UIPickerView 是一個選擇器控件, 它可以生成單列的選擇器,也可生成多列的選擇器,而且開發者完全可以自定義選擇項的外觀,因此用法非常靈活,下面來看看它的用法。

系統的UIPickerView很簡單，樣式也是很簡單單調，界面感覺很單調不怎麼好看，有時候就需要我們來自己自定義，做出自己想要的樣式。首先給出普通樣式的UIPickerView示例，貼上代碼：

#import "zidingyipikViewController.h"
 
@interface zidingyipikViewController ()<UIPickerViewDelegate,UIPickerViewDataSource>{
    //記錄滾輪是否滑動
    NSString *guildStr;
    NSString *selectStr;
    NSMutableArray *dataMutArray;
    UIButton *bgButton;
}
 
@end
 
@implementation zidingyipikViewController
 
- (void)viewDidLoad {
    [super viewDidLoad];
    dataMutArray = [NSMutableArray arrayWithArray:@[@"學生",@"工人",@"教師",@"保安",@"醫生",@"護士",@"服務員"]];
    UIButton *button = [[UIButton alloc] initWithFrame:CGRectMake(80, 140, 70, 30)];
    [button setTitle:@"彈出框" forState:UIControlStateNormal];
    [button setTitleColor:[UIColor whiteColor] forState:UIControlStateNormal];
    button.backgroundColor = [UIColor orangeColor];
    [button addTarget:self action:@selector(buttonAction) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:button];
}
#pragma mark - 彈框
- (void)buttonAction{
    guildStr = @"0";
    bgButton = [[UIButton alloc] initWithFrame:CGRectMake(0, 0, kScreenWidth, kScreenHeight)];
    bgButton.backgroundColor = RGBA(0, 0, 0, 0.3);
    [bgButton addTarget:self action:@selector(bgButtonAction:) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:bgButton];
    
    UIView *cycanView = [[UIView alloc] initWithFrame:CGRectMake(0, kScreenHeight - 180, kScreenWidth, 40)];
    cycanView.backgroundColor = [UIColor orangeColor];
    [bgButton addSubview:cycanView];
    
    UILabel *titleLabel = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, kScreenWidth, cycanView.height)];
    titleLabel.text = @"選擇身份";
    titleLabel.font = FONT(14);
    titleLabel.textColor = [UIColor whiteColor];
    titleLabel.textAlignment = NSTextAlignmentCenter;
    [cycanView addSubview:titleLabel];
    
    UIButton *cancelButton = [[UIButton alloc] initWithFrame:CGRectMake(0, 0, 48, cycanView.height)];
    [cancelButton setTitle:@"取消" forState:UIControlStateNormal];
    [cancelButton setTitleColor:[UIColor whiteColor] forState:UIControlStateNormal];
    cancelButton.titleLabel.font = FONT(14);
    [cancelButton addTarget:self action:@selector(bgButtonAction:) forControlEvents:UIControlEventTouchUpInside];
    [cycanView addSubview:cancelButton];
    
    UIButton *confirmButton = [[UIButton alloc] initWithFrame:CGRectMake(kScreenWidth - 48, 0, 48, cycanView.height)];
    [confirmButton setTitle:@"確定" forState:UIControlStateNormal];
    [confirmButton setTitleColor:[UIColor whiteColor] forState:UIControlStateNormal];
    confirmButton.titleLabel.font = FONT(14);
    [confirmButton addTarget:self action:@selector(confirmButtonAction:) forControlEvents:UIControlEventTouchUpInside];
    [cycanView addSubview:confirmButton];
    
    UIPickerView *selectPickerView = [[UIPickerView alloc] initWithFrame:CGRectMake(0, kScreenHeight - 140, kScreenWidth, 140)];
    // 顯示選中框
    selectPickerView.showsSelectionIndicator = NO;
    selectPickerView.backgroundColor = [UIColor whiteColor];
    selectPickerView.delegate = self;
    selectPickerView.dataSource = self;
    selectPickerView.autoresizingMask = UIViewAutoresizingFlexibleWidth;
    [bgButton addSubview:selectPickerView];
}
#pragma mark - 隱藏彈框
- (void)bgButtonAction:(UIButton *)sender{
    [bgButton removeFromSuperview];
}
#pragma mark - 彈框確定按鈕
- (void)confirmButtonAction:(UIButton *)sender{
    if ([guildStr isEqualToString:@"0"]) {
        selectStr = [NSString stringWithFormat:@"%@",dataMutArray[0]];
    }
    [self showHUDTextOnly:selectStr];
    [bgButton removeFromSuperview];
}
#pragma mark - UIPickerView代理方法
// pickerView 列數
- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView {
    return 1;
}
// pickerView 每列個數
- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component {
    return dataMutArray.count;
}
// 每列寬度
- (CGFloat)pickerView:(UIPickerView *)pickerView widthForComponent:(NSInteger)component {
    return kScreenWidth - 85 * 2;
}
// 返回選中的行
- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component
{
    guildStr = @"1";
    selectStr = [NSString stringWithFormat:@"%@",[dataMutArray objectAtIndex:row]];
    NSLog(@"selectStr:%@",selectStr);
}
//返回當前行的內容,此處是將數組中數值添加到滾動的那個顯示欄上
-(NSString*)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component
{
    return [dataMutArray objectAtIndex:row];
}

接下來，如果要改變樣式，自定義自己需要的UIPickerView樣式，只要重寫方法就行了。方法：

//重寫方法,改變字體大小
- (UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(UIView *)view{
    UILabel *pickerLabel = (UILabel *)view;
    if (!pickerLabel){
        pickerLabel = [[UILabel alloc] init];
        pickerLabel.font = FONT(17);
        pickerLabel.textColor = [UIColor blackColor];
        pickerLabel.textAlignment = 1;
        [pickerLabel setBackgroundColor:[UIColor clearColor]];
    }
    pickerLabel.text = [self pickerView:pickerView titleForRow:row forComponent:component];
    //在該代理方法裡添加以下兩行代碼刪掉上下的黑線
    [[pickerView.subviews objectAtIndex:1] setHidden:YES];
    [[pickerView.subviews objectAtIndex:2] setHidden:YES];
    
    UIView *lineView1 = [[UIView alloc] initWithFrame:CGRectMake(85, 55, kScreenWidth - 85 * 2, 1.8)];
    lineView1.backgroundColor = RGB(245, 245, 245);
    [pickerView addSubview:lineView1];
    
    UIView *lineView2 = [[UIView alloc] initWithFrame:CGRectMake(85, 82, kScreenWidth - 85 * 2, 1.8)];
    lineView2.backgroundColor = RGB(245, 245, 245);
    [pickerView addSubview:lineView2];
    
    return pickerLabel;
}
注：
// 當前屏幕寬度
#define kScreenWidth [UIScreen mainScreen].bounds.size.width
// 當前屏幕高度
#define kScreenHeight [UIScreen mainScreen].bounds.size.height