Java 将ImageView中的图像缩放到高度，将纵横比保持在屏幕边界之外，并向右对齐

我有一个图像，我想匹配屏幕的高度，延伸超过屏幕的左边缘，将图像的右侧与屏幕的右侧对齐

XML解决方案更好，但Java解决方案也可以

我该怎么做？

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您需要使用矩阵缩放并自行设置矩阵。这并不难

您必须在布局视图后执行此操作，以便获得

图像视图的尺寸。您还需要设置的
可绘制
或
位图的尺寸


首先，您必须计算出图像的缩放（倍增）程度，以便高度与
ImageView
的高度相同。为此，只需将
ImageView
高度除以图像高度即可

现在您也知道了图像的宽度。要使图像的右边缘与
ImageView
对齐，需要将图像向左移动（平移）其宽度，然后将其移回
ImageView
的宽度。因此，转换只是图像宽度和
ImageView
宽度的差异


我是这样做的：

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        final ImageView imageView = (ImageView) findViewById(R.id.imageview);

        imageView.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
            @Override
            public void onGlobalLayout() {

                BitmapDrawable drawable = null;
                if (Build.VERSION.SDK_INT >= 21) {
                    drawable = (BitmapDrawable) getResources().getDrawable(R.drawable.sunset, getTheme());
                } else {
                    drawable = (BitmapDrawable) getResources().getDrawable(R.drawable.sunset);
                }
                Bitmap bitmap = drawable.getBitmap();

                // get the scale factor that will have to be applied to
                // the image to make it the same height as your ImageView
                float factor = (float) imageView.getHeight() / (float) bitmap.getHeight();

                // now the image will have to be shifted over all of its
                // width minus the width of the ImageView.  This will make
                // the right edges line up.
                int scaledImageWidth = (int) (bitmap.getWidth() * factor);
                int translateX = imageView.getWidth() - scaledImageWidth;

                // you can also use drawable.getIntrinsicWidth() and
                //     drawable.getIntrinsicHeight()

                Matrix matrix = new Matrix();
                matrix.setScale(factor, factor);
                matrix.postTranslate(translateX, 0);

                imageView.setScaleType(ImageView.ScaleType.MATRIX);
                imageView.setImageMatrix(matrix);
                imageView.setImageBitmap(bitmap);
            }
        });
    }

您需要使用矩阵缩放并自行设置矩阵。这并不难

您必须在布局视图后执行此操作，以便获得
图像视图的尺寸。您还需要设置的
可绘制
或
位图的尺寸


首先，您必须计算出图像的缩放（倍增）程度，以便高度与
ImageView
的高度相同。为此，只需将
ImageView
高度除以图像高度即可

现在您也知道了图像的宽度。要使图像的右边缘与
ImageView
对齐，需要将图像向左移动（平移）其宽度，然后将其移回
ImageView
的宽度。因此，转换只是图像宽度和
ImageView
宽度的差异


我是这样做的：

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        final ImageView imageView = (ImageView) findViewById(R.id.imageview);

        imageView.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
            @Override
            public void onGlobalLayout() {

                BitmapDrawable drawable = null;
                if (Build.VERSION.SDK_INT >= 21) {
                    drawable = (BitmapDrawable) getResources().getDrawable(R.drawable.sunset, getTheme());
                } else {
                    drawable = (BitmapDrawable) getResources().getDrawable(R.drawable.sunset);
                }
                Bitmap bitmap = drawable.getBitmap();

                // get the scale factor that will have to be applied to
                // the image to make it the same height as your ImageView
                float factor = (float) imageView.getHeight() / (float) bitmap.getHeight();

                // now the image will have to be shifted over all of its
                // width minus the width of the ImageView.  This will make
                // the right edges line up.
                int scaledImageWidth = (int) (bitmap.getWidth() * factor);
                int translateX = imageView.getWidth() - scaledImageWidth;

                // you can also use drawable.getIntrinsicWidth() and
                //     drawable.getIntrinsicHeight()

                Matrix matrix = new Matrix();
                matrix.setScale(factor, factor);
                matrix.postTranslate(translateX, 0);

                imageView.setScaleType(ImageView.ScaleType.MATRIX);
                imageView.setImageMatrix(matrix);
                imageView.setImageBitmap(bitmap);
            }
        });
    }