Question

我需要一个可以触摸放大/缩小和平移的ImageView。每当我触摸ImageView时，我都需要知道源图像的触摸位置。例如，图像分辨率为1280 * 720，即使ImageView中的图像被放大，我仍然确切地知道图像的触摸位置（不是ImageView的触摸位置）

感谢。

Answer 1

为什么不跳过所有这些并使用现有的库？

试试这个：PhotoView在API 23上完美适用于我，只需几行代码就可以放大/缩小并平移

compile 'com.github.chrisbanes:PhotoView:1.3.0'

repositories {
    ...
    maven { url "https://jitpack.io" }
}

示例

ImageView mImageView;
PhotoViewAttacher mAttacher;

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

// Any implementation of ImageView can be used!
mImageView = (ImageView) findViewById(R.id.iv_photo);

// Set the Drawable displayed
Drawable bitmap = getResources().getDrawable(R.drawable.wallpaper);
mImageView.setImageDrawable(bitmap);

// Attach a PhotoViewAttacher, which takes care of all of the zooming functionality.
// (not needed unless you are going to change the drawable later)
mAttacher = new PhotoViewAttacher(mImageView);
}

// If you later call mImageView.setImageDrawable/setImageBitmap/setImageResource/etc then you just need to call
mAttacher.update();

Answer 2

最后，我使用了这个开源代码 https://github.com/sephiroth74/ImageViewZoom

我修改了代码，但是在这个开源项目中仍然存在很多错误，我修复了其中的几个。

以下函数已添加到ImageViewTouch.GestureListener类中，该类用于将接触点（在屏幕中）转移到真实图像中的点（无论图像是放大/缩小）。

    private PointF calculatePositionInSourceImage(PointF touchPointF) {
        //point relative to imageRect
        PointF touchPointRelativeToImageRect = new PointF();
        RectF imageRect = getBitmapRect();
        touchPointRelativeToImageRect.set(touchPointF.x - imageRect.left,
                touchPointF.y - imageRect.top);

        //real image resolution
        int imageWidth = getDrawable().getIntrinsicWidth();
        int imageHeight = getDrawable().getIntrinsicHeight();

        //touch point in image
        PointF touchPointRelativeToImage = new PointF();
        touchPointRelativeToImage.set(touchPointRelativeToImageRect.x/imageRect.width() * imageWidth,
                touchPointRelativeToImageRect.y/imageRect.height() * imageHeight);

        if(touchPointRelativeToImage.x < 0 || touchPointRelativeToImage.y < 0 )
            touchPointRelativeToImage.set(0,0);

        return  touchPointRelativeToImage;
    }

任何Android开源ImageView？

2 个答案: