iOS中的黑科技(一些方法或者功能的实现)

1. 获取键盘高度

此方法来自于SVProgressHUD, 在查阅SVProgressHUD源码时候想要作一些修改, 想要主动的获取键盘的高度, 百度Google上没有找到方法, 最后却发现SVProgressHUD自己就提供了一个这样的方法.

- (CGFloat)visibleKeyboardHeight {
#if !defined(SV_APP_EXTENSIONS)
    UIWindow *keyboardWindow = nil;
    for (UIWindow *testWindow in [[UIApplication sharedApplication] windows]) {
        if(![[testWindow class] isEqual:[UIWindow class]]) {
            keyboardWindow = testWindow;
            break;
        }
    }
    
    for (__strong UIView *possibleKeyboard in [keyboardWindow subviews]) {
        if([possibleKeyboard isKindOfClass:NSClassFromString(@"UIPeripheralHostView")] || [possibleKeyboard isKindOfClass:NSClassFromString(@"UIKeyboard")]) {
            return CGRectGetHeight(possibleKeyboard.bounds);
        } else if([possibleKeyboard isKindOfClass:NSClassFromString(@"UIInputSetContainerView")]) {
            for (__strong UIView *possibleKeyboardSubview in [possibleKeyboard subviews]) {
                if([possibleKeyboardSubview isKindOfClass:NSClassFromString(@"UIInputSetHostView")]) {
                    return CGRectGetHeight(possibleKeyboardSubview.bounds);
                }
            }
        }
    }
#endif
    return 0;
}