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

 @Override

    public 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() {

        @Override

        public 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();

        }

    }