android开发时为啥ViewHolder cannot be resolved to a type 急
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参考技术A 这明显是找不到这个类，或这个类的声明的范围不够大，你使用的地方引用不到 参考技术B 没有定义ViewHolder这个类！这明显是找不到这个类，或这个类的声明的范围不够大，你使用的地方引用不到
public View getView(final int position, View convertView, ViewGroup parent)
VideoItem videoitem = null;
View view = null;
if (convertView == null)
videoitem = new VideoItem();
view = inflater.inflate(R.layout.player_videolist_item, null);
videoitem.videoname = (TextView) view.findViewById(R.id.videoname);
videoitem.nameTextView = (TextView) view
.findViewById(R.id.titleName);
videoitem.title_layout = (LinearLayout) view
.findViewById(R.id.title_layout);
videoitem.content_layout = (LinearLayout) view
.findViewById(R.id.content_layout);
view.setTag(videoitem);
else
view = convertView;
Object tag = view.getTag();
if (tag instanceof VideoItem)
videoitem = (VideoItem) view.getTag();
Object obj = partandVideos.get(position);
if (obj instanceof String)
String partname = (String) obj;
videoitem.nameTextView.setText(partname);
videoitem.nameTextView.setTextColor(normalTextColor);
videoitem.content_layout.setVisibility(View.GONE);
videoitem.title_layout.setVisibility(View.VISIBLE);
else
Video video = (Video) obj;
videoitem.title_layout.setVisibility(View.GONE);
videoitem.content_layout.setVisibility(View.VISIBLE);
videoitem.videoname.setText(video.getVideoName());
String demotype = video.getDemotype();
if (position == currPostion)
videoitem.videoname.setTextColor(currTextColor);
else
videoitem.videoname.setTextColor(normalTextColor);
if (!PageExtra.isBuy() && Constants.VIDEO_CHARGE.equals(demotype))
videoitem.videoname.setTextColor(main_videolist_no);
return view;
参考技术C 没有定义ViewHolder这个类！本回答被提问者采纳
Android简单开发之 通用Adapter ViewHolder
我们寻常使用Adapter的方式
public class BusbaseSearchApadter extends SimpleBaseApadter {
private List<Busbase> busbases = new ArrayList<Busbase>();
public Context context;
public void setList(List<Busbase> busbases) {
this.busbases = busbases;
}
public BusbaseSearchApadter(Context context) {
super(context);
this.context = context;
}
@Override
public int getCount() {
return busbases.size();
}
@Override
public Object getItem(int position) {
return busbases.get(position);
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
Busbase busbase = busbases.get(position);
ViewHolder holder = null;
if(convertView == null){
holder = new ViewHolder();
convertView = LayoutInflater.from(context).inflate(R.layout.hx_item_search_bus, parent, false);
holder.hx_item_bus_search_image = (ImageView)convertView.findViewById(R.id.hx_item_bus_search_image);
holder.hx_item_bus_search_name = (TextView)convertView.findViewById(R.id.hx_item_bus_search_name);
holder.hx_item_bus_search_mobile = (TextView)convertView.findViewById(R.id.hx_item_bus_search_mobile);
convertView.setTag(holder);
}else{
holder = (ViewHolder)convertView .getTag();
}
bitmapUtils.display(holder.hx_item_bus_search_image, busbase.getShopLogo());
holder.hx_item_bus_search_name.setText(busbase.name);
holder.hx_item_bus_search_mobile.setText(busbase.mobile);
return convertView;
}
class ViewHolder{
ImageView hx_item_bus_search_image;
TextView hx_item_bus_search_name;
TextView hx_item_bus_search_mobile;
}能够看出当中 实用的代码仅仅有仅仅有getView 和ViewHolder 可是其它的代码又不得不写，太痛苦 了不得不反复的写无数adapter 和ViewHoder.
