Question

我在片段中创建了一个接口，如下所示：

public interface SGFCallBackInterface {
    void itemSelected(Item item);
}

private SGFCallBackInterface mCallbackInterface;

@Override
public void onAttach(Context context) {
    super.onAttach(context);

    if (context instanceof SGFCallBackInterface) {
        mCallbackInterface = (SGFCallBackInterface) context;
    } else {
        throw new RuntimeException(context.toString() + " must implement SelectGdsFragment.SGFCallBackInterface");
    }
}

public void setSGFCallBackInterface(SGFCallBackInterface mCallbackInterface) {
    this.mCallbackInterface = mCallbackInterface;
}

我将在另一个片段中实现，如下所示

public class SaleMenageFragment extends Fragment implements SelectGdsFragment.SGFCallBackInterface { 

    ...

    SelectGdsFragment selectGdsFragment = new SelectGdsFragment();
    selectGdsFragment.setSGFCallBackInterface(SaleMenageFragment.this);

    ...

}

@Override
public void onItemSelected(Item item) {
    ...
}

但它仍然无效，这是错误日志：

E/AndroidRuntime: FATAL EXCEPTION: main
              Process: com.leo.test, PID: 3853
              java.lang.RuntimeException: com.leo.test.Control.IndexActivity@2a66aece must implement SelectGdsFragment.SGFCallBackInterface
                  at com.leo.test.Control.Fragment.SaleManagement.SelectGdsClsFragment.onAttach(SelectGdsFragment.java:42)
                  at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1019)
                  at android.support.v4.app.BackStackRecord.setLastIn(BackStackRecord.java:779)
                  at android.support.v4.app.BackStackRecord.calculateFragments(BackStackRecord.java:819)
                  at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:660)
                  at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1617)
                  at android.support.v4.app.FragmentManagerImpl$1.run(FragmentManager.java:517)
                  at android.os.Handler.handleCallback(Handler.java:739)
                  at android.os.Handler.dispatchMessage(Handler.java:95)
                  at android.os.Looper.loop(Looper.java:135)
                  at android.app.ActivityThread.main(ActivityThread.java:5254)
                  at java.lang.reflect.Method.invoke(Native Method)
                  at java.lang.reflect.Method.invoke(Method.java:372)
                  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
                  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)

我认为错误日志意味着我的IndexActivity没有实现SelectGdsFragment.SGFCallBackInterface。

但我不想在IndexActivity中实现它我想在SaleMenageFragment中实现它。

我该怎么做？

Answer 1

只需删除onAttach（Context context）方法中的部分，如下所示：

public interface SGFCallBackInterface {
    void itemSelected(Item item);
}

private SGFCallBackInterface mCallbackInterface;

@Override
public void onAttach(Context context) {
    super.onAttach(context);

    if (context instanceof SGFCallBackInterface) {
        mCallbackInterface = (SGFCallBackInterface) context;
    } // this wont throw an exception if the activity does not implement that interface
}

public void setSGFCallBackInterface(SGFCallBackInterface mCallbackInterface) {
    this.mCallbackInterface = mCallbackInterface;
}

Answer 2

我担心你必须在Activity

中实施它

参见文档

Communicating with Fragments

希望它有所帮助！

如何在我的界面的片段中实现另一个片段

2 个答案: