activity 给 fragment 传递参数

在activity中加载 frament，并传递给它参数
        //setArguments
                //1.实例化Fragment
                Fragment f1 = new Fragment1();
                //2.实例化一个Bundle对象
                Bundle bundle = new Bundle();
                //3.存入数据到Bundle对象中
                bundle.putString("msg1","这是由Activity发往Fragment的数据");
                //4.调用Fragment的setArguments方法，传入Bundle对象
                f1.setArguments(bundle);
                //5.添加/替换显示的Fragment
                transaction.replace(R.id.container,f1);

    //Fragment创建视图
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        Log.e("TAG","onCreateView--Fragment视图创建好了");
        View v = inflater.inflate(R.layout.fragment_fragment1, container, false);

        Bundle b = getArguments();
        String msg1 = b.getString("msg1");
        ((TextView)v.findViewById(R.id.txt1)).setText(msg1);

        return v;
    }

public class MainActivity extends AppCompatActivity {
　　public String msg = "How are you ";
}

    @Override
    public void onAttach(Context context) {
        super.onAttach(context);
        String msg = ((MainActivity)context).msg;
        Toast.makeText(context,msg,Toast.LENGTH_SHORT).show();
        Log.e("TAG","onAttach--Fragment与Activity关联");
    }