android ListView通过优化重用历史缓存实现。listview相应的数据适配器一般使用自己定义BaseAdapter子类，重用历史缓冲区来提高性能。

例如，下面的示例代码演示：

1、listView数据适配器

/**	 * 待处理请假信息的数据适配器类	 * @author yqq	 *	 */	private  class LeaveInfoAdapter extends BaseAdapter{					@Override		public int getCount() {			// TODO Auto-generated method stub			return mleaveInfos.size();		}		@Override		public Object getItem(int position) {			// TODO Auto-generated method stub			return mleaveInfos.get(position);		}		@Override		public long getItemId(int position) {			// TODO Auto-generated method stub			return position;		}		@Override		public View getView(int position, View convertView, ViewGroup parent) {				View view=null;			ViewHolder holder=null;			if (convertView!=null && convertView instanceof LinearLayout) {				view=convertView;				holder=(ViewHolder) view.getTag();							}else{				view=View.inflate(getApplicationContext(), R.layout.leave_info_item, null);				holder=new ViewHolder();				holder.name=(TextView)view.findViewById(R.id.tv_name);				holder.workIdAndDepartment=(TextView)view.findViewById(R.id.tv_workid_depart);				holder.leaveinfo=(TextView)view.findViewById(R.id.tv_leave_info);				holder.date=(TextView)view.findViewById(R.id.tv_date);				holder.endDate=(TextView)view.findViewById(R.id.tv_endtime);				view.setTag(holder);											}			LeaveInfo info=mleaveInfos.get(position);			Log.i("測试",info.toString());			holder.name.setText(info.getName());			holder.workIdAndDepartment.setText("(工号:"+info.getWorkId()+"部门:"+info.getDepartment()+")");			holder.leaveinfo.setText(info.getLeaveInfo());			holder.date.setText("假期起止:"+info.getLeaveData()+"\n");			holder.endDate.setText("-"+info.getEndleaveDate());						return view;		}					}		private static class ViewHolder{		TextView name;//员工姓名显示控件		TextView workIdAndDepartment;//员工工号和部门显示		TextView leaveinfo;//员工请假信息		TextView date;//员工请假日期		TextView endDate;			}

2、每项数据显示的布局

leave_info_item.xml

xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" > <LinearLayout android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="horizontal" > <ImageView android:id="@+id/iv_headcolor" android:layout_width="wrap_content" android:layout_height="80dp" android:src="@drawable/light_green" /> <RelativeLayout android:layout_width="match_parent" android:layout_height="match_parent" android:layout_marginLeft="5dp" android:layout_marginTop="5dp" > <TextView android:id="@+id/tv_name" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="姓名" android:textColor="#ff0000" android:textSize="15sp" /> <TextView android:id="@+id/tv_leave_info" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_below="@+id/tv_name" android:paddingTop="8dp" android:text="请假理由" android:textSize="20sp" /> <TextView android:id="@+id/tv_date" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_above="@+id/tv_leave_info" android:layout_alignParentRight="true" android:text="日期" android:textColor="#000000" android:textSize="10sp" /> <TextView android:id="@+id/tv_endtime" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_below="@+id/tv_date" android:layout_alignParentRight="true" android:text="日期2" android:textColor="#000000" android:textSize="10sp" /> <TextView android:id="@+id/tv_workid_depart" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignParentTop="true" android:layout_toRightOf="@+id/tv_name" android:gravity="center_horizontal" android:paddingLeft="5dp" android:text="姓名和部门" android:textColor="#0000ff" android:textSize="13sp" /> </RelativeLayout> </LinearLayout> <View android:layout_width="match_parent" android:layout_height="2dp" android:background="@android:drawable/divider_horizontal_dark" /> </LinearLayout>

3、利用异步任务载入数据

/**	 * 使用异步载入数据，填充待处理请假信息listView	 */	private void fillData(){		new AsyncTask
     
      () {					@Override			protected void onPostExecute(Void result) {								if(mAdapter==null){					mAdapter=new LeaveInfoAdapter();					//设置数据适配器					mLVleaveInfos.setAdapter(mAdapter);					Log.i("測试", "异步任务显示后台获得数据库数据");					}				else {					mAdapter.notifyDataSetChanged();									}																super.onPostExecute(result);			}			@Override			protected Void doInBackground(Void... params) {				//获得要显示的数据				mleaveInfos=mLeaveInfosDao.findAll();				if (mleaveInfos==null) {					Toast.makeText(HomeActivity.this,"请假数据不存在或是已经清除！
     

", 500).show(); } Log.i("測试", "异步任务后台获得数据库数据"+mleaveInfos.size()); return null; } }.execute(); }

4、为列表每项绑定事件监听

mLVleaveInfos.setOnItemClickListener(new OnItemClickListener() {			@Override			public void onItemClick(AdapterView
      parent, View view,					int position, long id) {				Object object=mLVleaveInfos.getItemAtPosition(position);				Log.i("允许測试",object+"");				if(object instanceof LeaveInfo){					tmpInfo=(LeaveInfo)object;					Log.i("允许測试",tmpInfo.toString());					showAcceptOrNo();				}															}});

