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android - onBackPressed() 应用程序未关闭

问题描述

我有 3 个活动第一个是登录第二个是注册第三个带有底部导航的家庭活动 (Bottom_nav)，并且有 3 个片段 A、B、C。

登录活动是启动器活动。

在登录用户已经登录或未检查如果用户未登录它重定向到注册活动否则到家庭活动。

我已经在家庭活动中实现了 onBackPressed() 但是在双击后退按钮活动时会暂停并恢复。

这是我的代码：

 boolean doubleBackToExitPressedOnce = false;

@Override
public void onBackPressed() {
    if (doubleBackToExitPressedOnce) {
        super.onBackPressed();
        Bottom_nav.this.finish();
        return;
    }

    this.doubleBackToExitPressedOnce = true;
    Toast.makeText(this, "Please click BACK again to exit", Toast.LENGTH_SHORT).show();

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

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




private BottomNavigationView.OnNavigationItemSelectedListener mOnNavigationItemSelectedListener
        = new BottomNavigationView.OnNavigationItemSelectedListener() {

    @Override
    public boolean onNavigationItemSelected(@NonNull MenuItem item) {
        switch (item.getItemId()) {
            case R.id.navigation_home:
                getSupportFragmentManager().beginTransaction().replace(R.id.MainFrame, new HomeFragment()).commit();
                return true;
            case R.id.navigation_dashboard:
                getSupportFragmentManager().beginTransaction().replace(R.id.MainFrame, new ProfileFragment()).addToBackStack(null).commit();
                return true;
            case R.id.navigation_notifications:
                getSupportFragmentManager().beginTransaction().replace(R.id.MainFrame, new NotificationFragment()).addToBackStack(null).commit();
                return true;
        }
        return false;
    }
};

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_bottom_nav);

    getSupportFragmentManager().beginTransaction().add(R.id.MainFrame, new HomeFragment()).commit();
    BottomNavigationView navigation = (BottomNavigationView) findViewById(R.id.navigation);
    navigation.setOnNavigationItemSelectedListener(mOnNavigationItemSelectedListener);

}

这是日志

V/FA: Recording user engagement, ms: 2650
V/FA: Activity paused, time: 132340044
D/FA: Logging event (FE): user_engagement(_e), 
Bundle[{firebase_event_origin(_o)=auto, engagement_time_msec(_et)=2650, 
firebase_screen_class(_sc)=Bottom_nav, 
firebase_screen_id(_si)=-4687850249260059972}]
D/FA: Logging event (FE): screen_view(_vs), 
Bundle[{firebase_event_origin(_o)=auto, 
firebase_previous_class(_pc)=Bottom_nav, 
firebase_previous_id(_pi)=-4687850249260059972, 
firebase_screen_class(_sc)=RegisterPhoneActivity, 
firebase_screen_id(_si)=-4687850249260059974}]
V/FA: onActivityCreated
V/FA: Activity resumed, time: 132340054
V/FA: Screen exposed for less than 1000 ms. Event not sent. time: 184
V/FA: Activity paused, time: 132340135
D/FA: Logging event (FE): screen_view(_vs), 
Bundle[{firebase_event_origin(_o)=auto, 
firebase_previous_class(_pc)=RegisterPhoneActivity, 
firebase_previous_id(_pi)=-4687850249260059974, 
firebase_screen_class(_sc)=Bottom_nav, 
firebase_screen_id(_si)=-4687850249260059971}]
V/FA: Activity resumed, time: 132340244
W/PathParser: Points are too far apart 4.000000000000002
Points are too far apart 4.000000000000002
W/PathParser: Points are too far apart 4.000002058290173
Points are too far apart 4.000002058290173
W/PathParser: Points are too far apart 4.000001624254724
W/PathParser: Points are too far apart 4.000002923700373
Points are too far apart 4.000002923700373
W/PathParser: Points are too far apart 4.00000093640932
V/FA: Inactivity, disconnecting from the service

我哪里错了？我没有找到任何相关的答案

标签： androidandroid-fragmentsfragmentonbackpressed

解决方案

请使用这个。

boolean doubleBackToExitPressedOnce = false;
@Override
public void onBackPressed() {
    if (!doubleBackToExitPressedOnce){
        this.doubleBackToExitPressedOnce = true;
        Toast.makeText(this, "Please click BACK again to exit", Toast.LENGTH_SHORT).show();
        new Handler().postDelayed(new Runnable() {
            @Override
            public void run() {
                doubleBackToExitPressedOnce = false;
            }
        }, 2000);


    }else {
        if (getSupportFragmentManager().getBackStackEntryCount() != 0) {
            getSupportFragmentManager().popBackStack();
        } else {
            super.onBackPressed();
            finish();
        }

    }
}

打开片段时，您必须使用它

getSupportFragmentManager().beginTransaction().replace(R.id.MainFrame, new HomeFragment()).addToBackStack(null).commit();

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