转载请标明原地址：[http://blog.csdn.net/gaolei1201/article/details/44037831 ](http://blog.csdn.net/gaolei1201/article/details/44037831)
在工作中我们经常会遇到Activity和Fragment交互。具体为什么要用Fragment，相信大家都懂的，这样可以减少Activity之间来回切换，还可以把不同模块独立化，降低耦合度。下面根据自己工作经验，详细总结一下Activity和Fragment的几种交互方式。
## 一、使用Bundle
这种方法只能用来传递数据，且只能是Activity向Fragmeng传递。
首先我们需要在Activity中动态添加Fragment时，用Bundle封装我们需要传递的数据
~~~
HomeFragment arg = new HomeFragment();
Bundle bundle = new Bundle();
bundle.putString("arg", edit.getText().toString());
arg.setArguments(bundle);
FragmentManager fm = getFragmentManager();
FragmentTransaction ft = fm.beginTransaction();
ft.replace(R.id.layout_fragment, arg);
ft.commit();
然后在Fragment的回调函数中通过Fragment提供的方法getArguments（）取出Bundle对象。
text = (TextView) view.findViewById(R.id.text);
Bundle bundle = getArguments();
text.setText(bundle.getString("arg"));
~~~
这种方法比较简单就不多说了
## 二、getActivity()、new Fragment()方式（ 这种方法比较经典，简单实用）
下面是Activity代码：
~~~
public class MainActivity extends FragmentActivity {
private TextView show_change_text;
private Button change_fragment_bt;
private HomeFragment homeFragment;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
homeFragment=new HomeFragment();
getSupportFragmentManager().beginTransaction()
.replace(R.id.fragment_content,homeFragment ).commit();
change_fragment_bt = (Button) findViewById(R.id.change_fragment_bt);
show_change_text = (TextView) findViewById(R.id.show_change_text);
change_fragment_bt.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
homeFragment.changeText();
}
});
}
public void changeText(){
show_change_text.setText("I am UI of activity,and I have changed");
}
public void onAttachFragment(Fragment fragment) {
super.onAttachFragment(fragment);
}
}
~~~
下面是Fragment代码：
~~~
public class HomeFragment extends Fragment {
private TextView show_change_text;
private Button change_activity_bt;
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
super.onCreateView(inflater, container, savedInstanceState);
View view = inflater.inflate(R.layout.home_fragment, null);
change_activity_bt = (Button) view
.findViewById(R.id.change_activity_bt);
show_change_text = (TextView) view.findViewById(R.id.show_change_text);
change_activity_bt.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
((MainActivity) getActivity()).changeText();
}
});
return view;
}
public void changeText(){
show_change_text.setText("I am UI of fragment,and I have changed");
}
public void onAttach(Activity activity) {
super.onAttach(activity);
}
}
~~~
[ getActivity()、new Fragment()方式源码下载地址.........................](http://download.csdn.net/detail/gaolei1201/8994197)
## 三、Handler方式
传递数据是比较容易实现，但是要用到Activity和Fragment之间互相改变彼此的UI，网上关于这个问题的解决方法还是很少的，我也没遇到合适的解决方案，自己在前人的基础上研究后创造了一种方法。使Activity和Fragment共享一个Handler，然后发送消息通知彼此更新。别的也不多说了，例子代码如下，
这是Activity的代码：
~~~
<span style="font-size:14px;color:#333333;">public class MainActivity extends FragmentActivity implements OnClickListener {
private Handler mHandler;
private long lastPressBack;
private boolean isFirstPressBack = true;
private Button change_fragment_bt;
private TextView show_change_text;
private HomeFragment homeFragment;
Handler handler = new Handler() {
@Override
public void handleMessage(Message msg) {
switch (msg.what) {
case 0:
show_change_text.setText("I am UI of activity,and I have changed");
break;
}
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
change_fragment_bt=(Button)findViewById(R.id.change_fragment_bt);
show_change_text=(TextView)findViewById(R.id.show_change_text);
change_fragment_bt.setOnClickListener(this);
getSupportFragmentManager().beginTransaction()
.replace(R.id.fragment_content, new HomeFragment())
.commit();
}
public void onAttachFragment(Fragment fragment) {
super.onAttachFragment(fragment);
homeFragment=(HomeFragment) fragment;
homeFragment.setHandler(handler) ;
}
public boolean onKeyDown(int keyCode, KeyEvent event) {
super.onKeyDown(keyCode, event);
//点击和Fragment交互，改变Fragment的UI
if (keyCode == KeyEvent.KEYCODE_BACK && event.getRepeatCount() == 0) {
if(HomeFragment.changeText){
Message msg = mHandler.obtainMessage();
msg.what =0;
mHandler.sendMessage(msg);
HomeFragment.changeText=false;
return false;
}
if (!isFirstPressBack) {
if (System.currentTimeMillis() - lastPressBack > 2 * 1000) {
lastPressBack = System.currentTimeMillis();
} else {
finish();
}
}
lastPressBack = System.currentTimeMillis();
Toast.makeText(this,getString(R.string.exit_app),Toast.LENGTH_SHORT).show();
isFirstPressBack = false;
return false;
}
return false;
}
public void setHandler(Handler handler) {
mHandler = handler;
}
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
