Use of selectors

Today, let's write about the use of selectors ：
Selectors are very common to us , At the address , We all use selectors in the choice of time , Previously, I saw that many selectors return to the initial state after selection , However, some requirements require that the selected state be preserved , So I wrote one myself
First create a class QZPickerView, Inherited from UIView, Our selector is implemented here , Call where you want to show show The method is ok .
stay .h In file :

    // Because it is between the controller and view So at least two value transfer methods should be written here 
    //1. Pass the value in the controller to the selector   When the selector appears, it is on the value to be selected 
- (void)showPickerViewFirstStr:(NSString *)firstStr;
    //2. Pass the selected value in the selector to the controller  ( There are several ways to do this   You can use a proxy 、block And notice are ok   Personal habits   The agent I use here )
    @class QZPickerView;
@protocol QZPickerViewDelegate <NSObject>

- (void)pickerView:(QZPickerView *)pickerView firstStr:(NSString *)firstStr;

@interface QZPickerView : UIView
@property (nonatomic, weak) id<QZPickerViewDelegate> delegate;
@end

.m in ：

#import "QZPickerView.h"

#define kViewW self.frame.size.width
#define kViewH self.frame.size.height
@interface QZPickerView ()<UIPickerViewDelegate,UIPickerViewDataSource>

@property (nonatomic, strong) UILabel *titleLabel;
@property (nonatomic, strong) UIPickerView *pickerView;

@property (nonatomic, strong) NSArray *firstArr;
@property (nonatomic, strong) NSArray *secArr;
@property (nonatomic, strong) NSArray *thirArr;
@property (nonatomic, assign) NSInteger firstCurrentIndex;
@property (nonatomic, assign) NSInteger secondCurrentindex;
@property (nonatomic, assign) NSInteger thirdCurrentindex;

@end

@implementation QZPickerView

- (instancetype)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        [self setupSubViews];
    }
    return self;
}

- (void)setupSubViews
{   
    UILabel *titleLabel = [[UILabel alloc] initWithFrame:CGRectMake(0, kViewH *0.5 - 20, kViewW, 40)];
    titleLabel.textAlignment = NSTextAlignmentCenter;
    titleLabel.text = @" Set the time ";
    [self addSubview:titleLabel];

    [self addSubview:self.pickerView];

    UIButton *button = [[UIButton alloc] init];
    button.frame = CGRectMake(0, kViewH - 60, kViewW *0.5-0.5, 60);
    [self addSubview:button];
    button.backgroundColor = [UIColor blackColor];
    [button setTitle:@" Cancel " forState:UIControlStateNormal];
    [button addTarget:self action:@selector(hide) forControlEvents:UIControlEventTouchUpInside];

    UIButton *button2 = [[UIButton alloc] init];
    button2.frame = CGRectMake(kViewW *0.5+0.5, kViewH - 60, kViewW *0.5, 60);
    [self addSubview:button2];
    button2.backgroundColor = [UIColor grayColor];
    [button2 setTitle:@" determine " forState:UIControlStateNormal];
    [button2 addTarget:self action:@selector(completionBtnClick) forControlEvents:UIControlEventTouchUpInside];

}

- (void)show
{
    self.hidden = NO;
}

- (void)hide
{
    self.hidden = YES;
}
- (void)completionBtnClick
{
    NSString *firStr = @"";

    if (!self.firstCurrentIndex) {
        self.firstCurrentIndex = 0;
    }
    firStr = self.firstArr[self.firstCurrentIndex];
    [self hide];
    if ([self.delegate respondsToSelector:@selector(pickerView:firstStr:)]) {
        [self.delegate pickerView:self firstStr:firStr];
    }
}

- (void)showPickerViewFirstStr:(NSString *)firstStr
{
    self.firstArr = kDataManager.dataArray;
    if (firstStr.length >0) {
        for (NSInteger i = 0; i < self.firstArr.count; i++) {
            if ([self.firstArr[i] isEqualToString:firstStr]) {
                self.firstCurrentIndex = i;

            }
        }
    }
    [self.pickerView selectRow:self.firstCurrentIndex inComponent:0 animated:NO];
    [self show];
}

#pragma mark - UIPickerViewDataSource,UIPickerViewDelegate
- (void)selectRow:(NSInteger)row inComponent:(NSInteger)component animated:(BOOL)animated {
    return;
}

- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)thePickerView {
    return 1;
}
- (NSInteger)pickerView:(UIPickerView *)thePickerView numberOfRowsInComponent:(NSInteger)component {
        return self.firstArr.count;
}

- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component
{
        NSString *str = self.firstArr[row];
        return str;
}

- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component
{
        self.firstCurrentIndex = row;
    // This is used to refresh data when there is multi-level linkage 
// [self.pickerView reloadAllComponents];
}
- (UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(UIView *)view{
    UILabel* pickerLabel = (UILabel*)view;
    if (!pickerLabel){
        pickerLabel = [[UILabel alloc] init];
        pickerLabel.adjustsFontSizeToFitWidth = YES;
        [pickerLabel setTextAlignment:NSTextAlignmentCenter];
        [pickerLabel setBackgroundColor:[UIColor clearColor]];
        [pickerLabel setFont:[UIFont systemFontOfSize:16]];
    }
    // Fill the label text here
    pickerLabel.text = [self pickerView:pickerView titleForRow:row forComponent:component];
    return pickerLabel;
}

- (UIPickerView *)pickerView
{
    if (!_pickerView) {
        _pickerView = [[UIPickerView alloc] initWithFrame:CGRectMake(0, kViewH *0.5 + 30, kViewW, kViewH *0.3)];
        _pickerView.delegate = self;
        _pickerView.dataSource = self;
        [_pickerView selectRow:0 inComponent:0 animated:NO];
    }
    return _pickerView;
}

The rest is implemented in the controller ： introduce

#import "QZPickerView.h"

Statement

@property (nonatomic, strong) QZPickerView *pickerView;

Lazy loading

- (QZPickerView *)pickerView
{
    if (!_pickerView) {
        _pickerView = [[QZPickerView alloc] initWithFrame:self.view.bounds];
        [self.view addSubview:_pickerView];
        // Compliance agency   
        _pickerView.delegate = self;
    }
    return _pickerView;
}

Implementing agent methods

- (void)pickerView:(QZPickerView *)pickerView firstStr:(NSString *)firstStr { NSLog(@"%s",__func__); }

Loading method ：

- (void)show:(UIView *)sender
{
    NSString *firstStr = @"22";
    [self.pickerView showPickerViewFirstStr:firstStr];
}

complete ！！！