Fragment向Activity传值

xml布局文件

fragment_list.xml （控制fragment里面的内容）

Fragment的Java代码管理类

package com.administrator.fragmentdemo;

import android.content.Context;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

/**
 * 列表fragment
 */
public class ListFragment extends Fragment {

    public static final String BUNDLE_TITLE = "bundle_title";
    private String mTitle = "mo_ren_zhi";

    public static ListFragment newInstance(String title){
        ListFragment fragment = new ListFragment();
        Bundle bundle = new Bundle();//创建一个bundle对象对数据封装
        bundle.putString(BUNDLE_TITLE,title);//put一下，有很多比如char，int等基础数据，比如这里用String(key,Value)，还可以比如putChar();
        fragment.setArguments(bundle);//将封装好的bundle数据，通过fragment的setArgument方法传递。
        return fragment;
    }
    //创建视图
    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        //new view
        View view = inflater.inflate(R.layout.fragment_list,container,false);
        TextView textView = view.findViewById(R.id.textView);//需要根据根视图view进行findViewById
        textView.setText(mTitle);
        textView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if(mOnTitleClickListener!=null){
                    mOnTitleClickListener.onClick(mTitle);
                }
            }
        });
        return view;
    }
    @Override
    public void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        if(getArguments() != null){
            mTitle = getArguments().getString(BUNDLE_TITLE);
        }
    }

    //设置接口的方法
    public void setOnTitleClickListener(OnTitleClickListener onTitleClickListener){
        mOnTitleClickListener = onTitleClickListener;
    }

    //定义变量
    private OnTitleClickListener mOnTitleClickListener;
    /**
     * 当title被点击时，将title传递出去
     */
    //定义接口
    public interface OnTitleClickListener{
        void onClick(String title);
    }
}

在容器activity_main.xml中为fragment设置可以展示的区域

分别设置了listContainer和detailContainer这两个容器

装载Fragment的Activity的Java代码

package com.administrator.fragmentdemo;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;

public class MainActivity extends AppCompatActivity implements ListFragment.OnTitleClickListener{

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);


        //1.container容器 2.fragment 3.fragment-->container把fragment放到容器container中去
        //getSupportFragmentManager()获取一个fragment容器，beginTransaction()开启一个事物,add()把fragment放进去(关联进去)。commit()向系统提交
        //R.id.listContainer,listContainer是刚才设置的容器id，add里面把容器和fragment关联

        //fragment---> activity value  fragment往activity里传值
        ListFragment listFragment = ListFragment.newInstance("list");
        getSupportFragmentManager()
                .beginTransaction()
                .add(R.id.listContainer,listFragment)
                .commit();
        listFragment.setOnTitleClickListener(this);

        ListFragment detail = new ListFragment().newInstance("detail");
        getSupportFragmentManager()
                .beginTransaction()
                .add(R.id.detailContainer,detail)
                .commit();
        detail.setOnTitleClickListener(this);

    }

    @Override
    public void onClick(String title) {
        setTitle(title);
    }
}

比如说要传一个对象，不能用bundle传的时候

更改ListFragment.java文件

package com.administrator.fragmentdemo;

import android.content.Context;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

/**
 * 列表fragment
 */
public class ListFragment extends Fragment {

    public static final String BUNDLE_TITLE = "bundle_title";
    private String mTitle = "mo_ren_zhi";

    /**
     * 构建模拟的User对象
     */
    private User mUser;
    public void setUser(User user){
        mUser = user;
    }
    public class User{

    }

    public static ListFragment newInstance(String title,User user){//添加User参数
        ListFragment fragment = new ListFragment();
        Bundle bundle = new Bundle();//创建一个bundle对象对数据封装
        bundle.putString(BUNDLE_TITLE,title);//put一下，有很多比如char，int等基础数据，比如这里用String(key,Value)，还可以比如putChar();
        fragment.setArguments(bundle);//将封装好的bundle数据，通过fragment的setArgument方法传递。
        fragment.setUser(user);//设置User对象
        return fragment;
    }
    //创建视图
    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        //new view
        View view = inflater.inflate(R.layout.fragment_list,container,false);
        TextView textView = view.findViewById(R.id.textView);//需要根据根视图view进行findViewById
        textView.setText(mTitle);
        textView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if(mOnTitleClickListener!=null){
                    mOnTitleClickListener.onClick(mTitle);
                }
            }
        });
        return view;
    }
    @Override
    public void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        if(getArguments() != null){
            mTitle = getArguments().getString(BUNDLE_TITLE);
        }
    }

    //设置接口的方法
    public void setOnTitleClickListener(OnTitleClickListener onTitleClickListener){
        mOnTitleClickListener = onTitleClickListener;
    }

    //定义变量
    private OnTitleClickListener mOnTitleClickListener;
    /**
     * 当title被点击时，将title传递出去
     */
    //定义接口
    public interface OnTitleClickListener{
        void onClick(String title);
    }
}