placehold专题

借用runtime来实现UITextView的占位符placehold功能

1、 首先我们需要倒入runtime的头文件 #import <objc/runtime.h> unsigned int count = 0;Ivar *ivars = class_copyIvarList([UITextView class], &count);for (int i = 0; i < count; i ++) {Ivar ivar = ivars[i];const char *