I have created a fairly simple Activity in Mono for Android project:
[Activity(Label = "AndroidApplication1", MainLauncher = true, Icon = "#drawable/icon")]
public class Activity1 : Activity
{
private string value = "intitial";
[Export]
public string GetString()
{
return value;
}
[Export]
public void SetString(string newValue)
{
value = newValue;
}
}
The activity should only serve as a proof-of-concept, hence its simplicity. Now, I'd like to be able to call the method GetString() from the "normal", Java-based Android application.
In Xamarin's docs, I've read about Java to Managed interop, which seems to be exactly what I'm looking for. If I understand it correctly, when Mono for Android app compiles, it generates Java classes that are referred to as Android Callable Wrappers (ACW). I should be then able to call methods on these ACWs from Java-based Android application.
The question is, how exactly do I reference compiled Mono for Android application (the apk file) from the Java-based Android app?
This is where I'm now stuck and was unable to find any concrete examples. There are similar questions here on SO (this one and this one) and some blogposts, but they just boil down to "use ACWs". But how exactly? Maybe I am missing something obvious here, being no Android guy.
What I've tried is to dynamically load the dex file that I yanked from my Mono for Android apk. I've simply put it on the storage card and then tried to use DexClassLoader from Java-based Android app to load it (I've followed this blog post). The ACW class was found, but when I tried to create its instance, I got the following error:
No implementation found for native Lmno/android/Runtime;.register (Ljava/lang/String;Ljava/lang/Class;Ljava/lang/String;)
I suppose that I have to somehow include Mono for Android runtime to the Java-based app, but I have no idea how.
EDIT:
This is the code I am trying to load the dex with:
DexClassLoader cl = new DexClassLoader(dexInternalStoragePath.getAbsolutePath(),
optimizedDexOutputPath.getAbsolutePath(),
null,
getClassLoader());
try {
Class<?> classActivity1 = cl.loadClass("androidapplication1.Activity1");
// the following line throws the exception
Object a = classActivity1.newInstance();
Method getStringMethod = classActivity1.getMethod("GetString");
Object result = getStringMethod.invoke(angel);
result = null;
} catch (Exception e) {
e.printStackTrace();
}
EDIT2:
I am now reading here that it should be possible to directly start activities written in Mono for Android from Java. It is still not clear to me how to reference the Mono for Android from Java and Googling yields no relevant hits. Really stumped now.
If I'm understanding correctly what you're trying to do, this isn't really possible. As the error message you got implies, an Activity within a Mono for Android application relies on the Mono runtime in order to function properly. The callable wrapper isn't useful on its own in this case, since it's just a thin Java wrapper class that calls into the Mono runtime. You can actually see the generated callable wrappers yourself if you look in the obj/Debug/android/src folder after you build your project. For example:
package androidapplication9;
public class Activity1
extends android.app.Activity
implements
mono.android.IGCUserPeer
{
static final String __md_methods;
static {
__md_methods =
"n_onCreate:(Landroid/os/Bundle;)V:GetOnCreate_Landroid_os_Bundle_Handler\n" +
"";
mono.android.Runtime.register ("AndroidApplication9.Activity1, AndroidApplication9, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null", Activity1.class, __md_methods);
}
public Activity1 ()
{
super ();
if (getClass () == Activity1.class)
mono.android.TypeManager.Activate ("AndroidApplication9.Activity1, AndroidApplication9, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null", "", this, new java.lang.Object[] { });
}
public void onCreate (android.os.Bundle p0)
{
n_onCreate (p0);
}
private native void n_onCreate (android.os.Bundle p0);
java.util.ArrayList refList;
public void monodroidAddReference (java.lang.Object obj)
{
if (refList == null)
refList = new java.util.ArrayList ();
refList.add (obj);
}
public void monodroidClearReferences ()
{
if (refList != null)
refList.clear ();
}
}
That said, due to the way Android works, you could have a Java application start an activity that is defined in a Mono for Android application in the same way you'd start an external Java activity. This relies on both applications being installed, of course, but would result in the Mono for Android application and Mono runtime actually starting up to run that activity.
Edit
Updating to answer the questions you posed in your comment. The ExportAttribute basically just gives you some more control in how the ACW gets generated, allowing you to specify that a particular method or field should be present in the ACW and what name it should have. This can be useful when you want to use things like an android:onClick attribute in a layout, for example, where by default the ACW wouldn't contain the method you want to reference.
You can't get much use out of an ACW outside of the context of a Mono for Android application since the Mono runtime wouldn't be present. Code written in C# is executed on top of the Mono runtime, and not translated into Java behind the scenes during compilation or anything like that. At runtime there are then two runtimes going side by side, Dalvik (Android's runtime) and Mono, and the callable wrappers are there to allow the two to communicate back and forth. Because of that, even a Mono for Android class library would still depend on the Mono runtime, so you cannot use it independently of that runtime.
This diagram shows what the architecture looks like, and how the runtimes relate to each other:
Hope this helps clear things up!
Related
I have a c# library which provides some functionallity to upload data onto connected (android) devices. The dll itself gets exported via UnmangedExports to be used by an delphi application.
