![](/img/trans.png)
[英]My drawing app runs well, but when I want to see my drawing, I need to press my home button and launch it again
[英]I have multiple fragments.I want to save all Instances in backstack till the home button pressed again
我嘗試了很多方法來保存實例,但我很困惑如何將實例保存在后台堆棧中,因為沒有人描述如果有多個 Fragments.my 代碼在下面的 mainactivity 中如何使用它:
bottomNavigationView.setOnItemSelectedListener(item -> {
switch (item.getItemId()){
case R.id.home:
loadFragment(new HomeFragment(),0);
break;
case R.id.create:
loadFragment(new CreateFragment(),1);
break;
case R.id.profile:
loadFragment(new ProfileFragment(),1);
break;
}
return true;
});
public void loadFragment(Fragment fragment,int flag){
FragmentManager fragmentManager=getSupportFragmentManager();
FragmentTransaction fragmentTransaction=fragmentManager.beginTransaction();
if(flag==0){
fragmentTransaction.add(R.id.frame_layout,fragment);
fragmentManager.popBackStack(ROOT_FRAGMENT_TAG,FragmentManager.POP_BACK_STACK_INCLUSIVE);
fragmentTransaction.addToBackStack(ROOT_FRAGMENT_TAG);
}
else {
fragmentTransaction.replace(R.id.frame_layout,fragment);
fragmentTransaction.addToBackStack(null);
}
fragmentTransaction.commit();
}
我建議您將片段類設為單例。
private static MyFragment fragment;
public static MyFragment getInstance() {
if (fragment == null) {
fragment = new MyFragment();
}
return fragment;
}
然后使用getInstance()
方法來實例化你的片段
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.