iOS設(shè)置透明視圖（父視圖）上顯示不透明（子視圖）視圖

如題，開發(fā)中經(jīng)常會碰到需要背景透明，上面顯示的控件不透明的情況胳挎，一般首先都會想到先父子視圖布局，然后設(shè)置需要透明度的父視圖的alpha值溺森，但是慕爬，如果直接設(shè)置該視圖的alpha值，會導(dǎo)致該視圖上的所有子控件也具有相應(yīng)的透明度屏积。目前我用6種方法進(jìn)行解決澡罚，其中前四種的核心都是通過設(shè)置父視圖的背景顏色來達(dá)到目的。

效果圖：

效果圖.png

方法：

1肾请、如果是xib進(jìn)行UI布局，那么在父視圖上對背景進(jìn)行設(shè)置：

xib設(shè)置透明度.jpg

2更胖、使用colorWithWhite:alpha:方法
0表示黑色铛铁，1表示白色，可取0~1中間的值却妨。這種方法只能設(shè)置黑白之間的透明度
3饵逐、使用colorWithRed:green:blue:alpha:方法
這種方法可以設(shè)置任何我們需要的顏色

4、使用colorWithAlphaComponent:方法
這個方法是返回一個具有透明度的UIColor彪标，再將這個UIColor賦值給相應(yīng)的view
5倍权、父子視圖平級
即子視圖也直接添加在self.view上，這樣子視圖不是添加在父視圖上面捞烟，父視圖上設(shè)置相應(yīng)的alpha值就不會影響到子視圖
6.使用具有透明度的背景圖片薄声。
讓UI幫你做一張你需要的圖片，直接放上去题画。
代碼如下：

//1------
    UIView * fatherView1 = [[UIView alloc] initWithFrame:CGRectMake(50, 180, Width - 100 , 50)];
    fatherView1.backgroundColor = [UIColor colorWithWhite:0 alpha:0.5];
    [self.imageView addSubview:fatherView1];
    
    UILabel * subLabel = [[UILabel alloc] initWithFrame:CGRectMake(10, 10, fatherView1.frame.size.width - 20, 30)];
    subLabel.backgroundColor = [UIColor blueColor];
    subLabel.textColor = [UIColor whiteColor];
    subLabel.text = @"colorWithWhite:alpha:";
    [fatherView1 addSubview:subLabel];
    
    //2-------
    UIView * fatherView2 = [[UIView alloc] initWithFrame:CGRectMake(50, 260, Width - 100, 50)];
    fatherView2.backgroundColor = [UIColor colorWithRed:0 green:0 blue:0 alpha:0.5];
    [self.imageView addSubview:fatherView2];
    
    UILabel * subLabel2 = [[UILabel alloc] initWithFrame:CGRectMake(10, 10, fatherView2.frame.size.width - 20, 30)];
    subLabel2.textColor = [UIColor whiteColor];
    subLabel2.backgroundColor = [UIColor blueColor];
    subLabel2.text = @"colorWithRed:green:blue:alpha:";
    [fatherView2 addSubview:subLabel2];
    
    
    //3-------
    UIView * fatherView3 = [[UIView alloc] initWithFrame:CGRectMake(50, 340, Width - 100, 50)];
    UIColor * fatherColor = [UIColor blackColor];
    fatherView3.backgroundColor = [fatherColor colorWithAlphaComponent:0.5];
    [self.imageView addSubview:fatherView3];
    
    UILabel * subLabel3 = [[UILabel alloc] initWithFrame:CGRectMake(10, 10, fatherView3.frame.size.width - 20, 30)];
    subLabel3.backgroundColor = [UIColor blueColor];
    subLabel3.textColor = [UIColor whiteColor];
    subLabel3.text = @"colorWithAlphaComponent:";
    [fatherView3 addSubview:subLabel3];
    
    
    //4------
    UIView * fatherView4 = [[UIView alloc] initWithFrame:CGRectMake(50, 420, Width - 100, 50)];
    fatherView4.backgroundColor = [UIColor blackColor];
    fatherView4.alpha = 0.5;
    [self.imageView addSubview:fatherView4];
    
    UILabel * subLabel4 = [[UILabel alloc] initWithFrame:CGRectMake(60, 430, Width - 120, 30)];
    subLabel4.backgroundColor = [UIColor blueColor];
    subLabel4.text = @"父子視圖平級默辨，子視圖也直接添加在view上";
    subLabel4.textColor = [UIColor whiteColor];
    subLabel4.adjustsFontSizeToFitWidth = YES;
    [self.imageView addSubview:subLabel4];
    
    
    //5-------
    UIImageView * fatherImage = [[UIImageView alloc] initWithFrame:CGRectMake(50, 500, Width - 100, 50)];
    fatherImage.image = [UIImage imageNamed:@"bgColorAlpha.png"];
    [self.imageView addSubview:fatherImage];
    
    UILabel * subLabel5 = [[UILabel alloc] initWithFrame:CGRectMake(10, 10, fatherImage.frame.size.width - 20, 30)];
    subLabel5.backgroundColor = [UIColor blueColor];
    subLabel5.text = @"半透明背景圖";
    subLabel5.textColor = [UIColor whiteColor];
    [fatherImage addSubview:subLabel5];

最后編輯于：2019.01.30 16:19:56

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