| 知乎专栏 |
private List<Fragment> fragmentList = new ArrayList<>() {{
add(new ShareFullscreenFragment());
add(new StoryFullscreenFragment());
add(new MessageFullscreenFragment());
add(new MeFullscreenFragment());
}};
// 将Map Key 转化为List
List<String> mapKeyList = new ArrayList<String>(map.keySet());
System.out.println("mapKeyList:"+mapKeyList);
// 将Map Key 转化为List
List<String> mapValuesList = new ArrayList<String>(map.values());
System.out.println("mapValuesList:"+mapValuesList);
Set<Type> set = new Set<>(); Set<Type> set = new HashSet<>();
Set.toArray(IntFunction)
@Test
public void testCollectionToArray(){
Set<String> names = Set.of("Fred", "Wilma", "Barney", "Betty");
String[] copy = new String[names.size()];
names.toArray(copy);
System.out.println(Arrays.toString(copy));
System.out.println(Arrays.toString(names.toArray(String[]::new)));
}