Question

我有两个片段A和B并且接口将a与b通信，片段a有一个按钮并与b通信以改变文本但是无论何时方向改变按钮都会失去它的听众她是代码

MainActivtiy

    public class MainActivity extends AppCompatActivity implements ClicktoChange{
    FragmentB fragmentB;
    FragmentA fragmentA;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        fragmentB = new FragmentB();
        fragmentA = new FragmentA();
        FragmentTransaction fr = getFragmentManager().beginTransaction();
        fr.add(R.id.container2,fragmentA);
        fr.add(R.id.container,fragmentB);
        fr.addToBackStack(null);
        fr.commit();

    }

    @Override
    protected void onResume() {
        super.onResume();
       Log.d("im","in Resume");
        FragmentTransaction fr = getFragmentManager().beginTransaction();
        fr.replace(R.id.container2, fragmentA);
        fr.replace(R.id.container, fragmentB);
        fr.addToBackStack(null);
        fr.commit();

    }

    @Override
    public void changeTheText(String str) {
        Log.d("we are in main clicked ", "yay");

        fragmentB.changeText(str);
        FragmentTransaction fragmentTransaction = getFragmentManager().beginTransaction();
        fragmentTransaction.replace(R.id.container, fragmentB);
        fragmentTransaction.addToBackStack(null);
        fragmentTransaction.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE);

        fragmentTransaction.commit();


    }
}

以下是片段A

的代码

    public class FragmentA extends Fragment implements View.OnClickListener {
Button mButton ;
    int c;
ClicktoChange clicktoChange;
    public FragmentA() {
        // Required empty public constructor
    }


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        Log.d("we are ","frag A created!");
     View view=   inflater.inflate(R.layout.fragment_, container, false);
        // Inflate the layout for this fragment
        if(savedInstanceState!=null){
            c = savedInstanceState.getInt("counter");
            mButton = (Button) view.findViewById(R.id.change_text);
            Log.d("here we set the","the listener");
            mButton.setOnClickListener(this);
        }
        return view;

    }


    @Override
    public void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        outState.putInt("counter",c);
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        if(mButton!=null)
        mButton.setOnClickListener(this);
    }

    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        clicktoChange = (ClicktoChange) getActivity();
        Log.d("yay","interface init");
        mButton = (Button) getActivity().findViewById(R.id.change_text);
        mButton.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
        Log.d("we are in","onClick yay");
        c++;
        clicktoChange.changeTheText("oh baby "+c);
    }



}

和片段B

    public class FragmentB extends Fragment {

   TextView Text;
    String str;
    public FragmentB() {
        // Required empty public constructor
    }


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        Log.d("frag b","Yes I'v been created");
     View   view = inflater.inflate(R.layout.fragment_fragment_b, container, false);
        if(savedInstanceState!=null){
            str = savedInstanceState.getString("text");
            Text = (TextView) view.findViewById(R.id.textfrag );
            Text.setText(str);
        }
        return view;
    }


    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);

        Text = (TextView) getActivity().findViewById(R.id.textfrag);
        Log.d("the text is ", (Text == null) + "");
    }

    @Override
    public void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
    outState.putString("text",str);
    }

    public  void changeText(String str){
        this.str = str;
        Text.setText(str);
    }

}

最后是界面

public interface ClicktoChange {
    void changeTheText(String str);
}

Answer 1

旋转手机时，活动将被销毁并重新启动。你有两个选择。

1）告诉手机不要这样做，请在你的清单上添加一条configChanges线。

2）检测到这种情况发生了（当它发生时你将在onCreate中获得一个非空的Bundle）并重新创建并再次附加监听器。

旋转后按钮失去了它的监听器

1 个答案: