在新的嵌套片段 API 中未调用 onActivityResult() [英] onActivityResult() not called in new nested fragment API

问题描述

我一直在使用 Android 包含在支持中的新 嵌套片段 API图书馆.

I have been using the new nested fragment API that Android includes in the support library.

我在嵌套片段中面临的问题是，如果嵌套片段(即通过 getChildFragmentManager() 返回的 FragmentManager 添加到另一个片段的片段)) 调用 startActivityForResult()，嵌套片段的 onActivityResult() 方法不被调用.但是，父片段的 onActivityResult() 和活动的 onActivityResult() 都会被调用.

The problem that I am facing with nested fragments is that, if a nested fragment (that is, a fragment that has been added to another fragment via the FragmentManagerreturned by getChildFragmentManager()) calls startActivityForResult(), the nested fragment's onActivityResult() method is not called. However, both the parent fragment's onActivityResult() and activity's onActivityResult() do get called.

我不知道我是否遗漏了有关嵌套片段的内容，但我没想到所描述的行为.下面是重现此问题的代码.如果有人能指出我正确的方向并向我解释我做错了什么，我将不胜感激:

I don't know if I am missing something about nested fragments, but I did not expect the described behavior. Below is the code that reproduces this problem. I would very much appreciate if someone can point me in the right direction and explain to me what I am doing wrong:

package com.example.nestedfragmentactivityresult;

import android.media.RingtoneManager;
import android.os.Bundle;
import android.content.Intent;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.Toast;

public class MainActivity extends FragmentActivity
{
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        this.getSupportFragmentManager()
            .beginTransaction()
            .add(android.R.id.content, new ContainerFragment())
            .commit();
    }

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

        // This is called
        Toast.makeText(getApplication(),
            "Consumed by activity",
            Toast.LENGTH_SHORT).show();
    }

    public static class ContainerFragment extends Fragment
    {
        public final View onCreateView(LayoutInflater inflater,
                                       ViewGroup container,
                                       Bundle savedInstanceState)
        {
            View result = inflater.inflate(R.layout.test_nested_fragment_container,
                container,
                false);

            return result;
        }

        public void onActivityCreated(Bundle savedInstanceState)
        {
            super.onActivityCreated(savedInstanceState);
            getChildFragmentManager().beginTransaction()
                .add(R.id.content, new NestedFragment())
                .commit();
        }

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

            // This is called
            Toast.makeText(getActivity(),
                "Consumed by parent fragment",
                Toast.LENGTH_SHORT).show();
        }
    }

    public static class NestedFragment extends Fragment
    {
        public final View onCreateView(LayoutInflater inflater,
                                       ViewGroup container,
                                       Bundle savedInstanceState)
        {
            Button button = new Button(getActivity());
            button.setText("Click me!");
            button.setOnClickListener(new View.OnClickListener()
            {
                public void onClick(View v)
                {
                    Intent intent = new Intent(RingtoneManager.ACTION_RINGTONE_PICKER);
                    startActivityForResult(intent, 0);
                }
            });

            return button;
        }

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

            // This is NOT called
            Toast.makeText(getActivity(),
                "Consumed by nested fragment",
                Toast.LENGTH_SHORT).show();
        }
    }
}

test_nested_fragment_container.xml 是:

test_nested_fragment_container.xml is:

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/content"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

</FrameLayout>

推荐答案

是的，嵌套片段中的onActivityResult()不会被这种方式调用.

Yes, the onActivityResult() in nested fragment will not be invoked by this way.

onActivityResult(Android支持库中)的调用顺序是

The calling sequence of onActivityResult (in Android support library) is

1. Activity.dispatchActivityResult().
2. FragmentActivity.onActivityResult().
3. Fragment.onActivityResult().

第三步，在父Activity的FragmentMananger中找到fragment.所以在你的例子中，它是被发现调度 onActivityResult() 的容器片段，嵌套片段永远无法接收事件.

In the 3rd step, the fragment is found in the FragmentMananger of parent Activity. So in your example, it is the container fragment that is found to dispatch onActivityResult(), nested fragment could never receive the event.

我认为您必须在 ContainerFragment.onActivityResult() 中实现自己的调度，找到嵌套片段并调用将结果和数据传递给它.

I think you have to implement your own dispatch in ContainerFragment.onActivityResult(), find the nested fragment and invoke pass the result and data to it.

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