试试这个。
它有效，我已经测试过了。

try this. it works,I've tested.

#include <objc/runtime.h>
Class LSApplicationWorkspace_class = objc_getClass("LSApplicationWorkspace");
NSObject* workspace = [LSApplicationWorkspace_class performSelector:@selector(defaultWorkspace)];
NSLog(@"apps: %@", [workspace performSelector:@selector(allApplications)]);