初始化

    UIPickerView *flagPicker = [[UIPickerView alloc] init];    
     // 設(shè)置代理和數(shù)據(jù)源    
    flagPicker.dataSource = self;    
    flagPicker.delegate = self;

代理方法

// 每列寬度
- (CGFloat)pickerView:(UIPickerView *)pickerView widthForComponent:(NSInteger)component {
}
 // 返回選中的行
- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component
{
}
// 顯示每行每列的數(shù)據(jù)
-(NSString*)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component
{
}

數(shù)據(jù)源方法

// 幾列數(shù)據(jù)
- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView{  
}
// 每列的行數(shù)
- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component{  
 }

需求：點(diǎn)擊按鈕彈出鍵盤(pán)UIPickerView

將textFiled的鍵盤(pán)設(shè)置為pickerView；
然后將textFiled變?yōu)榈谝豁憫?yīng)者，這是彈出的鍵盤(pán)就是自定義的UIPickerView鍵盤(pán)；

- (IBAction)onclick:(id)sender {
    
    self.textFiled.inputView = self.pickerView;
    [self.textFiled becomeFirstResponder];
}