NSAlert用于弹出一个确认对话框，在程序中被广泛地使用。常见的场景是用户删除数据，会弹出对话框给用户确认，免得用户不小心导致了误操作。
NSAlert可以采用Modal Window的方式展示
//采用Modal Window的方式展示
- (IBAction)ShowNSAlertWindow:(id)sender
{
NSTextView *accessory = [[NSTextView alloc] initWithFrame:NSMakeRect(0,0,200,15)];
NSFont *font = [NSFont systemFontOfSize:[NSFont systemFontSize]];
NSDictionary *textAttributes = [NSDictionary dictionaryWithObject:font forKey:NSFontAttributeName];
[accessory insertText:[[NSAttributedString alloc] initWithString:@"Text in accessory view." attributes:textAttributes]];
[accessory setEditable:NO];
[accessory setDrawsBackground:NO];
NSAlert *alert = [[NSAlert alloc] init];
[alert setAlertStyle:NSWarningAlertStyle];
[alert setMessageText:@"message text"];
[alert setInformativeText:@"informative text"];
[alert setHelpAnchor:@"help anchor"];
//[alert setShowsSuppressionButton:YES];
[alert addButtonWithTitle:@"stop"];
[alert addButtonWithTitle:@"abort" ];
[alert addButtonWithTitle:@"Cancel"];
[alert setAccessoryView:accessory];
//__bridge_retained for arc
NSUInteger result = [alert runModal];
if (result == NSAlertFirstButtonReturn) {
NSLog(@"Stop");
}
else if (result == NSAlertSecondButtonReturn){
NSLog(@"abort");
}
else if (result == NSAlertThirdButtonReturn){
NSLog(@"cancel");
}
}
NSAlert也可以采用Sheet的方式展示
//采用Sheet的方式展示
- (IBAction)ShowNSAlertSheet:(id)sender
{
NSTextView *accessory = [[NSTextView alloc] initWithFrame:NSMakeRect(0,0,200,15)];
NSFont *font = [NSFont systemFontOfSize:[NSFont systemFontSize]];
NSDictionary *textAttributes = [NSDictionary dictionaryWithObject:font forKey:NSFontAttributeName];
[accessory insertText:[[NSAttributedString alloc] initWithString:@"Text in accessory view." attributes:textAttributes]];
[accessory setEditable:NO];
[accessory setDrawsBackground:NO];
NSAlert *alert = [[NSAlert alloc] init];
[alert setAlertStyle:NSWarningAlertStyle];
[alert setMessageText:@"message text"];
[alert setInformativeText:@"informative text"];
[alert setHelpAnchor:@"help anchor"];
//[alert setShowsSuppressionButton:YES];
[alert addButtonWithTitle:@"stop"];
[alert addButtonWithTitle:@"abort" ];
[alert addButtonWithTitle:@"Cancel"];
[alert setAccessoryView:accessory];
//__bridge_retained for arc
[alert beginSheetModalForWindow:[self window] completionHandler:^(NSInteger result){
if (result == NSAlertFirstButtonReturn) {
NSLog(@"Stop");
}
else if (result == NSAlertSecondButtonReturn){
NSLog(@"abort");
}
else if (result == NSAlertThirdButtonReturn){
NSLog(@"cancel");
}
}];
Instance Attributes:
-setAlertStyle:
@property NSAlertStyle alertStyle;
enum {
NSWarningAlertStyle = 0, //警告
NSInformationalAlertStyle = 1, //信息
NSCriticalAlertStyle = 2 //错误
};
typedef NSUInteger NSAlertStyle;
Message text -setMessageText:
@property(copy) NSString *messageText
Informative text -setInformativeText:
@property(copy) NSString *informativeText
Icon -setIcon:
@property(strong) NSImage *icon
Help -setHelpAnchor: -setShowsHelp:
@property(copy) NSString *helpAnchor
Response buttons -addButtonWithTitle:
//从右至左按钮的id是NSAlertFirstButtonReturn, NSAlertSecondButtonReturn, NSAlertThirdButtonReturn 再往后是NSAlertThirdButtonReturn +n
默认选中NSAlertFirstButtonReturn， 任何标为“Cancel”与快捷键ESC相连接
“Don’t Save”不是第一个按钮时，默认和快捷键Command-D连接
NSButton中- (void)setKeyEquivalent:(NSString *)charCode设置快捷键，-setTag：设置button的返回id
Suppression checkbox -setShowsSuppressionButton:
NSString *exampleAlertSuppress = @"ExampleAlertSuppress";
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
if ([defaults boolForKey:exampleAlertSuppress]) {
NSLog(@"ExampleAlert suppressed");
}
else {
NSAlert *alert = [[NSAlert alloc] init];
[alert setMessageText:@"Message text."];
[alert setInformativeText:@"Informative text."];
[alert setShowsSuppressionButton:YES];
[alert runModal];
if ([[alert suppressionButton] state] == NSOnState) {
//Suppress this alert from now on.
[defaults setBool:YES forKey:exampleAlertSuppress];
}
[alert release];
}
Accessory view -setAccesssoryView:
@property(strong) NSView *accessoryView
NSTextView *accessory = [[NSTextView alloc] initWithFrame:NSMakeRect(0,0,200,15)];
NSFont *font = [NSFont systemFontOfSize:[NSFont systemFontSize]];
NSDictionary *textAttributes = [NSDictionary dictionaryWithObject:font forKey:NSFontAttributeName];
[accessory insertText:[[NSAttributedString alloc] initWithString:@"Text in accessory view." attributes:textAttributes]];
[accessory setEditable:NO];
[accessory setDrawsBackground:NO];
NSAlert *alert = [[NSAlert alloc] init];
[alert setMessageText:@"Message text."];
[alert setInformativeText:@"Informative text."];
[alert setAccessoryView:accessory];
[alert runModal];
[alert release];