Unity uses macros

Can be in player setting It defines macros

It can also be defined by code

		PlayerSettings.SetScriptingDefineSymbolsForGroup(BuildTargetGroup.Standalone, item.Symbol);// Save information to macro information .  Parameters 1: To which platform   Parameters 2: What to save .

Official explanation

• I used to think that after defining a symbol , It is necessary to judge whether this symbol exists . But there is no need to .
  
  C# Instructions explain in detail

Use multi-channel packaging sdk

• This is very useful because it can be packaged through multiple channels sdk
• Define different channels symbol
• And these sdk All relevant access property codes take precompiled instructions
• When automated packaging , Define these symbol, Output different packages
• But I have another problem , That is to say , How to distinguish different files .
• That is to say oppo Need to rely on oppo.dll, Huawei needs to rely on huawei.dll
• How to eliminate these documents when typing different kinds of packages .

[CreateAssetMenu(order =12,menuName =" Create channel settings ")]
public class ChannelSetting : ScriptableObject
{
    
    public string Channel;
    public string Symbol;

}

	[MenuItem("Build/BuildAll")]
	static void BuildAllPlatform()
	{
    
		var settings = Resources.LoadAll<ChannelSetting>("ChannelSettings");
		foreach (var item in settings)
		{
    
			PlayerSettings.SetScriptingDefineSymbolsForGroup(BuildTargetGroup.Standalone, item.Symbol);// Save information to macro information .  Parameters 1: To which platform   Parameters 2: What to save .
			var path =Path.Combine( System.Environment.CurrentDirectory, item.Channel, $"{
      item.Channel}.exe");
			BuildPlayerOptions buildPlayerOptions = new BuildPlayerOptions();
			buildPlayerOptions.locationPathName = path;
			buildPlayerOptions.target = BuildTarget.StandaloneWindows;
			buildPlayerOptions.targetGroup = BuildTargetGroup.Standalone;
			var res = BuildPipeline.BuildPlayer(buildPlayerOptions);
		}


	}

• One of the more pitfalls is , When packaging, you need to specify the output folder , I always thought it was to specify folders , The results have been consistent Report errors UnityException: Build path contains project built with "Create Visual Studio Solution" option, which is incompatible with current build settings. Consider building your project into an empty directory.
• In fact, you need to add the name of the file