// 首先初始化activityItems参数
NSArray *activityItems = [[NSArray alloc]initWithObjects:
desc,url,img,nil];
// 初始化一个UIActivityViewController
UIActivityViewController *activityVC = [[[UIActivityViewController alloc]initWithActivityItems:activityItems applicationActivities:Nil] autorelease];
// 写一个bolck,用于completionHandler的初始化
UIActivityViewControllerCompletionHandler myBlock = ^(NSString *activityType,BOOL completed) {
if(completed) {
[target performSelector:sel withObject:nil];
} else
{
NSLog(@"cancled\\");
}
[activityVC dismissViewControllerAnimated:YES completion:Nil];
};
// 初始化completionHandler,当post结束之后(无论是done还是cancell)该blog都会被调用
activityVC.completionHandler = myBlock;
// 以模态方式展现出UIActivityViewController
[self presentViewController:activityVC animated:YES completion:Nil];