Question

我想知道如何在fragment.java文件中进行编码。首先，我是编码的初学者。我已经在底部导航栏中创建了带有三个导航按钮的Bottomnavigationview，并且为每个导航按钮都创建了Fragment活动。底部导航栏中的导航选项之一是“更多”，我添加了一个ID为"btn_Logoff"的按钮。当我单击按钮时，我希望它进入activity_login.xml或LoginActivity.java。我不知道它的代码是什么，以及在默认片段Java文件中的什么位置添加代码，因此，这是默认情况下写在片段文件上的内容：

文件名为MoreFragment.java

import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.Toast;


/**
 * A simple {@link Fragment} subclass.
 * Activities that contain this fragment must implement the
 * {@link MoreFragment.OnFragmentInteractionListener} interface
 * to handle interaction events.
 * Use the {@link MoreFragment#newInstance} factory method to
 * create an instance of this fragment.
 */
public class MoreFragment extends Fragment {
    // TODO: Rename parameter arguments, choose names that match
    // the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
    private static final String ARG_PARAM1 = "param1";
    private static final String ARG_PARAM2 = "param2";

    // TODO: Rename and change types of parameters
    private String mParam1;
    private String mParam2;

    private OnFragmentInteractionListener mListener;

    public MoreFragment() {
        // Required empty public constructor
    }

    /**
     * Use this factory method to create a new instance of
     * this fragment using the provided parameters.
     *
     * @param param1 Parameter 1.
     * @param param2 Parameter 2.
     * @return A new instance of fragment MoreFragment.
     */
    // TODO: Rename and change types and number of parameters
    public static MoreFragment newInstance(String param1, String param2) {
        MoreFragment fragment = new MoreFragment();
        Bundle args = new Bundle();
        args.putString(ARG_PARAM1, param1);
        args.putString(ARG_PARAM2, param2);
        fragment.setArguments(args);
        return fragment;
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        if (getArguments() != null) {
            mParam1 = getArguments().getString(ARG_PARAM1);
            mParam2 = getArguments().getString(ARG_PARAM2);
        }

    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        return inflater.inflate(R.layout.fragment_more, container, false);
    }

    // TODO: Rename method, update argument and hook method into UI event
    public void onButtonPressed(Uri uri) {
        if (mListener != null) {
            mListener.onFragmentInteraction(uri);
        }
    }

    @Override
    public void onAttach(Context context) {
        super.onAttach(context);
        if (context instanceof OnFragmentInteractionListener) {
            mListener = (OnFragmentInteractionListener) context;
        } else {
            Toast.makeText(context, "Notification Fragment Attached", Toast.LENGTH_SHORT).show();

        }
    }

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

    /**
     * This interface must be implemented by activities that contain this
     * fragment to allow an interaction in this fragment to be communicated
     * to the activity and potentially other fragments contained in that
     * activity.
     * <p>
     * See the Android Training lesson <a href=
     * "http://developer.android.com/training/basics/fragments/communicating.html"
     * >Communicating with Other Fragments</a> for more information.
     */
    public interface OnFragmentInteractionListener {
        // TODO: Update argument type and name
        void onFragmentInteraction(Uri uri);
    }
}

我经历了很多试验和错误，但仍然没有解决方法。任何帮助表示赞赏。谢谢。

Answer 1

您能解释一下这部分吗？

当我单击按钮时，我希望它进入activity_login.xml或LoginActivity.java。

您想在片段中单击按钮后在活动中执行某些操作吗？

您可以通过某些方式进行操作。最简单的方法是将监听器设置为单击按钮时的监听器。

创建界面：

public interface OnNavigationButtonClickListener {
    void onMoreClick();
}

在片段中创建侦听器变量：

private OnNavigationButtonClickListener navigationListener;

并为其设置：

public void setNavigationListener(OnNavigationButtonClickListener listener) {
    this.navigationListener = listener;
}

3。单击更多按钮时，通知您的听众片段：

        onMoreButton.setOnClickListener(new OnClickListener {
            navigationListener.onMoreClick();
        });

4。然后在您的活动中设置监听器：

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        fragment.setNavigationListener(new OnNavigationButtonClickListener() {
            @Override
            public void onMoreClick() {
                // you clicked 'more' button in fragment
                // do what you want
            }
        });

Answer 2

假设您已经使用findViewById和所有内容标识了btn_Logoff 您需要做的就是添加一个onclickListener来启动您想要的活动，您的clicklistener代码将类似于此

Button btn_Logoff;

your class{

btn_Logoff  = (Button)  findViewById(R.id.IdOfYourBtnInTheXmlFile);



    btn_Logoff.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                Intent intent = new Intent(getApplicationContext(), LoginActivity.class);

                startActivity(intent);
                }
            });

}

在Bottomnavigtaionview中的片段文件中添加代码

2 个答案: