Unity PlayerPrefs 的一個坑

本週在測試 deeplink 時遇到一個閃退的問題，提取日誌：

03-05 10:46:30.442  2633  2633 D Unity   : Uploading Crash Report
03-05 10:46:30.443  2633  2633 E Unity   : UnityException: TrySetSetString can only be called from the main thread.
03-05 10:46:30.443  2633  2633 E Unity   : Constructors and field initializers will be executed from the loading thread when loading a scene.
03-05 10:46:30.443  2633  2633 E Unity   : Don't use this function in the constructor or field initializers, instead move initialization code to the Awake or Start function.
03-05 10:46:30.443  2633  2633 E Unity   : 
03-05 10:46:30.443  2633  2633 E Unity   : Rethrow as TargetInvocationException: com.adjust.sdk.AdjustAndroid+DeferredDeeplinkListener.launchReceivedDeeplink(UnityEngine.AndroidJavaObject)
03-05 10:46:30.443  2633  2633 E Unity   :   at UnityEngine.AndroidJavaProxy.Invoke (System.String methodName, System.Object[] args) [0x00000] in <00000000000000000000000000000000>:0 
03-05 10:46:30.443  2633  2633 E Unity   :  
03-05 10:46:30.443  2633  2633 E Unity   : (Filename: currently not available on il2cpp Line: -1)
03-05 10:46:30.443  2633  2633 E Unity   : 

關鍵信息是 UnityException: TrySetSetString can only be called from the main thread，即 SetString 只能在主線程中被調用。

回到代碼處：

void DeferredDeeplinkCallback(string param)
{
	UnityEngine.PlayerPrefs.SetString(key, param); 
}

這個函數是在 adjust 初始化時注入的，也就是說實際進行 SetString 確實不是 unity 主線程。

解決這個問題的一個簡單思路是，將內容緩存下來，等待主線程去執行 SetString。

void checkDeeplink()
{
	if (!string.IsNullOrEmpty(_deeplink))
	{
		UnityEngine.PlayerPrefs.SetString(key, _deeplink);
		_deeplink = null;
	}
}