优化SimpleAdapter适配器加载效率的方法
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2022-05-30 18:24:51
在主activity中:
listview=(listview)findviewbyid(r.id.listview);getdata();
//为list...
在主activity中:
listview=(listview)findviewbyid(r.id.listview);getdata(); //为list添加数据overridesimpleadapter=new overridesimpleadapter(getcontext(),list,r.layout.list_item_layout, new string[]{"num","word","translates"}, new int[]{r.id.tv_num,r.id.tv_word,r.id.tv_translates}); listview.setadapter(overridesimpleadapter); 重写simpleadapter:/** * created by kewenc on 2017/1/26. */ public class overridesimpleadapter extends simpleadapter { /** * constructor * * @param context the context where the view associated with this simpleadapter is running * @param data a list of maps. each entry in the list corresponds to one row in the list. the * maps contain the data for each row, and should include all the entries specified in * "from" * @param resource resource identifier of a view layout that defines the views for this list * item. the layout file should include at least those named views defined in "to" * @param from a list of column names that will be added to the map associated with each * item. * @param to the views that should display column in the "from" parameter. these should all be * textviews. the first n views in this list are given the values of the first n columns */ private layoutinflater minflater; private arraylist<map<string, object>> list; private int mresource; private int[] mto; private string[] mfrom; public overridesimpleadapter(context context, arraylist<map<string, object>> data, int resource, string[] from, int[] to) { super(context, data, resource, from, to); this.list=data; this.minflater = layoutinflater.from(context); this.mresource = resource; this.mfrom = from; this.mto = to; } @override public int getcount() { return list.size(); } @override public object getitem(int position) { return list.get(position); } @override public long getitemid(int position) { return position; } @override public view getview(int position, view convertview, viewgroup parent) { viewholder holder = null; // 判断是否缓存 if (convertview == null) { holder = new viewholder(); // 通过layoutinflater实例化布局 convertview = minflater.inflate(mresource, null); // holder.img = (imageview) convertview.findviewbyid(r.id.imageview); holder.num = (textview) convertview.findviewbyid(mto[0]); holder.word = (textview) convertview.findviewbyid(mto[1]); holder.translates = (textview) convertview.findviewbyid(mto[2]); convertview.settag(holder); } else { // 通过tag找到缓存的布局 holder = (viewholder) convertview.gettag(); } // 设置布局中控件要显示的视图 // holder.img.setbackgroundresource(r.drawable.ic_launcher); holder.num.settext(list.get(position).get(mfrom[0]).tostring());// mfrom[0]为“num”key holder.word.settext(list.get(position).get(mfrom[1]).tostring()); holder.translates.settext(list.get(position).get(mfrom[2]).tostring()); return convertview; } public final class viewholder { // public imageview img; public textview num; public textview word; public textview translates; } }
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