Question

我不确定我的代码有什么问题。以下是我可能存在问题的3个功能。它是适用于iOS的Google地图应用。

错误消息：由于未捕获的异常终止应用＆＃39; NSInvalidArgumentException＆＃39;，原因：＆＃39; - [__ NSArrayI floatValue]：无法识别的选择器发送到实例0x60000042e680＆＃39; < / p>

     - (void)drawPolygon{
    GMSMutablePath *rect = [GMSMutablePath path];
    for (int i = 0; i <= [tappedCoordinates count]-1; i++) {
    event.latitude = [[tappedCoordinates objectAtIndex:i] floatValue];
    event.longitude = [[tappedCoordinates objectAtIndex:i] floatValue];
    [rect addCoordinate:event];
}
// first tapped point to connect with last point in order to close the polygon.
event.latitude = [[tappedCoordinates objectAtIndex:0] floatValue];
event.longitude = [[tappedCoordinates objectAtIndex:0] floatValue];
[rect addCoordinate:event];
...
}

  - (void)addMarker{
for (int i = 0; i <= [tappedCoordinates count]-1; i++) {
position.latitude = [[[tappedCoordinates objectAtIndex:i] objectAtIndex:0] floatValue];
position.longitude = [[[tappedCoordinates objectAtIndex:i] objectAtIndex:1] floatValue];
...
}

Answer 1

你只是没有深入到数组中以获得实际的长/纬度值：

for (int i = 0; i <= [tappedCoordinates count]-1; i++) {
    event.latitude = [[[tappedCoordinates objectAtIndex:i] objectAtIndex:0] floatValue];
    event.longitude = [[[tappedCoordinates objectAtIndex:i] objectAtIndex:1] floatValue];
    [rect addCoordinate:event];
}

event.latitude = [[[tappedCoordinates objectAtIndex:0] objectAtIndex:0] floatValue];
event.longitude = [[[tappedCoordinates objectAtIndex:0] objectAtIndex:1] floatValue];

修改只是为了澄清 - [tappedCoordinates objectAtIndex：0]是一个NSArray。当你在它上面调用floatValue时，NSArray不知道该怎么做，因为它不是一个数值。此外，您的方法的替代方法是拥有一个CGPoint对象数组（实现比嵌套数组稍好）：

NSMutableArray *coords = [NSMutableArray new]; CGPoint coord = CGPointMake(1.5f, 2.5f); [coords addObject:[NSValue valueWithCGPoint: coord]]; CGPoint storedCoord = [[coords objectAtIndex:0] CGPointValue]; NSLog (@"Lat: %f, long: %f", storedCoord.x, storedCoord.y);

您甚至可以更进一步创建一个子类CGPoint（名为Coordinate），它具有纬度和经度属性，可以分别返回x和y（主要是为了提高可读性）。

无法识别的选择器发送到实例错误 - 这是我的错误？

1 个答案: