IOS 开发之PickerView文字和随机数的使用

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#pragma mark - PickerView数据源方法 
 
// returns the number of 'columns' to display. 
- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView{ 
  return self.foods.count; 
} 
 
// returns the # of rows in each component.. 
- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component{ 
  NSArray *foodArray = self.foods[component]; // component是列 
  return foodArray.count; 
} 
 
#pragma mark - PickerView代理方法 
 
- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component{ 
  return self.foods[component][row]; 
} 

- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component{ 
  NSString *name = self.foods[component][row]; 
  switch (component) { 
    case 0: 
      self.fruitLabel.text = name; 
      break; 
    case 1: 
      self.mainLabel.text = name; 
      break; 
    case 2: 
      self.drinkLabel.text = name; 
      break; 
    default: 
      break; 
  } 
} 

for (int i = 0; i < self.foods.count; i++) { 
    [self pickerView:nil didSelectRow:0 inComponent:i]; 
  }