如何在不降低质量的情况下在任何屏幕上调整 png/jpg 图像？

Question

我知道这有点棘手，并且仍在思考是否可能，但是当我使用 vector Drawable 时，我想让我的图像在不降低任何 Android 设备上的图像质量的情况下进行调整非常方便，但有时向量的大小不是内存效率，所以我不想使用它们。虽然我想知道是否有任何方法可以调整简单的 PNG 或 JPEG 文件与 Android 中的分辨率和屏幕尺寸无关？

如果有人能给我方法，那将是很大的帮助！！

Answer 1

使用调整图像视图（自定义图像视图）

  public class ResizableImageView extends ImageView {
    public ResizableImageView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public ResizableImageView(Context context) {
        super(context);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        Drawable d = getDrawable();
        // get drawable from imageview
        if (d == null) {
            super.setMeasuredDimension(widthMeasureSpec, heightMeasureSpec);
            return;
        }

        int imageHeight = d.getIntrinsicHeight();
        int imageWidth = d.getIntrinsicWidth();
        // get height and width of the drawable
        int widthSize = MeasureSpec.getSize(widthMeasureSpec);
        int heightSize = MeasureSpec.getSize(heightMeasureSpec);
        // get width and height extracts the size from the supplied measure specification.
        float imageRatio = 0.0F;
        if (imageHeight > 0) {
            imageRatio = imageWidth / imageHeight;
        }
        float sizeRatio = 0.0F;
        if (heightSize > 0) {
            sizeRatio = widthSize / heightSize;
        }

        int width;
        int height;
        if (imageRatio >= sizeRatio) {
            // set width to maximum allowed
            width = widthSize;
            // scale height
            height = width * imageHeight / imageWidth;
        } else {
            // set height to maximum allowed
            height = heightSize;
            // scale width
            width = height * imageWidth / imageHeight;
        }

        setMeasuredDimension(width, height);
        // This method must be called to store the measured width and measured height. Failing to do so will trigger an exception at measurement time
    }
}