Android Fragment（三）ListFragment简单介绍以及Fragment之间通信-白红宇

Android Fragment（三）ListFragment简单介绍以及Fragment之间通信

阅读量：5809 次

发布时间：2019-06-18

本文共 8696 字，大约阅读时间需要 28 分钟。

一、Fragment通信简单介绍：Fragments之间是不能够直接通信的，他们之间的通信是通过Activity这个中间件来通信的，为了让Fragment跟它的Activity通信，我们可以在Fragment类中定义一个接口，并在它所属的Activity中实现该接口。Fragment在它的onAttach()方法执行期间捕获该接口的实现，然后就可以调用接口方法，以便跟Activity通信。

二、需求：利用ListFragment实现一个浮动的二级菜单，点击左边菜单在右边显示与之对应的二级菜单列表。效果如下图所示：

废话不多说了，直接给大家上代码：

一、ListFragmentLeft（左边的ListFragment菜单）

package com.yw.myapiupdate.fragment;import android.annotation.SuppressLint;import android.app.Activity;import android.app.ListFragment;import android.os.Bundle;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.ArrayAdapter;import android.widget.ListView;import android.widget.Toast;import com.yw.myapiupdate.R;@SuppressLint("NewApi")public class ListFragmentLeft extends ListFragment{    private LeftFragmentCallback callback;/*    String[] lists = new String[]{            "贾克斯",            "无双剑姬",            "蕾欧娜",            "安妮",            "潘森",            "盖伦"    };*/        @Override    public void onAttach(Activity activity) {        super.onAttach(activity);        try{            callback = (LeftFragmentCallback)activity;        }catch(Exception e){                    }    }    @Override    public View onCreateView(LayoutInflater inflater, ViewGroup container,            Bundle savedInstanceState) {        return inflater.inflate(R.layout.listfragmentleft_layout, container, false);    }    @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setListAdapter(new ArrayAdapter
     
      (getActivity(),                android.R.layout.simple_list_item_1,TestData.getInstance().getData(-1)));    }        @Override    public void onListItemClick(ListView l, View v, int position, long id) {        callback.leftCallback(position);        /*Toast.makeText(getActivity(),                      "You have selected:\t " + lists[position],                      Toast.LENGTH_SHORT).show();   */      }    /**     * 回调接口     * @author yw-tony     *     */    public interface LeftFragmentCallback{        public void leftCallback(int position);    }}

与之对应的布局文件：

二、点击左边菜单时弹出的右边菜单类（ListFragmentRight）

package com.yw.myapiupdate.fragment;import com.yw.myapiupdate.R;import android.annotation.SuppressLint;import android.app.ListFragment;import android.os.Bundle;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.ArrayAdapter;import android.widget.ListView;import android.widget.Toast;@SuppressLint("NewApi")public class ListFragmentRight extends ListFragment{/*    String[] listRight = new String[]{            "天启者",            "赵信",            "嘉文四世",            "稻草人",            "瑞文",            "船长",            "盲僧"    };*/    @Override    public View onCreateView(LayoutInflater inflater, ViewGroup container,            Bundle savedInstanceState) {        return inflater.inflate(R.layout.listfragment_right, container, false);    }    @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setListAdapter(new ArrayAdapter
     
      (getActivity(),                android.R.layout.simple_list_item_1,TestData.getInstance().getData(1)));    }    @Override    public void onListItemClick(ListView l, View v, int position, long id) {        ((MyFragmentActivity)getActivity()).windowDiss();        /*Toast.makeText(getActivity(),                      "You have selected:\t " + listRight[position],                      Toast.LENGTH_SHORT).show(); */        }}

