https://blog.csdn.net/u012702547/article/details/49786417

https://blog.csdn.net/carson_ho/article/details/75453770

一、接口方式
在fragment类中定义一个接口并在Activity中实现它。Fragment在onAttach()回调函数中获取接口的具体实现的对象。后面，fragment就可以调用接口中的方法实现与Activity的通信。

在Android5.0之后废除了onAttach(Activity activity)的方法，转而使用onAttach(Context context),也就是传递的参数发生变化

public interface showMsgListener{ void showMsg(String str); } private showMsgListener msgListener; @Override public void onAttach(Activity activity) { super.onAttach(activity); try { if(activity!=null){ msgListener=(MainActivity)activity; } } catch (ClassCastException e) { throw new ClassCastException(activity.toString() + " must implement showMsgListener"); } } mButton.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { msgListener.showMsg("Hello Android!(接口)"); } }); 

在Activity中需要实现该接口

 @Overridepublic void showMsg(String str) {Toast.makeText(MainActivity.this, str, Toast.LENGTH_SHORT).show(); } 

二、广播

在Activity中注册广播接收器,在Fragment中发送广播

    private BroadcastReceiver mBroadcastReceiver = new BroadcastReceiver() {@Overridepublic void onReceive(Context context, Intent intent) { String action = intent.getAction(); if (action.equals(ACTION_NAME)) { String msg = intent.getStringExtra("msg"); Toast.makeText(MainActivity.this, msg, Toast.LENGTH_SHORT).show(); } } }; public void registerBoradcastReceiver() { IntentFilter myIntentFilter = new IntentFilter(); myIntentFilter.addAction(ACTION_NAME); registerReceiver(mBroadcastReceiver, myIntentFilter); } @Override protected void onDestroy() { super.onDestroy(); unregisterReceiver(mBroadcastReceiver); } 

三、Fragment 从Activity获取数据

在Fragment 的getInstance()方法中setArguments()设置参数

public static Fragment getInstance(String msg){ Bundle bundle = new Bundle(); bundle.putString("msg",msg); MainFragment fragment=new MainFragment(); fragment.setArguments(bundle); return fragment; } 

再通过getArguments()方法获取

 public void initDatas() { Bundle bundle=getArguments(); if(bundle!=null){ String msg=bundle.getString("msg"); Toast.makeText(getActivity(), msg, Toast.LENGTH_SHORT).show(); } }