Android:ListView数据的分批加载
2016-01-06 12:13
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如果数据太多,就需要分批加载
item界面
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<TextView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:textSize="18sp"
android:textColor="#FFFFFF"
android:id="@+id/textView"
/>
</LinearLayout>
加载的时候的进度条,无限期进度条
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal" >
<ProgressBar android:id="@+id/c81_forthBar"
android:layout_width="50dp"
android:layout_height="wrap_content"
style="?android:attr/progressBarStyle" />
<TextView android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center_vertical"
android:textSize="20sp"
android:text="数据正在加载..."
/>
</LinearLayout>
public class MainActivity extends Activity {
private ListView listView;
private List<String> data = new ArrayList<String>();
ArrayAdapter<String> adapter;
View footer;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
footer = getLayoutInflater().inflate(R.layout.footer, null);
listView = (ListView) this.findViewById(R.id.listView);
listView.setOnScrollListener(new ScrollListener());
data.addAll(DataService.getData(0, 20));
adapter = new ArrayAdapter<String>(this, R.layout.listview_item, R.id.textView, data);
listView.addFooterView(footer);//添加页脚(放在ListView最后)
listView.setAdapter(adapter);
listView.removeFooterView(footer);
}
private int number = 20;//每次获取多少条数据
private int maxpage = 5;//总共有多少页
private boolean loadfinish = true;
private final class ScrollListener implements OnScrollListener{
public void onScrollStateChanged(AbsListView view, int scrollState) {
Log.i("MainActivity", "onScrollStateChanged(scrollState="+ scrollState+ ")");
}
public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
Log.i("MainActivity", "onScroll(firstVisibleItem="+ firstVisibleItem+ ",visibleItemCount="+
visibleItemCount+ ",totalItemCount="+ totalItemCount+ ")");
final int loadtotal = totalItemCount;
int lastItemid = listView.getLastVisiblePosition();//获取当前屏幕最后Item的ID
if((lastItemid+1) == totalItemCount){//达到数据的最后一条记录
if(totalItemCount > 0){
//当前页
int currentpage = totalItemCount%number == 0 ? totalItemCount/number : totalItemCount/number+1;
int nextpage = currentpage + 1;//下一页
if(nextpage <= maxpage && loadfinish){
loadfinish = false;
listView.addFooterView(footer);
new Thread(new Runnable() {
public void run() {
try {
Thread.sleep(3000);
} catch (InterruptedException e) {
e.printStackTrace();
}
List<String> result = DataService.getData(loadtotal, number);
handler.sendMessage(handler.obtainMessage(100, result));
}
}).start();
}
}
}
}
}
Handler handler = new Handler(){
public void handleMessage(Message msg) {
data.addAll((List<String>) msg.obj);
adapter.notifyDataSetChanged();//告诉ListView数据已经发生改变,要求ListView更新界面显示
if(listView.getFooterViewsCount() > 0) listView.removeFooterView(footer);
loadfinish = true;
}
};
}
public class DataService {
public static List<String> getData(int offset, int maxResult){//分页 limit 0,20
List<String> data = new ArrayList<String>();
for(int i=0 ; i < 20 ; i++){
data.add("ListView数据的分批加载"+ i);
}
return data;
}
}
item界面
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<TextView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:textSize="18sp"
android:textColor="#FFFFFF"
android:id="@+id/textView"
/>
</LinearLayout>
加载的时候的进度条,无限期进度条
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal" >
<ProgressBar android:id="@+id/c81_forthBar"
android:layout_width="50dp"
android:layout_height="wrap_content"
style="?android:attr/progressBarStyle" />
<TextView android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center_vertical"
android:textSize="20sp"
android:text="数据正在加载..."
/>
</LinearLayout>
public class MainActivity extends Activity {
private ListView listView;
private List<String> data = new ArrayList<String>();
ArrayAdapter<String> adapter;
View footer;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
footer = getLayoutInflater().inflate(R.layout.footer, null);
listView = (ListView) this.findViewById(R.id.listView);
listView.setOnScrollListener(new ScrollListener());
data.addAll(DataService.getData(0, 20));
adapter = new ArrayAdapter<String>(this, R.layout.listview_item, R.id.textView, data);
listView.addFooterView(footer);//添加页脚(放在ListView最后)
listView.setAdapter(adapter);
listView.removeFooterView(footer);
}
private int number = 20;//每次获取多少条数据
private int maxpage = 5;//总共有多少页
private boolean loadfinish = true;
private final class ScrollListener implements OnScrollListener{
public void onScrollStateChanged(AbsListView view, int scrollState) {
Log.i("MainActivity", "onScrollStateChanged(scrollState="+ scrollState+ ")");
}
public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
Log.i("MainActivity", "onScroll(firstVisibleItem="+ firstVisibleItem+ ",visibleItemCount="+
visibleItemCount+ ",totalItemCount="+ totalItemCount+ ")");
final int loadtotal = totalItemCount;
int lastItemid = listView.getLastVisiblePosition();//获取当前屏幕最后Item的ID
if((lastItemid+1) == totalItemCount){//达到数据的最后一条记录
if(totalItemCount > 0){
//当前页
int currentpage = totalItemCount%number == 0 ? totalItemCount/number : totalItemCount/number+1;
int nextpage = currentpage + 1;//下一页
if(nextpage <= maxpage && loadfinish){
loadfinish = false;
listView.addFooterView(footer);
new Thread(new Runnable() {
public void run() {
try {
Thread.sleep(3000);
} catch (InterruptedException e) {
e.printStackTrace();
}
List<String> result = DataService.getData(loadtotal, number);
handler.sendMessage(handler.obtainMessage(100, result));
}
}).start();
}
}
}
}
}
Handler handler = new Handler(){
public void handleMessage(Message msg) {
data.addAll((List<String>) msg.obj);
adapter.notifyDataSetChanged();//告诉ListView数据已经发生改变,要求ListView更新界面显示
if(listView.getFooterViewsCount() > 0) listView.removeFooterView(footer);
loadfinish = true;
}
};
}
public class DataService {
public static List<String> getData(int offset, int maxResult){//分页 limit 0,20
List<String> data = new ArrayList<String>();
for(int i=0 ; i < 20 ; i++){
data.add("ListView数据的分批加载"+ i);
}
return data;
}
}
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