Java Android-在ListView中显示更多元素
我使用setOnScrollListener来显示其他元素Java Android-在ListView中显示更多元素,java,android,listview,onscroll,Java,Android,Listview,Onscroll,我使用setOnScrollListener来显示其他元素 lvMain.setOnScrollListener(new OnScrollListener() { @Override public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
lvMain.setOnScrollListener(new OnScrollListener()
{
@Override
public void onScroll(AbsListView view, int firstVisibleItem,
int visibleItemCount, int totalItemCount) {
// TODO Auto-generated method stub
if(firstVisibleItem + visibleItemCount >= totalItemCount) {
boxAdapter.count += visibleItemCount;
boxAdapter.notifyDataSetChanged();
}
else
{}
}
@Override
public void onScrollStateChanged(AbsListView view, int scrollState) {
// TODO Auto-generated method stub
}
});
默认情况下,列表仅获取10个元素
@Override
public int getCount() {
//return objects.size();
return 10;
}
当我滚动时,所有内容都已加载,但当我到达应用程序的末尾时,应用程序将关闭。原因是什么
日志:
03-28 18:27:22.243: E/AndroidRuntime(31068): FATAL EXCEPTION: main
03-28 18:27:22.243: E/AndroidRuntime(31068): Process: com.example.warapp, PID: 31068
03-28 18:27:22.243: E/AndroidRuntime(31068): java.lang.IndexOutOfBoundsException: Invalid index 100, size is 100
03-28 18:27:22.243: E/AndroidRuntime(31068): at java.util.ArrayList.throwIndexOutOfBoundsException(ArrayList.java:255)
03-28 18:27:22.243: E/AndroidRuntime(31068): at java.util.ArrayList.get(ArrayList.java:308)
03-28 18:27:22.243: E/AndroidRuntime(31068): at com.example.warapp.BoxAdapter.getItem(BoxAdapter.java:49)
03-28 18:27:22.243: E/AndroidRuntime(31068): at com.example.warapp.BoxAdapter.getView(BoxAdapter.java:67)
03-28 18:27:22.243: E/AndroidRuntime(31068): at android.widget.AbsListView.obtainView(AbsListView.java:2240)
03-28 18:27:22.243: E/AndroidRuntime(31068): at android.widget.ListView.makeAndAddView(ListView.java:1790)
03-28 18:27:22.243: E/AndroidRuntime(31068): at android.widget.ListView.fillDown(ListView.java:691)
03-28 18:27:22.243: E/AndroidRuntime(31068): at android.widget.ListView.fillGap(ListView.java:655)
03-28 18:27:22.243: E/AndroidRuntime(31068): at android.widget.AbsListView.trackMotionScroll(AbsListView.java:5136)
03-28 18:27:22.243: E/AndroidRuntime(31068): at android.widget.AbsListView$FlingRunnable.run(AbsListView.java:4247)
03-28 18:27:22.243: E/AndroidRuntime(31068): at android.view.Choreographer$CallbackRecord.run(Choreographer.java:761)
03-28 18:27:22.243: E/AndroidRuntime(31068): at android.view.Choreographer.doCallbacks(Choreographer.java:574)
03-28 18:27:22.243: E/AndroidRuntime(31068): at android.view.Choreographer.doFrame(Choreographer.java:543)
03-28 18:27:22.243: E/AndroidRuntime(31068): at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:747)
03-28 18:27:22.243: E/AndroidRuntime(31068): at android.os.Handler.handleCallback(Handler.java:733)
03-28 18:27:22.243: E/AndroidRuntime(31068): at android.os.Handler.dispatchMessage(Handler.java:95)
03-28 18:27:22.243: E/AndroidRuntime(31068): at android.os.Looper.loop(Looper.java:136)
03-28 18:27:22.243: E/AndroidRuntime(31068): at android.app.ActivityThread.main(ActivityThread.java:5017)
03-28 18:27:22.243: E/AndroidRuntime(31068): at java.lang.reflect.Method.invokeNative(Native Method)
03-28 18:27:22.243: E/AndroidRuntime(31068): at java.lang.reflect.Method.invoke(Method.java:515)
03-28 18:27:22.243: E/AndroidRuntime(31068): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
03-28 18:27:22.243: E/AndroidRuntime(31068): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
03-28 18:27:22.243: E/AndroidRuntime(31068): at dalvik.system.NativeStart.main(Native Method)
基本适配器:
public class BoxAdapter extends BaseAdapter {
Context ctx;
LayoutInflater lInflater;
ArrayList<ItemInfo> objects;
