Android Fragment Back Stack [英] Android Fragment Back Stack

问题描述

我在项目中使用了多个片段.我想保存一个Fragment的状态并在回到该状态时恢复该状态.在此片段中，我显示了多个图像，这些图像在单击按钮时会发生变化.我为此使用以下代码:

I have used multiple Fragments in my Project. I want to save a Fragment's state and restore this state when I come back to this. In this Fragment I show multiple images which change on button click. I use the following code for this:

String backStateName = fragment.getClass().getName();
FragmentManager fragmentManager = getSupportFragmentManager();
boolean fragmentPopped = fragmentManager.popBackStackImmediate(backStateName, 0);
if (!fragmentPopped) {
 FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
 fragmentTransaction.replace(R.id.container_body, fragment);
 fragmentTransaction.addToBackStack(backStateName);
 fragmentTransaction.commit();
}

工作正常&它保存状态，但不显示先前的图像.

It works fine & it saves state, but it does not show previous image's.

任何帮助，建议或教程将不胜感激.谢谢.

Any help, suggestion or tutorials would be highly appreciated. Thank you.

推荐答案

我正在尝试使用片段列表....

I am trying with the fragment list ....

初始化框架列表

Initilize the framents list

  static List<String> fragments = new ArrayList<String>();

代码片段更改并带回堆栈

Code to fragment change and take in back stack

   String backStateName = fragment.getClass().getName();
    FragmentManager manager = getSupportFragmentManager();
    //fragment not in back stack, create it.
    FragmentTransaction ft = manager.beginTransaction();
    if(!fragments.contains(backStateName)) {

       // ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE);
        // ft.setCustomAnimations(R.anim.fade_in, R.anim.fade_out);
        ft.replace(R.id.frame, fragment);
        ft.addToBackStack(backStateName);
        ft.commit();

        fragments.add(backStateName);
        System.out.println("backStateName" + fragments);
    }
    else
    {


        ft.replace(R.id.frame, fragment);
        ft.commit();

    }

onBackpressed

onBackpressed

 @Override
public void onBackPressed() {
    if(fragments.size()>0)
        {
            fragments.remove(fragments.size()-1);
        }
        super.onBackPressed();
}

用于向后移除堆栈

for back remove stack

 final android.app.FragmentManager fm = getFragmentManager();

    fm.addOnBackStackChangedListener(new android.app.FragmentManager.OnBackStackChangedListener() {
        @Override
        public void onBackStackChanged() {

            if (getSupportFragmentManager().getBackStackEntryCount() ==0) {
               // dLayout.closeDrawers();
                finish();
            }
            else
            {
               // dLayout.closeDrawers();

            }
        }
    });

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