关于在定制阵列适配器的getView方法中回收视图,我有一个不清楚的问题.
我明白元素被重用,但是如何在if语句的第一部分中确切地知道要实现的内容,第二个是什么呢？
现在我正在使用以下代码.我来到这个问题,因为在语句的第二部分中删除了代码,导致了前9个元素的列表,这些元素是重复次数而不是所有元素.我真的不知道究竟是什么导致的…
@Override
public View getView(int position,View convertView,ViewGroup parent) {
View row = convertView;
if (row == null) {
LayoutInflater inflater = ((Activity) context).getLayoutInflater();
row = inflater.inflate(layoutResourceId,parent,false);
title = getItem(position).getTitle();
size = calculateFileSize(position);
txtTitle = (TextView) row.findViewById(R.id.txtTitle);
tvFileSize = (TextView) row.findViewById(R.id.tvFileSize);
txtTitle.setText(title);
tvFileSize.setText(size);
} else {
title = getItem(position).getTitle();
size = calculateFileSize(position);
txtTitle = (TextView) row.findViewById(R.id.txtTitle);
tvFileSize = (TextView) row.findViewById(R.id.tvFileSize);
txtTitle.setText(title);
tvFileSize.setText(size);
}
return row;
}
解决方法
I understand that elements are reused,but how do I know exact what to implement in the first part of the if statement,and what in the second?
一旦你得到它的组织是非常简单的：
public View getView(int position,ViewGroup parent) {
if (convertView == null) {
/* This is where you initialize new rows,by:
* - Inflating the layout,* - Instantiating the ViewHolder,* - And defining any characteristics that are consistent for every row */
} else {
/* Fetch data already in the row layout,* primarily you only use this to get a copy of the ViewHolder */
}
/* Set the data that changes in each row,like `title` and `size`
* This is where you give rows there unique values. */
return convertView;
}
有关ListView的RecycleBin的工作原理以及ViewHolders为什么重要的Turbo Charge your UI的详细说明,Android的领先的ListView程序员的Google I / O演示.