与之对应的布局文件：

三、以上两者之间的通信桥梁Activity（MyFragmentActivity）

package com.yw.myapiupdate.fragment;import android.annotation.SuppressLint;import android.app.Activity;import android.app.FragmentManager;import android.graphics.drawable.BitmapDrawable;import android.os.Bundle;import android.view.LayoutInflater;import android.view.View;import android.view.View.OnClickListener;import android.view.WindowManager;import android.widget.ArrayAdapter;import android.widget.Button;import android.widget.PopupWindow;import com.yw.myapiupdate.R;import com.yw.myapiupdate.fragment.ListFragmentLeft.LeftFragmentCallback;@SuppressLint("NewApi")public class MyFragmentActivity extends Activity implements LeftFragmentCallback,OnClickListener{/*    String[] lists = new String[]{            "天启者",            "赵信",            "嘉文四世",            "稻草人",            "瑞文",            "船长",            "盲僧",            "那身男爵"    };*/    private Button btn;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        TestData.getInstance().setData();        setContentView(R.layout.listfragment_layout);        btn = (Button)findViewById(R.id.listfragment_btn);        btn.setOnClickListener(this);        /*Display display = getWindowManager().getDefaultDisplay();        if(display.getWidth() > display.getHeight()){            FragmentRed red = new FragmentRed();            getFragmentManager().beginTransaction().replace(R.id.fragment_linear_layout, red).commit();        }else{            FragmentYellow yellow = new FragmentYellow();            getFragmentManager().beginTransaction().replace(R.id.fragment_linear_layout, yellow).commit();        }*/        initMenu();    }    private LayoutInflater inflater;    private View view;    private PopupWindow window;    private void initMenu(){        inflater = LayoutInflater.from(this);        view = inflater.inflate(R.layout.popupwindow_layout, null);        window = new PopupWindow(view,WindowManager.LayoutParams.FILL_PARENT,WindowManager.LayoutParams.FILL_PARENT);        window.setWidth(WindowManager.LayoutParams.FILL_PARENT);        window.setHeight(WindowManager.LayoutParams.FILL_PARENT);        window.setFocusable(true);        window.setOutsideTouchable(true);        window.setBackgroundDrawable(new BitmapDrawable());            }    /**     * 显示窗体     * @param anchor     */    public void show(View anchor){        if(window!=null && !window.isShowing()){            window.showAsDropDown(anchor);        }    }    /**     * 关闭窗体     */    public void windowDiss(){        if(window!=null && window.isShowing()){            window.dismiss();        }    }    @Override    public void leftCallback(int position) {        try{            /*ListFragmentRight listRight = (ListFragmentRight)                    getFragmentManager.findFragmentById(                    R.id.listfragment_right);*/            FragmentManager manager = getFragmentManager();            ListFragmentRight listRight = (ListFragmentRight) manager.findFragmentById(R.id.listfragment_right);            if(listRight != null){                listRight.setListAdapter(new ArrayAdapter
     
      (MyFragmentActivity.this,                android.R.layout.simple_list_item_1,TestData.getInstance().getData((position+1))));            }else{                            }        }catch(Exception e){                    }                    }    @Override    public void onClick(View v) {        switch(v.getId()){            case R.id.listfragment_btn:                if(window!=null && !window.isShowing()){                    show(btn);                }                break;        }            }        }

与之对应的布局：

四、提供静态数据源的工具类

package com.yw.myapiupdate.fragment;import java.util.ArrayList;import java.util.List;public class TestData {    private List
     
       listParent = new ArrayList
      
       ();    private List
       
         listA = new ArrayList
        
         ();    private List
         
           listB = new ArrayList
          
           (); private List
           
             listC = new ArrayList
            
             (); private List
             
               listD = new ArrayList
              
               (); private TestData(){} private static TestData instance; public static TestData getInstance(){ if(instance == null){ synchronized (TestData.class) { if(instance == null){ instance = new TestData(); } } } return instance; } /** * 获取数据 * @param target * @return */ public List
               
                 getData(int target){// List
                
                  lists = new ArrayList
                 
                  (); switch(target){ case 1: return listA;// break; case 2: return listB;// break; case 3: return listC;// break; case 4: return listD;// break; } return listParent; } public void setData(){ listParent.add("A"); listParent.add("B"); listParent.add("C"); listParent.add("D"); listA.add("A1"); listA.add("A2"); listA.add("A3"); listB.add("B1"); listB.add("B2"); listB.add("B3"); listB.add("B4"); listC.add("C1"); listC.add("C2"); listD.add("D1"); listD.add("D2"); listD.add("D3"); listD.add("D4"); listD.add("D5"); }}

程序运行后的效果图：

好了，ListFragment以及他们之间的通信到此就结束了，你？弄明白了吗？

转载于:https://www.cnblogs.com/tony-yang-flutter/p/3391822.html

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