5、列表的其它监听和分页载入对于本地数据不须要分页载入，对于server端数据应该分页载入节省流量。

//下拉列表的时候分页载入数据		mRubishSms.setOnScrollListener(new OnScrollListener() {						@Override			public void onScrollStateChanged(AbsListView view, int scrollState) {				switch (scrollState) {				//在下拉列表空暇的时候显示数据				case OnScrollListener.SCROLL_STATE_IDLE:					//获得分页载入的每页最大值					int position=mRubishSms.getLastVisiblePosition();					int total=0;					if(mInfos!=null){						// total=maxNum;						total=mInfos.size();											}					 					if(position==total-1){						//到达该分页载入的末尾位置						offset+=maxNum;						if(offset>totalNums){							Toast.makeText(RubishSmsActivity.this,"数据已经载入完。没有很多其它的数据了...", 300).show();							return;													}						//异步任务载入数据						fillData();											}															break;								}							}						@Override			public void onScroll(AbsListView view, int firstVisibleItem,					int visibleItemCount, int totalItemCount) {				// TODO Auto-generated method stub							}		});				fillData();				//每一个条目绑定监听		mRubishSms.setOnItemClickListener(new OnItemClickListener() {			View m_view=View.inflate(RubishSmsActivity.this,R.layout.show_rubish_sms_operation,null);			@Override			public void onItemClick(AdapterView
      parent, View view,					int position, long id) {				//获得条目相应的每一个对象				 			Object object=mRubishSms.getItemAtPosition(position);			if(object instanceof RubishSmsInfo){				final RubishSmsInfo info=(RubishSmsInfo) object;				//对对象的操作1、删除2、恢复到收件箱3、增加黑名单				Dialog builder=new Dialog(RubishSmsActivity.this);				builder.setTitle("提示");				builder.setContentView(m_view);								//删除				((TextView)m_view.findViewById(R.id.tv_delete)).setOnClickListener(new OnClickListener() {										@Override					public void onClick(View v) {						mInfos.remove(info);						if(mRubishSmsInfoDao==null){							mRubishSmsInfoDao=new RubishSmsInfoDao(getApplicationContext());													}						mRubishSmsInfoDao.deleteSmsInfos(info);						if(mAdapter==null){							mAdapter=new RubishSmsInfosAdapter();							mRubishSms.setAdapter(mAdapter);						}else{							mAdapter.notifyDataSetChanged();						}																						}				});				//恢复到收件箱				((TextView)m_view.findViewById(R.id.tv_recovery_sms)).setOnClickListener(new OnClickListener() {										@Override					public void onClick(View v) {											}										});				//增加黑名单				((TextView)m_view.findViewById(R.id.tv_add_black_number)).setOnClickListener(new OnClickListener() {										@Override					public void onClick(View v) {																	}				});								builder.show();							}																							}					});					}

6、BaseExpandableListAdapter演示样例demo:

public class CommonNumberActivity extends Activity {	private ExpandableListView elv;	private List
     
       groupNames;	private Map
      
       > childrenCacheInfos;	@Override	protected void onCreate(Bundle savedInstanceState) {		super.onCreate(savedInstanceState);		childrenCacheInfos = new HashMap
       
        >();		setContentView(R.layout.activity_common_num);		elv = (ExpandableListView) findViewById(R.id.elv);		elv.setAdapter(new MyAdapter());						elv.setOnChildClickListener(new OnChildClickListener() {						@Override			public boolean onChildClick(ExpandableListView parent, View v,					int groupPosition, int childPosition, long id) {				Intent intent = new Intent();				intent.setAction(Intent.ACTION_DIAL);				String number = childrenCacheInfos.get(groupPosition).get(childPosition).split("\n")[1];				intent.setData(Uri.parse("tel:"+number));				startActivity(intent);				return false;			}		});	}	private class MyAdapter extends BaseExpandableListAdapter {		// 返回多少个分组		@Override		public int getGroupCount() {			// return CommonNumDao.getGroupCount();			groupNames = CommonNumDao.getGroupInfos();			return groupNames.size();		}		@Override		public int getChildrenCount(int groupPosition) {// 0 開始			List
        
