Question

例如，我有2个片段，包括1个整数变量和1个TextView。其中一个有一个按钮。我希望此按钮可以更改所有整数和TextView，包括其他片段。如何访问其他片段的Variable和TextView？请用示例代码解释。

Answer 1

片段到片段通信基本上是通过一个活动来实现的，该活动通常托管片段，在片段A中定义一个接口，让你的Activity实现该接口。现在，您可以调用Fragment中的接口方法，并且您的Activity将接收该事件。现在，在您的活动中，您可以调用第二个片段以使用收到的值更新textview（例如）：

// You Activity implements your interface which is defined in FragmentA
public class YourActivity implements FragmentA.TextClicked{
    @Override
    public void sendText(String text){
        // Get instance of Fragment B using FragmentManager
        FraB frag = (FragB)
            getSupportFragmentManager().findFragmentById(R.id.fragment_b);
        frag.updateText(text);
    }
}


// Fragment A defines an Interface, and calls the method when needed
public class FragA extends Fragment{

    TextClicked mCallback;

    public interface TextClicked{
        public void sendText(String text);
    }

    @Override
    public void onAttach(Activity activity) {
        super.onAttach(activity);

        // This makes sure that the container activity has implemented
        // the callback interface. If not, it throws an exception
        try {
            mCallback = (TextClicked) activity;
        } catch (ClassCastException e) {
            throw new ClassCastException(activity.toString()
                + " must implement TextClicked");
        }
    }

    public void someMethod(){
        mCallback.sendText("YOUR TEXT");
    }

    @Override
    public void onDetach() {
        mCallback = null; // => avoid leaking
        super.onDetach();
    }
}

// Fragment B has a public method to do something with the text
public class FragB extends Fragment{

    public void updateText(String text){
        // Here you have it
    }
}

从Fragment访问其他Fragment变量或元素

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