Activity和Fragment相互通信或者改变UI

      转载请标明原地址：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，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：

[html]
view plain
copy

print?





 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);  
    }  
  
}

<span style="font-size:14px;">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);
}

}</span>

下面是Fragment代码：

[html]
view plain
copy

print?





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);  
    }  
}

<span style="font-size:14px;">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);
}
}</span>

   

  
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：

[html]
view plain
copy

print?





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 style="font-size:14px;"><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></span>

这是Fragment的代码：

[html]
view plain
copy

print?





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);  
    }  
}  
 

<span style="font-size:14px;">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);
}
}
</span>

 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：

[html]
view plain
copy

print?





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 style="font-size:14px;"><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></span>

显示Fragment的代码：

[html]
view plain
copy

print?





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 style="font-size:14px;"><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></span>

       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

[html]
view plain
copy

print?





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;  
        }  
    }  
}

<span style="font-size:14px;">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;
}
}
}</span>

下面是SecondActivity代码

[html]
view plain
copy

print?





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();  
            }  
        });  
    }  
} 

<span style="font-size:14px;">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();
}
});
}
}</span>

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：

[html]
view plain
copy

print?





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);    
    };    
}  

<span style="font-size:14px;">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);
};
} </span>

下面是AnotherActivity代码：

[html]
view plain
copy

print?





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();    
            }    
        });    
    }    
}  

<span style="font-size:14px;">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();
}
});
}
}  </span>