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【安卓笔记】ExpandableListView的使用

栏目:综合技术时间:2014-12-16 08:12:40

实现效果:

便可舒展的ListView



其实跟普通的ListView使用没啥区分,只是ListView改成了ExpandableListView,另外适配器由BaseAdapter也换成了BaseExpandableListAdapter。

步骤:

1.编写布局文件。

分为3个,分别是主布局,group分组布局,group item布局:
activity_main.xml:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" tools:context="com.example.expandablelistviewdemo.MainActivity" > <ExpandableListView android:id="@+id/elv" android:layout_width="match_parent" android:layout_height="match_parent" android:divider="#000" android:dividerHeight="2.5dp" android:indicatorLeft="?android:attr/expandableListPreferredItemIndicatorLeft" > </ExpandableListView> </RelativeLayout>

list_group.xml:
<?xml version="1.0" encoding="utf⑻"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" > <TextView android:id="@+id/listTitle" android:layout_width="fill_parent" android:layout_height="wrap_content" android:paddingBottom="10dp" android:paddingLeft="?android:attr/expandableListPreferredItemPaddingLeft" android:paddingTop="10dp" android:textColor="#A4C739" /> </LinearLayout>
list_item.xml:

<?xml version="1.0" encoding="utf⑻"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" > <TextView android:id="@+id/expandedListItem" android:layout_width="fill_parent" android:layout_height="wrap_content" android:paddingBottom="10dp" android:paddingLeft="?android:attr/expandableListPreferredChildPaddingLeft" android:paddingTop="10dp" /> </LinearLayout>
2.编写适配器代码:

package com.example.expandablelistviewdemo; import java.util.HashMap; import java.util.List; import android.content.Context; import android.view.View; import android.view.ViewGroup; import android.widget.BaseExpandableListAdapter; import android.widget.TextView; public class MyExpandableListAdapter extends BaseExpandableListAdapter { private Context mContext; private List<String> expandableListTitle; private HashMap<String, List<String>> expandableListDetail; public MyExpandableListAdapter(List<String> expandableListTitle,HashMap<String,List<String>> expandableListDetail,Context mContext) { this.expandableListDetail = expandableListDetail; this.expandableListTitle = expandableListTitle; this.mContext = mContext; } @Override public int getGroupCount()//分组数 { return this.expandableListTitle.size(); } @Override public int getChildrenCount(int groupPosition)//分组内的item数 { return this.expandableListDetail.get(expandableListTitle.get(groupPosition)).size(); } @Override public Object getGroup(int groupPosition)//获得分组数据 { return this.expandableListTitle.get(groupPosition); } @Override public Object getChild(int groupPosition, int childPosition)//获得第几分组第几个item的数据 { return this.expandableListDetail.get(this.expandableListTitle.get(groupPosition)).get(childPosition); } @Override public long getGroupId(int groupPosition) { return groupPosition; } @Override public long getChildId(int groupPosition, int childPosition) { return childPosition; } @Override public boolean hasStableIds() { return false; } @Override public View getGroupView(int groupPosition, boolean isExpanded, View convertView, ViewGroup parent) { String data = this.expandableListTitle.get(groupPosition); if(convertView == null) { convertView = View.inflate(mContext,R.layout.list_group, null); } TextView tv = (TextView) convertView.findViewById(R.id.listTitle); tv.setText(data); return convertView; } @Override public View getChildView(int groupPosition, int childPosition, boolean isLastChild, View convertView, ViewGroup parent) { // String data = this.expandableListDetail.get(this.expandableListTitle.get(groupPosition)).get(childPosition); String data = (String) this.getChild(groupPosition, childPosition); if(convertView == null) { convertView = View.inflate(mContext, R.layout.list_item, null); } TextView tv = (TextView) convertView.findViewById(R.id.expandedListItem); tv.setText(data); return convertView; } @Override public boolean isChildSelectable(int groupPosition, int childPosition) { return true; } }

可以看到,适配器中有两个getView的方法,分别去构造group和child的view。

3.构造数据源
package com.example.expandablelistviewdemo; import java.util.ArrayList; import java.util.HashMap; import java.util.List; public class ExpandableListDataPump { public static HashMap<String, List<String>> getData() { HashMap<String, List<String>> expandableListDetail = new HashMap<String, List<String>>(); List<String> technology = new ArrayList<String>(); technology.add("Beats sued for noise-cancelling tech"); technology.add("Wikipedia blocks US Congress edits"); technology.add("Google quizzed over deleted links"); technology.add("Nasa seeks aid with Earth-Mars links"); technology.add("The Good, the Bad and the Ugly"); List<String> entertainment = new ArrayList<String>(); entertainment.add("Goldfinch novel set for big screen"); entertainment.add("Anderson stellar in Streetcar"); entertainment.add("Ronstadt receives White House honour"); entertainment.add("Toronto to open with The Judge"); entertainment.add("British dancer return from Russia"); List<String> science = new ArrayList<String>(); science.add("Eggshell may act like sunblock"); science.add("Brain hub predicts negative events"); science.add("California hit by raging wildfires"); science.add("Rosetta's comet seen in close-up"); science.add("Secret of sandstone shapes revealed"); expandableListDetail.put("TECHNOLOGY NEWS", technology); expandableListDetail.put("ENTERTAINMENT NEWS", entertainment); expandableListDetail.put("SCIENCE & ENVIRONMENT NEWS", science); return expandableListDetail; } }

4.编写主界面的代码
package com.example.expandablelistviewdemo; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import android.annotation.SuppressLint; import android.app.Activity; import android.os.Bundle; import android.view.View; import android.widget.ExpandableListView; import android.widget.ExpandableListView.OnChildClickListener; import android.widget.ExpandableListView.OnGroupCollapseListener; import android.widget.ExpandableListView.OnGroupExpandListener; import android.widget.Toast; public class MainActivity extends Activity { private ExpandableListView elv = null; private MyExpandableListAdapter adapter = null; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); elv = (ExpandableListView) findViewById(R.id.elv); final HashMap<String,List<String>> itemData = ExpandableListDataPump.getData(); final List<String> title = new ArrayList<String>(itemData.keySet()); adapter = new MyExpandableListAdapter(title,itemData,this); elv.setAdapter(adapter); //去掉箭头 // elv.setGroupIndicator(null); //收缩 elv.setOnGroupCollapseListener(new OnGroupCollapseListener() { @Override public void onGroupCollapse(int groupPosition) { Toast.makeText(MainActivity.this,title.get(groupPosition)+" group collapse..... ", 0).show(); } }); //舒展 elv.setOnGroupExpandListener(new OnGroupExpandListener() { @Override public void onGroupExpand(int groupPosition) { Toast.makeText(MainActivity.this,title.get(groupPosition)+" group expand... ", 0).show(); } }); //子条目点击 elv.setOnChildClickListener(new OnChildClickListener() { @Override public boolean onChildClick(ExpandableListView parent, View v, int groupPosition, int childPosition, long id) { Toast.makeText(MainActivity.this,itemData.get(title.get(groupPosition)).get(childPosition)+" click", 0).show(); return false; } }); } }

ok,完成。
这里需要注意的是ExpandableListView有多个监听器,group收缩和舒展和子条目点击等等,按需监听。
另外,默许情况下显示的时候有个箭头,你可以通过setGroupIndicator方法设置你需要的标识。

源码地址:https://github.com/Rowandjj/ExpandableListViewDemo




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