在OS X Java应用程序中处理自定义URL方案 [英] Handle custom URL schemes in an OS X Java application

问题描述

基于Java的应用程序的 Info.plist 包含以下条目：

The Info.plist of our Java-based application contains following entries:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist SYSTEM "file://localhost/System/Library/DTDs/PropertyList.dtd">
<plist version="0.9">
    <dict>
        ...
        <key>CFBundleURLTypes</key>
        <array>
            <dict>
                <key>CFBundleURLName</key>
                <string>myApp handler</string>
                <key>CFBundleURLSchemes</key>
                <array>
                    <string>myapp</string>
                </array>
            </dict>
        </array>
        ...
    </dict>
</plist>

它应该处理像 myapp：// foobar / bazz这样的网址。打开应用程序工作正常，但应用程序应如何获取单击的URL？

It should handle an URL like myapp://foobar/bazz. Opening the application works fine, but how the application should obtain the clicked URL?

推荐答案

对于Objective C，可以在此处找到答案：当通过注册的URL方案启动OS X应用程序时，如何访问完整的URL？

For Objective C the answer can be found here: When an OS X app is launched by a registered URL scheme, how do you access the full URL?

Java的解决方案是将ObjC代码重写为普通的C，然后在 org.eclipse.swt下的一组类的帮助下将其转换为Java。 internal.cocoa。* 。

The solution for Java is to rewrite the ObjC code into plain C, then translate that into Java, with the help of a set of classes under org.eclipse.swt.internal.cocoa.*.

作为ObjC-to-C翻译的参考，我们需要Apple的 Objective-C运行时参考。

As a reference for the ObjC-to-C translation, we need Apple's Objective-C Runtime Reference.

首先，让我们翻译

[[NSAppleEventManager sharedAppleEventManager]
    setEventHandler:targetObject
        andSelector:@selector(handleAppleEvent:withReplyEvent:)
      forEventClass:kInternetEventClass
         andEventID:kAEGetURL];

进入普通C.要在普通C中调用ObjC函数，我们使用 objc_msgSend（）。此外， @selector（method_footprint）被 sel_registerName（method_footprint）替换，并且用 objc_getClass（）。类型 id 和 SEL 等同于指针（例如void *）或全尺寸int（即与空白相同的大小*）。

into plain C. To invoke a ObjC function in plain C, we use objc_msgSend(). Furthermore, @selector(method_footprint) is substituted by sel_registerName("method_footprint"), and classes are looked up with objc_getClass(). The types id and SEL are equivalent to a pointer (such as void*) or a full-size int (i.e. same size as a void*).

结果：

// id mgr = [NSAppleEventManager sharedAppleEventManager]
SEL sel_ sharedAppleEventManager = sel_registerName("sharedAppleEventManager");
id mgr = objc_msgSend (objc_getClass("NSAppleEventManager"), sharedAppleEventManager);

// and the rest
SEL sel_setEventHandler = sel_registerName("setEventHandler:andSelector:forEventClass:andEventID:");
SEL sel_handleAppleEvent = sel_registerName("handleAppleEvent:withReplyEvent:");
objc_msgSend (mgr, sel_setEventHandler, targetObject, sel_handleAppleEvent, kInternetEventClass, kAEGetURL);

如你所见，我们在这里有两个子程序调用：第一个调用 sharedAppleEventManager NSAppleEventManager 类的消息，从该类中检索单个对象。第二个调用是将setEventHandler ...消息发送到该对象，传递4个参数（目标对象，目标消息和两个事件说明符）。

As you can see, we have two subroutine invocations here: The first calls the sharedAppleEventManager message of the NSAppleEventManager class, retrieving a singleton object from that class. The second call is sending the setEventHandler... message to that object, passing 4 arguments (target object, target message, and two event specifiers).

回调函数的声明，最初：

The callback function's declaration, originally:

- (void)handleAppleEvent:(NSAppleEventDescriptor *)event withReplyEvent:(NSAppleEventDescriptor *)replyEvent

在普通C中看起来像这样：

looks like this in plain C:

void handleAppleEvent (id self, SEL selector, NSAppleEventDescriptor* event, NSAppleEventDescriptor* replyEvent)

这意味着当函数被调用时，它不仅会发送它的对象引用（id），还会发送它的方法足迹（选择器）。

This means that when the function gets called, it gets sent not only its object reference (id) but also its method footprint (selector).

回调代码看起来像这在ObjC中获取URL：

The callback code looks like this in ObjC to get to the URL:

NSString url = [[event paramDescriptorForKeyword:keyDirectObject] stringValue];

在普通C中：

id desc_id = objc_msgSend (event_id, sel_registerName("paramDescriptorForKeyword:"), '----');
id url_id = objc_msgSend (desc_id, desc_id, sel_registerName("stringValue"));

一部分仍然缺失：

在调用上面的代码之前需要初始化 targetObject ，并且需要匹配 handleAppleEvent：withReplyEvent：足迹的方法在该目标对象中创建，然后链接到我们的普通C事件处理程序（ handleAppleEvent（））。

targetObject needs to be initialized before invoking the code above, and a method matching the handleAppleEvent:withReplyEvent: footprint needs to be created in that target object, and then linked to our plain C event handler (handleAppleEvent()).

