Android：在图像按钮上有拉伸/缩放问题

Question

I have been struggling with what I think is something simple. I am setting an image on an image button using a class. I want the image to fit the constraints of the screen, but without stretching. That is, if it's too wide to fit the screen, I want the height to be scaled to accommodate so that it doesn't get stretched . And if the height is too tall, I want the image height to be reduced, thereby shrinking the width too.

I have seen this question asked a couple times and I have tried every bit of the advice, but it makes absolutely no difference for me. I think this may have something to do with usnig an ImageButton instead of an ImageView?

Here are some relevant chunks of code (badly broken) ...

In my class:

          ImageView img = (ImageButton) dialog.findViewById(R.id.fullsizeimage);
          img.setScaleType(ImageView.ScaleType.CENTER_INSIDE);  //Changing ScaleType here has no effect
          img.setImageBitmap(useThisBitmap);

And here is the xml layout contents ...

 <?xml version="1.0" encoding="utf-8"?>
   <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >

<ImageButton
    android:id="@+id/fullsizeimage"
    android:background="@null"
    android:layout_width="wrap_content" 
    android:layout_height="fill_parent"
    android:adjustViewBounds="true"
    />

 </RelativeLayout>

Some of that junk in the XML file is probably wrong. But I have changed it so many times, and it has ZERO effect.

Any and all advise is greatly appreciated.

Answer 1

I think that ImageButton will always stretch the background image in order to fill its whole background. An ImageView can be easily made clickable on its own, have you tried that?

A more complicated option is to use a custom view which can draw your image on canvas any way you like and can have onTouch listener.