在菜单打开时覆盖 BackButton

Question

我想要实现的是，当用户在 MENU 可见时单击后退按钮时，menuActual 和 MENU 的状态从可见变为不可见。如果 MENU 未打开并且用户单击返回，则会显示 Toast 并显示 "Press again to Exit"，如果您在 2 秒内单击返回，应用程序将关闭。

我拥有的代码：

@Override
    public void finish() {

    if (MENU.getVisibility() == View.VISIBLE){
        MENU.setVisibility(View.INVISIBLE);
        menuActual.setVisibility(View.INVISIBLE);

    }else {
        if (doubleBackToExitPressedOnce) {
            super.onBackPressed();
            moveTaskToBack(true);

            return;
        }else {

            this.doubleBackToExitPressedOnce = true;
            Toast.makeText(this, "Tap again to Exit!", Toast.LENGTH_SHORT).show();

            new Handler().postDelayed(new Runnable() {

                @Override
                public void run() {
                    doubleBackToExitPressedOnce=false;
                }
            }, 2000);
        }
    }
}`

我已经声明了boolean doubleBackToExitPressedOnce = false;

应用程序会显示 Toast 说 "Press again to Exit"，但如果再次单击后退，应用程序会显示 "AppName isn't responding"

努力弄清楚这是为什么，这是漫长的一天。

谢谢！

Answer 1

在 onBackPressed 中这样做：

private boolean doubleBackToExitPressedOnce = false;
private Handler handler;
private Runnable runnable;

@Override
public void onBackPressed() {
    if (MENU.getVisibility() == View.VISIBLE) {
        MENU.setVisibility(View.INVISIBLE);
        menuActual.setVisibility(View.INVISIBLE);
        return;
    }

    if (!doubleBackToExitPressedOnce) {
        doubleBackToExitPressedOnce = true;
        Toast.makeText(this, "Tap again to Exit!", Toast.LENGTH_SHORT).show();

        handler = new Handler();
        handler.postDelayed(runnable = new Runnable() {

            @Override
            public void run() {
                doubleBackToExitPressedOnce = false;
            }
        }, 2000);
        return;
    }

    // Removes the callBack
    handler.removeCallbacks(runnable);

    // Replace this next line with finishAffinity() if you want to close the app.
    super.onBackPressed();
}

在菜单打开时覆盖 BackButton

Override BackButton while menu is Open

java

android

back-button