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技術社區[雲棲]
Android ListView 按鈕點擊分頁顯示
列表的顯示需要三個元素：
1．ListVeiw 用來展示列表的View。
2．適配器 用來把數據映射到ListView上的中介。
3．數據 具體的將被映射的字符串，圖片，或者基本組件。
根據列表的適配器類型，列表分為三種，ArrayAdapter，SimpleAdapter和SimpleCursorAdapter
其中以ArrayAdapter最為簡單，隻能展示一行字。SimpleAdapter有最好的擴充性，可以自定義出各種效果。 SimpleCursorAdapter可以認為是SimpleAdapter對數據庫的簡單結合，可以方麵的把數據庫的內容以列表的形式展示出來。
當數據羅列過多的時候，我們需要Listview分頁顯示，此時怎麼辦呢
下麵一個簡單的例子介紹一下
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"
};
//用於顯示每列5個Item項。
int VIEW_COUNT = 5;
//用於顯示頁號的索引
int index = 0;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.listview);
//加載Listview和2個Button
initView();
//設置ListView的Adapter
ma = new MoreAdapter(this);
lv.setAdapter(ma);
//此處是雙向綁定嗎？
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個Button的監聽事件。
btnLeft.setOnClickListener(cl);
btnRight.setOnClickListener(cl);
//檢查2個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);
}
//點擊左邊的Button，表示向前翻頁，索引值要減1.
public void leftView(){
index--;
//刷新ListView裏麵的數值。
ma.notifyDataSetChanged();
//檢查Button是否可用。
checkButton();
}
//點擊右邊的Button，表示向後翻頁，索引值要加1.
public void rightView(){
index++;
//刷新ListView裏麵的數值。
ma.notifyDataSetChanged();
//檢查Button是否可用。
checkButton();
}
public void checkButton(){
//索引值小於等於0，表示不能向前翻頁了，以經到了第一頁了。 //將向前翻頁的按鈕設為不可用。
if(index <=0){
btnLeft.setEnabled(false);
}
//值的長度減去前幾頁的長度，剩下的就是這一頁的長度，如果這一頁的長度比View_Count小，表示這是最後的一頁了，後麵在沒有了。
//將向後翻頁的按鈕設為不可用。
else if(data.length - index*VIEW_COUNT <= VIEW_COUNT){
btnRight.setEnabled(false);
}
//否則將2個按鈕都設為可用的。
else {
btnLeft.setEnabled(true);
btnRight.setEnabled(true);
}
}
//ListView的Adapter，這個是關鍵的導致可以分頁的根本原因。
public class MoreAdapter extends BaseAdapter {
Activity activity;
public MoreAdapter(Activity a){
activity = a;
}
//設置每一頁的長度，默認的是View_Count的值。
@Override
public int getCount() {
// TODO Auto-generated method stub
//return data.length
//ori表示到目前為止的前幾頁的總共的個數。
int ori = VIEW_COUNT * index;
//值的總個數-前幾頁的個數就是這一頁要顯示的個數，如果比默認的值小，說明這是最後一頁，隻需顯示這麼多就可以了
if(data.length - ori < VIEW_COUNT ){
return data.length - ori;
}
//如果比默認的值還要大，說明一頁顯示不完，還要用換一頁顯示，這一頁用默認的值顯示滿就可以了。
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要顯示的是當前的位置+前幾頁已經顯示的位置個數的對應的位置上的值。
tv.setText(data[position+index*VIEW_COUNT]);
return tv;
}
}
}
HeaderBottomListDemo_MORE_PAGES_.rar (473.5
KB)
最後更新：2017-04-02 22:15:49