从片段调用活动

// 在Fragment中
Intent intent = new Intent(getActivity(), TargetActivity.class);
startActivity(intent);

// 定义接口
public interface OnFragmentInteractionListener {
    void onButtonClick();
}

// 在Activity中实现接口
public class MainActivity extends AppCompatActivity implements OnFragmentInteractionListener {
    @Override
    public void onButtonClick() {
        Intent intent = new Intent(this, TargetActivity.class);
        startActivity(intent);
    }
}

// 在Fragment中调用接口方法
public class MyFragment extends Fragment {
    private OnFragmentInteractionListener listener;

    @Override
    public void onAttach(Context context) {
        super.onAttach(context);
        if (context instanceof OnFragmentInteractionListener) {
            listener = (OnFragmentInteractionListener) context;
        } else {
            throw new RuntimeException(context.toString() + " must implement OnFragmentInteractionListener");
        }
    }

    @Override
    public void onDetach() {
        super.onDetach();
        listener = null;
    }

    // 在某个事件中调用接口方法
    public void someEvent() {
        if (listener != null) {
            listener.onButtonClick();
        }
    }
}