chating

• 隐藏相同时间的label

- (NSArray *)messages
{
    if (_messages == nil) {
        // 加载plist中的字典数组
        NSString *path = [[NSBundle mainBundle] pathForResource:@"messages.plist" ofType:nil];
        NSArray *dictArray = [NSArray arrayWithContentsOfFile:path];

        // 字典数组 -> 模型数组
        NSMutableArray *messageArray = [NSMutableArray array];
        // 用来记录上一条消息模型
        XMGMessage *lastMessage = nil;
        for (NSDictionary *dict in dictArray) {
            XMGMessage *message = [XMGMessage messageWithDict:dict];
            //埋下伏笔，加载数据时，判断哪个时间值相等。
            message.hideTime = [message.time isEqualToString:lastMessage.time];
            [messageArray addObject:message];

            lastMessage = message;
        }

        _messages = messageArray;
    }
    return _messages;
}

• 图片拉伸

  UIImageView *imageView = [[UIImageView alloc] init];
    imageView.frame = CGRectMake(10, 10, 250, 150);
    imageView.image = [UIImage imageNamed:@"chat_send_nor"];
    [self.view addSubview:imageView];

    // 加载原图
//    UIImage *image = [UIImage imageNamed:@"chat_send_nor"];

    // 拉伸处理（说明需要保护的区域）
//    image = [image resizableImageWithCapInsets:UIEdgeInsetsMake(30, 30, 30, 30) resizingMode:UIImageResizingModeStretch];

//    image = [image stretchableImageWithLeftCapWidth:image.size.width * 0.5 topCapHeight:image.size.height * 0.5];

• 设置按钮

  // 设置按钮的文字
    [showTextButton setTitle:self.message.text forState:UIControlStateNormal];
  
    // 强制更新
    [showTextButton layoutIfNeeded];
  
    // 设置按钮的高度就是titleLabel的高度
    [showTextButton updateConstraints:^(MASConstraintMaker *make) {
        CGFloat buttonH = showTextButton.titleLabel.frame.size.height;
        make.height.equalTo(buttonH);
    }];
  

  • 设置field文本框左边

    // 设置文本框左边的内容
    UIView *leftView = [[UIView alloc] init];
    leftView.frame = CGRectMake(0, 0, 10, 0);
    self.messageField.leftView = leftView;
    self.messageField.leftViewMode = UITextFieldViewModeAlways;
    

• 键盘处理

double duration = [note.userInfo[UIKeyboardAnimationDurationUserInfoKey] doubleValue];
    // 修改约束
    self.bottomSpacing.constant = rect.size.height;
    [UIView animateWithDuration:duration animations:^{
        [self.view layoutIfNeeded];
    }];
}
   - (void)keyboardWillHide:(NSNotification *)note {
    // 取出键盘弹出需要花费的时间
    double duration = [note.userInfo[UIKeyboardAnimationDurationUserInfoKey] doubleValue];
    // 修改约束
    self.bottomSpacing.constant = 0;
    [UIView animateWithDuration:duration animations:^{
        [self.view layoutIfNeeded];
    }];
}

• 退出键盘

- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView
{
    // 退出键盘
//    [self.messageField resignFirstResponder];
//    [self.messageField endEditing:YES];
    [self.view endEditing:YES];
}

• 另一种方式

  // 监听键盘通知
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillChangeFrame:) name:UIKeyboardWillChangeFrameNotification object:nil];
    - (void)keyboardWillChangeFrame:(NSNotification *)note {
        // 取出键盘最终的frame
        CGRect rect = [note.userInfo[UIKeyboardFrameEndUserInfoKey] CGRectValue];
        // 取出键盘弹出需要花费的时间
        double duration = [note.userInfo[UIKeyboardAnimationDurationUserInfoKey] doubleValue];
  
        // 修改约束
        self.bottomSpacing.constant = [UIScreen mainScreen].bounds.size.height - rect.origin.y;
        [UIView animateWithDuration:duration animations:^{
            [self.view layoutIfNeeded];
        }];
    }
  

• 一定要移除监听通知

- (void)dealloc
{
    [[NSNotificationCenter defaultCenter] removeObserver:self];
}