          childreninfos;			if (childrenCacheInfos.containsKey(groupPosition)) {				childreninfos = childrenCacheInfos.get(groupPosition);			} else {				childreninfos = CommonNumDao						.getChildrenInfosByPosition(groupPosition);				childrenCacheInfos.put(groupPosition, childreninfos);			}			return childreninfos.size();		}		@Override		public Object getGroup(int groupPosition) {			return null;		}		@Override		public Object getChild(int groupPosition, int childPosition) {			return null;		}		@Override		public long getGroupId(int groupPosition) {			return 0;		}		@Override		public long getChildId(int groupPosition, int childPosition) {			return 0;		}		@Override		public boolean hasStableIds() {			return false;		}		@Override		public View getGroupView(int groupPosition, boolean isExpanded,				View convertView, ViewGroup parent) {			TextView tv;			if(convertView!=null&&convertView instanceof TextView){				tv = (TextView) convertView;			}else{				tv = new TextView(getApplicationContext());			}						tv.setTextSize(25);			tv.setTextColor(Color.RED);			// tv.setText("      "+CommonNumDao.getGroupName(groupPosition));			tv.setText("      " + groupNames.get(groupPosition));			return tv;		}		@Override		public View getChildView(int groupPosition, int childPosition,				boolean isLastChild, View convertView, ViewGroup parent) {			TextView tv;			if(convertView!=null&&convertView instanceof TextView){				tv = (TextView) convertView;			}else{				tv = new TextView(getApplicationContext());			}			tv.setTextSize(18);			tv.setTextColor(Color.BLUE);//			tv.setText(CommonNumDao.getChildInfoByPosition(groupPosition,//					childPosition));			tv.setText(childrenCacheInfos.get(groupPosition).get(childPosition));			return tv;		}		@Override		public boolean isChildSelectable(int groupPosition, int childPosition) {			return true;		}	}}
        
       
      
     

7、BaseAdapter数据适配器的还有一种使用方法demo:

package com.example.yqqmobilesafe;import com.example.yqqmobilesafe.cleanache.CleanCacheActivity;import android.app.Activity;import android.content.Intent;import android.os.Bundle;import android.util.Log;import android.view.View;import android.view.ViewGroup;import android.widget.AdapterView;import android.widget.AdapterView.OnItemClickListener;import android.widget.BaseAdapter;import android.widget.GridView;import android.widget.ImageView;import android.widget.LinearLayout;import android.widget.TextView;public class OftenUseFunctionActivity extends Activity {	private boolean D=true;	 private GridView mGridView;//经常使用功能显示	 private GVAdapter mAdapter;	 	 private String[] items={"清理加速","话费流量","骚扰拦截","防吸费","支付保镖","手机杀毒"};	 private int[] icons={R.drawable.exam_frequently_used_tools_icon_clean,R.drawable.exam_frequently_used_tools_icon_net_traffic,R.drawable.exam_frequently_used_tools_icon_block_anoy,R.drawable.exam_frequently_used_tools_icon_costguard,R.drawable.exam_frequently_used_tools_icon_guardpay,R.drawable.exam_frequently_used_tools_icon_malware};	public OftenUseFunctionActivity() {		// TODO Auto-generated constructor stub	}	@Override	protected void onCreate(Bundle savedInstanceState) {		// TODO Auto-generated method stub		super.onCreate(savedInstanceState);		setContentView(R.layout.activity_tab_often_use_function);		//数据适配		mGridView=(GridView)this.findViewById(R.id.gv_home);		mAdapter=new GVAdapter();		mGridView.setAdapter(mAdapter);				setListener();	}		  private void setListener() {		  mGridView.setOnItemClickListener(new OnItemClickListener() {			@Override			public void onItemClick(AdapterView
      parent, View view,					int position, long id) {				switch (position) {				case 0:					Intent intent=new Intent(OftenUseFunctionActivity.this,CleanCacheActivity.class);					startActivity(intent);					if(D){					Log.i("OftenUseFunctionActivity","清理加速");					}					break;				case 1:					if(D){						Log.i("OftenUseFunctionActivity","话费流量");						}					break;				case 2:					if(D){						Log.i("OftenUseFunctionActivity","骚扰拦截");												}					Intent intent2=new Intent(OftenUseFunctionActivity.this,StopAnonyActivity.class);					startActivity(intent2);					break;				case 3:					if(D){						Log.i("OftenUseFunctionActivity","防吸费");						}					break;				case 4:					if(D){						Log.i("OftenUseFunctionActivity","支付保镖");						}					break;				case 5:					Intent intent6=new Intent(OftenUseFunctionActivity.this,KillVirusActivity.class);					startActivity(intent6);										if(D){						Log.i("OftenUseFunctionActivity","手机杀毒");						}					break;								}							}			  		});			}	//採用功能的数据适配器    private class GVAdapter extends BaseAdapter{		@Override		public int getCount() {			// TODO Auto-generated method stub			return items.length;		}		@Override		public Object getItem(int position) {			// TODO Auto-generated method stub			return null;		}		@Override		public long getItemId(int position) {			// TODO Auto-generated method stub			return position;		}		@Override		public View getView(int position, View convertView, ViewGroup parent) {									View view=View.inflate(OftenUseFunctionActivity.this,R.layout.home_item,null);				ImageView ivIcon=(ImageView) view.findViewById(R.id.iv_home_icon);				TextView tvFunName=(TextView) view.findViewById(R.id.tv_home_function_name);							ivIcon.setImageResource(icons[position]);				tvFunName.setText(items[position]);																			return view;		}    	    	    }        static class ViewHolder{    	ImageView ivIcon;//功能图标    	TextView tvFunName;//功能描写叙述    	    }}

home_item.xml

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