Ios Swift错误：Struct'；XX和x27；必须在将成员存储到之前完全初始化

我试图用Swift定义AudioStreamBasicDescription

在Objective-C中，我使用了如下代码

AudioStreamBasicDescription ASBD;
ASBD.mSampleRate            = 8000;
ASBD.mFormatID              = kAudioFormatLinearPCM;
ASBD.mFormatFlags           = kAudioFormatFlagsCanonical | kAudioFormatFlagIsSignedInteger | kAudioFormatFlagIsPacked;
ASBD.mFramesPerPacket       = 1;
ASBD.mChannelsPerFrame      = 1;
ASBD.mBitsPerChannel        = 16;
ASBD.mBytesPerPacket        = 2;
ASBD.mBytesPerFrame         = 2;

我转换的Swift代码如下

var ASBD: AudioStreamBasicDescription
ASBD.mSampleRate = 8000  // ERROR here
ASBD.mFormatID = kAudioFormatLinearPCM
ASBD.mFormatFlags = kAudioFormatFlagIsSignedInteger | kAudioFormatFlagIsPacked
ASBD.mFramesPerPacket = 1
ASBD.mChannelsPerFrame = 1
ASBD.mBitsPerChannel = 16
ASBD.mBytesPerPacket = 2
ASBD.mBytesPerFrame = 2

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但是swift代码的第二行抛出了这个错误。我不知道为什么会出现这个错误。有人能帮我吗？

这意味着在使用结构之前需要完全初始化它

AudioStreamBasicDescription

是一种结构，因此在使用它之前需要对其进行初始化。正确的代码如下所示：

var ASBD: AudioStreamBasicDescription! = AudioStreamBasicDescription()
ASBD.mSampleRate = 8000
ASBD.mFormatID = kAudioFormatLinearPCM
ASBD.mFormatFlags = kAudioFormatFlagIsSignedInteger | kAudioFormatFlagIsPacked
ASBD.mFramesPerPacket = 1
ASBD.mChannelsPerFrame = 1
ASBD.mBitsPerChannel = 16
ASBD.mBytesPerPacket = 2
ASBD.mBytesPerFrame = 2

---

是

必要！