学习之路之Fragment和Fragment之间的传值

第一:先把FragmentA中的数据传到绑定的Activity中, 然后再把Activity的值传到FragmentB中,实现两个Fragment之间的传值;

Activity和Fragment之间的传值和可以利用接口回调的机制进行传值,具体的代码如下

先让Activity实现回调的接口并重写方法

public class MainActivity extends AppCompatActivity  implements FragmentA.CallBackFragmentA{
    private TextView tv;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        tv = (TextView) findViewById(R.id.tv);
        FragmentManager manager = getFragmentManager();
        FragmentTransaction beginTransaction = manager.beginTransaction();
        beginTransaction.add(R.id.rl, new FragmentA());
        beginTransaction.commit();
    }


    @Override
    public void dataHand(String s) {
        if (!TextUtils.isEmpty(s)) {
            tv.setText(s);
        }
    }
}

在Fragment的类中有一个回调接口的对象(即Activity) 并实例化,然后调用接口中的方法,这时,其实是在执行Activity中重写的接口方法;

public class FragmentA extends Fragment {
    private EditText et;
    private Button bt;
    CallBackFragmentA callBackFragmentA;
    @Override
    public void onAttach(Activity activity) {
        super.onAttach(activity);
        callBackFragmentA = (CallBackFragmentA) activity;
    }

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
      View view=  inflater.inflate(R.layout.item, container, false);
        bt = (Button) view.findViewById(R.id.bt);
        et = (EditText) view.findViewById(R.id.et1);
        bt.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String s= et.getText().toString();
                callBackFragmentA.dataHand(s);

            }
        });
        return view;
    }

    public interface CallBackFragmentA {
        public  void    dataHand(String s);
    }
//    public  void  onclick(View view) {
//       String s= et.getText().toString();
//        callBackFragmentA.dataHand(s);
//    }
}

这里要注意buttton控件不要用OnClick方法因为Fragment是Activity中的一个控件,所以

OnClick应该在Activity中被使用,但是你的控件是在Fragment的xml文件中生成的...

第二种:直接在FragmentA的类中得到在FragmentB类中的控件,然后直接设置文本即可

具体的代码如下:

public class FragmentA extends Fragment {
    private EditText et;
    private Button bt;
    String s;

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragmenta, container, false);
        bt = (Button) view.findViewById(R.id.bt);
        et = (EditText) view.findViewById(R.id.et);

        bt.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                s= et.getText().toString();

		//得到在FragmentB类中的TextView的控件对象
               TextView tv = (TextView) getActivity().findViewById(R.id.tv);

		//直接设置文本
                tv.setText(s);
         
            }
        });
        return view;
    }
}

第三种:在FragmentA类中得到FragmentB类的对象然后调用在FragmentB类中的方法

具体的代码如下:

public class FragmentA extends Fragment {
    private EditText et;
    private Button bt;
    String s;

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragmenta, container, false);
        bt = (Button) view.findViewById(R.id.bt);
        et = (EditText) view.findViewById(R.id.et);

        bt.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                s= et.getText().toString();
              FragmentB fragmentB= (FragmentB) getFragmentManager().findFragmentById(R.id.fragment2);
                fragmentB.settextVable(s);
            }
        });
        return view;
    }
}