iOS 點擊按鈕動態添加 UIView 實戰指南

需求

點擊按鈕，在當前視圖中間彈出一個半屏大小的綠色 UIView。

核心代碼

- (IBAction)showHalfScreenView:(UIButton *)sender {
    CGFloat width = self.view.bounds.size.width * 0.9;
    CGFloat height = self.view.bounds.size.height * 0.5;
    CGFloat x = (self.view.bounds.size.width - width) * 0.5;
    CGFloat y = (self.view.bounds.size.height - height) * 0.5;

    UIView *customView = [[UIView alloc] initWithFrame:CGRectMake(x, y, width, height)];
    customView.backgroundColor = [UIColor greenColor];
    customView.layer.cornerRadius = 12;
    customView.layer.masksToBounds = YES;

    // 添加關閉按鈕示例
    UIButton *closeBtn = [UIButton buttonWithType:UIButtonTypeSystem];
    closeBtn.frame = CGRectMake(width - 50, 10, 40, 40);
    [closeBtn setTitle:@"×" forState:UIControlStateNormal];
    [closeBtn addTarget:self action:@selector(dismissCustomView:) forControlEvents:UIControlEventTouchUpInside];
    [customView addSubview:closeBtn];

    // 彈出動畫
    customView.alpha = 0;
    customView.transform = CGAffineTransformMakeScale(0.8, 0.8);
    [self.view addSubview:customView];
    [UIView animateWithDuration:0.25 animations:^{
        customView.alpha = 1;
        customView.transform = CGAffineTransformIdentity;
    }];
}

- (void)dismissCustomView:(UIButton *)btn {
    UIView *customView = btn.superview;
    [UIView animateWithDuration:0.2 animations:^{
        customView.alpha = 0;
        customView.transform = CGAffineTransformMakeScale(0.8, 0.8);
    } completion:^(BOOL finished) {
        [customView removeFromSuperview];
    }];
}

關鍵點解析

• Frame 計算：用 bounds 而非 frame 適配旋轉/安全區。
• 層級管理：直接 addSubview 置於頂層；若需模態效果，可先添加半透明遮罩 UIView *mask = [[UIView alloc] initWithFrame:self.view.bounds]; mask.backgroundColor = [UIColor blackColor]; mask.alpha = 0.4;。
• 動畫細節：transform 縮放 + alpha 淡入，體驗優於直接顯示。
• 內存管理：按鈕通過 superview 找到容器移除，避免強引用循環。

進階替代方案

總結

幾行代碼即可實現動態 UIView 彈出，核心在於 Frame 精確計算、層級正確添加、動畫提升體驗。複雜業務建議升級至 UIPresentationController 或 SwiftUI。