1

keyBoard/Class/AiTalk/V/Chat/KBChatTableView.m

@@ -31,6 +31,11 @@ static const NSTimeInterval kTimestampInterval = 5 * 60; // 5 分钟
 @property (nonatomic, strong) AiVM *aiVM;
 @property (nonatomic, assign) BOOL hasMoreData;
 @property (nonatomic, assign) CGFloat contentBottomInset;
+@property (nonatomic, copy) NSString *introFooterText;
+@property (nonatomic, strong) UIView *introFooterContainer;
+@property (nonatomic, strong) UILabel *introFooterLabel;
+@property (nonatomic, assign) CGSize lastIntroFooterTableSize;
+@property (nonatomic, assign) BOOL applyingIntroFooter;
 
 @end
 
@@ -135,6 +140,7 @@ static const NSTimeInterval kTimestampInterval = 5 * 60; // 5 分钟
     
     self.tableView.transform = inverted ? CGAffineTransformMakeScale(1, -1) : CGAffineTransformIdentity;
     [self updateContentBottomInset:self.contentBottomInset];
+    [self updateIntroFooterText:self.introFooterText];
     [self.tableView reloadData];
     [self.tableView layoutIfNeeded];
 }
@@ -880,6 +886,85 @@ static inline CGFloat KBChatAbsTimeInterval(NSTimeInterval interval) {
     [self.tableView reloadRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationNone];
 }
 
+- (void)updateIntroFooterText:(nullable NSString *)text {
+    if (self.applyingIntroFooter) {
+        return;
+    }
+    self.applyingIntroFooter = YES;
+    self.introFooterText = text ?: @"";
+    if (self.introFooterText.length == 0) {
+        self.tableView.tableFooterView = nil;
+        self.lastIntroFooterTableSize = CGSizeZero;
+        self.applyingIntroFooter = NO;
+        return;
+    }
+    
+    if (!self.introFooterContainer) {
+        self.introFooterContainer = [[UIView alloc] initWithFrame:CGRectZero];
+        self.introFooterContainer.backgroundColor = [UIColor clearColor];
+        
+        self.introFooterLabel = [[UILabel alloc] initWithFrame:CGRectZero];
+        self.introFooterLabel.numberOfLines = 0;
+        self.introFooterLabel.font = [UIFont systemFontOfSize:14];
+        self.introFooterLabel.textColor = [[UIColor whiteColor] colorWithAlphaComponent:0.9];
+        self.introFooterLabel.textAlignment = NSTextAlignmentCenter;
+        [self.introFooterContainer addSubview:self.introFooterLabel];
+    }
+    
+    self.introFooterLabel.text = self.introFooterText;
+    self.introFooterContainer.transform = self.inverted ? CGAffineTransformMakeScale(1, -1) : CGAffineTransformIdentity;
+    
+    CGFloat width = CGRectGetWidth(self.tableView.bounds);
+    if (width <= 0) {
+        width = CGRectGetWidth(self.bounds);
+    }
+    CGFloat height = CGRectGetHeight(self.tableView.bounds);
+    if (height <= 0) {
+        height = CGRectGetHeight(self.bounds);
+    }
+    self.lastIntroFooterTableSize = CGSizeMake(width, height);
+    
+    CGFloat horizontalPadding = 24;
+    CGFloat verticalPadding = 16;
+    CGFloat labelWidth = MAX(0, width - horizontalPadding * 2);
+    CGSize labelSize = [self.introFooterLabel sizeThatFits:CGSizeMake(labelWidth, CGFLOAT_MAX)];
+    CGFloat containerHeight = MAX(height, labelSize.height + verticalPadding * 2);
+    
+    self.introFooterContainer.frame = CGRectMake(0, 0, width, containerHeight);
+    self.introFooterLabel.frame = CGRectMake(horizontalPadding, verticalPadding, labelWidth, labelSize.height);
+    self.tableView.tableFooterView = self.introFooterContainer;
+    
+    dispatch_async(dispatch_get_main_queue(), ^{
+        [self.tableView layoutIfNeeded];
+        CGFloat contentHeight = self.tableView.contentSize.height;
+        CGFloat tableHeight = CGRectGetHeight(self.tableView.bounds);
+        CGFloat minOffset = -self.tableView.contentInset.top;
+        CGFloat maxOffset = contentHeight - tableHeight + self.tableView.contentInset.bottom;
+        if (maxOffset < minOffset) {
+            maxOffset = minOffset;
+        }
+        CGFloat targetOffset = self.inverted ? maxOffset : minOffset;
+        [self.tableView setContentOffset:CGPointMake(0, targetOffset) animated:NO];
+    });
+    self.applyingIntroFooter = NO;
+}
+
+- (void)layoutSubviews {
+    [super layoutSubviews];
+    if (self.introFooterText.length == 0 || self.applyingIntroFooter) {
+        return;
+    }
+    CGFloat width = CGRectGetWidth(self.tableView.bounds);
+    CGFloat height = CGRectGetHeight(self.tableView.bounds);
+    if (width <= 0 || height <= 0) {
+        return;
+    }
+    CGSize size = CGSizeMake(width, height);
+    if (!CGSizeEqualToSize(size, self.lastIntroFooterTableSize)) {
+        [self updateIntroFooterText:self.introFooterText];
+    }
+}
+
 /// 判断是否需要插入时间戳
 - (BOOL)shouldInsertTimestampForMessage:(KBAiChatMessage *)message {
     // 第一条消息总是显示时间