如何将数据从一个片段传递到前一个片段？

Question

我要去 FragmentA->FragmentB。现在我想从 FragmentB 将数据传递给 FragmentA。那么我该怎么做呢？？

目前正在使用 getCustomFragmentManager().popBackStack(); 进行 FragmentB->FragmentA 但没有传递任何值。

Answer 1

在片段A中

    FragmentTransaction ft = getActivity().getFragmentManager().beginTransaction();
    FragmentB frgamentB = new FrgamentB();
    fragmentB.setTargetFragment(FrgamentA.this, AppConstant.FRAGMENT_CODE);
    ft.addToBackStack(fragment.getClass().getName());
    ft.add(R.id.content, fragment, tag);
    ft.commit();

现在在 FragmentA 中覆盖 onActivityResult()

public void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);

    if (resultCode == RESULT_OK) {
      if (requestCode==AppConstant.FRAGMENT_CODE){
         int addID = data.getIntExtra("addressID", 0);
         String addressLine=data.getStringExtra("addressLine");
      }
    }
}

在 FragmentB 中（点击后退按钮）

Intent intent = new Intent(context, FragmentB.class);
intent.putExtra("addressID", list.get(position).getId());
intent.putExtra("addressLine", list.get(position).getAddressLine1());
getTargetFragment().onActivityResult(getTargetRequestCode(), RESULT_OK, intent);
getFragmentManager().popBackStack();

---

在 Kotlin 中更新

片段扩展

fun Fragment.addFragment(fragment: Fragment,targetFragment: Fragment,requestCode: Int, isAddToBackStack: Boolean = false, init: Bundle.() -> Unit = {}) {
    requireFragmentManager().inTransaction {
        val bundle = Bundle()
        bundle.init()
        fragment.arguments = bundle
        setTargetFragment(targetFragment,requestCode)
        if (isAddToBackStack) {
            addToBackStack(fragment::class.java.simpleName)
        }
        add(R.id.content, fragment, fragment::class.java.simpleName)
    }
}


inline fun FragmentManager.inTransaction(func: FragmentTransaction.() -> Unit) {
        val fragmentTransaction = beginTransaction()
        fragmentTransaction.func()
        fragmentTransaction.commit()
    }

fun Fragment.removeFragment(fragment: Fragment, enter: Int = 0, exit: Int = 0) {
    requireFragmentManager().inTransaction {
        remove(fragment)
    }
}

在片段A中

addFragment(FrgamentB(),this,AppConstant.FRAGMENT_CODE,true)

现在覆盖 FragmentA 中的 onActivityResult()

override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
        super.onActivityResult(requestCode, resultCode, data)
        if (requestCode == FRAGMENT_CODE && resultCode == Activity.RESULT_OK) {
            val addID = data?.getIntExtra("addressID", 0)
            val addressLine = data?.getStringExtra("addressLine")
        }
 }

在 FragmentB 中（点击后退按钮）

val intent = Intent(context, FragmentB::class.java)
intent.putExtra("addressID", list.get(position).getId()) 
intent.putExtra("addressLine",list.get(position).getAddressLine1())                
targetFragment.onActivityResult(targetRequestCode,RESULT_OK, intent)
fragmentManager.popBackStack()

Answer 2

如果使用 Kotlin 和 android 导航架构，您可以使用来自 Navigation 2.3.0-alpha02 版本的like this。

在片段 B 上设置结果：

findNavController().previousBackStackEntry?.savedStateHandle?.set("key", result)

在 Fragment A 上观察结果，使用相同的键：

    findNavController().currentBackStackEntry?.savedStateHandle?.getLiveData<Type>("key")?.observe(
    viewLifecycleOwner) {result ->
    // Do something with the result.
}

Answer 3

为我工作。

在 FragmentB 中像这样创建接口回调

private FragmentCallBacks fragmentCallBacks;

public interface FragmentCallBacks{
    void onCallBack(String data);
}

public void setFragmentCallBacks(FragmentCallBacks fragmentCallBacks) {
    this.fragmentCallBacks = fragmentCallBacks;
}

//onDestroy add this code
@Override
public void onDestroy() {
    super.onDestroy();
    fragmentCallBacks.onCallBack("This data from FragmentB");
}

并在 FragmentA 中添加此代码

FragmentB fragment = new FragmentB();
replaceFragment(fragment, "TAG");
fragment.setFragmentCallBacks(data -> {
    //do something here with your data
});

public void replaceFragment(Fragment fragment, String tag) {
    FragmentManager fragmentManager = getSupportFragmentManager();
    FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
    fragmentTransaction.replace(R.id.frameLayout, fragment);
    fragmentTransaction.addToBackStack(tag);
    fragmentTransaction.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
    fragmentTransaction.commit();
}

希望对您有所帮助。

Answer 4

因为 setTargetFragment 一直是deprecated。你可以使用setFragmentResultListener。

在片段A

setFragmentResultListener("KEY") { reqKey, bundle ->
    if (reqKey == "KEY")
    {
        val result = bundle.getString("RESULT")
        Toast.makeText(requireContext(), "Result: $result", Toast.LENGTH_LONG).show()
    }
}

在片段B

val resultBundle = Bundle().apply { putString("RESULT", "result from FragmentB") }
setFragmentResult("KEY", resultBundle)

Answer 5

FragmentA 使用替换调用FragmentB：

getFragmentManager!!.beginTransaction().replace(R.id.frame, fragmentB, tag).addToBackStack(null).commit()

然后FragmentB按：

fragmentManager.popBackStack()

FragmentA 在 override fun onViewCreated() 尝试听：

fragmentManager!!.addOnBackStackChangedListener {
  if (fragmentManager!!.backStackEntryCount == 0) {
           // Here your code
  }
}