android Context

讲解Context的一篇不错的文章http://www.cppblog.com/life02/archive/2012/03/19/168328.aspx

 

调用service时需要一个Context实例！

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public void startWifi(Context context) {         WifiManager wifiManager = (WifiManager)context.getSystemService(Context.WIFI_SERVICE);         wifiManager.setWifiEnabled(true);     }

如果方法所在的类继承Activity，则上面代码可换为

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public void startWifi(Context context) {         WifiManager wifiManager = (WifiManager)WifiActivity.this.getSystemService(Context.WIFI_SERVICE);         wifiManager.setWifiEnabled(true);     }