UIPickerView selection indicator not visible in iOS10

问题

I build my project in Xcode 8. UIPickerView separator lines are not visible in iOS 10 simulator and the devices, but works fine on iOS 9.3 devices and simulator. I tried to adjust the UIPickerView back ground color, auto layouts and everything possible in the XIB, but nothing works. Anyone have an idea on this?

This is a custom view which contains a UIPickerView

-(void)layoutSubviews{
isShown = NO;
[super layoutSubviews];

//self.selectedDic = nil;

self.doneBtn.tintColor = COLOR_DB3535;
self.pickerView.backgroundColor = COLOR_DEDEDE;
self.pickerView.showsSelectionIndicator = YES;

[self.doneBtn setTitle:NSLocalizedString(@"App_Generic_Button_Text_Done", @"")];
}


-(UIView*)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(UIView *)view{
UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, 320, 50)];
label.tintColor = [UIColor clearColor];
label.backgroundColor = [UIColor yellowColor];
label.textColor = COLOR_666;
label.font = [FontsManager getFONT_ROBOTO_LIGHT_16];
label.textAlignment = NSTextAlignmentCenter;
NSDictionary *dict = [dataArray objectAtIndex:row];
label.text = @"Test";
return label;
}

回答1:

I had this exact issue when I rebuilt a couple of solutions for iOS10 and deployed to iOS10 on both simulators and devices.

I narrowed the problem in my case to be down to selecting an item in the picker during initialisation. ie. I populate my picker and if we have already got a selection for this property then I preselect it and the lines are present. I do this during the initialisation when I set up my picker.

So my fix, which worked in my use case, was to select the 0 element in the case of no existing value.

Objective-C

UIPickerView *pickerView;

...

[pickerView selectRow:0 inComponent:0 animated:YES];

Swift

let pickerView: UIPickerView

...

pickerView.selectRow(0, inComponent: 0, animated: true)

This was fine for my solution since I effectively select row zero on setup.

I haven't had chance to dig into the reasoning or look for a cleaner solution, but since I've solved my problem I thought I'd share it here to help you all out if I can.

回答2:

UIPickerView *pickerView = [[UIPickerView alloc] initWithFrame:CGRectMake(0, 44, 320, 200)];
pickerView.backgroundColor = [UIColor whiteColor];
pickerView.dataSource = self;
pickerView.delegate = self;
[pickerView selectRow:0 inComponent:0 animated:YES];
[self.view addSubview:pickerView];

add the code [pickerView selectRow:0 inComponent:0 animated:YES]; before pickerView added to superView.

回答3:

I have faced the same issue in iOS10, too. Here is my problem:

And I solved this problem by:

 self.pickerView.backgroundColor = COLOR_DEDEDE;
 self.pickerView.showsSelectionIndicator = YES;
    for (UIView *view in self.pickerView.subviews) {
        if (view.bounds.size.height < 2.0f && view.backgroundColor == nil) {
            view.backgroundColor = PICK_Line_COLOR; // line color
        }
    }

Note:

this code mush be called after method:[self.view addSubview:pickeView];

The final result：

it works in my project. Hope it helps to you.

回答4:

I'm not sure what "separator lines" you are talking about. I don't see "separator lines" in iOS 9 either.

The only "lines" missing from your screen shot are the selection indicator. You can get them by setting the picker view's showsSelectionIndicator to YES. But you shouldn't have to; showing the selection indicator is the default. The docs say:

On iOS 7 and later ... the selection indicator is always shown

回答5:

This is my code:

-(UIView*)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(UIView *)view{

    for(UIView *single in pickerView.subviews)
    {
        if (single.frame.size.height < 1)
        {
            single.backgroundColor = [UIColor grayColor];
        }
    }
   //other code

}

回答6:

Solved this problem using subclass of UIPickerView:

import UIKit

    class FixedPickerView: UIPickerView, UIPickerViewDelegate {

        override func willMove(toSuperview newSuperview: UIView?) {
            self.delegate = self
            self.selectRow(0, inComponent: 0, animated: true)
            self.delegate = nil
            super.willMove(toSuperview: newSuperview)
        }
    }

回答7:

I am also facing the same issue. Below is my code for creating the UIPickerView:

self.pickerView = [[UIPickerView alloc] initWithFrame:CGRectMake(0, frame.size.height - 216, frame.size.width, 216)];
self.pickerView.dataSource = self;
self.pickerView.delegate = self;
self.pickerView.backgroundColor = [UIColor whiteColor];
self.pickerView.showsSelectionIndicator = YES;
[self addSubview:self.pickerView];

来源：https://stackoverflow.com/questions/39564660/uipickerview-selection-indicator-not-visible-in-ios10

标签

ios

objective-c

uipickerview

ios10

xcode8