Pickerview的值不是在UITextField中更新

Question

我在storyboard中使用viewWithTags创建了tableview，在那里我显示了一个数据列表。

为了选择一定数量的药物，我使用UIPickerView，为了分配所选的值，我使用UITextField。

问题是，第一次从UIPickerView中选择一个值时，该值在UITextField中正确显示，但是在我第一次更新它之后，传递给UITextField的值为nil。

- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView{

    return 1;
}


- (nullable NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component {

    return [NSString stringWithFormat:@"%li",row+1];
}


- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component {

    NSLog(@"didSelectRow------%li",row);
    selectedQuantity = [NSString stringWithFormat:@"%@",[NSString stringWithFormat:@"%li",row+1]];
    NSLog(@"selectedQuantity------%@",selectedQuantity);

}


- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component{

    return [self.quantityOfPicker integerValue];
}


#pragma mark:- UITableView Delegate & Datasource Methods
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath{
    return 104;
}


- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section{
    return medicineBrnadArray.count;
}


- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{

    BuyhereTableViewCell *buyhereCell = [tableView dequeueReusableCellWithIdentifier:@"BuyhereCell"];
    if (buyhereCell==nil) {
        buyhereCell = [[BuyhereTableViewCell alloc]initWithStyle:UITableViewCellStyleDefault reuseIdentifier:@"BuyhereCell"];
    }
    buyhereCell.backgroundColor = [UIColor colorWithRed:230.0/255.0 green:229.0/255.0 blue:237.0/255.0 alpha:1.0];

    UIView *borderView = (UIView *) [buyhereCell viewWithTag:1000];
    borderView.backgroundColor = [UIColor whiteColor];
    borderView.layer.cornerRadius = 5;
    borderView.layer.borderColor = [UIColor lightGrayColor].CGColor;
    borderView.layer.borderWidth = 2.0;
    [buyhereCell.contentView addSubview:borderView];

    UIImageView *imgView = (UIImageView *) [buyhereCell viewWithTag:1001];
    imgView.image = [UIImage imageNamed:[buyHereImagesArray objectAtIndex:indexPath.row]];
    [buyhereCell.contentView addSubview:imgView];

    UILabel *medicineNameLbl = (UILabel *) [buyhereCell viewWithTag:1002];
    medicineNameLbl.text = [medicineBrnadArray objectAtIndex:indexPath.row];
    [buyhereCell.contentView addSubview:medicineNameLbl];

    UILabel *despLabel = (UILabel *) [buyhereCell viewWithTag:1003];
    despLabel.text = [medicineDescrpArray objectAtIndex:indexPath.row];
    [buyhereCell.contentView addSubview:despLabel];

    UILabel *priceLabel = (UILabel *) [buyhereCell viewWithTag:1004];
    priceLabel.text = [medicinePriceArray objectAtIndex:indexPath.row];
    [buyhereCell.contentView addSubview:priceLabel];

    UITextField *quantityTextField = (UITextField *) [buyhereCell viewWithTag:1005];
    quantityTextField.delegate = self;

    UIImageView *imgViewForDownArrow = [[UIImageView alloc]initWithFrame:CGRectMake(0, 0, 22, 22)];
    imgViewForDownArrow.image = [UIImage imageNamed:@"downArrow"];
    [imgViewForDownArrow setContentMode:UIViewContentModeCenter];
    quantityTextField.rightView = imgViewForDownArrow;
    quantityTextField.rightViewMode = UITextFieldViewModeAlways;


    UIPickerView *quantityPickerView= [[UIPickerView alloc]init];
    quantityPickerView.delegate = self;
    quantityPickerView.dataSource = self;
    UIToolbar *toolBar = [[UIToolbar alloc]initWithFrame:CGRectMake(0, 0, 320, 44)];
    UIBarButtonItem *doneBtn = [[UIBarButtonItem alloc]initWithBarButtonSystemItem:UIBarButtonSystemItemDone target:self action:@selector(doneBtnClicked:)];
    doneBtn.tag = indexPath.row;
    [toolBar setItems:[NSArray arrayWithObject:doneBtn] animated:NO];
    quantityTextField.inputAccessoryView = toolBar;
    quantityTextField.inputView = quantityPickerView;
    [buyhereCell.contentView addSubview:quantityTextField];


    UIButton *buyBtn = (UIButton *) [buyhereCell viewWithTag:1006];
    buyBtn.tag = indexPath.row;
    [buyBtn addTarget:self action:@selector(buyBtnClicked:) forControlEvents:UIControlEventTouchUpInside];
    [buyhereCell.contentView addSubview:buyBtn];

    return buyhereCell;
}


- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath{
    [tableView deselectRowAtIndexPath:indexPath animated:NO];
    NSLog(@"selected indexPath.row----%ld",indexPath.row);
}



-(void)doneBtnClicked:(UIBarButtonItem *)sender{

    NSLog(@"sender.tag-----%ld",sender.tag);
NSIndexPath *indexPath=[NSIndexPath indexPathForItem:sender.tag inSection:0];
BuyhereTableViewCell *buyCell= [self.buyhereTableView cellForRowAtIndexPath:indexPath];
UITextField *quantityTextField = (UITextField *) [buyCell viewWithTag:1005];
NSLog(@"quantityTextField-----%@",quantityTextField);

quantityTextField.tag = indexPath.row;
quantityTextField.text = selectedQuantity;
[quantityTextField setDelegate: self];
[self.view endEditing:YES];

}

我得到了以下回复

2018-02-21 16:36:13.263524-0800 DoctorMyTPA[8043:262939] didSelectRow------3
2018-02-21 16:36:13.263775-0800 DoctorMyTPA[8043:262939] selectedQuantity------4
2018-02-21 16:36:15.069352-0800 DoctorMyTPA[8043:262939] didSelectRow------2
2018-02-21 16:36:15.069542-0800 DoctorMyTPA[8043:262939] selectedQuantity------3
2018-02-21 16:36:16.204510-0800 DoctorMyTPA[8043:262939] sender.tag-----0
2018-02-21 16:36:16.205001-0800 DoctorMyTPA[8043:262939] quantityTextField-----(null)