将接口传递给Fragment

Question

让我们考虑一下我拥有Fragment A和的情况Fragment B.

B 声明:

public interface MyInterface {
    public void onTrigger(int position);
}

A 实现这个接口.

当Fragment B进入堆栈时,我应该如何传递Fragment A它的引用,Bundle以便在需要时A获得onTrigger回调.

我使用的情况是,A具有ListView与项目,并B具有ViewPager与项目.两者都包含相同的项目,当用户从B -> A弹出之前开始B它应该触发回调A以更新它的ListView位置以匹配B寻呼机位置.

谢谢.

Answer 1

Passing interface to Fragment

我想你们正在两个人之间进行沟通 Fragment

为此,您可以查看与其他片段进行通信

public class FragmentB extends Fragment{
    MyInterface mCallback;

    // Container Activity must implement this interface
    public interface MyInterface {
        public void onTrigger();
    }

    @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 = (MyInterface ) activity;
        } catch (ClassCastException e) {
            throw new ClassCastException(activity.toString()
                    + " must implement MyInterface ");
        }
    }

    ...
}

Answer 2

对于 Kotlin 1.0.0-beta-3595

interface SomeCallback {}

class SomeFragment() : Fragment(){

    var callback : SomeCallback? = null //some might want late init, but I think this way is safer

    override fun onCreateView(inflater: LayoutInflater?, container: ViewGroup?, savedInstanceState: Bundle?): View? {
        callback = activity as? SomeCallback //returns null if not type 'SomeCallback'

        return inflater!!.inflate(R.layout.frag_some_view, container, false);
    }
}