如何將UIPickerView對象的選擇導出到CSV文件？

Question

我正在編寫一個小型iOS應用程序，希望對我的現場工作有所幫助。 我在OS X El Capitan 10.11.4上，使用Xcode 7.3並為iOS 9.3編寫應用程序。

這是整個想法：我不想將數據插入紙中，而是將所有內容都寫到了要在iPad上使用的基本表單形式的應用程序中，然后讓該應用程序將數據傳輸到.csv文件中。

我已經弄清了幾乎所有東西（應用程序的結構，傳輸和檢索數據的協議等），但是有一件事情使我發瘋。 在向您展示我正在使用的代碼之前，這是問題所在。 當我單擊“保存”按鈕，然后再去檢查已保存的數據時，我無法獲得UIPickerView對象選擇的值以將其傳輸到.csv文件。 其他一切正常。 我有兩個UIPickerView對象。 我有一個性別信息，編碼為M，F和M / F。 另一個具有關於年齡的信息，編碼為Adu，Juv，Hat。 我想要的是該應用程序保存所選的值，但我不太清楚。

任何幫助深表感謝。 謝謝。

這是我用於ViewController.h的代碼

#import <UIKit/UIKit.h>

@interface ViewController : UIViewController<UIPickerViewDataSource, UIPickerViewDelegate>
@property (strong, nonatomic) IBOutlet UIDatePicker *day;
@property (strong, nonatomic) IBOutlet UITextField *species;
@property (strong, nonatomic) IBOutlet UITextField *island;
@property (strong, nonatomic) IBOutlet UITextField *cay;
@property (strong, nonatomic) IBOutlet UITextField *pit;
@property (strong, nonatomic) IBOutlet UITextField *coordinatesN;
@property (strong, nonatomic) IBOutlet UITextField *coordinatesW;
@property (strong, nonatomic) IBOutlet UIPickerView *sex;
@property (strong, nonatomic) IBOutlet UIPickerView *age;

- (IBAction)saveInfo:(id)sender;
- (IBAction)retrieveInfo:(id)sender;
- (IBAction)retractKeyboard:(id)sender;

@property (strong, nonatomic) IBOutlet UITextView *resultView;

@end

這是我用於ViewConntroller.m的代碼

#import "ViewController.h"

@interface ViewController ()
{
    NSArray *pickerDataSex;
    NSArray *pickerDataAge;
}
@end

@implementation ViewController

@synthesize resultView;
@synthesize day;
@synthesize species;
@synthesize island;
@synthesize cay;
@synthesize pit;
@synthesize coordinatesW;
@synthesize coordinatesN;
@synthesize sex;
@synthesize age;

- (IBAction)retractKeyboard:(id)sender {
    [self resignFirstResponder];
}

- (IBAction)saveInfo:(id)sender {
    NSString *resultLine=[NSString stringWithFormat:@"%@,%@,%@,%@,%@,%@,%@,%@,%@\n",
                          self.day.date,
                          self.species.text,
                          self.island.text,
                          self.cay.text,
                          self.pit.text,
                          self.coordinatesN.text,
                          self.coordinatesW.text,
                          self.sex.dataSource,
                          self.age.dataSource];
    NSString *docPath =[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES )objectAtIndex:0];

    //resultView.text = docPath;}

    NSString *surveys=[docPath stringByAppendingPathComponent:@"results.csv"];

    if (![[NSFileManager defaultManager] fileExistsAtPath:surveys]) {
       [[NSFileManager defaultManager] createFileAtPath:surveys contents:nil attributes:nil];
    }
    NSFileHandle *fileHandle = [NSFileHandle fileHandleForUpdatingAtPath:surveys];
    [fileHandle seekToEndOfFile];
    [fileHandle writeData:[resultLine dataUsingEncoding:NSUTF8StringEncoding]];
    [fileHandle closeFile];
    self.species.text=@"";
    self.island.text=@"";
    self.cay.text=@"";
    self.pit.text=@"";
    self.coordinatesN.text=@"";
    self.coordinatesW.text=@"";
    NSLog(@"info saved");
}

- (IBAction)retrieveInfo:(id)sender {
    NSString *docPath =[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES )objectAtIndex:0];
    //resultView.text = docPath;
    NSString *surveys=[docPath stringByAppendingPathComponent:@"results.csv"];

    if ([[NSFileManager defaultManager] fileExistsAtPath: surveys]) {
        NSFileHandle *fileHandle = [NSFileHandle fileHandleForReadingAtPath:surveys];
        NSString *surveyResults = [[NSString alloc]initWithData:[fileHandle availableData] encoding:NSUTF8StringEncoding];
        [fileHandle closeFile];
        self.resultView.text = surveyResults;
    }


}



- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.

    //Initialize picker data
    pickerDataSex = @[@"M",@"F",@"M/F"];
    pickerDataAge = @[@"Adu",@"Juv",@"Hat"];

    //Connect data to picker
    self.sex.dataSource = self;
    self.sex.delegate = self;

    self.age.dataSource = self;
    self.age.delegate = self;

}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

//Number of columns of the data
- (NSInteger)numberOfComponentsInPickerView: (UIPickerView *)pickerView
{
    if (pickerView==self.sex){
        return 1;
    } else if (pickerView==self.age){
       return 1;
    }

    return 0;
}

//Number of rows of data
- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component
{
    if (pickerView==self.sex){
        return pickerDataSex.count;
    } else if (pickerView==self.age){
        return pickerDataAge.count;
    }
    return 0;
}

//The data to return for the row and component (column) that's being passed
-(NSString*)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component
{
    if (pickerView==self.sex){
        return pickerDataSex[row];
    } else if (pickerView==self.age){
        return pickerDataAge[row];
    }
    return 0;
}

@end

Answer 1

您可以通過以下方式從UIPickerViews中獲取值：

NSInteger selectedRowSex = [self.sex selectedRowInComponent:0];
NSInteger selectedRowAge = [self.age selectedRowInComponent:0];

NSString *selectedSex = [pickerDataSex objectAtIndex:selectedRowSex];
NSString *selectedAge = [pickerDataAge objectAtIndex:selectedRowAge];

然后

NSString *resultLine = [NSString stringWithFormat:@"%@,%@,%@,%@,%@,%@,%@,%@,%@\n",
                      self.day.date,
                      self.species.text,
                      self.island.text,
                      self.cay.text,
                      self.pit.text,
                      self.coordinatesN.text,
                      self.coordinatesW.text,
                      selectedSex,
                      selectedAge];

Answer 2

您具有填充選擇器視圖的代碼，但未顯示任何從選擇器視圖獲取選定值的代碼。

處理該問題的最簡單方法是在您的saveInfo方法中添加代碼，該方法在您的選擇器視圖上調用selectedRowInComponent來獲取當前值。

或者，您可以實現pickerView:didSelectRow:inComponent委托方法，並在每次更改時讀取新選擇的選擇器值。