Unity iOS本地插件的制作

iOS中，将C、C++、Objective-C代码，以及实现面向iOS编译的库作为本地插件使用。
以制作一个获取地理位置的本地插件为例。
创建名为 “LocationPlugin.mm” 的文件，放在Assets/Plugins/iOS文件夹下，代码如下：

// LocationPlugin.mm
#import <Foundation/Foundation.h>
#import <CoreLocation/CoreLocation.h>


@interface LocationPlugin : NSObject<CLLocationManagerDelegate>
// 采用CLLocationManagerDelegate协议
{
	CLLocationManager *locationManager;	
	NSString *callbackTarget;			
	bool isReverseGeocoding;			// 是否处于反地理编码处理
}

+ (LocationPlugin *)sharedInstance;		

@end

// LocationPlugin类定义
@implementation LocationPlugin

// 单例
static LocationPlugin *sharedInstance = nil;
+ (id)sharedInstance
{
	@synchronized(self)
	{
		if(sharedInstance == nil)
		{
			sharedInstance = [[self alloc] init];
		}
	}
	return sharedInstance;
}

// 开始获取位置信息
- (BOOL)startUpdatingLocation:(NSString *)newCallbackTarget
{
	// 缓存回调
	callbackTarget = newCallbackTarget;
	
	if(locationManager == nil)
	{
		locationManager = [[CLLocationManager alloc] init];
	}

	// 确认位置信息服务是否有效且被许可
	BOOL isEnabledAndAuthorized = NO;
	if([CLLocationManager locationServicesEnabled])
	{
		CLAuthorizationStatus status = [CLLocationManager authorizationStatus];
		if(status == kCLAuthorizationStatusAuthorizedAlways || 
		   status == kCLAuthorizationStatusAuthorizedWhenInUse)
		{
			isEnabledAndAuthorized = YES;
		}
	}
	if(!isEnabledAndAuthorized)
	{
		// 位置信息服务无效且未被许可时，请求用户授权
		[locationManager requestWhenInUseAuthorization];
		return NO;
	}
	
	// 开始获取位置信息
	locationManager.delegate = self;
	locationManager.desiredAccuracy = kCLLocationAccuracyBest;
	[locationManager startUpdatingLocation];

	return YES;
}

// 停止获取位置信息
- (void)stopUpdatingLocation
{
	if(locationManager != nil)
	{
		[locationManager stopUpdatingLocation];
	}
}

#pragma mark - CLLocationManagerDelegate协议的方法实现

// 更新位置信息时调用
- (void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations
{
	if(isReverseGeocoding)
	{
		return;
	}
	
	// 基于获取的位置信息进行反地理编码以获取地址
	isReverseGeocoding = YES;
	
	CLLocation *location = [locations lastObject];
	CLGeocoder *geocoder = [[CLGeocoder alloc] init];
	[geocoder reverseGeocodeLocation:location
				   completionHandler:^(NSArray *placemarks, NSError *error) {
		isReverseGeocoding = NO;

		// 从CLPlacemark对象的FormattedAddressLines中获取地址的字符串
		NSString *addressString = @"";
		if(placemarks.count >= 1)
		{
			CLPlacemark *placemark = [placemarks firstObject];
			NSArray *addressLines = 
				[placemark addressDictionary][@"FormattedAddressLines"];
			addressString = [addressLines componentsJoinedByString:@" "];
		}

		// 创建作为参数传递的字符串
		NSString *parameter = [NSString stringWithFormat:@"%f\t%f\t%f\t%f\t%@",
							   location.coordinate.latitude, 
							   location.coordinate.longitude,
							   location.speed, location.horizontalAccuracy,
							   addressString];

		// 使用UnitySendMessage方法调用Unity的OnUpdateLocation方法
		UnitySendMessage([callbackTarget cStringUsingEncoding:NSUTF8StringEncoding],
						 "OnUpdateLocation",
						 [parameter cStringUsingEncoding:NSUTF8StringEncoding]);
	}];
}

// 其他必须的方法
- (void)locationManager:(CLLocationManager *)manager
	  didDetermineState:(CLRegionState)state forRegion:(CLRegion *)region {}

