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添加删除按钮

• 每个 Cell 还缺少 删除按钮, 在 HMEmoticonPageCell 里面懒加载 删除按钮

  /// 删除按钮
  private lazy var deleteButton: UIButton = {
    let button = UIButton()
  
    button.setImage(UIImage(named: "compose_emotion_delete"), for: UIControlState.normal)
    button.setImage(UIImage(named: "compose_emotion_delete_highlighted"), for: UIControlState.highlighted)
  
    return button
  }()
  

• 删除按钮 添加到 cell 里.

  /// 准备UI
  private func setupUI() {
    backgroundColor = UIColor(white: 237 / 255.0, alpha: 1)
  
    addEmoticonButtons()
    contentView.addSubview(deleteButton)
    contentView.addSubview(messageLabel)
  }
  

• 在 layoutEmoticonButtons 方法中 设置删除按钮的位置

  /// 重新布局按钮位置
  private func layoutEmoticonButtons() {
    let margin: CGFloat = 5
    let bottomMargin: CGFloat = 25
  
    // 计算表情按钮的宽度与高度
    let itemW = (frame.width - 2 * margin) / CGFloat(HMEmoticonColumnOfPage)
    let itemH = (frame.height - bottomMargin) / CGFloat(HMEmoticonRowOfPage)
  
    for i in 0..<emoticonButtons.count {
        let button = emoticonButtons[i]
  
        // 计算当前按钮是处于哪一行和哪一列
        let column = i % HMEmoticonColumnOfPage
        let row = i / HMEmoticonColumnOfPage
  
        // 计算x和y值
        let x = itemW * CGFloat(column) + margin
        let y = itemH * CGFloat(row)
        button.frame = CGRect(x: x, y: y, width: itemW, height: itemH)
    }
  
    // 设置删除按钮的位置
    let deleteX = (CGFloat(HMEmoticonColumnOfPage) - 1) * itemW + margin
    let deleteY = (CGFloat(HMEmoticonRowOfPage) - 1) * itemH
    deleteButton.frame = CGRect(x: deleteX, y: deleteY, width: itemW, height: itemH)
  }
  

• 运行，效果如下