片段addToBackStack关闭应用程序 [英] Fragment addToBackStack closing App

问题描述

我没有找到我的问题的任何解决方案。

I didnt find any solution for my problem.

我有几个片段（动态创建的），但我的后退按钮不工作， pressing它将关闭应用程序，无论片段是积极的。

I got several Fragments (dynamically created), but my Back Button is not working at all, pressing it will close the App, whatever fragment is "active".

@Override
public boolean onOptionsItemSelected(MenuItem item) {
// TODO Auto-generated method stub
switch (item.getItemId()) {

case R.id.itemAdd:
FragmentTransaction tx = getFragmentManager().beginTransaction();
    Fragment fragment = new NeuesProduktFrag();

    tx.setCustomAnimations(R.anim.slide_in_left, R.anim.slide_out_right,
             R.anim.slide_in_left, R.anim.slide_out_right);
     tx.replace(R.id.main, fragment);
     tx.addToBackStack(null);
     tx.commit();
    return true;

一切工作正常，但进入后NeuesProduktFrag片段和pressing后退按钮我的应用程序关闭。在不同的按钮等试了一下 重写onBack pressed是没有必要吧？ addToBackStack应该做的伎俩不？

Everything works fine, but after entering "NeuesProduktFrag" Fragment and pressing Back-Button my App closes. Tried it in different Buttons etc. Overriding onBackPressed is not needed right ? addToBackStack should do the trick or not ?

推荐答案

在我struggeled很长一段时间，这是我最后的code：

After i struggeled a long time, this is my final Code:

@Override
public void onBackPressed() {

// initialize variables
FragmentManager fm = getFragmentManager();
FragmentTransaction ft = fm.beginTransaction();

// check to see if stack is empty
if (fm.getBackStackEntryCount() > 0) {          
    fm.popBackStack();
    ft.commit();    
}
else {
    if (this.lastBackPressTime < System.currentTimeMillis() - 4000) {
Toast.makeText(this, "Nochmal drücken zum Beenden!", 4000).show();
this.lastBackPressTime = System.currentTimeMillis();
} else{
        super.onBackPressed();
    }        
}
}

我用它在我的FragmentActivity并增加了双卡，关闭应用程序最后。

I used it in my FragmentActivity and added a double tab to close the App finally.

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