我们能够写一个通用的ViewHolder
public class ViewHolder {
private final SparseArray<View> mViews;
private int mPosition;
private View mConvertView;
protected BitmapUtils bitmapUtils;
private ViewHolder(Context context, ViewGroup parent, int layoutId,
int position)
{
bitmapUtils = new BitmapUtils(context);
bitmapUtils.configDefaultLoadingImage(R.drawable.hx_loodding);
bitmapUtils.configDefaultLoadFailedImage(R.drawable.hx_loodding);
bitmapUtils.configDefaultBitmapConfig(Bitmap.Config.RGB_565);
this.mPosition = position;
this.mViews = new SparseArray<View>();
mConvertView = LayoutInflater.from(context).inflate(layoutId, parent,
false);
// setTag
mConvertView.setTag(this);
}
/**
* 拿到一个ViewHolder对象
*
* @param context
* @param convertView
* @param parent
* @param layoutId
* @param position
* @return
*/
public static ViewHolder get(Context context, View convertView,
ViewGroup parent, int layoutId, int position)
{
if (convertView == null)
{
return new ViewHolder(context, parent, layoutId, position);
}
return (ViewHolder) convertView.getTag();
}
public View getConvertView()
{
return mConvertView;
}
/**
* 通过控件的Id获取对于的控件，假设没有则增加views
*
* @param viewId
* @return
*/
public <T extends View> T getView(int viewId)
{
View view = mViews.get(viewId);
if (view == null)
{
view = mConvertView.findViewById(viewId);
mViews.put(viewId, view);
}
return (T) view;
}
/**
* 为TextView设置字符串
*
* @param viewId
* @param text
* @return
*/
public ViewHolder setText(int viewId, String text)
{
TextView view = getView(viewId);
view.setText(text);
return this;
}
/**
* 为ImageView设置图片
*
* @param viewId
* @param drawableId
* @return
*/
public ViewHolder setImageResource(int viewId, int drawableId)
{
ImageView view = getView(viewId);
view.setImageResource(drawableId);
return this;
}
/**
* 为ImageView设置图片
*
* @param viewId
* @param drawableId
* @return
*/
public ViewHolder setImageBitmap(int viewId, Bitmap bm)
{
ImageView view = getView(viewId);
view.setImageBitmap(bm);
return this;
}
/**
* 为ImageView设置图片
*
* @param viewId
* @param drawableId
* @return
*/
public ViewHolder setImageByUrl(int viewId, String url)
{
bitmapUtils.display((ImageView) getView(viewId), url);
return this;
}
public int getPosition()
{
return mPosition;
}使用一个SparseArray将View存起来
如今Adapter这样写
public abstract class AbstuctBaseApadter<T> extends SimpleBaseApadter {
protected LayoutInflater mInflater;
protected Context mContext;
protected List<T> mDatas;
protected int mItemLayoutId;
public AbstuctBaseApadter(Context context) {
super(context);
}
public AbstuctBaseApadter(Context context, List<T> mDatas, int itemLayoutId)
{
this(context);
this.mContext = context;
this.mInflater = LayoutInflater.from(mContext);
this.mDatas = mDatas;
this.mItemLayoutId = itemLayoutId;
}
public void setList(List<T> mDatas){
this.mDatas = mDatas;
}
@Override
public int getCount()
{
return mDatas.size();
}
@Override
public T getItem(int position)
{
return mDatas.get(position);
}
@Override
public long getItemId(int position)
{
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent)
{
final ViewHolder viewHolder = getViewHolder(position, convertView,
parent);
convert(viewHolder, getItem(position));
return viewHolder.getConvertView();
}
public abstract void convert(ViewHolder helper, T item);
private ViewHolder getViewHolder(int position, View convertView,
ViewGroup parent)
{
return ViewHolder.get(mContext, convertView, parent, mItemLayoutId,
position);
}
如今我们仅仅须要重写 convert方法 看activity里面怎么使用
AbstuctBaseApadter abstuctBaseApadter = new AbstuctBaseApadter<Map<String,Object>>(activity,list_map,R.layout.hx_money_item) {
public void convert(ViewHolder helper, Map<String, Object> item) {
helper.setText(R.id.id_item_1, item.get("time").toString());
helper.setText(R.id.id_item_3, item.get("sourcename").toString());
}
};
哈哈 打工改成
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Android简单开发之 通用Adapter ViewHolder