动态修改UITableView footerView的高度

在开发中遇到了一个需求就是动态修改footerView的高度，footerView的高度随着用户输入内容的变化，改变输入框的高度，并且改变footerView的高度，通常情况下我们会直接创建footerView,并且给footer一个frame,但是如果想动态修改footerView的高度，或者让footerView高度自适应，我们就需要需改footerView的高度，并且重新赋值给tableView

CGRect newFrame = viewHeader.frame;
newFrame.size.height = newFrame.size.height + webView.frame.size.height;
viewHeader.frame = newFrame;
[self.tableView setTableHeaderView: viewHeader];

@interface ETCAuditViewController ()<UITableViewDelegate,UITableViewDataSource>
@property(nonatomic,strong)UITableView *mineTableView;
@property(nonatomic,strong)AuditFooterView *footerView;
@end

@implementation ETCAuditViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    self.navigationItem.title = AppLocalString(@"bulk_task_list_query");
    self.edgesForExtendedLayout = UIRectEdgeNone;
    [self.view addSubview:self.mineTableView];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(changeFooterViewHeight:) name:@"changeHeight" object:nil];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{
    AuditTableViewCell *cell = [AuditTableViewCell cellWithTableView:tableView];
    return cell;
}
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath{
        
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section{
    return 10;
}
- (UITableView *)mineTableView{
    if (!_mineTableView) {
        if (kDevice_iPhoneX) {
            _mineTableView = [[BaseTableView alloc] initWithFrame:CGRectMake(0, 0, SCREEN_WIDTH, SCREEN_HEIGHT-TotaliPhoneX) style:UITableViewStylePlain];
            NSLog(@"SCREEN_HEIGHT=%f  TotaliPhoneX = %f",SCREEN_HEIGHT,TotaliPhoneX);
        }else{
            _mineTableView = [[BaseTableView alloc] initWithFrame:CGRectMake(0, 0, SCREEN_WIDTH,SCREEN_HEIGHT-NAVIGATION_BAR_HEIGHT) style:UITableViewStylePlain];
        }
        _mineTableView.backgroundColor = TableViewBackColor;
        _mineTableView.delegate = self;
        _mineTableView.dataSource = self;
        _mineTableView.rowHeight = UITableViewAutomaticDimension;
        _mineTableView.separatorColor = [UIColor whiteColor];
        _mineTableView.estimatedRowHeight = 160;
        AuditHeaderView *headerView = [[AuditHeaderView alloc] init];
        headerView.frame = CGRectMake(0, 0, SCREEN_WIDTH, 30);
        _mineTableView.tableHeaderView = headerView;
        self.footerView = [[AuditFooterView alloc] init];
        _footerView.frame = CGRectMake(0, 0, SCREEN_WIDTH, 120);
        _mineTableView.tableFooterView = _footerView;
    }   
    return _mineTableView;
}
- (void)changeFooterViewHeight:(NSNotification *)note{
    NSDictionary *dic = note.userInfo;
    CGFloat totalHeight =  [dic[@"totalHeight"] floatValue];
    self.footerView.frame = CGRectMake(0, 0, SCREEN_WIDTH, totalHeight);
    [self.mineTableView.tableFooterView setNeedsLayout];
    self.mineTableView.tableFooterView = self.footerView;
}

自定义footerView内部

#import "AuditFooterView.h"
@interface AuditFooterView()<UITextViewDelegate>
{
    CGFloat _initHeight;

}
@end
@implementation AuditFooterView
- (instancetype)init{
    self = [super init];
    if (self) {
        self = [[[NSBundle mainBundle] loadNibNamed:@"AuditFooterView" owner:self options:nil] lastObject];
        self.opinion.delegate = self;
        _initHeight  = 30;
        self.opinion.layer.borderColor = [UIColor greenColor].CGColor;

        self.opinion.layer.borderWidth = 1.0f;
        self.opinion.textContainerInset =  UIEdgeInsetsMake(2, 0, 0, 0);
    }
    return self;
}        
- (void)awakeFromNib{
    [super awakeFromNib];
}
/** textView文本内容改变时回调 */
- (void)textViewDidChange:(UITextView *)textView{
    // 计算高度
    CGSize size = CGSizeMake(self.opinion.frame.size.width, CGFLOAT_MAX);
    NSDictionary *dic = [NSDictionary dictionaryWithObjectsAndKeys:self.opinion.font,NSFontAttributeName, nil];
    CGFloat curheight = [textView.text boundingRectWithSize:size
                                                    options:NSStringDrawingUsesLineFragmentOrigin | NSStringDrawingUsesFontLeading
                                                 attributes:dic
                                                    context:nil].size.height;
    // 如果高度小于初始化时的高度，则不赋值(仍采用最初的高度)
    if (curheight < _initHeight) {
//        self.frame = CGRectMake(self.frame.origin.x, self.frame.origin.y, self.frame.size.width, _initHeight);
//        self.opinion.frame = CGRectMake(self.opinion.frame.origin.x, self.opinion.frame.origin.y, self.opinion.frame.size.width, _initHeight);
        self.textViewHeight.constant = _initHeight;
        CGFloat totalHeight = 120;
        [[NSNotificationCenter defaultCenter] postNotificationName:@"changeHeight" object:nil userInfo:@{@"totalHeight":[NSString stringWithFormat:@"%f",totalHeight]}];
    }else{
        // 重新给frame赋值(改变高度)
//        self.frame = CGRectMake(self.frame.origin.x, self.frame.origin.y, self.frame.size.width, curheight+20);
//        self.opinion.frame = CGRectMake(self.opinion.frame.origin.x, self.opinion.frame.origin.y, self.opinion.frame.size.width, curheight+20);
        self.textViewHeight.constant = curheight+20;
        CGFloat totalHeight = 120 + curheight  - 30;
        [[NSNotificationCenter defaultCenter] postNotificationName:@"changeHeight" object:nil userInfo:@{@"totalHeight":[NSString stringWithFormat:@"%f",totalHeight]}];
    }

//    // 如果文本为空，显示placeholder
//    if (textView.text.length == 0) {
//        self.placeholderLabel.hidden = NO;
//        self.placeholderLabel.center = self.textView.center;
//    }else{
//        self.placeholderLabel.hidden = YES;
//    }
}

@end