ios13 UITextField 设置leftView不响应

 _leftImageView = [[UIImageView alloc] init];

        UIView*leftView = [[UIViewalloc]init];

        leftView.frame=CGRectMake(0,0,30,30);

        _leftImageView.image = [UIImage imageNamed:@"dm_search_left_icon"];

        _leftImageView.backgroundColor = [UIColor clearColor];

        [leftViewaddSubview:_leftImageView];

        [_leftImageView mas_makeConstraints:^(MASConstraintMaker *make) {

            make.left.equalTo(leftView.mas_left).with.offset(10);

            make.centerY.equalTo(leftView.mas_centerY).with.offset(0);

            make.size.mas_equalTo(CGSizeMake(18,18));

        }];

        UIImage*backgroudImage = [UIImageimageNamed:@"dtww_reservation_input_bg"];

        _textField = [[UITextField alloc] init];

        _textField.font = [UIFont systemFontOfSize:12];

        _textField.leftViewMode = UITextFieldViewModeAlways;

        _textField.clearButtonMode = UITextFieldViewModeWhileEditing;

        _textField.returnKeyType = UIReturnKeySearch;

        _textField.delegate = self;

        [self addSubview:_textField];

调试发现是leftView覆盖了textfield  尝试更新leftview的约束,发现_textField.superview拿到的值是nil,暂时把leftView放在textfiled左侧

        if(@available(iOS13.0, *)) {

            UIImageView*bgView = [[UIImageViewalloc]init];

            bgView.image= backgroudImage;

            [selfaddSubview:bgView];

            [bgViewmas_makeConstraints:^(MASConstraintMaker*make) {

                make.edges.equalTo(ws).insets(UIEdgeInsetsZero);

            }];

            [selfaddSubview:leftView];

            [leftViewmas_makeConstraints:^(MASConstraintMaker*make) {

                make.left.equalTo(ws.mas_left).with.offset(0);

                make.centerY.equalTo(ws.mas_centerY);

                make.size.mas_equalTo(CGSizeMake(30,30));

            }];

            [_textField mas_makeConstraints:^(MASConstraintMaker *make) {

                make.left.equalTo(leftView.mas_right).offset(0);

                make.top.bottom.right.equalTo(ws);

            }];

        }else{

            _textField.leftView= leftView;

            [_textFieldsetBackground:backgroudImage];

            [_textField mas_makeConstraints:^(MASConstraintMaker *make) {

                make.edges.equalTo(ws).with.insets(UIEdgeInsetsZero);

            }];

        }