Android的列表视图viewholder。什么时候使用它，什么时候不 [英] android listview viewholder. when to use it, and when not to

问题描述

我有一个自定义列表适配器一个ListView。在getView（）方法，现在用的是ViewHolder'模式'如图所示的API演示的ListView14.java。当我第一次呈现清单似乎正确加载。但是，我快到的问题是，当我滚动列表，我看到的数据列表显示在错误的行（即一个TextView应该是在第10行是显示在第2行，例如）。然而，当我不使用viewholder，而是调用findViewById（）每一次，则列表视图呈现正常。

解决方案

  

不过，我快到的问题是   当我滚动列表，我是   看到数据的列表中显示出来   错了行（即一个TextView   这应该是在第10行中显示出来   在例如第2行）。

最有可能的，你是不正确的回收行，使得 ViewHolders 你操纵是不正确的药粥行要返回。

下面是从我的书一个进入更多的行回收一个免费的摘录 - 也许这将有助于您确定事情会出错。

I have a ListView with a custom list adapter. In the getView() method, am using the ViewHolder 'pattern' as shown in the API Demos for ListView14.java. When i first render the list it seems to load correctly. However, the issue i'm running into is that when i scroll the list, i'm seeing the data for the list show up in the wrong rows (i.e. a TextView that should be in row 10 is showing up in row 2 for example). However, when I do not use the viewholder, and instead call findViewById() every time, then the list view renders correctly.

解决方案

However, the issue i'm running into is that when i scroll the list, i'm seeing the data for the list show up in the wrong rows (i.e. a TextView that should be in row 10 is showing up in row 2 for example).

Most likely, you are improperly recycling your rows, such that the ViewHolders you are manipulating are not the right ones for the row you are returning.

Here is a free excerpt from one of my books that goes into more about row recycling -- perhaps it will help you identify where things are going wrong.

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