简单介绍：
为什么要用Fragment？使用Fragment能够在一个Activity中实现不同的界面。
Fragment与Fragment之间的动画切换，远比Activity与Activity之间的动画切换变化方式多。非常多时候，我们通过使用一个Activity，切换多个Fragment。本次博客，主要列举一下Fragment与它的Activity之间进行数据交换的方式。
1.Fragment中通过getActivity()然后进行强制转化，调用Activity中的公有方法
((XXXXActivity)getActivity()).fun();
2.Activity在切换Fragment的时候，通过setArguments向Fragment传递參数，Fragment通过getArguments();获得从activity中传递过来的值
3.Activity实现一个接口。Fragment在onAttach方法中。将该Activity转化为该接口。在须要调用的时候回调。
注意：本Demo是通过FragmentManager来管理Fragment的。通过FragmentManager管理，我们创建Fragment和销毁Fragment的时候，能够通过栈的方式：
a.FragmentTransaction的add方法，加入一个Fragment
b.FragmentTransaction的popBackStack()弹出该Fragment
演示实例：
fragment1.xml
MyFragment1.java
/* * $filename: MyFragment.java,v $ * $Date: 2014-5-16 $ * Copyright (C) ZhengHaibo, Inc. All rights reserved. * This software is Made by Zhenghaibo. */package com.example.testfragment;import android.app.Activity;import android.os.Bundle;import android.support.v4.app.Fragment;import android.view.LayoutInflater;import android.view.View;import android.view.View.OnClickListener;import android.view.ViewGroup;import android.widget.Button;/* *@author: ZhengHaibo *web: http://blog.csdn.net/nuptboyzhb *mail: zhb931706659@126.com *2014-5-16 Nanjing,njupt,China */public class MyFragment1 extends Fragment { FragmentCallBack fragmentCallBack = null; Button btn; @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { View rootView = inflater.inflate(R.layout.fragment1, container, false); btn = (Button)rootView.findViewById(R.id.btn); btn.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { // TODO Auto-generated method stub fragmentCallBack.callbackFun1(null); } }); return rootView; } @Override public void onAttach(Activity activity) { // TODO Auto-generated method stub super.onAttach(activity); fragmentCallBack = (MainActivity)activity; }} fragment2.xml
MyFragment2.java
/* * $filename: MyFragment.java,v $ * $Date: 2014-5-16 $ * Copyright (C) ZhengHaibo, Inc. All rights reserved. * This software is Made by Zhenghaibo. */package com.example.testfragment;import android.app.Activity;import android.os.Bundle;import android.support.v4.app.Fragment;import android.view.LayoutInflater;import android.view.View;import android.view.View.OnClickListener;import android.view.ViewGroup;import android.widget.Button;import android.widget.Toast;/* *@author: ZhengHaibo *web: http://blog.csdn.net/nuptboyzhb *mail: zhb931706659@126.com *2014-5-16 Nanjing,njupt,China */public class MyFragment2 extends Fragment { FragmentCallBack fragmentCallBack = null; Button btn1; Button btn2; @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { View rootView = inflater.inflate(R.layout.fragment2, container, false); Bundle data = getArguments();//获得从activity中传递过来的值 Toast.makeText(getActivity(), data.getString("TEXT"), Toast.LENGTH_SHORT).show(); btn1 = (Button)rootView.findViewById(R.id.btn1); btn1.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { // 直接调用Activity中的方法 ((MainActivity)getActivity()).changeButtonColor(); } }); btn2 = (Button)rootView.findViewById(R.id.btn2); btn2.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { // 回调的方式 fragmentCallBack.callbackFun2(null); } }); return rootView; } @Override public void onAttach(Activity activity) { // TODO Auto-generated method stub super.onAttach(activity); fragmentCallBack = (MainActivity)activity; }} 回调接口：
/* * $filename: FragmentCallBack.java,v $ * $Date: 2014-5-16 $ * Copyright (C) ZhengHaibo, Inc. All rights reserved. * This software is Made by Zhenghaibo. */package com.example.testfragment;import android.os.Bundle;/* *@author: ZhengHaibo *web: http://blog.csdn.net/nuptboyzhb *mail: zhb931706659@126.com *2014-5-16 Nanjing,njupt,China */public interface FragmentCallBack { public void callbackFun1(Bundle arg); public void callbackFun2(Bundle arg);} main.xml
MainActivity.java
package com.example.testfragment;import android.graphics.Color;import android.os.Bundle;import android.support.v4.app.Fragment;import android.support.v4.app.FragmentManager;import android.support.v4.app.FragmentTransaction;import android.support.v7.app.ActionBarActivity;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;public class MainActivity extends ActionBarActivity implements FragmentCallBack{ private Button btn; private MyFragment1 fragment1; private MyFragment2 fragment2; private FragmentManager fragmentManager; private Fragment currentFragment; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); fragmentManager = getSupportFragmentManager(); FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction(); fragmentTransaction.setCustomAnimations(android.R.anim.fade_in, android.R.anim.fade_out); fragment1 = new MyFragment1(); Bundle data = new Bundle(); data.putString("TEXT", "这是Activiy通过Bundle传递过来的值"); fragment1.setArguments(data);//通过Bundle向Activity中传递值 fragmentTransaction.add(R.id.rl_container,fragment1);//将fragment1设置到布局上 fragmentTransaction.addToBackStack(null); fragmentTransaction.commitAllowingStateLoss(); currentFragment = fragment1; //初始化button控件 btn = (Button)findViewById(R.id.btn); btn.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { if(currentFragment instanceof MyFragment1){ switchFragment(); }else{//当前是fragment2，因此，仅仅须要将fragment2出栈就可以变成fragment1 fragmentManager.popBackStack(); currentFragment = fragment1; } } }); } /** * 切换Fragment */ private void switchFragment(){ if(null == fragment2){//能够避免切换的时候反复创建 fragment2 = new MyFragment2(); } Bundle data = new Bundle(); data.putString("TEXT", "传递给fragment2"); fragment2.setArguments(data); FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction(); fragmentTransaction.setCustomAnimations(android.R.anim.fade_in, android.R.anim.fade_out); fragmentTransaction.add(R.id.rl_container,fragment2); fragmentTransaction.addToBackStack(null); fragmentTransaction.commitAllowingStateLoss(); currentFragment = fragment2; } public void changeButtonColor(){ btn.setBackgroundColor(Color.RED); } @Override public void callbackFun1(Bundle arg) { // TODO Auto-generated method stub switchFragment();//通过回调方式切换 } @Override public void callbackFun2(Bundle arg) { // TODO Auto-generated method stub changeButtonColor();//通过回调方式调用Activity中的方法 }} 
初始画面
切换到第二个Fragment之后，通过Fragment2回调，改变按钮背景后的截图。
注意：
1.直接在Fragment中通过getActivity然后强转Activity的方式调用Activity的方法。这个方式不推荐！由于这会使Fragment的适配性变差。
解决方法：在使用之前，使用instanceof 推断一下Activity的类型
2.FragmentTransaction通过使用setCustomAnimations方法，能够为Fragment的切换增添各种不同的动画。变化方式远比Activity与Activity之间的切换动画要多。
3.多个Fragment之间，能够通过Activity复用非常多代码。提高效率。
4.我们还能够通过ViewPager来管理Fragment，通过Adapter加入多个Fragment，然后通过setcurrentitem进行切换。我们相同能够通过setArguments向Fragment传递数据。