UIPickerView入门使用

//首先，在头文件里遵循两个协议
<UIPickerViewDataSource,UIPickerViewDelegate>

//数据源协议中两个必须的方法

//有多少部件
-(NSInteger)numberOfComponentsInPickerView:(UIPickerView*)pickerView{
   return 2;
}


//每个部件有多少行
-(NSInteger)pickerView:(UIPickerView*)pickerView numbersOfRowsInComponent:(NSInteger)component{
    if(component == 0 ){
        return [activities count]
    }
    if(component == 1 ){
        return [feelings count]
    }
}


//代理协议中只有一个必须的方法
-(NSString*)pickerView:(UIPickerView*)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component{
    switch (component){
        case 0:
            return [activities objectAtIndex:row];
        case 1:
            return [feelings objectAtIndex:row];
    }
    return nil;

}
//别忘了在interface  builder 去连接代理