获取 ImageView 中显示的图像的大小

Question

获取 ImageView 中显示的图像的大小

21

代码很简单：

<ImageView android:layout_width="fill_parent"
           android:layout_height="fill_parent"
           android:src="@drawable/cat"/>

注意ImageView使用了fill_parent来设置宽度和高度。

图片cat很小，会被放大以适应ImageView，并保持宽高比。

我的问题是如何获取图像的显示尺寸？我尝试过：

imageView.getDrawable().getIntrinsicHeight()

但是猫图片的原始高度是多少呢？

我尝试过：

imageView.getDrawable().getBounds()

但是它返回了Rect(0,0,0,0)。

- Freewind

你可以使用ViewTreeObserver在运行时获取任何视图的真实尺寸。http://developer.android.com/reference/android/view/ViewTreeObserver.html - Arpit Garg

谢谢，我正在看。顺便问一下：这是获取大小的最佳/唯一方法吗？ - Freewind

1

抱歉，即使使用了ViewTreeObserver，我仍然不知道如何获取图像的显示大小。 - Freewind

可能重复：尝试获取ImageView中图像的显示大小 - btalb

4个回答

8

这是一个帮助函数，用于获取imageView中图像的边界。

/**
 * Helper method to get the bounds of image inside the imageView.
 *
 * @param imageView the imageView.
 * @return bounding rectangle of the image.
 */
public static RectF getImageBounds(ImageView imageView) {
    RectF bounds = new RectF();
    Drawable drawable = imageView.getDrawable();
    if (drawable != null) {
        imageView.getImageMatrix().mapRect(bounds, new RectF(drawable.getBounds()));
    }
    return bounds;
}

- Nabin Bhandari

0

我猜很多人来自这个例子https://developer.android.com/training/animation/zoom.html，不想使用 android:scaleType="centerCrop" （也许因为ImageView在约束布局中，你想看到未裁剪的小图像），别担心，我帮你！只需替换以

开头的整个块。

// Adjust the start bounds to be the same aspect ratio as the final
// bounds using the "center crop" technique.

使用以下内容

//adjust for scaled image to constraint
int realheight = ResourcesCompat.getDrawable(getResources(),imageResId,null).getIntrinsicHeight();
int realwidth = ResourcesCompat.getDrawable(getResources(),imageResId,null).getIntrinsicWidth();

// Adjust the start bounds to be the same aspect ratio as the final
// bounds using ueen's adjusteddimensions technique. This prevents undesirable
// stretching during the animation. Also calculate the start scaling
// factor (the end scaling factor is always 1.0).
float startScale;
if ((float) finalBounds.width() / finalBounds.height()
        > (float) startBounds.width() / startBounds.height()) {
    // Extend start bounds horizontally
    // after check whether height or width needs adjusting
    if ((float) startBounds.width() / startBounds.height() < (float) realwidth / realheight) {
        int adjustedheight = realheight*startBounds.width()/realwidth;
        int adjustedoffset = (startBounds.height()-adjustedheight) / 2;
        startScale = (float) adjustedheight / finalBounds.height();
        float startWidth = startScale * finalBounds.width();
        float deltaWidth = (startWidth - startBounds.width()) / 2;
        startBounds.left -= deltaWidth;
        startBounds.right += deltaWidth;
        startBounds.offset(+0, +adjustedoffset);
    } else {
        int adjustedwidth = realwidth*startBounds.height()/realheight;
        int adjustedoffset = (startBounds.width()-adjustedwidth) / 2;
        startScale = (float) startBounds.height() / finalBounds.height();
        float startWidth = startScale * finalBounds.width();
        float deltaWidth = (startWidth - adjustedwidth) / 2;
        startBounds.left -= deltaWidth;
        startBounds.right += deltaWidth;
        startBounds.offset(+adjustedoffset, +0);
    }
} else {
    // Extend start bounds vertically
    // after check whether height or width needs adjusting
    if ((float) startBounds.width() / startBounds.height() > (float) realwidth / realheight) {
        int adjustedwidth = realwidth*startBounds.height()/realheight;
        int adjustedoffset = (startBounds.width()-adjustedwidth) / 2;
        startScale = (float) adjustedwidth / finalBounds.width();
        float startHeight = startScale * finalBounds.height();
        float deltaHeight = (startHeight - startBounds.height()) / 2;
        startBounds.top -= deltaHeight;
        startBounds.bottom += deltaHeight;
        startBounds.offset(+adjustedoffset, +0);
    } else {
        int adjustedheight = realheight*startBounds.width()/realwidth;
        int adjustedoffset = (startBounds.height()-adjustedheight) / 2;
        startScale = (float) startBounds.width() / finalBounds.width();
        float startHeight = startScale * finalBounds.height();
        float deltaHeight = (startHeight - adjustedheight) / 2;
        startBounds.top -= deltaHeight;
        startBounds.bottom += deltaHeight;
        startBounds.offset(+0, +adjustedoffset);
    }
}

非常好用，不客气 :)

进一步解释：通常我们会检查图片是否比宽度更高（扩展后的图片高度应与 expandedImageView 的高度匹配）或反之。然后我们检查原始（较小）ImageView（thumbView）中的图片是否与宽度或高度匹配，以便我们可以调整空间。这样，我们就可以实现平滑的缩放动画，同时不裁剪 thumbView 中的图片，无论其尺寸如何（当使用约束时，它们可能会因设备而异）或图片的尺寸。

- ueen

1

实际上，我来自一个OCR库，该库返回相对于原始图像的单词位置，并且我必须将它们放置在缩放后的“ImageView”上。不过，你的起源故事很不错。 - Abandoned Cart

-1

使用

// For getting imageview height
imgObj.getMeasuredHeight()


// For getting imageview width
imgObj.getMeasuredWidth();


//For getting image height inside ImageView
 imgObj.getDrawable().getIntrinsicHeight();


//For getting image width inside ImageView
 imgObj.getDrawable().getIntrinsicWidth();

- RajeshVijayakumar

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可以查看英文原文，
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- fsegaux · Accepted Answer

以下内容可行：

ih=imageView.getMeasuredHeight();//height of imageView
iw=imageView.getMeasuredWidth();//width of imageView
iH=imageView.getDrawable().getIntrinsicHeight();//original height of underlying image
iW=imageView.getDrawable().getIntrinsicWidth();//original width of underlying image

if (ih/iH<=iw/iW) iw=iW*ih/iH;//rescaled width of image within ImageView
else ih= iH*iw/iW;//rescaled height of image within ImageView

(iw x ih)现在代表了视图中图像的实际重新缩放后的尺寸（换句话说，图像的显示大小）。

编辑：我觉得更好的写法（并适用于整数）如下：

final int actualHeight, actualWidth;
final int imageViewHeight = imageView.getHeight(), imageViewWidth = imageView.getWidth();
final int bitmapHeight = ..., bitmapWidth = ...;
if (imageViewHeight * bitmapWidth <= imageViewWidth * bitmapHeight) {
    actualWidth = bitmapWidth * imageViewHeight / bitmapHeight;
    actualHeight = imageViewHeight;
} else {
    actualHeight = bitmapHeight * imageViewWidth / bitmapWidth;
    actualWidth = imageViewWidth;
}

return new Point(actualWidth,actualHeight);