ListView 分頁(yè)加載更新實(shí)例分享

2020-04-11 12:42:23

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供稿：網(wǎng)友

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(guò)多，需要分頁(yè)加載增加程序運(yùn)行效率！
本demo是將更新的監(jiān)聽(tīng)放在listview的foot中，通過(guò)底部按鈕點(diǎn)擊觸發(fā)或者通過(guò)滑動(dòng)事件監(jiān)聽(tīng)，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); 
} 