If zoom lock has been switched on , the map has been zoomed in or out , and you then click the button again to switch off zoom lock , the map will be redrawn to show the default data for the view level which is appropriate to its current field of view 如果你在缩放锁定功能开启时缩放了星图，再点击按钮取消锁定后，星图设置会按照最适合当前视场范围的视场等级重设。
For example , it might call this method while the user is sitting in her chair , not touching the keyboard ; however , it might also call the method while the user is typing , moving the mouse , scrolling , clicking a button . it doesn t matter what the user is doing 比方说，可能在用户坐在椅子上手没有碰键盘的时候调用该方法，但是也可能在用户输入、移动鼠标、滚动屏幕或者点击按钮时调用该方法。它并不关心用户在做什么。