//点击和Fragment交互，改变Fragment的UI
Message msg = mHandler.obtainMessage();
msg.what =0;
mHandler.sendMessage(msg);
HomeFragment.changeText=false;
}
}
</span>
~~~
这是Fragment的代码：
~~~
public class HomeFragment extends Fragment implements OnClickListener{
private TextView show_change_text;
private Button change_activity_bt;
private MainActivity mActivity;
public static boolean changeText=true;
Handler handler = new Handler() {
@Override
public void handleMessage(Message msg) {
switch (msg.what) {
case 0:
show_change_text.setText("I am UI of fragment,and I have changed");
break;
}
}
};
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
super.onCreateView(inflater, container, savedInstanceState);
View view = inflater.inflate(R.layout.home_fragment, null);
show_change_text=(TextView)view.findViewById(R.id.show_change_text);
change_activity_bt=(Button)view.findViewById(R.id.change_activity_bt);
change_activity_bt.setOnClickListener(this);
return view;
}
public void onAttach(Activity activity) {
super.onAttach(activity);
mActivity = (MainActivity) activity;
mActivity.setHandler(handler);
}
public void setHandler(Handler handler) {
this.handler = handler;
}
public void onDestroy(){
super.onDestroy();
changeText=true;
}
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
//点击和Activity交互，改变ActivityUI
Message msg = handler.obtainMessage();
msg.what =0;
handler.sendMessage(msg);
}
}
~~~
[Handler方式源码下载地址....................](http://download.csdn.net/detail/gaolei1201/8929807)
## 四、接口回调方式
接口真是个好东西，条件是两个类，一个接口，两个类之间交互。任何两个类之间交互都可以用接口回调，针对接口编程能降低两个类之间的耦合度。
下面是Activity的代码：
~~~
<span style="font-size:14px;color:#333333;">public class MainActivity extends FragmentActivity implements OnActivityChangeListener{
private TextView show_change_text;
private Button change_fragment_bt;
public static OnFragmentChangeListener onFragmentChangeListener;
public static void setOnFragmentChangeListener(
OnFragmentChangeListener onFragmentChangeListener) {
MainActivity.onFragmentChangeListener = onFragmentChangeListener;
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
getSupportFragmentManager().beginTransaction()
.replace(R.id.fragment_content, new HomeFragment()).commit();
change_fragment_bt = (Button) findViewById(R.id.change_fragment_bt);
show_change_text = (TextView) findViewById(R.id.show_change_text);
// new HomeFragment().setOnActivityChangeListener(this);
// 这样set是不行的，因为这样又重新创造了一个HomeFragment,和原来初始化的那个不是一个，回报空指针，因为HomeFragment的listener没有被set
//所以应该这样 HomeFragment.setOnActivityChangeListener(this);
change_fragment_bt.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
//在这里执行接口方法
onFragmentChangeListener.onFragmentChange();
}
});
}
public void onAttachFragment(Fragment fragment) {
super.onAttachFragment(fragment);
// 除了这种方式传递子类对象，还可以在Fragment中
// setOnFragmentChangeListener,可以去那里面看一下，我已经注释过
onFragmentChangeListener = (OnFragmentChangeListener) fragment;
}
@Override
public void onActivityChange() {
// TODO Auto-generated method stub
// 在子类中实现接口的方法
show_change_text.setText("I am UI of activity,and I have changed");
}
}</span>
~~~
显示Fragment的代码：
~~~
<span style="font-size:14px;color:#333333;">public class HomeFragment extends Fragment implements OnFragmentChangeListener {
private TextView show_change_text;
private Button change_activity_bt;
public static OnActivityChangeListener onActivityChangeListener;
public void setOnActivityChangeListener(OnActivityChangeListener onActivityChangeListener){
HomeFragment.onActivityChangeListener=onActivityChangeListener;
}
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
super.onCreateView(inflater, container, savedInstanceState);
View view = inflater.inflate(R.layout.home_fragment, null);
change_activity_bt = (Button) view
.findViewById(R.id.change_activity_bt);
show_change_text = (TextView) view.findViewById(R.id.show_change_text);
// new MainActivity().setOnFragmentChangeListener(this);
// 这样set是不行的，因为这样又重新创造了一个MainActivity,和原来初始化的那个不是一个，回报空指针，因为activity的listener没有被set
//所以应该这样 MainActivity.setOnFragmentChangeListener(this);
change_activity_bt.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
//在这里执行接口方法
onActivityChangeListener.onActivityChange();
}
});
return view;
}
public void onAttach(Activity activity) {
super.onAttach(activity);
// 除了这种方式传递子类对象，还可以在Activity中
// setOnActivityChangeListener,可以去那里面看一下，我已经注释过
onActivityChangeListener=(OnActivityChangeListener) activity;
}
@Override
public void onFragmentChange() {
// 在子类中实现接口的方法
show_change_text.setText("I am UI of fragment,and I have changed");
}
}
</span>
~~~
[
Interface方式代码下载地址.....................](http://download.csdn.net/detail/gaolei1201/8929815)
