在android中,我们经常要用到HashMap,经常用list存放HashMap,我们对List中的元素进行排序的时候,就要用到构造器了,下面具体用列子说说:
假如在main方法中有:
public List<HashMap<String, Object>> listitem;
listitem.add(new HashMap("name","one"));
listitem.add(new HashMap("name","张三"));
listitem.add(new HashMap("name","李四"));
listitem.add(new HashMap("name","王五"));
listitem.add(new HashMap("name","two"));
Comparent comparent = new Comparent();
Collections.sort(listitem, comparent);
其中在Comparent.java文件中定义方法如下:
import java.text.Collator;
import java.util.Comparator;
import java.util.HashMap;
import java.util.Locale;
public class Comparent implements Comparator<Object> {
@SuppressWarnings("unchecked")
@Override
public int compare(Object arg0, Object arg1) {
HashMap<String, Object> name1 = (HashMap<String, Object>)arg0;
HashMap<String, Object> name2 = (HashMap<String, Object>)arg1;
Collator ca = Collator.getInstance(Locale.CHINA);
int flags = 0;
if (ca.compare((String) name1.get("name"), (String)name2.get("name")) < 0) {
flags = -1;
}
else if(ca.compare((String) name1.get("name"), (String)name2.get("name")) > 0) {
flags = 1;
}
else {
flags = 0;
}
return flags;
}
}