Android淡入淡出动画问题

Alpha Animation

这个 第一 当我点击按钮时,什么都没发生。当我再次单击按钮时,它会出现,然后立即消失。当我点击按钮a时 第三 时间,它平滑地设置“淡入”运动的动画。然后,当我第四次点击它时,它会平滑地为“淡出”运动设置动画,等等。。。

下面是这个简单程序中的代码:

public class MainActivity extends AppCompatActivity {
public Button toggleButton;
public Button helloButton;
public boolean isVisible = false;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    helloButton = (Button)findViewById(R.id.helloButton);

    toggleButton = (Button)findViewById(R.id.toggleButton);
    toggleButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            if (!isVisible) {
                //helloButton.setVisibility(View.VISIBLE);
                AlphaAnimation fadeInAnimation = new AlphaAnimation(0, 1); // start alpha, end alpha
                fadeInAnimation.setDuration(250); // time for animation in milliseconds
                fadeInAnimation.setFillAfter(true); // make the transformation persist
                fadeInAnimation.setAnimationListener(new Animation.AnimationListener() {
                    @Override
                    public void onAnimationEnd(Animation animation) {
                        helloButton.setVisibility(View.VISIBLE);
                    }

                    @Override
                    public void onAnimationRepeat(Animation animation) { }

                    @Override
                    public void onAnimationStart(Animation animation) {
                        helloButton.setVisibility(View.GONE);
                    }
                });
                helloButton.startAnimation(fadeInAnimation);
                isVisible = true;
                System.out.println("Button is invisible... Time to Fade IN");
            }
            else {
                //helloButton.setVisibility(View.GONE);
                AlphaAnimation fadeOutAnimation = new AlphaAnimation(1, 0); // start alpha, end alpha
                fadeOutAnimation.setDuration(250); // time for animation in milliseconds
                fadeOutAnimation.setFillAfter(true); // make the transformation persist
                fadeOutAnimation.setAnimationListener(new Animation.AnimationListener() {
                    @Override
                    public void onAnimationEnd(Animation animation) {
                        helloButton.setVisibility(View.GONE);
                    }

                    @Override
                    public void onAnimationRepeat(Animation animation) { }

                    @Override
                    public void onAnimationStart(Animation animation) {
                        helloButton.setVisibility(View.VISIBLE);
                    }
                });
                helloButton.startAnimation(fadeOutAnimation);
                isVisible = false;
                System.out.println("Button is visible... Time to Fade OUT");
            }
        }
    });

  }
}

我觉得这很简单;然而,这是我第一次在android开发中遇到动画。如有任何建议,我们将不胜感激!