activity 給 fragment 傳遞數據

在activity中加載 frament，並傳遞給它參數
        //setArguments
                //1.實例化Fragment
                Fragment f1 = new Fragment1();
                //2.實例化一個Bundle對象
                Bundle bundle = new Bundle();
                //3.存入數據到Bundle對象中
                bundle.putString("msg1","這是由Activity發往Fragment的數據");
                //4.調用Fragment的setArguments方法，傳入Bundle對象
                f1.setArguments(bundle);
                //5.添加/替換顯示的Fragment
                transaction.replace(R.id.container,f1);

 

在fragment.java， 接收到參數

    //Fragment創建視圖
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        Log.e("TAG","onCreateView--Fragment視圖創建好了");
        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;
    }

 

也可以通過 public void onAttach(Context context)

來得到activity，然后操作activity。

MainActivity.java

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

 

fragment.java

    @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與Activity關聯");
    }