java 从 ArrayList<HashMap<String, String>> 取值
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Take values from ArrayList<HashMap<String, String>>
提问by kareth
I have a problem about getting a value from my ArrayList<HashMap<String, String>>.
我在从我的ArrayList<HashMap<String, String>>.
My code is:
我的代码是：
ArrayList<HashMap<String, String>> myArrayList;
and then:
接着：
HashMap<String, String> map = new HashMap<String, String>();
map.put(TAG_ID, id);
map.put(TAG_NAME, name);
myArrayList.add(map);
If I want to get the name, for example, I tried as follow but I obtain a runtime error (the application crashes):
例如，如果我想获取名称，我尝试了以下操作，但出现运行时错误（应用程序崩溃）：
System.out.println(myArrayList.get(1).get(TAG_NAME));
How can I solve it?
我该如何解决？
Thank you very much!
非常感谢你！
回答by zw324
System.out.println(myArrayList.get(1).get(TAG_NAME));
System.out.println(myArrayList.get(1).get(TAG_NAME));
ArrayListis 0-based. get(0)instead.
ArrayList是基于 0 的。get(0)反而。
回答by NullPointerException
You can loop through the list like this
您可以像这样遍历列表
for(Map<String, String> map : myArrayList)
{
String tagName = map.get(TAG_NAME);
System.out.println(tagNAme);
}
