Android-如何将数据从活动传递到片段? [英] Android - How to pass data from activity to fragment?

问题描述

我需要将数据从活动传递到片段.我知道我可以使用bundle，但是一旦我传递了数据，就不能不调用并再次创建片段而发送数据.

I need to pass data from activity to fragment. I know I can use bundle , but once I passed data,I can't send data without calling and creating fragment again.

在我的活动中，某些事情可能会更改，我需要在不重新创建片段的情况下将这些更改通知我的片段.

In my activity, some thing may be changed and I need to notify my fragment for these changes without recreating fragment.

推荐答案

在Activity中创建一个interface，然后将数据通过interface传递到fragment.在您的fragment中实现该interface以获取数据.

Create one interface in your Activity and pass your data via the interface to the fragment. Implement that interface in your fragment to get data.

例如

MainActivity.class

public class MainActivity extends AppCompatActivity {

    DataFromActivityToFragment dataFromActivityToFragment;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        FragmentA fr = new FragmentA();
        FragmentManager fm = getFragmentManager();
        dataFromActivityToFragment = (DataFromActivityToFragment) fr;
        FragmentTransaction fragmentTransaction = fm.beginTransaction();
        fragmentTransaction.replace(R.id.fragment_place, fr);
        fragmentTransaction.commit();


        final Handler handler = new Handler();

        final Runnable r = new Runnable() {
            public void run() {
                dataFromActivityToFragment.sendData("Hi");
            }
        };

        handler.postDelayed(r, 5000);


    }

    public interface DataFromActivityToFragment {
        void sendData(String data);
    }
}

FragmentA.class

public class FragmentA extends Fragment implements MainActivity.DataFromActivityToFragment {

    TextView text;

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.content_main, null);
        text = (TextView) rootView.findViewById(R.id.fragment_text);

        return rootView;
    }

    @Override
    public void onViewCreated(View view, Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
    }

    @Override
    public void sendData(String data) {
        if(data != null)
        text.setText(data);
    }
}

activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <LinearLayout
        android:id="@+id/fragment_place"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="horizontal">
    </LinearLayout>

</LinearLayout>

content_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <TextView
        android:id="@+id/fragment_text"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

</LinearLayout>

在上面的示例中，我采用Runnable只是为了在创建fragment之后延迟5秒发送数据.

In above example I have taken Runnable just to send data with delay of 5 seconds after creation of fragment.

这篇关于Android-如何将数据从活动传递到片段?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！