适配器（adapter）与fragment之间、fragment与activity之间的通信问题

一、适配器（adapter）与fragment之间通信

通过本地广播进行通信

步骤如下

在adapter中代码

声明本地广播管理

private LocalBroadcastManager localBroadcastManager; 

在viewholder中初始化和建立通信intent

localBroadcastManager = LocalBroadcastManager.getInstance(context);
final Intent intent = new Intent(MessageFragment.LOCAL_BROADCAST);
发送广播
intent.putExtra("readIds", readIds);   //通知fragment,让它去调用queryCity()方法
intent.putExtra("list", (Serializable) list);
localBroadcastManager.sendBroadcast(intent);   //发送本地广播   通知fragment该刷新了


在fragment中代码
private IntentFilter intentFilter;
private LocalReceiver localReceiver;    //本地广播接收者
private LocalBroadcastManager localBroadcastManager;   //本地广播管理者   可以用来注册广播

private class LocalReceiver extends BroadcastReceiver {

    @Override
    public void onReceive(Context context, Intent intent) {

        String action = intent.getAction();
        if(!action.equals(LOCAL_BROADCAST)){
            return ;
        }
        String[] readIds =intent.getStringArrayExtra("readIds");
        List<Message> messages = (List<Message>) intent.getSerializableExtra("list");
        setList(messages,readIds);
    }
}
/**
 * 发送本地广播的action
 */
public static final String LOCAL_BROADCAST = "com.xfhy.casualweather.LOCAL_BROADCAST";
在onCreateView中初始化
//获取LocalBroadcastManager   本地广播管理者实例
localBroadcastManager = LocalBroadcastManager.getInstance(getContext());
localReceiver = new LocalReceiver();
intentFilter = new IntentFilter();
intentFilter.addAction(LOCAL_BROADCAST);   //添加action
localBroadcastManager.registerReceiver(localReceiver,intentFilter);


二、fragment与activity之间的通信问题

通过回调函数

在fragment中

声明
private CallBackValue callBackValue;
/**
 * fragment与activity产生关联是  回调这个方法
 */
@SuppressWarnings("deprecation")
@Override
public void onAttach(Activity activity) {
    // TODO Auto-generated method stub
    super.onAttach(activity);
    //当前fragment从activity重写了回调接口  得到接口的实例化对象
    callBackValue =(CallBackValue) getActivity();
}
//定义一个回调接口
public interface CallBackValue{
    public void SendMessageValue(String strValue);
}
使用时调用
callBackValue.SendMessageValue(response.getJSONObject("message_unread").getJSONObject("data").getString("unread_count"));
在activity中
重写方法
@Override
public void SendMessageValue(String strValue) {
    // TODO Auto-generated method stub
 if (strValue == "0" || strValue.isEmpty() || strValue.equals("0")) {
        count.setVisibility(View.GONE);
    } else {
        count.setText(strValue);
        count.setVisibility(View.VISIBLE);
    }
原文参考 https://blog.csdn.net/xfhy_/article/details/61195558