java - 如何在 Android 应用程序的事件监听器回调中使用标志

Question

预期结果

按钮可以像切换开关一样起作用，这样， (1)第一次点击按钮向右移动 (2)第二次点击按钮向左移动 (3)第三次点击按钮向右移动 等等......

问题

标志变量flagToggleButton不能在按钮的OnClickListener事件监听器回调函数中使用。

Main.java

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.widget.Button;

public class Main extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        final Button b = (Button) findViewById(R.id.button1);
        boolean flagToggleButton = false;
        b.setOnClickListener(new OnClickListener () {
            @Override
            public void onClick(View arg0) {
                if (flagToggleButton == false) {
                    Animation anim = AnimationUtils.loadAnimation(Main.this, 
                                       R.anim.animation_move_right);
                    b.startAnimation(anim);
                    flagToggleButton = true;
                }
                else {
                    Animation anim = AnimationUtils.loadAnimation(Main.this, 
                                       R.anim.animation_move_left);
                    b.startAnimation(anim);
                    flagToggleButton = false;
                }
            }
        });
    }
}

Answer 1

使其成为类的成员变量。换句话说，在 onCreate()

之外定义它

public class Main extends Activity {

    boolean flagToggleButton = false;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
    // rest of your code