public class ArrayListTest {

public static void main(String[] args) {

ArrayList<String> arrayList = new ArrayList<String>();

//ArrayList arrayList = new ArrayList();

//共有的方法

arrayList.add("1");

arrayList.add("2");

arrayList.add("4");

arrayList.add("5");

arrayList.add(2, "3");

System.out.println(arrayList);//1,2,3,4,5

int lenght = arrayList.size();//5

System.out.println(lenght);//5

String two = arrayList.get(2);//强制转换 3

System.out.println(two); //3

System.out.println(arrayList.contains("6"));//false

arrayList.remove("5");//1,2,3,4

System.out.println(arrayList.size());//4

arrayList.remove(0);//2,3,4

System.out.println(arrayList.contains("1"));//false

System.out.println(arrayList.indexOf("2"));//0

System.out.println(arrayList.lastIndexOf("4"));//2

arrayList.set(0, "0");//0,3,4

System.out.println(arrayList.contains("2"));//false

System.out.println(arrayList.indexOf("0"));//0

//存对象数据

ArrayList<News> arrayList2 = new ArrayList<News>();

News news0 = new News("1", "12");

News news1 = new News("2", "23");

News news2 = new News("3", "34");

News news3 = new News("4", "45");

arrayList2.add(news0);

arrayList2.add(news1);

arrayList2.add(news2);

arrayList2.add(news3);

}

}