android单例模式怎么实现

在Android中，可以通过以下几种方式实现单例模式：

1. 懒汉式

public class Singleton { private static Singleton instance; private Singleton() {} public static synchronized Singleton getInstance() { if (instance == null) { instance = new Singleton(); } return instance; } } 

2. 饿汉式

public class Singleton { private static final Singleton instance = new Singleton(); private Singleton() {} public static Singleton getInstance() { return instance; } } 

3. 双重检查锁定

public class Singleton { private volatile static Singleton instance; private Singleton() {} public static Singleton getInstance() { if (instance == null) { synchronized (Singleton.class) { if (instance == null) { instance = new Singleton(); } } } return instance; } } 

4. 静态内部类

public class Singleton { private static class SingletonHolder { private static final Singleton INSTANCE = new Singleton(); } private Singleton() {} public static Singleton getInstance() { return SingletonHolder.INSTANCE; } } 

以上是几种常见的Android中实现单例模式的方式，具体选择哪种方式取决于实际需求和性能要求。