String name;
int count = 10;
BoxAdapter(Context context, ArrayList<ItemInfo> products) {
ctx = context;
objects = products;
lInflater = (LayoutInflater) ctx
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
// кол-во элементов
@Override
public int getCount() {
//return objects.size();
return count;
}
// элемент по позиции
@Override
public ItemInfo getItem(int position) {
return objects.get(position);
}
// id по позиции
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View view = convertView;
if (view == null) {
view = lInflater.inflate(R.layout.item, parent, false);
}
ItemInfo p = getItem(position);
if (p.username.contains("null"))
{
name = "Автор: Неизвестен";
}
else
{
name = "Автор: " + p.username;
}
((TextView) view.findViewById(R.id.name)).setText(name);
return view;
}
}
公共类BoxAdapter扩展了BaseAdapter{
上下文ctx;
拉平机;
阵列列表对象;
字符串名;
整数计数=10;
BoxAdapter(上下文、ArrayList产品){
ctx=上下文;
对象=产品;
lInflater=(LayoutInflater)ctx
.getSystemService(上下文布局\充气机\服务);
}
// кол-во элементов
@凌驾
public int getCount(){
//返回objects.size();
返回计数;
}
// элемент по позиции
@凌驾
public ItemInfo getItem(int位置){
返回对象。获取(位置);
}
//身份证
@凌驾
公共长getItemId(int位置){
返回位置;
}
@凌驾
公共视图getView(int位置、视图转换视图、视图组父视图){
视图=转换视图;
如果(视图==null){
视图=lInflater.充气(R.layout.item,父项,false);
}
ItemInfo p=getItem(位置);
如果(p.username.contains(“null”))
{
name=“Аццззцц”;
}
其他的
{
name=“Ацц”:+p.username;
}
((TextView)view.findviewbyd(R.id.name)).setText(name);
返回视图;
}
}
我改进了适配器,并添加了一个loadAdditionalItems()
方法。因此,当您到达列表视图的底部时,只需调用以下命令:
adapter.loadAdditionalItems();
下面是适配器:
public class BoxAdapter extends BaseAdapter {
private final Context context;
private final LayoutInflater inflater;
private final ArrayList<ItemInfo> itemInfos;
private final int loadCount = 10;
private int count = 10;
private String name;
BoxAdapter(Context context, ArrayList<ItemInfo> products) {
this.context = context;
this.itemInfos = products;
this.inflater = LayoutInflater.from(context);
}
@Override
public int getCount() {
return this.count;
}
@Override
public ItemInfo getItem(int position) {
return itemInfos.get(position);
}
@Override
public long getItemId(int position) {
return position;
}
public void loadAdditionalItems() {
this.count += this.loadCount;
if (this.count > this.itemInfos.size()) {
this.count = this.itemInfos.size();
}
notifyDataSetChanged();
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View view = convertView;
if (view == null) {
view = inflater.inflate(R.layout.item, parent, false);
}
// You should implement the ViewHolder pattern, google for it.
ItemInfo p = getItem(position);
if (p.username.contains("null")) {
name = "Автор: Неизвестен";
} else {
name = "Автор: " + p.username;
}
((TextView) view.findViewById(R.id.name)).setText(name);
return view;
}
}
公共类BoxAdapter扩展了BaseAdapter{
私人最终语境;
私人充气机;
私人最终ArrayList itemInfos;
私有最终整数装载计数=10;
私有整数计数=10;
私有字符串名称;
BoxAdapter(上下文、ArrayList产品){
this.context=上下文;
this.itemInfos=产品;
this.inflater=layoutiner.from(上下文);
}
@凌驾
public int getCount(){
返回这个.count;
}
@凌驾
public ItemInfo getItem(int位置){
返回itemInfos.get(位置);
}
@凌驾
公共长getItemId(int位置){
返回位置;
}
公共void loadAdditionalItems(){
this.count+=this.loadCount;
如果(this.count>this.itemInfos.size()){
this.count=this.itemInfos.size();
}
notifyDataSetChanged();
}
@凌驾
公共视图getView(int位置、视图转换视图、视图组父视图){
视图=转换视图;
如果(视图==null){
视图=充气机。充气(R.layout.item,父项,false);
}
//你应该实现ViewHolder模式,谷歌就可以了。
ItemInfo p=getItem(位置);
如果(p.username.contains(“null”)){
name=“Аццззцц”;
}否则{
name=“Ацц”:+p.username;
}
((TextView)view.findviewbyd(R.id.name)).setText(name);
返回视图;
}
}
有一个名为的库,你可以使用它来实现你想要做的事情
是关于如何在应用程序中使用它的教程 我有100个元素,我想显示10,当用户到达终点时,我想再获得10个元素,以此类推,直到100我怀疑你想做类似的事情。你已经试过我的建议了吗?它起作用了吗?如果没有,请发布更多代码。特别是从你的适配器。我用对了吗?