开发技巧Tips

2017-01-25

1、继承自UIScrollView 键盘

typedef NS_ENUM(NSInteger, UIScrollViewKeyboardDismissMode) {
UIScrollViewKeyboardDismissModeNone,
UIScrollViewKeyboardDismissModeOnDrag, // dismisses the keyboard when a drag begins 拖拽时隐藏键盘
UIScrollViewKeyboardDismissModeInteractive, // the keyboard follows the dragging touch off screen, and may be pulled upward again to cancel the dismiss 表示键盘可以随着手指下滑而移出屏幕。
} NS_ENUM_AVAILABLE_IOS(7_0);

例：

tableView.keyboardDismissMode = UIScrollViewKeyboardDismissModeOnDrag;
其中keyboardDismissMode是UIScrollView的属性,

2、按钮图片和文字位置

默认情况下，是图片在左，文字在右，垂直居中显示，如下图：

1 2	button.titleEdgeInsets = UIEdgeInsetsZero; button.imageEdgeInsets = UIEdgeInsetsZero;

设置如下布局后，图片和文字都居中显示。

button.titleEdgeInsets = UIEdgeInsetsMake(0, -button.imageView.frame.size.width, 0, 0);
// button.imageEdgeInsets = UIEdgeInsetsMake(0, 0, 0, -button.titleLabel.frame.size.width);
// 由于iOS8中titleLabel的size为0，用上面这样设置有问题，修改一下即可
button.imageEdgeInsets = UIEdgeInsetsMake(0, 0, 0, -button.titleLabel.intrinsicContentSize.width);

如果想图片在上，文字在下，水平居中显示，则按下面设置即可：

button.titleEdgeInsets = UIEdgeInsetsMake(0, -button.imageView.frame.size.width, -button.imageView.frame.size.height, 0);
// button.imageEdgeInsets = UIEdgeInsetsMake(-button.titleLabel.frame.size.height, 0, 0, -button.titleLabel.frame.size.width);
// 由于iOS8中titleLabel的size为0，用上面这样设置有问题，修改一下即可
button.imageEdgeInsets = UIEdgeInsetsMake(-button.titleLabel.intrinsicContentSize.height, 0, 0, -button.titleLabel.intrinsicContentSize.width);

如果觉得图片和文字离的太近了，稍微分开一点：

CGFloat offset = 40.0f;
button.titleEdgeInsets = UIEdgeInsetsMake(0, -button.imageView.frame.size.width, -button.imageView.frame.size.height-offset/2, 0);
// button.imageEdgeInsets = UIEdgeInsetsMake(-button.titleLabel.frame.size.height-offset/2, 0, 0, -button.titleLabel.frame.size.width);
// 由于iOS8中titleLabel的size为0，用上面这样设置有问题，修改一下即可
button.imageEdgeInsets = UIEdgeInsetsMake(-button.titleLabel.intrinsicContentSize.height-offset/2, 0, 0, -button.titleLabel.intrinsicContentSize.width);

文字左对齐，图片右对齐

1
2

button.titleEdgeInsets = UIEdgeInsetsMake(0, -button.imageView.frame.size.width - button.frame.size.width + button.titleLabel.intrinsicContentSize.width, 0, 0);
button.imageEdgeInsets = UIEdgeInsetsMake(0, 0, 0, -button.titleLabel.frame.size.width - button.frame.size.width + button.imageView.frame.size.width);