ios - Google map ios - 如何始终显示标记信息窗口？

Question

我正在努力防止信息窗口消失。为了展示它我用过

[mapView_ setSelectedMarker:marker];

但是当用户在某处点击地图时，信息窗口就会消失。我尝试将其重新设置为，didTapAtCoordinate但在取消选择任何标记之前会调用它。怎么做？

Answer 1

对于任何想在Swift 4中测试 Hanton 解决方案的人，简化为在页面加载后始终显示信息窗口：

override func viewDidLoad() {
    mapView.addObserver(self, forKeyPath: "selectedMarker", options: [.new, .old], context: nil)
}

override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) {
    if keyPath == "selectedMarker" {
        if change?[.newKey] as? NSObject is NSNull {
            mapView.selectedMarker = change?[.oldKey] as? GMSMarker
        }
    }
}

这确实有效，尽管当用户点击时信息窗口会短暂闪烁并消失并重新出现。

Answer 2

Key Value Observing 是本案例的设计模式。这个答案对我有用。

- (void)viewDidLoad {
  [super viewDidLoad];
  self.shouldShowInfoView = NO;
  [self.mapView addObserver:self
            forKeyPath:@"selectedMarker"
               options:(NSKeyValueObservingOptionNew |
                        NSKeyValueObservingOptionOld)
               context:NULL];
}

- (void)needToShowInfoView {
  self.shouldShowInfoView = YES;
}

- (void)observeValueForKeyPath:(NSString *)keyPath
                      ofObject:(id)object
                        change:(NSDictionary *)change
                       context:(void *)context {

  if ([keyPath isEqual:@"selectedMarker"]) {
    if (self.shouldShowInfoView) {
      if ([[change objectForKey:NSKeyValueChangeNewKey] isKindOfClass:[NSNull class]]) {
        self.mapView.selectedMarker = [change objectForKey:NSKeyValueChangeOldKey];
      }
    }
  }
}