Android – Resizing ImageView to fit to aspect ratio

androidimageview

I need to resize an ImageView such that it fits to the screen, maintains the same aspect ratio. The following conditions hold:

  • Images are a fixed width (size of the width of screen)
  • Images are downloaded from the Internet, i.e. size can only be determined later
  • Aspect ratio for each image will vary; some are tall, some are square, some are flat
  • ImageView's height needs to change, either bigger or smaller based on the aspect ratio of the
  • Excess height is cropped, can't have a lot of empty space like it is by default.

For example, a tiny 50×50 image on a 400 px width screen would scale the image up to 400×400 px. A 800×200 image would scale to 400×100.

I've looked at most of the other threads, and many proposed solutions like simply changing adjustViewBounds and scaleType will only scale down an image, and not scale it up.

Best Answer

I created it with the help of this Bob Lee's answer in this post: Android: How to stretch an image to the screen width while maintaining aspect ratio?

package com.yourpackage.widgets;

import android.content.Context;
import android.util.AttributeSet;
import android.widget.ImageView;

public class AspectRatioImageView extends ImageView {

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

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

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

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        int width = MeasureSpec.getSize(widthMeasureSpec);
        int height = width * getDrawable().getIntrinsicHeight() / getDrawable().getIntrinsicWidth();
        setMeasuredDimension(width, height);
    }
}

Now to use it in the XML:

<com.yourpackage.widgets.AspectRatioImageView android:layout_centerHorizontal="true"
    android:src="@drawable/yourdrawable" android:id="@+id/image"
    android:layout_alignParentTop="true" android:layout_height="wrap_content"
    android:layout_width="match_parent" android:adjustViewBounds="true" />

Have fun!

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