列表的显示需要三个元素：
1．ListVeiw 用来展示列表的View。
2．适配器 用来把数据映射到ListView上的中介。
3．数据 具体的将被映射的字符串，图片，或者基本组件。
根据列表的适配器类型，列表分为三种，ArrayAdapter，SimpleAdapter和SimpleCursorAdapter
其中以ArrayAdapter最为简单，只能展示一行字。SimpleAdapter有最好的扩充性，可以自定义出各种效果。 SimpleCursorAdapter可以认为是SimpleAdapter对数据库的简单结合，可以方面的把数据库的内容以列表的形式展示出来。
当数据罗列过多的时候，我们需要Listview分页显示，此时怎么办呢
下面一个简单的例子介绍一下
【Java代码】
package com.ideasandroid.demo;
import android.app.Activity;
import android.os.Bundle;
import android.view.Gravity;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.Button;
import android.widget.ListView;
import android.widget.TextView;
public class listMoreTest extends Activity {
ListView lv;
Button btnLeft, btnRight;
View.OnClickListener cl;
MoreAdapter ma;
String[] data = {
"0","1","2","3","4","5","6","7","8","9","10",
"11","12","13","14","15","16","17","18","19","20",
"21","22","23","24","25","26","27","28","29","30",
"31","32","33","34","35","36","37","38","39","40",
"41","42","43","44","45","46","47","48","49","50",
"51","52","53","54","55","56","57","58","59","60",
"61","62","64","64","65","66","67","68","69","70",
"71","72","73","74","75","76","77","78","79","80",
"81","82","83","84","85","86","87","88","89","90",
"91","92","93","94","95","96","97","98","99","100"
};
//用于显示每列5个Item项。
int VIEW_COUNT = 5;
//用于显示页号的索引
int index = 0;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.listview);
//加载Listview和2个Button
initView();
//设置ListView的Adapter
ma = new MoreAdapter(this);
lv.setAdapter(ma);
//此处是双向绑定吗？
cl = new Button.OnClickListener(){
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
switch(v.getId()){
case R.id.btnLeft:
leftView();
break;
case R.id.btnRight:
rightView();
break;
}
}
};
//添加2个Button的监听事件。
btnLeft.setOnClickListener(cl);
btnRight.setOnClickListener(cl);
//检查2个Button是否是可用的
checkButton();
}
public void initView(){
lv = (ListView)findViewById(R.id.list);
btnLeft = (Button)findViewById(R.id.btnLeft);
btnRight = (Button)findViewById(R.id.btnRight);
}
//点击左边的Button，表示向前翻页，索引值要减1.
public void leftView(){
index--;
//刷新ListView里面的数值。
ma.notifyDataSetChanged();
//检查Button是否可用。
checkButton();
}
//点击右边的Button，表示向后翻页，索引值要加1.
public void rightView(){
index++;
//刷新ListView里面的数值。
ma.notifyDataSetChanged();
//检查Button是否可用。
checkButton();
}
public void checkButton(){
//索引值小于等于0，表示不能向前翻页了，以经到了第一页了。 //将向前翻页的按钮设为不可用。
if(index <=0){
btnLeft.setEnabled(false);
}
//值的长度减去前几页的长度，剩下的就是这一页的长度，如果这一页的长度比View_Count小，表示这是最后的一页了，后面在没有了。
//将向后翻页的按钮设为不可用。
else if(data.length - index*VIEW_COUNT <= VIEW_COUNT){
btnRight.setEnabled(false);
}
//否则将2个按钮都设为可用的。
else {
btnLeft.setEnabled(true);
btnRight.setEnabled(true);
}
}
//ListView的Adapter，这个是关键的导致可以分页的根本原因。
public class MoreAdapter extends BaseAdapter {
Activity activity;
public MoreAdapter(Activity a){
activity = a;
}
//设置每一页的长度，默认的是View_Count的值。
@Override
public int getCount() {
// TODO Auto-generated method stub
//return data.length
//ori表示到目前为止的前几页的总共的个数。
int ori = VIEW_COUNT * index;
//值的总个数-前几页的个数就是这一页要显示的个数，如果比默认的值小，说明这是最后一页，只需显示这么多就可以了
if(data.length - ori < VIEW_COUNT ){
return data.length - ori;
}
//如果比默认的值还要大，说明一页显示不完，还要用换一页显示，这一页用默认的值显示满就可以了。
else {
return VIEW_COUNT;
}
}
@Override
public Object getItem(int position) {
// TODO Auto-generated method stub
return position;
}
@Override
public long getItemId(int position) {
// TODO Auto-generated method stub
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
// TODO Auto-generated method stub
//return addTestView(position);
TextView tv = new TextView(activity);
tv.setGravity(Gravity.CENTER);
//TextView要显示的是当前的位置+前几页已经显示的位置个数的对应的位置上的值。
tv.setText(data[position+index*VIEW_COUNT]);
return tv;
}
}
}