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，可以使UI更灵活，还可以把不同模块独立化，降低耦合度。Activity和Fragment之间传值还是比较常见，但是要互相改变彼此UI还是有一定技巧的。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、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 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");
}
}
下面是Fragment代码：
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");
}
}
getActivity()、new Fragment()方式源码下载地址.........................
二、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：
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;
}
}
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....................
三、接口回调方式（这个尽量不要用，因为会创建static对象，而static对象不会被回收，很占内存）
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：
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");
}
}
显示Fragment的代码：
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");
}
}
Interface方式代码下载地址.....................
四、使用startActivityForResult（Fragment和Activity、两个Activity之间交互都行）
下面是Fragment的代码
public class HomeFragment extends Fragment {
private TextView fragment_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);
fragment_text = (TextView) view.findViewById(R.id.fragment_text);
change_activity_bt.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
Intent intent = new Intent(getActivity(), SecondActivity.class);
startActivityForResult(intent, 0);
}
});
return view;
}
public void onActivityResult(int requestCode, int resultCode, Intent intent) {
if (intent == null)
return;
String change01 = intent.getStringExtra("change01");
// 根据上面发送过去的请求吗来区别
switch (requestCode) {
case 0:
fragment_text.setText(change01);
break;
default:
break;
}
}
}
下面是SecondActivity代码
public class SecondActivity extends FragmentActivity {
private Button change_fragment_bt;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.second_activity);
change_fragment_bt = (Button) findViewById(R.id.change_fragment_bt);
change_fragment_bt.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
Intent mIntent = new Intent();
mIntent.putExtra("change01", "Change HomeFragment By SecondActivity");
mIntent.putExtra("change02", "Change MainActivity By SecondActivity");
// 设置结果，并进行传送
setResult(0, mIntent);
finish();
}
});
}
}
stratActivityForResult方式源码，点击下载......
五、万能的BroadCastReceiver（Fragment和Activity、两个Activity之间交互都行）
虽然广播比较万能，但是它是由系统决定，且有优先级，可能会造成延迟。
下面是MainActivity 代码：
public class MainActivity extends Activity {
TextView textView;
Button sButton;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
textView = (TextView) findViewById(R.id.show);
sButton = (Button) findViewById(R.id.startAnother);
sButton.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
startActivity(new Intent(MainActivity.this,AnotherActivity.class));
}
});
IntentFilter filter = new IntentFilter(AnotherActivity.action);
registerReceiver(broadcastReceiver, filter);
}
BroadcastReceiver broadcastReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
// TODO Auto-generated method stub
textView.setText(intent.getExtras().getString("data"));
}
};
protected void onDestroy() {
unregisterReceiver(broadcastReceiver);
};
}
下面是AnotherActivity代码：
public class AnotherActivity extends Activity {
public static final String action = "jason.broadcast.action";
Button update;
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.another);
update = (Button) findViewById(R.id.updateMain);
update.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
Intent intent = new Intent(action);
intent.putExtra("data", "yes i am data");
sendBroadcast(intent);
finish();
}
});
}
}
六、可以使用第三方框架EventBus，可参考：http://blog.csdn.net/lmj623565791/article/details/40794879