这是我的下面的代码，我的列表看起来像
position 1 | image1 image2 image3
----------------------------------------
position 2 | image1 image2 image3
我的意思是根据列表中的项目数量动态添加我的图像，例如，如果我的列表有21个项目，则mylist在每个位置填充3个图像，并创建总共7个位置。我的代码工作正常
public class ListViewAdapter extends BaseAdapter {
private static final String TAG = "Book-shelf";
private Activity activity;
private int totalBooks = 0;
private int bookItem = 0;
private int numberOfBookRows = 0;
private int extraBooks = 0;
int layoutId;
private int bookImage;
private ArrayList<HashMap<String, String>> dataList;
private static LayoutInflater inflater = null;
public ListViewAdapter(Activity a, int listRow,
ArrayList<HashMap<String, String>> fileList) {
super();
activity = a;
dataList = fileList;
layoutId = listRow;
inflater = (LayoutInflater) activity
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
@Override
public int getCount() {
// TODO Auto-generated method stub
return dataList.size();
}
修改后的版本适用于上述getCount方法
@Override
public Object getCount() {
// TODO Auto-generated method stub
return numberOfBookRows;
}
@Override
public Object getItem(int position) {
// TODO Auto-generated method stub
return dataList.get(position);
}
@Override
public long getItemId(int position) {
// TODO Auto-generated method stub
return position;
}
public void calculateRowsAndColms() {
totalBooks = 0;
bookItem = 0;
numberOfBookRows = 0;
extraBooks = 0;
totalBooks = dataList.size();
bookItem = 3;// TODO: make it dynamic
if (totalBooks < bookItem && totalBooks > 0) {
numberOfBookRows = 1;
} else {
numberOfBookRows = (totalBooks / bookItem);
extraBooks = (totalBooks % bookItem);
if (extraBooks != 0)
numberOfBookRows++;
}
Log.d(TAG, " Total books:" + totalBooks);
Log.d(TAG, " Number of books to be displayed:" + bookItem);
Log.d(TAG, " Number of rows occupying the books:" + numberOfBookRows);
Log.d(TAG, " Number of extra books(odd count):" + extraBooks);
}
这是我的arrayadapter视图代码
@Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder;
View v = convertView;
Log.d("View", "view" + v);
calculateRowsAndColms();
bookImage = R.drawable.book1;
Log.d("Datalist","size="+dataList.size());
if (convertView == null) {
holder = new ViewHolder();
v = inflater.inflate(layoutId, null, false);
ImageView image1 = (ImageView) v.findViewById(R.id.image1);
ImageView image2 = (ImageView) v.findViewById(R.id.image2);
ImageView image3 = (ImageView) v.findViewById(R.id.image3);
TextView t1 = (TextView) v.findViewById(R.id.textView1);
TextView t2 = (TextView) v.findViewById(R.id.textView2);
TextView t3 = (TextView) v.findViewById(R.id.textView3);
holder.imgList.add(image1);
holder.imgList.add(image2);
holder.imgList.add(image3);
holder.textList.add(t1);
holder.textList.add(t2);
holder.textList.add(t3);
v.setTag(holder);
} else {
holder = (ViewHolder) v.getTag();
}
int k;
if ((position == numberOfBookRows - 1) && extraBooks != 0) {
for (int i = 0; i < extraBooks; i++) {
Log.d("inside if", "position" + position);
Log.d("inside if", "numberofbookrows" + numberOfBookRows);
int k = (position * bookItem) + i;
holder.imgList.get(i).setBackgroundResource(bookImage);
holder.imgList.get(i).setOnClickListener(
new OnBookClickListner());
holder.imgList.get(i).setVisibility(View.VISIBLE);
holder.imgList.get(i).setId(k);
holder.textList.get(i).setText(dataList.get(k).get("pdf"));
Log.d("if k value","k="+k+"value="+dataList.get(k).get("pdf"));
}
} else if((position <= numberOfBookRows - 1) && totalBooks<bookItem)
{
for (int i = 0; i < totalBooks; i++) {
Log.d("inside else", "position" + position);
Log.d("inside else", "numberofbookrows" + numberOfBookRows);
int k = (position * bookItem) + i;
holder.imgList.get(i).setBackgroundResource(bookImage);
holder.imgList.get(i).setOnClickListener(
new OnBookClickListner());
holder.imgList.get(i).setVisibility(View.VISIBLE);
holder.imgList.get(i).setId(k);
holder.textList.get(i).setText(dataList.get(k).get("pdf"));
Log.d("2nd if k value","k="+k+"value="+dataList.get(k).get("pdf"));
}
}
else
{
for (int i = 0; i < bookItem; i++) {
int k = (position * bookItem) + i;
holder.imgList.get(i).setBackgroundResource(bookImage);
holder.imgList.get(i).setOnClickListener(
new OnBookClickListner());
holder.imgList.get(i).setVisibility(View.VISIBLE);
