在视图转换后图像超出范围

Question

我在显示图像时遇到问题.

我有一个想要全屏显示的图像.所以我有这个带有match_parent和20dp填充的Imageview.

它看起来不错但是当我对它应用旋转时,似乎视图的边界不会改变,并且图像可能会被截断出屏幕!完全不希望发生这种情况!如何重新缩放图像,以便在旋转90度时图像也适合ImageView.

这是我的XML WITH旋转.

编辑:

如何修复图像的边界,使文本在图像上方对齐？

Answer 1

在测量视图和计算比例时,不考虑旋转.一个可能的解决方案是自己做:

public class RotatedImageView extends ImageView {

    ...
    constructors
    ...


    private double mRotatedWidth;
    private double mRotatedHeight;

    private boolean update() {
        Drawable d = getDrawable();

        if (d == null) {
            return false;
        }

        int drawableWidth = d.getIntrinsicWidth();
        int drawableHeight = d.getIntrinsicHeight();

        if (drawableWidth <= 0 || drawableHeight <= 0) {
            return false;
        }

        double rotationRad = getRotation() / 180 * Math.PI;

        // calculate intrinsic rotated size
        // see diagram

        mRotatedWidth = (Math.abs(Math.sin(rotationRad)) * drawableHeight
                + Math.abs(Math.cos(rotationRad)) * drawableWidth);
        mRotatedHeight = (Math.abs(Math.cos(rotationRad)) * drawableHeight
                + Math.abs(Math.sin(rotationRad)) * drawableWidth);

        return true;
    }


    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {

        if (update()) {
            double ratio = mRotatedWidth / mRotatedHeight;

            int wMax = Math.min(getDefaultSize(Integer.MAX_VALUE, widthMeasureSpec), getMaxWidth());
            int hMax = Math.min(getDefaultSize(Integer.MAX_VALUE, heightMeasureSpec), getMaxHeight());

            int w = (int) Math.min(wMax, hMax * ratio);
            int h = (int) Math.min(hMax, wMax / ratio);

            setMeasuredDimension(w, h);
        } else {
            super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        }

    }

    private final float[] values = new float[9];

    protected void onDraw(Canvas canvas) {

        if (update()) {
            int availableWidth = getMeasuredWidth();
            int availableHeight = getMeasuredHeight();

            float scale = (float) Math.min(availableWidth / mRotatedWidth, availableHeight / mRotatedHeight);

            getImageMatrix().getValues(values);

            setScaleX(scale / values[Matrix.MSCALE_X]);
            setScaleY(scale / values[Matrix.MSCALE_Y]);
        }

        super.onDraw(canvas);
    }

    @Override
    public void setRotation(float rotation) {
        super.setRotation(rotation);
        requestLayout();
    }
}

adjustViewBounds 一定是真的:

<com.mypackage.RotatedImageView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_margin="20dp"
    android:adjustViewBounds="true"
    android:rotation="90"
    android:maxWidth="100dp"
    android:maxHeight="100dp"
    android:scaleType="fitCenter"
    android:src="@drawable/test" />

由Cheticamp提供的计算的一个很好的解释:

更新:现在尝试调整边界.wrap_content和之间没有区别match_parent(根据图像方面,两者都增长很多).您应该使用maxWidth和/或maxHeight将其放入LinearLayout0大小和重量.

它也是不可动画的,调整边界虽然动画需要每帧的布局通过,这是非常低效的.有关可用的版本,请参阅其他答案View.animate()