在ios8之前用uiactionsheet和uialertview來提供按鈕選擇和提示性資訊，比如uiactionsheet可以這樣寫：
uiactionsheet *actionsheet = [[uiactionsheet alloc]
initwithtitle:@"title,nil時不顯示"
delegate:self
cancelbuttontitle:@"取消"
destructivebuttontitle:@"确定"
otherbuttontitles:@"第一項", @"第二項",nil];
actionsheet.actionsheetstyle = uiactionsheetstyleblackopaque;
[actionsheet showinview:self.view];
然後在協定中實作代理:
(void)actionsheet:(uiactionsheet *)actionsheet clickedbuttonatindex:(nsinteger)buttonindex
{
if (buttonindex == 0) {
nslog(@"确定");
}else if (buttonindex == 1) {
nslog(@"第一項");
}else if(buttonindex == 2) {
nslog(@"第二項");
}else if(buttonindex == actionsheet.canclebuttonindex) {
nslog(@"取消");
}
}
- (void)actionsheetcancel:(uiactionsheet *)actionsheet{
}
-(void)actionsheet:(uiactionsheet *)actionsheet diddismisswithbuttonindex:(nsinteger)buttonindex{
-(void)actionsheet:(uiactionsheet *)actionsheet willdismisswithbuttonindex:(nsinteger)buttonindex{
如果需要修改按鈕字型、顔色等可以實作以下代理：
- (void)willpresentactionsheet:(uiactionsheet *)actionsheet {
for (uiview *subviwe in actionsheet.subviews) {
if ([subviwe iskindofclass:[uilabel class]]) {
uilabel *label = (uilabel *)subviwe;
label.font = [uifont systemfontofsize:16];
label.frame = cgrectmake(cgrectgetminx(label.frame), cgrectgetminy(label.frame), cgrectgetwidth(label.frame), cgrectgetheight(label.frame)+20);
}
if ([subviwe iskindofclass:[uibutton class]]) {
uibutton *button = (uibutton*)subviwe;
if ([button.titlelabel.text isequaltostring:@"确定"]) {
[button settitlecolor:[uicolor redcolor] forstate:uicontrolstatenormal];
} else {
[button settitlecolor:[wtdevice getgreencolor] forstate:uicontrolstatenormal];
}
button.titlelabel.font = [uifont systemfontofsize:18];
}
}
以上代碼（代理部分），在ios7及以下版本中是有效的，但是在ios8中卻不起作用，因為ios8抛棄了uiactionsheet和uialertview，取而代之的是uialertcontroller，其使用方法如下(代替uialertview)：
#ifdef __iphone_8_0
if (target_is_ios8) {
uialertcontroller *actionsheetcontroller = [uialertcontroller alertcontrollerwithtitle:@"提示"
message:@"需要設定允許通路相機，操作方法見“設定”->“幫助中心”"
preferredstyle:uialertcontrollerstylealert];
uialertaction *actioncancel = [uialertaction actionwithtitle:@"确定"
style:uialertactionstyledestructive
handler:^(uialertaction * action) {}];
[actionsheetcontroller addaction:actioncancel];
[actionsheetcontroller.view settintcolor:[wtdevice getgreencolor]];
[self presentviewcontroller:actionsheetcontroller animated:yes completion:nil];
#endif
if (target_not_ios8) {
uialertview *alert = [[uialertview alloc] initwithtitle:@"提示" message:@"需要設定允許通路相機，操作方法見“設定”->“幫助中心”" delegate:self cancelbuttontitle:@"取消" otherbuttontitles:nil];
[alert show];
代替uiactionsheet：
if (target_is_ios8) {
uialertcontroller *actionsheetcontroller = [uialertcontroller alertcontrollerwithtitle:@"action選項"
message:nil
preferredstyle:uialertcontrollerstyleactionsheet];
uialertaction *action0 = [uialertaction actionwithtitle:@"選項一"
style:uialertactionstyledefault
handler:^(uialertaction * action) {
[self custommethod1];
}];
[actionsheetcontroller addaction:action0];
uialertaction *action = [uialertaction actionwithtitle:@"選項二"
[self <span style="font-family: arial, helvetica, sans-serif;">custommethod2</span>];
uialertaction *action1 = [uialertaction actionwithtitle:@"選項三"
style:uialertactionstyledefault
handler:^(uialertaction * action) {
[self custommethod3];
}];
uialertaction *actioncancel = [uialertaction actionwithtitle:@"取消"
style:uialertactionstylecancel
handler:^(uialertaction * action) {}];
[actionsheetcontroller addaction:action];
[actionsheetcontroller addaction:action1];
[actionsheetcontroller addaction:actioncancel];
[actionsheetcontroller.view settintcolor:[uicolor greencolor]];
[self presentviewcontroller:actionsheetcontroller animated:yes completion:nil];
if (target_not_ios8) {
uiactionsheet *as = [[uiactionsheet alloc] initwithtitle:@"action選項" delegate:self cancelbuttontitle:@"取消" destructivebuttontitle:nil otherbuttontitles:@"選項一",@"選項二",@"選項三", nil nil];
[as showinview:self.view];
至于兩者的差別，可以看到，ios8之前是在controller的view上邊又覆寫了一層view，ios8之後則是present了一個controller并且将代理換成了block，代碼顯得更加緊湊。