如何从片段中的 RecyclerView 适配器启动活动 [重复]

Question

我不能从RecyclerViewAdapter点击RecyclerView到一个新的Activity。

我在这里打电话给ItemClick。

DayAdapter.java：

holder.setItemClickListener(new ItemClickListener() {
        @Override
        public void onClick(View view, int position, boolean isLongClick) {
            openProgramActivity(view, position);
        }
    });
}

这个函数打开一个新的Activity：

public void openProgramActivity(View view, int position) {
    //Intent openProgramActivity = new Intent(context, ProgramActivity.class);
    Intent openProgramActivity = new Intent(view.getContext(), ProgramActivity.class);
    openProgramActivity.putExtra("index",position);
    view.getContext().startActivity(openProgramActivity);
}

FragmentDay30.java：

public class FragmentDay30 extends Fragment {

private View view;

public static FragmentDay30 newInstance() {
    FragmentDay30 fragment = new FragmentDay30();
    Bundle args = new Bundle();
    fragment.setArguments(args);
    return fragment;
}

@Override
public void onCreate(@Nullable Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
}

@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, Bundle savedInstanceState) {

    view = inflater.inflate(R.layout.fragment_30day, container,false);

    ViewPager slideViewPager = (ViewPager) view.findViewById(R.id.slideViewPager);
    SlideAdapter slideAdapter = new SlideAdapter(getActivity());
    slideViewPager.setAdapter(slideAdapter);

    RecyclerView fragment30datRecyclerView = (RecyclerView) view.findViewById(R.id.fragment30dayRecyclerView);
    LinearLayoutManager linearLayoutManager = new LinearLayoutManager(getActivity(),LinearLayoutManager.VERTICAL,false);
    fragment30datRecyclerView.setLayoutManager(linearLayoutManager);
    DayAdapter dayAdapter = new DayAdapter(getActivity());
    fragment30datRecyclerView.setAdapter(dayAdapter);

    return view;
}

我尝试使用getActvity() 和getContext()，但不使用新的Activity。

Answer 1

像这样将 contaxt 传递给 recyclerview 适配器构造函数

Context context;
MyAdapter(Context context, .....){
this.context=context;
}

通话活动

context.startActivity(......);

Answer 2

虽然您可以通过传递上下文的适配器类启动 Activity，但正如文档所述，它是

1. 不是一个好的设计模式
2. 也是一种不好的做法。

我宁愿建议在您的 Adapter 类中定义一个接口，该接口将由 Fragment 类实现。片段类初始化适配器，传递它的引用，您可以将其 typeCast 到这样的接口

DayAdpater.class

public class DayAdapter extends RecyclerView.Adapter<DayAdapter.ViewHolder> {

    private OnActionListener mListener;

    DayAdapter(OnActionListener listener){
        this.mListener=listener;
    }

     holder.setItemClickListener(new ItemClickListener() {
        @Override
        public void onClick(View view, int position, boolean isLongClick) {
                mListener.startActivity(position);
        }
    });

    interface OnActionListener{
        public void startActivity(int position);
    }

}

FragmentDay30.class

public class FragmentDay30 extends Fragment implements DayAdapter.OnActionListener{

    @Override
    public void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    }

    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, Bundle savedInstanceState) {

        view = inflater.inflate(R.layout.fragment_30day, container,false);

        RecyclerView fragment30datRecyclerView = (RecyclerView) view.findViewById(R.id.fragment30dayRecyclerView);
        LinearLayoutManager linearLayoutManager = new LinearLayoutManager(getActivity(),LinearLayoutManager.VERTICAL,false);
        fragment30datRecyclerView.setLayoutManager(linearLayoutManager);
        DayAdapter dayAdapter = new DayAdapter(getActivity(), this);
        fragment30datRecyclerView.setAdapter(dayAdapter);

        return view;
    }

    /**
    * this is the place where you should start a new activity
    */
    public void startActivity(int position) {
        //Intent openProgramActivity = new Intent(context, ProgramActivity.class);
        Intent openProgramActivity = new Intent(getActivity(), ProgramActivity.class);
        openProgramActivity.putExtra("index",position);
        getActivity.startActivity(openProgramActivity);
    }

}

这是您的 adpater 类与片段类交互的方式。

希望这会有所帮助。

Answer 3

在您用于setAdapter 的RecyclerView 适配器构造函数中传递context，如下所示：

Context context;

MyCustomAdapter(Context context, .....){
this.context=context;
}

对于使用的通话活动：

context.startActivity(......);