How set imageview scaletype to topCrop

问题

I'm coding android and I have a imageview. I want to set scaletype of this to topcrop. I could find centercrop in options, but it's not my request. How do I do?

回答1:

Custom Android ImageView for top-crop scaling of the contained drawable.

import android.content.Context;
import android.graphics.Matrix;
import android.widget.ImageView;

/**
* ImageView to display top-crop scale of an image view.
*
* @author Chris Arriola
*/
public class TopCropImageView extends ImageView {

public TopCropImageView(Context context) {
    super(context);
    setScaleType(ScaleType.MATRIX);
}

@Override
protected boolean setFrame(int l, int t, int r, int b) {
    final Matrix matrix = getImageMatrix();

    float scale;
    final int viewWidth = getWidth() - getPaddingLeft() - getPaddingRight();
    final int viewHeight = getHeight() - getPaddingTop() - getPaddingBottom();
    final int drawableWidth = getDrawable().getIntrinsicWidth();
    final int drawableHeight = getDrawable().getIntrinsicHeight();

    if (drawableWidth * viewHeight > drawableHeight * viewWidth) {
        scale = (float) viewHeight / (float) drawableHeight;
    } else {
        scale = (float) viewWidth / (float) drawableWidth;
    }

    matrix.setScale(scale, scale);
    setImageMatrix(matrix);

    return super.setFrame(l, t, r, b);
}        
}

https://gist.github.com/arriolac/3843346

回答2:

I just wanted a temporary solution without excess work . Try this

<ImageView
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:scaleType="centerCrop"
    android:scrollY="-100dp"
    android:id="@+id/poster"
   />

scrollY pulls your image up or down. Try it with different dp's and you 'll find the right size.

回答3:

I don't believe you need a custom Image View for this. All you have to do is set the scaleType to matrix and set a custom matrix to the ImageView.

Refer: https://stackoverflow.com/a/38049348/4747587

来源：https://stackoverflow.com/questions/29783358/how-set-imageview-scaletype-to-topcrop

标签

android

imageview

scaletype