1.打印viewcontroller

po [[UIApplication sharedApplication].keyWindow.rootViewController _printHierarchy]

打印结果

2.打印UIView对象

po [[UIApplication sharedApplication].keyWindow recursiveDescription]

po [self.view recursiveDescription]

打印结果

3.简化的recursiveDescription

po [[UIApplication sharedApplication].keyWindow _autolayoutTrace]

4.打印某个对象所有instance的名字和值

po [self.view _ivarDescription]

5.打印对象的类方法、实例方法、属性

po [self.view _methodDescription]