Question

所以我有3个视图控制器，命名为：

- Dashboard
- Map
- Location List

在MapVC中，我附加了一个大的uiview和自定义类的XMapView。在XMapView内部我有这段代码

- (id)initWithFrame:(CGRect)aRect {
if ((self = [super initWithFrame:aRect])) {
    [self commonInit];
}
return self;
}

- (id)initWithCoder:(NSCoder*)coder {
if ((self = [super initWithCoder:coder])) {
    [self commonInit];
}
return self;
}

- (void)commonInit{
UIView *mapView = [[[NSBundle mainBundle] loadNibNamed:@"XMapView"
                                                 owner:self
                                               options:nil] objectAtIndex:0];

mapView.frame = self.bounds;
mapView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
[self addSubview: mapView];
}

所以基本上MapVC只是注入XmapView并显示它。

我在MapVC控制器中有这个代码。请注意，我已将MapVC内的自定义类视图发布到.h文件。

//.h file
@property (strong, nonatomic) IBOutlet XMapView *mapStoreView;

//.m file
- (void)viewWillAppear:(BOOL)animated{
[super viewWillAppear:animated];

// this following code will load the Map from the XMapView to the MapVC
[self.mapStoreView loadMap:self.results viewController:self selectedOutletFromList:self.selectedOutletFromList];
}
- (void)viewWillDisappear:(BOOL)animated{
[super viewWillDisappear:animated];
[self.mapStoreView removeFromSuperview];
self.mapStoreView = nil;
self.mapStoreView.mkMapView.delegate = nil;
[self.mapStoreView.mkMapView removeAnnotations:self.mapStoreView.mkMapView.annotations];
self.results = nil;
}

序列是仪表板 - ＆gt; MapVC - ＆gt;位置清单

测试用例：

1. Dashboard -> MapVC, map will load.
2. MapVC -> Location List -> MapVC, map will not load.
3. Dashboard -> MapVC -> Dashboard -> MapVC, map will always load.

这里有什么问题？我错过了什么吗？

Answer 1

在您的代码中

- (void)viewWillDisappear:(BOOL)animated{
[super viewWillDisappear:animated];
[self.mapStoreView removeFromSuperview];
self.mapStoreView = nil;
self.mapStoreView.mkMapView.delegate = nil;
[self.mapStoreView.mkMapView removeAnnotations:self.mapStoreView.mkMapView.annotations];
self.results = nil;
}

当您推送到名为Location List的新viewController时，您从超级视图中删除了mapStoreView，当您返回时，您没有恢复mapStoreView，所以它已经消失。

如果self消失，将调用viewDidDisappear，包括推送一个新的viewcontroller，从navigationController弹出，提供一个新的viewcontroller并关闭自我控制器。

如果你想释放内存，你应该在dealloc方法中执行这些工作，这将在取消分配控制器时调用。

像这样：

        -dealloc
        {
[self.mapStoreView removeFromSuperview];
        self.mapStoreView = nil;
        self.mapStoreView.mkMapView.delegate = nil;
        [self.mapStoreView.mkMapView removeAnnotations:self.mapStoreView.mkMapView.annotations];
        self.results = nil;
    }

Answer 2

更改如下：

你是mapStoreView的nil IBOutlet所以当你来自位置时它不会加载

它将HomeVc加载到MapVc，因为你正在创建mapVc的新实例，以便在那里创建新的iboutlet。

您的测试用例

1. Dashboard -> MapVC, map will load. - because new instance of MapVC created on  Dashboard 
2. MapVC -> Location List -> MapVC, map will not load. - because you are nil iboutlet in ViewDidDisappear so it is not longer for load.
3. Dashboard -> MapVC -> Dashboard -> MapVC, map will always load. - because new instance of MapVC created on  Dashboard always.

进行如下更改

- (void)viewWillDisappear:(BOOL)animated{
   [super viewWillDisappear:animated];
}

当您的viewcontroller取消分配时，此方法会自动调用。

 -(void)dealloc
            {
             [self.mapStoreView removeFromSuperview];
            self.mapStoreView = nil;
            self.mapStoreView.mkMapView.delegate = nil;
            [self.mapStoreView.mkMapView removeAnnotations:self.mapStoreView.mkMapView.annotations];
            self.results = nil;
        }

使用自定义类init的iOS Obj-C视图

2 个答案: