如何在方法完成时通知

Question

How can i notify and execute instantly a method from the MainActivity class when a method from a non-activity class has finished?

MainActivity class:

public class MainActivity extends AppCompatActivity {

private ExpandableListViewAdapter mExpandableListViewAdapter;
PreselectionAplicationUseCases preselectionAplicationUseCases;

    public void Preselection(){
    if(preselectionAplicationUseCases.isMsg100PreselectionAplication()) {
        mExpandableListViewAdapter.setSelectedChild(-1);
    }
}

Non-activity class:

public class MSG0100  implements PreselectionAplicationUseCases {
    msg100PreselectionAplication=true;
}
public boolean isMsg100PreselectionAplication() {
    return msg100PreselectionAplication;
}

public void setMsg100PreselectionAplication(boolean msg100PreselectionAplication) {
    this.msg100PreselectionAplication = msg100PreselectionAplication;
}

And the interface:

public interface PreselectionAplicationUseCases {
boolean isMsg100PreselectionAplication();

void setMsg100PreselectionAplication(boolean msg100PreselectionAplication);
}

So how can I execute the method Preselection automatically when this happens msg100PreselectionAplication=true; in the non-activity class. I was thinking that i can use a thread with wait and notify, but i think that can give some problems to the UI thread.

Answer 1

Couldn't you just use Observer pattern?

public class MSG0100  implements PreselectionAplicationUseCases {
    private OnMsg100PreselectionChanged listener = null;


    public void setOnMsgPreselectionChanged(OnMsg100PreselectionChanged listener) {
        this.listener = listener;
    }

    public void setMsg100PreselectionAplication(boolean msg100PreselectionAplication) {
        if(listener != null) {
            listener.onPreselectionChanged(msg100PreselectionAplication);
        }
    }
}

interface OnMsg100PreselectionChanged {
    void onPreselectionChanged(boolean isChanged);
}

public class MainActivity extends AppCompatActivity {

    private ExpandableListViewAdapter mExpandableListViewAdapter;
    PreselectionAplicationUseCases preselectionAplicationUseCases;

    public void Preselection(){
        preselectionApplicationUseCases.setOnMsgPreselectionChanged(new OnMsg100PreselectionChanged {

            @Override
            void onPreselectionChanged(boolean isChanged) {
                //do something with changed boolean
            }
        });
    }
}

Answer 2

You can create inteface like this and implement it in your activity class:

   public interface OnMethodFinishedListener {
    
    void onMethodFinish();
    }

then make method call in your non-activity class:

 public class MSG0100  implements PreselectionAplicationUseCases {
        msg100PreselectionAplication=true;
    }
    
    private OnMethodFinishedListener mListener
    public MSG0100 (OnMethodFinishedListener listner){
        mListener = listener;
    }
    
    public boolean isMsg100PreselectionAplication() {
        return msg100PreselectionAplication;
    }
    
    public void setMsg100PreselectionAplication(boolean msg100PreselectionAplication) {
        this.msg100PreselectionAplication = msg100PreselectionAplication;
              //here for example. or anywhere you need
         mListener.onMethodFinish
    }

And that is it - your activity will get call in overrided onMethodFinished method

Answer 3

This could be done also using while

while(msg100PreselectionAplication=true){
  //do something to notify after that we set preselection again to false
    msg100PreselectionAplication=false;
}