android-singleton

说明

在android项目中，我们经常会需要用到一些singleton模式，除了java中常用的单例模式的写法，这里提出一种非静态的单例模式，而且还带有android的生命周期，生命周期跟随application而变化

• 创建一个这样的单例类(是不是和java的单利模式很像)

    public class Singleton {
        private Singleton(Application application) {
            this.application = application;
        }
      
        public static Singleton getInstance(Context context) {
            Application app = (Application) context.getApplicationContext();
            if (null == app.getSingleton()) {
                app.setSingleton(new Singleton(app));
            }
            return app.getSingleton();
        }
      
        public void onTerminate() {
        }
      
        public void onLowMemory() {
        }
      
        public void onTrimMemory(int level) {
        }
      
        //other methods
      
    }
  

• 在application 中这样写

    public class MyApplication extends Application {
        private Singleton singleton;
      
        @Override
        public void onCreate() {
            super.onCreate();
            singleton=Singleton.getInstance(this);
        }
      
        public Singleton getSingleton() {
            return singleton;
        }
      
        public void setSingleton(Singleton singleton) {
            this.singleton = singleton;
        }
      
        @Override
        public void onTerminate() {
            super.onTerminate();
            singleton.onTerminate();
        }
      
        @Override
        public void onConfigurationChanged(Configuration newConfig) {
            super.onConfigurationChanged(newConfig);
        }
      
        @Override
        public void onLowMemory() {
            super.onLowMemory();
            singleton.onLowMemory();
        }
      
        @Override
        public void onTrimMemory(int level) {
            super.onTrimMemory(level);
            singleton.onTrimMemory(level);
        }
    }
  

• 配置mainfest

      <application
            android:name=".MyApplication"
  

• 使用，是不是很简单，但是是单例的，因为application只有一个

     Singleton.getInstance(this)