TableCell自适应输入框

image.png

知识点：

一.AutoLayout有两个重要的属性：
1.Content Compression Resistance 百度翻译（内容压缩抗力）

2.Content Hugging    百度翻译(内容拥抱) 

Content Compression Resistance = 变大！（保持自己更大）
这个属性的优先级（Priority）越高，越不“容易”被压缩。也就是说，当整体的空间装不下所有的View的时候，Content Compression Resistance优先级越高的，现实的内容越完整。
 
[self.labelTwosetContentCompressionResistancePriority:UILayoutPriorityDefaultHighforAxis:UILayoutConstraintAxisHorizontal];
 
Content Hugging = 抱紧！（保持自己更小）
这个属性的优先级越高，整个View就要越“抱紧”View里面的内容。也就是View的大小不会随着父级View的扩大而扩大。
[self.labelOnesetContentHuggingPriority:UILayoutPriorityDefaultHighforAxis:UILayoutConstraintAxisHorizontal];

typedef NS_OPTIONS(NSUInteger, UIViewAutoresizing) {
    UIViewAutoresizingNone                 = 0,
    UIViewAutoresizingFlexibleLeftMargin   = 1 << 0,
    UIViewAutoresizingFlexibleWidth        = 1 << 1,
    UIViewAutoresizingFlexibleRightMargin  = 1 << 2,
    UIViewAutoresizingFlexibleTopMargin    = 1 << 3,
    UIViewAutoresizingFlexibleHeight       = 1 << 4,
    UIViewAutoresizingFlexibleBottomMargin = 1 << 5
};
UIViewAutoresizingNone  不会随父视图的改变而改变
UIViewAutoresizingFlexibleLeftMargin    自动调整view与父视图左边距，以保证右边距不变
UIViewAutoresizingFlexibleWidth 自动调整view的宽度，保证左边距和右边距不变
UIViewAutoresizingFlexibleRightMargin   自动调整view与父视图右边距，以保证左边距不变
UIViewAutoresizingFlexibleTopMargin 自动调整view与父视图上边距，以保证下边距不变
UIViewAutoresizingFlexibleHeight    自动调整view的高度，以保证上边距和下边距不变
UIViewAutoresizingFlexibleBottomMargin  自动调整view与父视图的下边距，以保证上边距不变

纯代码实现cell布局，利用约束实现自适应布局。
下面展示的为实现自适应输入框的部分关键代码

[图片上传中...(image-89a2f0-1569465337493-0)]

初始化cell

- (instancetype)initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(NSString *)reuseIdentifier {
   self=[super initWithStyle:style reuseIdentifier:reuseIdentifier];
   if (self) {
       [self updateViewConstraint];
   }
   return self;
}

设置布局的约束条件

- (void)setupViewConstraint {
    [self.labelBeizhu mas_makeConstraints:^(MASConstraintMaker *make) {
        make.leading.mas_equalTo(self.labelPriceTip.mas_leading);
        make.top.mas_equalTo(self);
        make.height.mas_equalTo(@(44));
        make.width.mas_equalTo(@(50));
    }];

    [self.textViewBeiZhu mas_makeConstraints:^(MASConstraintMaker *make) {
        make.leading.mas_equalTo(self.labelBeizhu.mas_trailing).offset(10);
        make.top.mas_equalTo(self).offset(6);
        make.height.mas_equalTo(@(32));
        make.trailing.mas_equalTo(self).offset(-10);
        make.bottom.mas_equalTo(self).priorityLow();
    }];

}

textView的属性设置

- (UITextView *)textViewBeiZhu {
    if (_textViewBeiZhu == nil) {
        UITextView *textView = [[UITextView alloc] init];
        textView.font = [UIFont systemFontOfSize:15];
        textView.backgroundColor = [UIColor whiteColor];
        textView.showsVerticalScrollIndicator = NO;
        textView.scrollEnabled=NO;
        textView.autoresizingMask = UIViewAutoresizingFlexibleHeight;
        _textViewBeiZhu = textView;
        [self addSubview:_textViewBeiZhu];
    }
    return _textViewBeiZhu;
}

在textViewDidChange中实时计算textview的高度并更新

- (void)textViewDidChange:(UITextView *)textView {
//计算textview高度
    CGRect frame = textView.frame;
    CGSize constraintSize = CGSizeMake(frame.size.width, MAXFLOAT);
    CGSize size = [textView sizeThatFits:constraintSize];
    [self.textViewBeiZhu mas_updateConstraints:^(MASConstraintMaker *make) {
//更新height
        make.height.mas_equalTo(@(size.height));
    }];
// 重点
    [self.mtableView beginUpdates];
    [self.mtableView endUpdates];
}

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初始化cell

- (instancetype)initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(NSString *)reuseIdentifier {
   self=[super initWithStyle:style reuseIdentifier:reuseIdentifier];
   if (self) {
       [self updateViewConstraint];
   }
   return self;
}

设置布局的约束条件

- (void)setupViewConstraint {
    [self.labelBeizhu mas_makeConstraints:^(MASConstraintMaker *make) {
        make.leading.mas_equalTo(self.labelPriceTip.mas_leading);
        make.top.mas_equalTo(self);
        make.height.mas_equalTo(@(44));
        make.width.mas_equalTo(@(50));
    }];

    [self.textViewBeiZhu mas_makeConstraints:^(MASConstraintMaker *make) {
        make.leading.mas_equalTo(self.labelBeizhu.mas_trailing).offset(10);
        make.top.mas_equalTo(self).offset(6);
        make.height.mas_equalTo(@(32));
        make.trailing.mas_equalTo(self).offset(-10);
        make.bottom.mas_equalTo(self).priorityLow();
    }];

}

textView的属性设置

- (UITextView *)textViewBeiZhu {
    if (_textViewBeiZhu == nil) {
        UITextView *textView = [[UITextView alloc] init];
        textView.font = [UIFont systemFontOfSize:15];
        textView.backgroundColor = [UIColor whiteColor];
        textView.showsVerticalScrollIndicator = NO;
        textView.scrollEnabled=NO;
        textView.autoresizingMask = UIViewAutoresizingFlexibleHeight;
        _textViewBeiZhu = textView;
        [self addSubview:_textViewBeiZhu];
    }
    return _textViewBeiZhu;
}

在textViewDidChange中实时计算textview的高度并更新

- (void)textViewDidChange:(UITextView *)textView {
//计算textview高度
    CGRect frame = textView.frame;
    CGSize constraintSize = CGSizeMake(frame.size.width, MAXFLOAT);
    CGSize size = [textView sizeThatFits:constraintSize];
    [self.textViewBeiZhu mas_updateConstraints:^(MASConstraintMaker *make) {
//更新height
        make.height.mas_equalTo(@(size.height));
    }];
// 重点
    [self.mtableView beginUpdates];
    [self.mtableView endUpdates];
}