在UITableView重新加载时以编程方式打开/关闭UITextField的inputView

Question

I have a UITextField that is part of a UITableViewCell , the table should be a dumb component.

The events triggered by the UITextField are handled by a custom delegate, which:

1. Every value change (typing, spinning the picker,...) triggers a chain of events to store and process the data
2. At the end of the chain UITableView is fully reloaded.
3. The full reload causes the inputView to disappear.

While I want 1. and 2., I don't want 3. The inputView should remain open and focused on the UITextField being edited -> I am looking for a way to open/close it programmatically and perhaps place it in -(void)prepareForReuse of the UITableViewCell

My most generic custom UITableViewCell initialization:

- (id)initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(NSString *)reuseIdentifier {
    self = [super initWithStyle:style reuseIdentifier:reuseIdentifier];
    if (self) {
        self.inputField = [UITextField new];
        [self.inputField addTarget:self
                  action:@selector(textFieldDidChange:)
        forControlEvents:UIControlEventEditingChanged];

        [self.contentView addSubview:self.inputField];

        [self.inputField setTranslatesAutoresizingMaskIntoConstraints:NO];
        [self.inputField.leftAnchor constraintEqualToAnchor:self.contentView.leftAnchor].active = YES;
        [self.inputField.rightAnchor constraintEqualToAnchor:self.contentView.rightAnchor].active = YES;
        [self.inputField.topAnchor constraintEqualToAnchor:self.contentView.topAnchor].active = YES;
        [self.inputField.bottomAnchor constraintEqualToAnchor:self.contentView.bottomAnchor].active = YES;
    }
    return self;
}

Example of change handling ( inputView could be a standard keyboard, UIPickerView , or something custom):

-(void) textFieldDidChange:(UITextField *)textField {
    NSString *valueString = textField.text;

    [self.delegate handleValueChange:valueString forAttributeID:self.attributeID];
}

Answer 1

I think the problem is that once you call reloadData , new cells will be created for all visible sections/rows, so the original input view loses its first responder state.

There are many ways you could circumvent this. Maybe the most easy one is to not call reloadData , but instead just reload the cells that are "changed" (´reloadRowsAtIndexPaths:withRowAnimation:`) - and especially not to reload the cell with the inputView that caused the change

Or, you could store the "active" IndexPath, and after refresh let the appropriate inputView become first responder again.

There might be other solutions to think of - all of them depend on your workflow.