扩展android View类并影响所有子类

Question

I need to extends View class in Android in order to override couple of methods.

public class ExtendedView extends View {

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

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        if (event.getAction() == MotionEvent.ACTION_MOVE && getParent() != null) 
            getParent().requestDisallowInterceptTouchEvent(true);
        return super.onTouchEvent(event);
    }

     ...
}

There are couple of view type in android which derive from View such as ImageView and etc.

They do not access to overridden methods in ExtendedView class.

One solution is creating extended classes for all of them such as :

public class ExtendedImageView extends ImageView

And override the methods.

But is there any better solution to avoid such a code redundancy?

Answer 1

Create a BaseActivity implementing onTouchEventListener (or something like that, dont remember), then when you have a view which requires to handle it, just setOnTouchListener(this)

Of course, make your activities extend BaseActivity

Regards

Answer 2

As per me this is simple and decent way. Here, your code is centralized and one common implementation is given which all intended ExtendedView classes will use.

class MyImplementation
{
 public boolean methodA(View v, MotionEvent event)
 {
  boolean someBoolean = false;
  // some impl of your spl method.
  if(v instanceOf ExtendedImageView)
   {
     // ImageView called this method.
   }

 }
 return someBoolean;
}

Image View implementation

public class ExtendedImageView extends ImageView{
    public boolean onTouchEvent (MotionEvent event)
     {
       MyImplementaion a  = new MyImplemenation();
       boolean b = a.methodA(this, event);
       return b;
     }
}

For Some other View

public class ExtendedMapView extends MapView{

       public boolean onTouchEvent (MotionEvent event)
       {
        MyImplementaion a  = new MyImplemenation();
        boolean b = a.methodA(this, event);
        return b;
       }
}