Is there an easy way to enlarge the image?

Among Android open sources, there is a very good open source called TouchImageView. https://github.com/MikeOrtiz/TouchImageView For more information, visit here.

TouchImageView img = (TouchImageView) findViewById(R.id.img); By default, this is how you use it.

In xml,

<com.example.touch.TouchImageView
    android:id="@+id/img”
    android:layout_width="match_parent"
    android:layout_height="match_parent" />

It's defined like this.