添加按钮文字预览提示

CustomKeyboard/View/KBKeyPreviewView.m

@@ -0,0 +1,56 @@
+//
+//  KBKeyPreviewView.m
+//  CustomKeyboard
+//
+
+#import "KBKeyPreviewView.h"
+#import "KBKey.h"
+
+@interface KBKeyPreviewView ()
+@property (nonatomic, strong) UILabel *label;
+@property (nonatomic, strong) UIImageView *iconView;
+@end
+
+@implementation KBKeyPreviewView
+
+- (instancetype)initWithFrame:(CGRect)frame {
+    if (self = [super initWithFrame:frame]) {
+        self.backgroundColor = [UIColor colorWithWhite:1 alpha:1.0];
+        self.layer.cornerRadius = 8.0;
+        self.layer.masksToBounds = YES;
+        self.layer.borderWidth = 0.5;
+        self.layer.borderColor = [UIColor colorWithWhite:0 alpha:0.15].CGColor;
+        self.layer.shadowColor = [UIColor colorWithWhite:0 alpha:0.3].CGColor;
+        self.layer.shadowOpacity = 0.6;
+        self.layer.shadowOffset = CGSizeMake(0, 2);
+        self.layer.shadowRadius = 4.0;
+
+//        _iconView = [[UIImageView alloc] initWithFrame:CGRectZero];
+//        _iconView.contentMode = UIViewContentModeScaleAspectFit;
+//        _iconView.translatesAutoresizingMaskIntoConstraints = NO;
+//        [self addSubview:_iconView];
+
+        _label = [[UILabel alloc] initWithFrame:CGRectZero];
+        _label.font = [UIFont systemFontOfSize:28 weight:UIFontWeightSemibold];
+        _label.textAlignment = NSTextAlignmentCenter;
+        _label.textColor = [UIColor blackColor];
+        _label.translatesAutoresizingMaskIntoConstraints = NO;
+        [self addSubview:_label];
+
+        // 预览只使用文本：尽量靠近顶部显示，上下留少量安全距离。
+        [NSLayoutConstraint activateConstraints:@[
+            [_label.leadingAnchor constraintEqualToAnchor:self.leadingAnchor constant:4],
+            [_label.trailingAnchor constraintEqualToAnchor:self.trailingAnchor constant:-4],
+            [_label.topAnchor constraintEqualToAnchor:self.topAnchor constant:2],
+            [_label.bottomAnchor constraintEqualToAnchor:self.bottomAnchor constant:-2],
+        ]];
+    }
+    return self;
+}
+
+- (void)configureWithKey:(KBKey *)key icon:(UIImage *)icon {
+    NSString *text = key.output.length > 0 ? key.output : key.title;
+    self.label.text = text;
+}
+
+@end