Activity和Fragment的几种交互方式（Activity可以改变Fragment的UI,Fragment也可以改变ActivityUI）

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：


<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

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

<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：

<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：

<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>

六、可以使用第三方框架EventBus，可参考：http://blog.csdn.net/lmj623565791/article/details/40794879