- (void)locationManagerDidPauseLocationUpdates:(CLLocationManager *)manager {}

- (void)locationManagerDidResumeLocationUpdates:(CLLocationManager *)manager {}

@end

#pragma mark - 接口

// 为回避C++命名粉碎，以C linkage进行声明
extern "C" {
	// 用于调用开始获取位置信息方法的接口
	BOOL _startUpdatingLocation(const char *callbackTarget)
	{
		LocationPlugin *instance = [LocationPlugin sharedInstance];
		@synchronized(instance)
		{
			return [instance startUpdatingLocation:
				[NSString stringWithUTF8String:callbackTarget]];
		}
	}

	// 用于调用停止获取位置信息方法的接口
	void _stopUpdatingLocation()
	{
		LocationPlugin *instance = [LocationPlugin sharedInstance];
		@synchronized(instance)
		{
			[instance stopUpdatingLocation];
		}
	}
}

注意选中LocationPlugin.mm脚本后，可以在Inspector面板中选择platforms for plugin，要选择iOS
接下来是从Unity方的脚本实现调用本地插件接口
创建名为 “LocationPluginInterface.cs” 的文件，代码如下

using UnityEngine;
using System.Runtime.InteropServices;

public class LocationPluginInterface
{
#if UNITY_IOS
	// 访问本地插件接口的声明
	[DllImport ("__Internal")]
	private static extern bool _startUpdatingLocation(string callbackTarget);

	[DllImport ("__Internal")]
	private static extern void _stopUpdatingLocation();
#endif
	

	// 开始获取位置信息
	public static bool StartUpdatingLocation(string callbackTarget)
	{
#if !UNITY_EDITOR
		return _startUpdatingLocation(callbackTarget);
#else
		return false;
#endif
	}
	
	// 停止获取位置信息
	public static void StopUpdatingLocation()
	{
#if !UNITY_EDITOR
		_stopUpdatingLocation();
#endif
	}
}

接下来是测试，测试脚本LocationExample.cs，代码如下（含有一些ui逻辑，根据实际需求进行设计），注意LocationExample.cs要挂到场景中的某个物体上，并且物体的名字要读一无二，因为本地插件回调是通过名字来找对应的物体的）

// LocationExample.cs
using UnityEngine;
using UnityEngine.UI;

public class LocationExample : MonoBehaviour
{
	[SerializeField] private Text addressLabel;		// 地址
	[SerializeField] private Text latitudeLabel;	// 维度
	[SerializeField] private Text longitudeLabel;	// 经度
	[SerializeField] private Text speedLabel;		// 移动速度
	[SerializeField] private Text accuracyLabel;	// 精度
	
	// 是否正在获取位置信息
	private bool IsUpdatingLocation { get; set; }
	
	void Awake()
	{
		IsUpdatingLocation = false;
		UpdateUpdateLocationButton();
	}

	private void UpdateUpdateLocationButton()
	{
		Animator animator = GetComponent<Animator>();
		if(animator != null)
		{
			animator.SetTrigger(IsUpdatingLocation? "Started": "Stopped");
		}
	}
	
	// 按下开始/停止获取位置信息按钮
	public void OnPressUpdateLocationButton()
	{
		IsUpdatingLocation = !IsUpdatingLocation;
		if(IsUpdatingLocation)
		{
			// 开始获取位置信息
			if(!LocationPluginInterface.StartUpdatingLocation(this.name))
			{
				IsUpdatingLocation = false;
				return;
			}
		}
		else
		{
			// 停止获取位置信息
			LocationPluginInterface.StopUpdatingLocation();
		}
		UpdateUpdateLocationButton();
	}
	
	// 位置信息更新时，从本地插件中回调过来
	public void OnUpdateLocation(string parameter)
	{
		// 取出参数
		string[] components = parameter.Split(new char[] {'\t'}, 5);
		float latitude = float.Parse(components[0]);
		float longitude = float.Parse(components[1]);
		float speed = float.Parse(components[2]);
		float accuracy = float.Parse(components[3]);
		string address = components[4];

		addressLabel.text = address;
		latitudeLabel.text = string.Format("{0:0}° {1:0}′", 
			Mathf.Floor(latitude), (latitude - Mathf.Floor(latitude)) * 60);
		longitudeLabel.text = string.Format("{0:0}° {1:0}′", 
			Mathf.Floor(longitude), (longitude - Mathf.Floor(longitude)) * 60);
		speedLabel.text = string.Format("{0:0.0} m/s", (speed >= 0.0f)? speed: 0.0f);
		accuracyLabel.text = string.Format("{0} m", accuracy);
	}
}

原文地址：https://linxinfa.blog.csdn.net

Unity iOS本地插件的制作

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