http://my.oschina.net/joanfen/blog/160156
http://my.oschina.net/joanfen/blog/160156
http://code4app.com/ios/iOS7-Sampler/5254b2186803faba0d000003
http://my.oschina.net/joanfen/blog/160156
http://code4app.com/ios/iOS7-Sampler/5254b2186803faba0d000003