status bar的差别，

用了 window.frame.size.height,这个对于两个版本（ios7以及ios7以下的）来说是不同的，ios7里面是包括了statusbar的，而后者没有包括，             

message detail,

 self.inputView.frame = CGRectMake(self.inputView.frame.origin.x, SharedAppDelegate.window.frame.size.height  - self.faceInputView.frame.size.height - contentSize.height  - 5 , self.inputView.frame.size.width,contentSize.height + 5);

 

chatting message,

bottomView.frame = CGRectMake(bottomView.frame.origin.x, self.contentView.frame.size.height - keyboardHeight - contentSize.height - textViewBgAndCursor*2, bottomView.frame.size.width, contentSize.height + textViewBgAndCursor * 2);