如何在Android中为ImageView设置最小和最大大小

Question

我想指定这两个分钟.宽度/高度和最大值 ImageView的宽度/高度.图像应缩放以适合.

这样做:

<ImageView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:minWidth="100dp"
    android:maxWidth="200dp"
    android:minHeight="100dp"
    android:maxHeight="200dp"
    android:src="@drawable/ic_launcher" />

最小的 宽度和高度按照应有的方式执行,但最大值 宽度和高度被忽略.

如果我设置android:adjustViewBounds ="true":

<ImageView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:adjustViewBounds="true"
    android:scaleType="fitCenter"
    android:minWidth="100dp"
    android:maxWidth="200dp"
    android:minHeight="100dp"
    android:maxHeight="200dp"
    android:src="@drawable/ic_launcher" />

比,最大 宽度和高度按照应有的方式执行,但最小值.宽度和高度被忽略.

有两种方法可以同时拥有吗？

Answer 1

最后,我创建了自己的视图,它可以访问ImageView并覆盖onMeasure():

public class ResizingImageView extends ImageView {

    private int mMaxWidth;
    private int mMaxHeight;

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

    public ResizingImageView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public ResizingImageView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }

    @Override
    public void setMaxWidth(int maxWidth) {
        super.setMaxWidth(maxWidth);
        mMaxWidth = maxWidth;
    }

    @Override
    public void setMaxHeight(int maxHeight) {
        super.setMaxHeight(maxHeight);
        mMaxHeight = maxHeight;
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);

        Drawable drawable = getDrawable();
        if (drawable != null) {

            int wMode = MeasureSpec.getMode(widthMeasureSpec);
            int hMode = MeasureSpec.getMode(heightMeasureSpec);
            if (wMode == MeasureSpec.EXACTLY || hMode == MeasureSpec.EXACTLY) {
                return;
            }

            // Calculate the most appropriate size for the view. Take into
            // account minWidth, minHeight, maxWith, maxHeigh and allowed size
            // for the view.

            int maxWidth = wMode == MeasureSpec.AT_MOST
                    ? Math.min(MeasureSpec.getSize(widthMeasureSpec), mMaxWidth)
                    : mMaxWidth;
            int maxHeight = hMode == MeasureSpec.AT_MOST
                    ? Math.min(MeasureSpec.getSize(heightMeasureSpec), mMaxHeight)
                    : mMaxHeight;

            int dWidth = Helpers.dipsToPixels(drawable.getIntrinsicWidth());
            int dHeight = Helpers.dipsToPixels(drawable.getIntrinsicHeight());
            float ratio = ((float) dWidth) / dHeight;

            int width = Math.min(Math.max(dWidth, getSuggestedMinimumWidth()), maxWidth);
            int height = (int) (width / ratio);

            height = Math.min(Math.max(height, getSuggestedMinimumHeight()), maxHeight);
            width = (int) (height * ratio);

            if (width > maxWidth) {
                width = maxWidth;
                height = (int) (width / ratio);
            }

            setMeasuredDimension(width, height);
        }
    }
}

现在可以使用此视图,如:

<my.package.ResizingImageView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:minWidth="100dp"
    android:maxWidth="200dp"
    android:minHeight="100dp"
    android:maxHeight="200dp"
    android:src="@drawable/ic_launcher" />

这可以按照我的意愿工作,但是不应该有更简单的解决方案吗？

Answer 2

这在过去仅使用 XML 几乎是不可能的，但现在使用ConstraintLayout，这非常简单。

<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content">

    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintWidth_min="100dp"
        app:layout_constraintWidth_max="200dp"
        app:layout_constraintHeight_min="100dp"
        app:layout_constraintHeight_max="200dp"
        app:layout_constrainedWidth="true"
        app:layout_constrainedHeight="true"
        android:scaleType="centerCrop" />
</androidx.constraintlayout.widget.ConstraintLayout>

您可以使用scaleTypeoffitXY或centerCrop; 其他人不会强迫图像适合ImageView.