有没有一种方法可以通过引用将成员函数传递给方法？ [JAVA]

Question

I'm trying to implement a counter in my app that increases every time the button is clicked. I then want to take the whatever the final value of the counter is and have it displayed in a dialog.

The problem is that when I call the variable, it returns the value that it initially had, not the one modified by the onClick method (This is weird to explain but I commented in my code to show what I mean).

    final TextView points = (TextView) findViewById(R.id.points);
    points.setText("Points = 0");

    class ButtonClick implements View.OnClickListener {
        int value = 0;
        public void onClick(View v) {
            value++;
            changeLocation(theButton);
            points.setText("Points = " + value); // This value increases
        }

        public int getValue() {
            return value;
        } // This returns 0.
    }

    final ButtonClick buttonClicked = new ButtonClick();
    theButton.setOnClickListener(buttonClicked);

    final int finalValue = buttonClicked.getValue(); // This still equals zero.

Answer 1

Code is executed synchronously line by line:

      // define and instantiate button listener 
1)    final ButtonClick buttonClicked = new ButtonClick();
      // attach listener to button
2)    theButton.setOnClickListener(buttonClicked);

            <------ here you still didn't executed onClick :) 

      // trying get value 
3)    final int finalValue = buttonClicked.getValue(); // This still equals zero.

When you hit line 3, you are getting value 0 because value is zero.

Try clicking (perform click -> do event or whatsoever ) then get value.

To see if it works, you need a second asynchronous method example:

new Thread(new Runnable() {

        @Override
        public void run() {

            while(buttonClicked.getValue() ==0) {
                   // you didn't click

                     Thread.sleep(10000);
            }
       };
}).start();

Answer 2

There are couple of issues that I can see, 1) onClick is not the overridden method, so try @Override annotation like this:

@Override
public void onClick(View v) { ... }

2) When a variable has to be used across, try to declare it in class level with getters and setters also at class level.

Hope these tips will help.