这意味着我们必须创建一个Objective C类，向它添加一个方法，然后创建一个它的对象实例：

This means that we have to create an Objective C class, add a method to it, and then create an object instance of it:

// create an NSObject subclass for our target object
char objcClassName[] = "ObjCAppleEventHandler";
id objcClass = objc_allocateClassPair (objc_getClass("NSObject"), objcClassName);

// add the callback method to the class
SEL sel_handleAppleEvent = sel_registerName("handleAppleEvent:withReplyEvent:");
class_addMethod (objcClass, sel_handleAppleEvent, handleAppleEvent, "i@:@@");

// register the class
objc_registerClassPair (objcClass)

// create an object instance
id targetObject = class_createInstance (objcClass, 0);

// ... here follows the above code with the setEventHandler invocation
// (note: `SEL sel_handleAppleEvent` appears twice - the 2nd one can be removed)

普通C版本到此结束。

（注：上面的代码是在没有测试的情况下编写的，所以它可能包含错误。但是，下面的Java代码已经过测试。）

(Note: The above code was written without testing it, so it may contain errors. The Java code below, however, has been tested.)

从普通C到Java的翻译现在相当简单。

Translation from Plain C to Java is now fairly straight-forward.

前面提到的ObjC运行时函数都可以从org.eclipse.swt获得.internal.cocoa.OS。

The aforementioned ObjC Runtime functions are all available from org.eclipse.swt.internal.cocoa.OS.

首先，一些预设：

static final long class_NSAppleEventManager = OS.objc_getClass("NSAppleEventManager");
static final long sel_sharedAppleEventManager = OS.sel_registerName("sharedAppleEventManager");
static final long sel_setEventHandler = OS.sel_registerName("setEventHandler:andSelector:forEventClass:andEventID:");
static final long sel_handleAppleEvent = OS.sel_registerName("handleAppleEvent:withReplyEvent:");
static final long sel_paramDescriptorForKeyword = OS.sel_registerName("paramDescriptorForKeyword:");
static final long sel_stringValue = OS.sel_registerName("stringValue");

static final long kInternetEventClass = 0x4755524C; // 'GURL'
static final long kAEGetURL = 0x4755524C; // 'GURL'
static final long kCoreEventClass = 0x61657674; // 'aevt'
static final long kAEOpenApplication = 0x6F617070; // 'oapp'
static final long kAEReopenApplication = 0x72617070; // 'rapp'
static final long keyDirectObject = 0x2d2d2d2d; // '----'

回调函数：

static long handleAppleEvent (long id, long sel, long event_id, long reply_id) {
    // This is a handler for AppleEvents that are registered with [NSAppleEventManager setEventHandler:...]
    // It matches this selector (footprint):
    //   - (void)handleAppleEvent:(NSAppleEventDescriptor *)event withReplyEvent:(NSAppleEventDescriptor *)reply

    // Invoke [[event paramDescriptorForKeyword:keyDirectObject] stringValue] to get the direct object containing the URL
    long direct_desc_id = OS.objc_msgSend (event_id, sel_paramDescriptorForKeyword, keyDirectObject);
    long direct_str_id = OS.objc_msgSend (direct_desc_id, sel_stringValue);
    NSString nsStr = new NSString (direct_str_id);
    String str = nsStr.getString();
    // now 'str' contains the URL

    System.out.println ("handleAppleEvent invoked -- argument: "+url);
    return 0;
}

注册回调函数的代码：

// Get access to a callback function for receiving the sel_handleAppleEvent message
aeCallback = new Callback(Main.class, "handleAppleEvent", 4);
long aeProc = aeCallback.getAddress();

// Create a ObjC class that provides a method with the sel_handleAppleEvent footprint
String objcClassName = "ObjCAppleEventHandler";
long objcClass = OS.objc_allocateClassPair(OS.class_NSObject, objcClassName, 0);
OS.class_addMethod(objcClass, sel_handleAppleEvent, aeProc, "i@:@@");
OS.objc_registerClassPair(objcClass);
long objcHandlerInstance = OS.class_createInstance (objcClass, 0);

// Invoke [[NSAppleEventManager sharedAppleEventManager] setEventHandler:objcHandlerInstance andSelector:sel_handleAppleEvent forEventClass:kInternetEventClass andEventID:kAEGetURL]
long sharedAppleEventMgr = OS.objc_msgSend (class_NSAppleEventManager, sel_sharedAppleEventManager);
OS.objc_msgSend (sharedAppleEventMgr, sel_setEventHandler, objcHandlerInstance, sel_handleAppleEvent, kInternetEventClass, kAEGetURL);

剩下要做的是从此代码构建应用程序包，然后将CFBundleURLTypes条目添加到其中Info.plist。

What's left to do is to build an app bundle from this code and then add the CFBundleURLTypes entries to its Info.plist.

可在此处下载完整的示例源文件： http://files.tempel.org/Various/ObjectiveC-bridging.java.zip

A complete sample source file can be downloaded here: http://files.tempel.org/Various/ObjectiveC-bridging.java.zip

这篇关于在OS X Java应用程序中处理自定义URL方案的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！