holder.imgList.get(i).setId(k);
holder.textList.get(i).setText(dataList.get(k).get("pdf"));
Log.d("3rd if k value","k="+k+"value="+dataList.get(k).get("pdf"));
}
}
return v;
}
static class ViewHolder {
ArrayList<ImageView> imgList = new ArrayList<ImageView>();
ArrayList<TextView> textList = new ArrayList<TextView>();
// ImageView image1, image2 ,image3;
}
public class OnBookClickListner implements OnClickListener {
@Override
public void onClick(View v) {
Log.d(TAG, " ITEM SELECTED IN LIST VIEW:" + v.getId());
/*
* Intent intent = new Intent(MainActivity.this,
* MainActivity.class); startActivity(intent);
*/
}
}
}
现在，当我运行此代码时，我得到了我预期的输出，但当我尝试滚动列表时，应用程序关闭，我得到了致命的异常
07-22 03:57:26.501: E/AndroidRuntime(1314): FATAL EXCEPTION: main
07-22 03:57:26.501: E/AndroidRuntime(1314): java.lang.IndexOutOfBoundsException: Invalid index 21, size is 20
07-22 03:57:26.501: E/AndroidRuntime(1314): at java.util.ArrayList.throwIndexOutOfBoundsException(ArrayList.java:255)
07-22 03:57:26.501: E/AndroidRuntime(1314): at java.util.ArrayList.get(ArrayList.java:308)
07-22 03:57:26.501: E/AndroidRuntime(1314): at com.example.samplebookshelfdesign.ListViewAdapter.getView(ListViewAdapter.java:151)
07-22 03:57:26.501: E/AndroidRuntime(1314): at android.widget.AbsListView.obtainView(AbsListView.java:2161)
07-22 03:57:26.501: E/AndroidRuntime(1314): at android.widget.ListView.makeAndAddView(ListView.java:1840)
07-22 03:57:26.501: E/AndroidRuntime(1314): at android.widget.ListView.fillDown(ListView.java:675)
07-22 03:57:26.501: E/AndroidRuntime(1314): at android.widget.ListView.fillGap(ListView.java:639)
07-22 03:57:26.501: E/AndroidRuntime(1314): at android.widget.AbsListView.trackMotionScroll(AbsListView.java:4970)
07-22 03:57:26.501: E/AndroidRuntime(1314): at android.widget.AbsListView.scrollIfNeeded(AbsListView.java:3126)
07-22 03:57:26.501: E/AndroidRuntime(1314): at android.widget.AbsListView.onTouchEvent(AbsListView.java:3400)
07-22 03:57:26.501: E/AndroidRuntime(1314): at android.view.View.dispatchTouchEvent(View.java:7384)
07-22 03:57:26.501: E/AndroidRuntime(1314): at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2203)
07-22 03:57:26.501: E/AndroidRuntime(1314): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1938)
07-22 03:57:26.501: E/AndroidRuntime(1314): at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2209)
07-22 03:57:26.501: E/AndroidRuntime(1314): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1952)
07-22 03:57:26.501: E/AndroidRuntime(1314): at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2209)
07-22 03:57:26.501: E/AndroidRuntime(1314): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1952)
07-22 03:57:26.501: E/AndroidRuntime(1314): at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2209)
07-22 03:57:26.501: E/AndroidRuntime(1314): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1952)
07-22 03:57:26.501: E/AndroidRuntime(1314): at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2209)
07-22 03:57:26.501: E/AndroidRuntime(1314): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1952)
07-22 03:57:26.501: E/AndroidRuntime(1314): at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:1966)
07-22 03:57:26.501: E/AndroidRuntime(1314): at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1418)
07-22 03:57:26.501: E/AndroidRuntime(1314): at android.app.Activity.dispatchTouchEvent(Activity.java:2424)
07-22 03:57:26.501: E/AndroidRuntime(1314): at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:1914)
07-22 03:57:26.501: E/AndroidRuntime(1314): at android.view.View.dispatchPointerEvent(View.java:7564)
07-22 03:57:26.501: E/AndroidRuntime(1314): at android.view.ViewRootImpl$ViewPostImeInputStage.processPointerEvent(ViewRootImpl.java:3883)
07-22 03:57:26.501: E/AndroidRuntime(1314): at android.view.ViewRootImpl$ViewPostImeInputStage.onProcess(ViewRootImpl.java:3778)
答案 0 :(得分：1)
问题在于你的if / else条件。您不处理position超过行数的情况。
if ((position == numberOfBookRows - 1) && extraBooks != 0) {
// ...
} else {
// This will also get executed if position > numberOfBooksRows -1
}
你可能应该增加一名警卫：
if ((position == numberOfBookRows - 1) && extraBooks != 0) {
// ...
} else if (position < numberOfBookRows - 1) {
// ...
}