || drawable.getIntrinsicHeight() <= 0) {
                bitmap = Bitmap.createBitmap(1, 1, Bitmap.Config.ARGB_8888); // Single color bitmap will be created of 1x1 pixel
            } else {
                bitmap = Bitmap.createBitmap(drawable.getIntrinsicWidth(), drawable.getIntrinsicHeight(), Bitmap.Config.ARGB_8888);
            }

            Canvas canvas = new Canvas(bitmap);
            drawable.setBounds(0, 0, canvas.getWidth(), canvas.getHeight());
            drawable.draw(canvas);
            return bitmap;
        }

如何通过旋转保存图像

1 个答案: