如何遍历数组的元素<UnsafeMutablePointer>在斯威夫特

Question

I am new to Swift and wanted to loop through an array of MKMapPoints<UnsafeMutablePointer> which I get from an MKPolygon by calling myPoly.points() . However, I am stuck as to how to loop through every element of the C-Array of pointers.

for element in myPointsArray {} 

does not work and I don't know how to determine the number of elements of this kind of array in Swift. Any ideas? Thanks for your help!

Answer 1

UnsafeBufferPointer presents an unsafe pointer and a count as a collection so you can for..in over it, subscript it safely, pass it to algorithms that work on collections etc:

for point in UnsafeBufferPointer(start: poly.points(), count: poly.pointCount) {
    println("\(point.x),\(point.y)")
}

Answer 2

You can get the count of points from MKPolygon.pointCount property. And iterate points with traditional for ; ; {} for ; ; {} for ; ; {} loop:

let myPointsArray = myPoly.points()

for var i = 0, len = myPoly.pointCount; i < len; i++ {
    let point = myPointsArray[i]
    println(point)
}