objective-c - 用户从 xcode 中的多组件选择器中选择某些值后,如何显示某个消息/警报?
问题描述
当用户从 double 中选择 2 个值时,我试图显示一条消息component picker
。
如果用户选择“高烧”和“强烈咳嗽”,请使用警报视图显示一条消息,指示:“您应该进行 PCR 测试”。
如果用户选择“高烧”和“中度咳嗽”或“中度发烧”和“严重咳嗽”,则显示一条消息,指示:“这只是普通流感”。
在所有其他可能选择的情况下,显示一条消息:“放松...没什么好担心的!”
下面是代码:
#import "FirstViewController.h"
#define kFeverComponent 0
#define kCoughComponent 1
@interface FirstViewController ()
@property (strong, nonatomic) NSArray *feverTypes;
@property (strong, nonatomic) NSArray *coughTypes;
@property (weak, nonatomic) IBOutlet UIPickerView *dependentPicker;
@end
@implementation FirstViewController
- (void)viewDidLoad {
[super viewDidLoad];
self.feverTypes = @[@"High Fever", @"Medium Fever", @"No Fever"];
self.coughTypes = @[@"Strong Cough", @"Medium Cough", @"No Cough"];
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
}
- (IBAction)symptomsButtonPressed:(id)sender {
NSInteger feverRow = [self.dependentPicker selectedRowInComponent: kFeverComponent];
NSInteger coughRow = [self.dependentPicker selectedRowInComponent: kCoughComponent];
NSString *fever = self.feverTypes[feverRow];
NSString *cough = self.coughTypes[coughRow];
NSString *message = [[NSString alloc] initWithFormat:
@"You chose %@ and %@.", fever, cough];
UIAlertController *alert =
[UIAlertController
alertControllerWithTitle:@"Thank you for choosing" message:message
preferredStyle:UIAlertControllerStyleAlert];
UIAlertAction *action = [UIAlertAction actionWithTitle:@"Okay"
style:UIAlertActionStyleDefault handler:nil];
[alert addAction:action];
[self presentViewController:alert animated:YES completion:nil];
}
#pragma mark -
#pragma mark Picker Data Source Methods
- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView {
return 2;
}
- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:
(NSInteger)component {
if (component == kCoughComponent) {
return [self.coughTypes count];
} else {
return [self.coughTypes count];
}
}
#pragma mark Picker Delegate Methods
- (NSString *)pickerView:(UIPickerView *)pickerView
titleForRow:(NSInteger)row
forComponent:(NSInteger)component {
if (component == kCoughComponent) {
return self.coughTypes[row];
} else {
return self.feverTypes[row];
}
}
@end
解决方案
您需要实现pickerview:didSelectRow:inComponent
委托方法。UIPickerViewDelegate
因此,通过将其添加到接口定义中来使您的类遵守协议,例如
@interface FirstViewController () < UIPickerViewDelegate >
然后实施例如
- ( void ) pickerView:( UIPickerView * ) pickerView
didSelectRow:( NSInteger ) row
inComponent:( NSInteger ) component
{
// logic here e.g.
NSInteger fever = [pickerView selectedRowInComponent:kCoughComponent];
NSInteger cough = [pickerView selectedRowInComponent:kFeverComponent];
NSString * msg;
if ( fever >= threshold && cough >= threshold )
{
msg = @"Seek help";
}
else
{
msg = @"All fine";
}
// Show alert with msg
}
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