Question

我在这段代码中得到了一个EXC_BAD_ACCESS错误，其中常量＆＃34; line＆＃34;被宣布。在表示＆＃34;行的行：CTLine = CTLineCreateWithAttributedString（attrString）＆＃34;。确切的错误是＆＃34;线程12：EXC_BAD_ACCESS（代码= 1，地址= 0x7e8）＆＃34;。

我可以帮助找出问题吗？

我也在类似问题的答案中看到了一些名为＆＃34; Zombie＆＃34;帮助调试。什么是僵尸，我该怎么做呢？

import UIKit
import MapKit
import CoreText

class LabelOverlayRenderer: MKOverlayRenderer {

    override func draw(_ mapRect: MKMapRect, zoomScale: MKZoomScale, in context: CGContext) {

//        let labelOverlay = overlay as! LabelOverlay

        let string: CFString
        let font: CTFont

        let nsString = NSString(string: "Hello" as CFString)
        string = nsString as CFString

        font = CTFontCreateUIFontForLanguage(.label, 17, "US" as CFString)!

        var keys: [CFString] = [kCTFontAttributeName]
        var values: [CFTypeRef] = [font]

        var mutablePointerKeys: UnsafeMutablePointer<UnsafeRawPointer?>!
        var rawPointerKeys: UnsafeRawPointer?

        rawPointerKeys = UnsafeRawPointer?(&keys)
        mutablePointerKeys = UnsafeMutablePointer<UnsafeRawPointer?>!(&rawPointerKeys)

        var mutablePointerValues: UnsafeMutablePointer<UnsafeRawPointer?>!
        var rawPointerValues: UnsafeRawPointer?

        rawPointerValues = UnsafeRawPointer?(&values)
        mutablePointerValues = UnsafeMutablePointer<UnsafeRawPointer?>!(&rawPointerValues)

        var cfTypeDictionaryKeyCallBacks = CFDictionaryKeyCallBacks()
        var cfTypeDictionaryValueCallBacks = CFDictionaryValueCallBacks()

        let attributes: CFDictionary = CFDictionaryCreate(kCFAllocatorDefault, mutablePointerKeys, mutablePointerValues, MemoryLayout.size(ofValue: keys)/MemoryLayout.size(ofValue: keys[0]), &cfTypeDictionaryKeyCallBacks, &cfTypeDictionaryValueCallBacks)

        let attrString: CFAttributedString = CFAttributedStringCreate(kCFAllocatorDefault, string, attributes)

        let line: CTLine = CTLineCreateWithAttributedString(attrString) // * Error occurs here. It says "Thread 12: EXC_BAD_ACCESS (code=1, address=0x7e8)". 

        context.textPosition = CGPoint(x: 10, y: 10)
        CTLineDraw(line, context)

    }
}

Answer 1

当您想要访问当前已分配的变量时，您将拥有EXC_BAD_ACCESS，启用Zombie后您可以看到该变量，请参阅此内容以启用它nszombie

使用核心文本的EXC_BAD_ACCESS错误

1 个答案: