请注意新编辑!!!!
所以我正在尝试创建一个从数组中加载注释并在地图上显示它们的应用程序...然后当您在左侧的UITable中选择一个位置时，它会缩放到右侧地图上的位置。下面是加载注释，设置部分数量（在UITable中查看），设置每个部分中的行数，最后将注释名称写入UITable的代码，以便它可以用作选择器。
问题：App运行但左侧的UITable（用于选择位置）在Hotels部分中没有显示任何内容，在AerialView部分显示单词“Empty”，并在Streets部分显示一个位置Streets部分中的剩余行为空。
很明显，注释名称没有正确加载到我的UITable中。有什么想法吗？
-(void) loadOutAnnotations
{
CLLocationCoordinate2D workingCoordinate;
//***********HOTELS**************************
workingCoordinate.latitude = 40.763856;
workingCoordinate.longitude = -73.973034;
iCodeBlogAnnotation *hotel1 = [[iCodeBlogAnnotation alloc] initWithCoordinate:workingCoordinate];
[hotel1 setTitle:@"Hotel 1"];
[hotel1 setSubtitle:@"This is Hotel #1"];
[hotel1 setAnnotationType:iCodeBlogAnnotationTypeHotels];
[mapView addAnnotation:hotel1];
workingCoordinate.latitude = 50.763856;
workingCoordinate.longitude = -83.973034;
iCodeBlogAnnotation *hotel2 = [[iCodeBlogAnnotation alloc] initWithCoordinate:workingCoordinate];
[hotel1 setTitle:@"Hotel 2"];
[hotel1 setSubtitle:@"This is Hotel #2"];
[hotel1 setAnnotationType:iCodeBlogAnnotationTypeHotels];
[mapView addAnnotation:hotel2];
workingCoordinate.latitude = 60.763856;
workingCoordinate.longitude = -93.973034;
iCodeBlogAnnotation *hotel3 = [[iCodeBlogAnnotation alloc] initWithCoordinate:workingCoordinate];
[hotel1 setTitle:@"Hotel 3"];
[hotel1 setSubtitle:@"This is Hotel #3"];
[hotel1 setAnnotationType:iCodeBlogAnnotationTypeHotels];
[mapView addAnnotation:hotel3];
workingCoordinate.latitude = 10.763856;
workingCoordinate.longitude = -23.973034;
iCodeBlogAnnotation *hotel4 = [[iCodeBlogAnnotation alloc] initWithCoordinate:workingCoordinate];
[hotel1 setTitle:@"Hotel 4"];
[hotel1 setSubtitle:@"This is Hotel #4"];
[hotel1 setAnnotationType:iCodeBlogAnnotationTypeHotels];
[mapView addAnnotation:hotel4];
workingCoordinate.latitude = 30.763856;
workingCoordinate.longitude = -43.973034;
iCodeBlogAnnotation *hotel5 = [[iCodeBlogAnnotation alloc] initWithCoordinate:workingCoordinate];
[hotel1 setTitle:@"Hotel 5"];
[hotel1 setSubtitle:@"This is Hotel #5"];
[hotel1 setAnnotationType:iCodeBlogAnnotationTypeHotels];
[mapView addAnnotation:hotel5];
// *****************AERIALS*****************************
workingCoordinate.latitude = 25.763856;
workingCoordinate.longitude = -15.973034;
iCodeBlogAnnotation *aerial1 = [[iCodeBlogAnnotation alloc] initWithCoordinate:workingCoordinate];
[hotel1 setTitle:@"Aerial 1"];
[hotel1 setSubtitle:@"This is Aerial #1"];
[hotel1 setAnnotationType:iCodeBlogAnnotationTypeAerialShots];
[mapView addAnnotation:aerial1];
workingCoordinate.latitude = 35.763856;
workingCoordinate.longitude = -25.973034;
iCodeBlogAnnotation *aerial2 = [[iCodeBlogAnnotation alloc] initWithCoordinate:workingCoordinate];
[hotel1 setTitle:@"Aerial 2"];
[hotel1 setSubtitle:@"This is Aerial #2"];
[hotel1 setAnnotationType:iCodeBlogAnnotationTypeAerialShots];
[mapView addAnnotation:aerial2];
workingCoordinate.latitude = 45.763856;
workingCoordinate.longitude = -35.973034;
iCodeBlogAnnotation *aerial3 = [[iCodeBlogAnnotation alloc] initWithCoordinate:workingCoordinate];
[hotel1 setTitle:@"Aerial 3"];
[hotel1 setSubtitle:@"This is Aerial #3"];
[hotel1 setAnnotationType:iCodeBlogAnnotationTypeAerialShots];
[mapView addAnnotation:aerial3];
workingCoordinate.latitude = 55.763856;
workingCoordinate.longitude = -45.973034;
iCodeBlogAnnotation *aerial4 = [[iCodeBlogAnnotation alloc] initWithCoordinate:workingCoordinate];
[hotel1 setTitle:@"Aerial 4"];
[hotel1 setSubtitle:@"This is Aerial #4"];
[hotel1 setAnnotationType:iCodeBlogAnnotationTypeAerialShots];
[mapView addAnnotation:aerial4];
workingCoordinate.latitude = 65.763856;
workingCoordinate.longitude = -55.973034;
iCodeBlogAnnotation *aerial5 = [[iCodeBlogAnnotation alloc] initWithCoordinate:workingCoordinate];
[hotel1 setTitle:@"Aerial 5"];
[hotel1 setSubtitle:@"This is Aerial #5"];
[hotel1 setAnnotationType:iCodeBlogAnnotationTypeAerialShots];
[mapView addAnnotation:aerial5];
// *****************STREETS*****************************
workingCoordinate.latitude = 27.763856;
workingCoordinate.longitude = -37.973034;
iCodeBlogAnnotation *street1 = [[iCodeBlogAnnotation alloc] initWithCoordinate:workingCoordinate];
[hotel1 setTitle:@"Street 1"];
[hotel1 setSubtitle:@"This is Street #1"];
[hotel1 setAnnotationType:iCodeBlogAnnotationTypeStreets];
[mapView addAnnotation:street1];
workingCoordinate.latitude = 37.763856;
workingCoordinate.longitude = -47.973034;
iCodeBlogAnnotation *street2 = [[iCodeBlogAnnotation alloc] initWithCoordinate:workingCoordinate];
[hotel1 setTitle:@"Street 2"];
[hotel1 setSubtitle:@"This is Street #2"];
[hotel1 setAnnotationType:iCodeBlogAnnotationTypeStreets];
[mapView addAnnotation:street2];
workingCoordinate.latitude = 57.763856;
workingCoordinate.longitude = -67.973034;
iCodeBlogAnnotation *street3 = [[iCodeBlogAnnotation alloc] initWithCoordinate:workingCoordinate];
[hotel1 setTitle:@"Street 3"];
[hotel1 setSubtitle:@"This is Street #3"];
[hotel1 setAnnotationType:iCodeBlogAnnotationTypeStreets];
[mapView addAnnotation:street3];
workingCoordinate.latitude = 77.763856;
workingCoordinate.longitude = -87.973034;
iCodeBlogAnnotation *street4 = [[iCodeBlogAnnotation alloc] initWithCoordinate:workingCoordinate];
[hotel1 setTitle:@"Street 4"];
[hotel1 setSubtitle:@"This is Street #4"];
[hotel1 setAnnotationType:iCodeBlogAnnotationTypeStreets];
[mapView addAnnotation:street4];
workingCoordinate.latitude = 87.763856;
workingCoordinate.longitude = -97.973034;
iCodeBlogAnnotation *street5 = [[iCodeBlogAnnotation alloc] initWithCoordinate:workingCoordinate];
[hotel1 setTitle:@"Street 5"];
[hotel1 setSubtitle:@"This is Street #5"];
[hotel1 setAnnotationType:iCodeBlogAnnotationTypeStreets];
[mapView addAnnotation:street5];
}
- (iCodeBlogAnnotationView *)mapView:(MKMapView *)mapView
viewForAnnotation:(id<MKAnnotation>)annotation
{
iCodeBlogAnnotationView *annotationView = nil;
iCodeBlogAnnotation *myAnnotation = (iCodeBlogAnnotation *)annotation;
if(myAnnotation.annotationType == iCodeBlogAnnotationTypeHotels)
{
NSString *identifier = @"Hotels";
iCodeBlogAnnotationView *newAnnotationView = (iCodeBlogAnnotationView*)[self.mapView dequeueReusableAnnotationViewWithIdentifier:identifier];
if (newAnnotationView == nil)
{
newAnnotationView = [[[iCodeBlogAnnotationView alloc] initWithAnnotation:myAnnotation reuseIdentifier:identifier]autorelease];
}
annotationView = newAnnotationView;
}
else if(myAnnotation.annotationType == iCodeBlogAnnotationTypeAerialShots)
{
NSString *identifier = @"AerialShots";
iCodeBlogAnnotationView *newAnnotationView = (iCodeBlogAnnotationView*)[self.mapView dequeueReusableAnnotationViewWithIdentifier:identifier];
if (newAnnotationView == nil)
{
newAnnotationView = [[[iCodeBlogAnnotationView alloc] initWithAnnotation:myAnnotation reuseIdentifier:identifier]autorelease];
}
annotationView = newAnnotationView;
}
else if(myAnnotation.annotationType == iCodeBlogAnnotationTypeStreets)
{
NSString *identifier = @"Streets";
iCodeBlogAnnotationView *newAnnotationView = (iCodeBlogAnnotationView*)[self.mapView dequeueReusableAnnotationViewWithIdentifier:identifier];
if (newAnnotationView == nil)
{
newAnnotationView = [[[iCodeBlogAnnotationView alloc] initWithAnnotation:myAnnotation reuseIdentifier:identifier]autorelease];
}
annotationView = newAnnotationView;
}
[annotationView setEnabled:YES];
[annotationView setCanShowCallout:YES];
return annotationView;
}
#pragma mark tableview dataSource methods
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
return 3;
}
- (NSString *)tableView:(UITableView *)tableView
titleForHeaderInSection:(NSInteger)section
{
if (section == iCodeBlogAnnotationTypeHotels)
{
return @"Hotels";
}
else if (section == iCodeBlogAnnotationTypeAerialShots)
{
return @"AerialShots";
}
else if (section == iCodeBlogAnnotationTypeStreets)
{
return @"Streets";
}
return nil;
}
- (NSInteger)tableView:(UITableView *)tableView
numberOfRowsInSection:(NSInteger)section
{
return 5;
}
- (UITableViewCell *)tableView:(UITableView *)tableView
cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = @"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil)
{
cell = [[[UITableViewCell alloc] initWithStyle:(UITableViewCellStyleDefault) reuseIdentifier:CellIdentifier]autorelease];
}
// here we are creating an array object BUT it is empty (it has no object in it)
NSMutableArray *annotations = [[NSMutableArray alloc] init];
if(indexPath.section == 0)
{
for(iCodeBlogAnnotation *annotation in [mapView annotations])
{
if([annotation annotationType] == iCodeBlogAnnotationTypeHotels)
{
// here is the line where we actually add objects to the array
[annotations addObject:annotation];
}
}
if ([annotations count] > indexPath.row)
{
cell.textLabel.text = [[annotations objectAtIndex:indexPath.row] title];
}
else
{
cell.textLabel.text = @"Empty";
}
}
else if (indexPath.section == 1)
{
for(iCodeBlogAnnotation *annotation in [mapView annotations])
{
if([annotation annotationType] == iCodeBlogAnnotationTypeAerialShots)
{
[annotations addObject:annotation];
}
}
if ([annotations count] > indexPath.row)
{
cell.textLabel.text = [[annotations objectAtIndex:indexPath.row] title];
}
else
{
cell.textLabel.text = @"Empty";
}
}
else if (indexPath.section == 2)
{
for(iCodeBlogAnnotation *annotation in [mapView annotations])
{
if([annotation annotationType] == iCodeBlogAnnotationTypeStreets)
{
[annotations addObject:annotation];
}
}
if ([annotations count] > indexPath.row)
{
cell.textLabel.text = [[annotations objectAtIndex:indexPath.row] title];
}
else
{
cell.textLabel.text = @"Empty";
}
}
return cell;
}
答案 0 :(得分：0)
就像这样，你访问一个数组：
cell.textLabel.text = [[annotations objectAtIndex:indexPath.row] title];
可能注释数组是空的！
答案 1 :(得分：0)
当您创建一个NSMutableArray *annotations = [[NSMutableArray alloc] init];的对象时，它存在，但它是空的。也就是说，它没有任何对象。您只需在此行中向对象添加对象：[annotations addObject:annotation];，您可能永远无法访问它。也就是说，您最终只会在正确的annotation的{{1}}中添加与[mapView annotations]一样多的对象。
然后盲目地访问数组的特定元素，而不检查是否有足够的元素。
至少，你应该替换这一行：
annotationType有这样的事情：
cell.textLabel.text = [[annotations objectAtIndex:indexPath.row] title];
更好的是，您应该更改
的实施方式if ([annotations count] > indexPath.row) {
cell.textLabel.text = [[annotations objectAtIndex:indexPath.row] title];
}
else {
cell.textLabel.text = @"Empty";
}
确保您永远不会说某个部分中的行数多于实际注释中的行数。
答案 2 :(得分：0)
这是一个坏主意。在viewDidLoad中初始化您的数组（否则每次有单元格时都会这样做）。在表执行之前，在viewDidLoad中使用值加载数组。如果你不能添加值，那么放一个if语句，确保如果数组大小为零，那么不要做任何访问数组的代码