listview是android中最常用的控件之一。
在實(shí)際運(yùn)用中往往會(huì)遇到一次性加載全部數(shù)據(jù)過多,需要分頁加載增加程序運(yùn)行效率!
本demo是將更新的監(jiān)聽放在listview的foot中,通過底部按鈕點(diǎn)擊觸發(fā)或者通過滑動(dòng)事件監(jiān)聽,當(dāng)滑動(dòng)到列表最底部的時(shí)候觸發(fā)。
有圖有真像:
列表初始狀態(tài)
觸發(fā)加載
加載后
部分代碼:
mainactivity
復(fù)制代碼 代碼如下:
private void initactivity() {
// todo auto-generated method stub
loadmoreview = getlayoutinflater().inflate(r.layout.loadmore, null);
loadmore_btn = (button) loadmoreview.findviewbyid(r.id.loadmore_btn);
loadmore_btn.setonclicklistener(new onclicklistener() {
@override
public void onclick(view v) {
// todo auto-generated method stub
doupdate();
}
});
listview = (listview) findviewbyid(r.id.listview);
listview.addfooterview(loadmoreview);
initadapter();
listview.setadapter(adapter);
listview.setonscrolllistener(new onscrolllistener() {
@override
public void onscrollstatechanged(abslistview view, int scrollstate) {
// todo auto-generated method stub
int itemslastindex = adapter.getcount() - 1;
int lastindex = itemslastindex + 1;
if (scrollstate == onscrolllistener.scroll_state_idle
&& visiblelast == lastindex) {
// 可在這添加滑到列表底的時(shí)候異步自動(dòng)加載
// doupdate();
}
}
@override
public void onscroll(abslistview view, int firstvisibleitem,
int visibleitemcount, int totalitemcount) {
// todo auto-generated method stub
visiblecount = visibleitemcount;
visiblelast = firstvisibleitem + visibleitemcount - 1;
}
});
}
protected void doupdate() {
// todo auto-generated method stub
loadmore_btn.settext("loading ...");
handler.postdelayed(new runnable() {
@override
public void run() {
// todo auto-generated method stub
loaddata();
adapter.notifydatasetchanged();// 通知adapter數(shù)據(jù)變化
listview.setselection(visiblelast - visiblecount + 1);
loadmore_btn.settext("load more");
}
}, 2000);
}
private void loaddata() {
// todo auto-generated method stub
int count = adapter.getcount();
for (int i = count; i < count + 10; i++) {
adapter.additem(string.valueof(i + 1));
}
}
private void initadapter() {
// todo auto-generated method stub
list<string> items = new arraylist<string>();
for (int i = 0; i < 10; i++) {
items.add(string.valueof(i + 1));
}
adapter = new listadapter(this, items);
}
@override
public boolean oncreateoptionsmenu(menu menu) {
// inflate the menu; this adds items to the action bar if it is present.
getmenuinflater().inflate(r.menu.activity_main, menu);
return true;
}
listadapter
復(fù)制代碼 代碼如下:
public listadapter(context context, list<string> items) {
this.items = items;
this.inflater = (layoutinflater) context
.getsystemservice(context.layout_inflater_service);
}
@override
public int getcount() {
// todo auto-generated method stub
return items.size();
}
@override
public object getitem(int position) {
// todo auto-generated method stub
return items.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) {
// todo auto-generated method stub
if (convertview == null) {
convertview = inflater.inflate(r.layout.list_item, null);
}
textview textview = (textview) convertview
.findviewbyid(r.id.list_item_text);
textview.settext(items.get(position));
return convertview;
}
/**
* 添加列表項(xiàng)
* @param item
*/
public void additem(string item){
items.add(item);
}
提醒一下:要下載android-support-v4.jar 這個(gè)第三方的jar包哦! 這里就不提供下載了!