Android数据缓存加载，listview显示

//listview显示数据，分布加载，下拉加载，功能类似QQ空间的无刷新加载数据

public class Safewei2_activity extends Activity {

 protected int startindex=0;

protected int maxsize=20;

private BlackpeopleDao dao;

protected ListView lv;

protected Adape adapters;

@Override

protected void onCreate(Bundle savedInstanceState) {

// TODO Auto-generated method stub

super.onCreate(savedInstanceState);

dao=new BlackpeopleDao(this);//创建SQLhelp类的对象

setContentView(R.layout.activitysafecommand2);

 

InitUI();//加载UI

 Initdata();//加载数据

}

private void InitUI() {

lv=(ListView) findViewById(R.id.lvblack); 

lv.setOnScrollListener(new OnScrollListener() {

//给listview的滚动设置监听事件

@Override

public void onScrollStateChanged(AbsListView view, int scrollState) {

switch (scrollState) {//判断listview的状态

case AbsListView.OnScrollListener.SCROLL_STATE_IDLE://滚动处于闲置状态

int lastposition=lv.getLastVisiblePosition();   //获取显示的listview的最后一条数据的位置

if(lastposition==(list.size()-1))

{

startindex+=maxsize;

if(startindex>=totalnumber)

{

Toast.makeText(Safewei2_activity.this,"没有更多数据", Toast.LENGTH_SHORT).show();

   //return;

}else

{

Initdata();

}

}

break;

}

}

@Override

public void onScroll(AbsListView view, int firstVisibleItem,

int visibleItemCount, int totalItemCount) {

// 重写的方法

}

});

}

Handler hand=new Handler(){

private Myadapter adapter;

public void handleMessage(android.os.Message msg) {

//处理数据

if(adapters==null)

{   

   adapters=new Adape(); 

     lv.setAdapter(adapters); 

}else{

adapters.notifyDataSetChanged(); //刷新界面

}

};

};

protected ArrayList<BlackpeopleInfo> list;

public ViewHolder holder;

private int totalnumber;

private void Initdata() {

totalnumber=dao.GetPage();

new Thread(){ //线程加载，防止阻塞主线程

@Override

public void run() {

if(list==null)

{

list=dao.Getpagelist2(startindex, maxsize); //加载list数据

 

}else{

list.addAll(dao.Getpagelist2(startindex, maxsize));

}

hand.sendEmptyMessage(0);

 

}

 

}.start();

}

 class Adape extends BaseAdapter{

@Override

public int getCount() {

// TODO Auto-generated method stub

return list.size();

}

@Override

public Object getItem(int position) {

// TODO Auto-generated method stub

return list.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) {

if(convertView==null)

{    

convertView=View.inflate(Safewei2_activity.this, R.layout.itemsafeactivity, null);

holder=new ViewHolder();

 holder.number= (TextView) convertView.findViewById(R.id.tvphone);

 holder.mode=(TextView) convertView.findViewById(R.id.tvmode);

 holder.img=(ImageView) convertView.findViewById(R.id.deles);

 convertView.setTag(holder);

        }else{

holder=(ViewHolder) convertView.getTag();

        

}

  

holder.number.setText(list.get(position).getNumber());

// mode.setText(list.get(position).getMode());

 

if(list.get(position).getMode().equals("1"))

{

holder.mode.setText("电话拦截");

}else if(list.get(position).getMode().equals("2"))

{

holder.mode.setText("短信拦截"); 

}else if(list.get(position).getMode().equals("3"))

{

holder.mode.setText("电话拦截和短信拦截");

}

final BlackpeopleInfo infos=list.get(position);

holder.img.setOnClickListener(new OnClickListener() {

@Override

public void onClick(View v) {

// TODO Auto-generated method stub

String number=infos.getNumber();

boolean rows=dao.Delete(number);

if(rows)

{

Toast.makeText(Safewei2_activity.this, "删除成功", Toast.LENGTH_SHORT).show();

   list.remove(infos);

   notifyDataSetChanged();

}

else{

Toast.makeText(Safewei2_activity.this, "删除失败", Toast.LENGTH_SHORT).show();

}

}

});

return  convertView;

}

 

 

 }

 

 

static class ViewHolder{

 TextView number;

 TextView mode;

 ImageView img;

}

}

======================================================

数据库代码

public ArrayList<BlackpeopleInfo> Getpagelist2(int startindex,int maxsize)
{
ArrayList<BlackpeopleInfo> list=new ArrayList<BlackpeopleInfo>();
SQLiteDatabase db=helper.getReadableDatabase();

Cursor cursor = db.rawQuery("select number,mode from blacknumber limit ? offset ?", new String[]{String.valueOf(maxsize),
               String.valueOf(startindex)});

while(cursor.moveToNext())
{
BlackpeopleInfo info=new BlackpeopleInfo();
info.setMode(cursor.getString(1));
info.setNumber(cursor.getString(0));
list.add(info);

}
cursor.close();
db.close();
return list;

}