Here is the function which gets called by the delphi application:
[DllExport]
[return: MarshalAs(UnmanagedType.LPStr)]
public static string getDevices()
{
try
{
var devices = string.Empty;
var collection = new PortableDeviceCollection();
collection.Refresh();
foreach (var device in collection)
{
device.Connect();
if (devices != string.Empty)
{
devices += ";";
}
devices += device.FriendlyName;
device.Disconnect();
}
return devices;
}
catch (Exception e)
{
SomeClass.WriteErrorToLogFile(e);
return "ERROR";
}
}
Here is the class PortableDeviceCollection:
public class PortableDeviceCollection : Collection<PortableDevice>
{
private readonly PortableDeviceApiLib.PortableDeviceManagerClass _deviceManager;
public PortableDeviceCollection()
{
this._deviceManager = new PortableDeviceApiLib.PortableDeviceManagerClass();
}
public bool Refresh()
{
this._deviceManager.RefreshDeviceList();
// Determine how many WPD devices are connected
var deviceIds = new string[1];
uint count = 1;
this._deviceManager.GetDevices(null, ref count);
if (count > 0)
{
// Retrieve the device id for each connected device
deviceIds = new string[count];
this._deviceManager.GetDevices(deviceIds, ref count);
foreach (var deviceId in deviceIds)
{
Add(new PortableDevice(deviceId));
}
return true;
}
else
return false;
}
}
I can create the dll with visual studio and use this inside of the delphi application. When the delphi application calls the getDevices() function, i get an error on the instantiation of the PortableDeviceCollection class:
The file or assembly "Interop.PortableDeviceApiLib, Version = 1.0.0.0,
Culture = neutral, PublicKeyToken = null" or a dependency of it was
not found. The assembly is created by a runtime that is more recent
than the currently loaded runtime and can not be loaded.
ProductXY.PortableDeviceCollection..ctor()
ProductXY.ProductXYMain.getDevices()
The targetframework for the c# project is set to .Net Framework 4. Using any lower version i get an error when i try to compile the project:
The primary reference "Interop.PortableDeviceApiLib" could not be
resolved because it has an indirect dependency on the .NET Framework
assembly "mscorlib, version = 4.0.0.0, Culture = neutral,
PublicKeyToken = b77a5c561934e089", which is a higher version 4.0.0.0
than version 2.0.0.0 in the current target framework.
Please note. I have neither written the c# library nor the delphi application. Both have worked together for years. Now i have to add a functionallity to the c# library. I have not added any code to the project. I just tried to compile it again and use the dll. The only thing i did was updating the RGiesecke.DLLExport.Metadata via NuGet Packetmanager. Without updating i got an error
"Microsoft.Build.Utilities.ToolLocationHelper could not find
ildasm.exe"
I am aware of this Enumerating Windows Portable Devices in C# question. But my error is thrown before the code which is treaded by the question is reached. I still tried the solution to the question, but the action (deassamble, find and replace in the dll) which is described in the answere has already been done (otherwise my code would not have compiled).
The error message doesn't make sense to me. Interop.PortableDeviceApiLib is a COM-Lib which is not available for download in different framework-versions. I think I am missing something here.
Can anyone help me?
I was finally able to solve this problem. To be honest I don't know what finally solved this. For every one who stumbles up on this, here are the things i tried to fix this problem. They are in no specific order (since i tried everything multiple times):
Updating the RGiesecke.DLLExport packet
Changing the plattform in the Konfigurations-Manager to x86
Disassamble, edit and reassable the Interop.PortableDeviceApiLib like in this question (answeres of Christophe Geers and Bruno Klein)
Delete the reference to the Interop.PortableDeviceApiLib
Delete the reference to the Interop.PortableDeviceTypesLib
Readding the reference to the Interop.PortableDeviceApiLib
Readding the reference to the Interop.PortableDeviceTypesLib
Rebuild the project
Setting the Interoptyp embeddet on both to false (I found various statements to NOT do this, but the project was set up like this when i got it and it worked (be carefull)) on both Interop-Libs.
At least this helped me.
I have the simplest of apps that I thought I would try on my device before I got too engrossed. However, I am getting the strangest error message when I run it on my iPhone (as apposed to the the emulator on my macbook).
Table has no (public) columns .
I am using the SQLite.Net PCL and I have built it from git hub as I had some problems with it not having the platform dlls for IOS otherwise.
Relevant code.
In my models I have this:
public class Setting
{
[PrimaryKey, AutoIncrement]
public long Id { get; set; }
[Indexed]
public string Key { get; set; }
public string Value { get; set; }
}
The code that throws this error message is the simple:
using (SQLiteConnection db = GetCon ()) {
db.CreateTable<Setting> ();
}
but in my opinion the strangest thing is that this code works fine on the emulator but crashes the application on the iphone itself.
If anyone has some ideas that would be great.
EDIT:
This error is thrown on the SQLite.Net-PCL library on this file line 380 but only on the device and not on the emulator.
For others to whom this may concern, I found the answer to my problem. The issue was with the Type not having any properties (the type in question the simple model class). Knowing that to be rubbish I found the following links that gave more information which I will relate in this post in case the links go dead:
Type.GetProperties returning nothing
NOTE: Be careful with assembly linker
If you're building with linker enabled you may need to use the class
somewhere, so it will not be ripped off at compile time. Sometimes,
only instantiating the class in your code is not enough, the linker
may detect that the instance is never used and will remove it anyway.
http://developer.xamarin.com/guides/ios/advanced_topics/linker/
The linking process can be customized via the linker behavior
drop-down in Project Options. To access this double-click on the iOS
project and browse to iOS Build > Linker Options, as illustrated below
(see link for details)
I have for now left it to be unlinked, however, I will try before release to get the linker to ignore these classes. Thanks for all your help.
I found my problem was just a (not that subtle) programming error. I was working with the TypeInfo class and wanted to use the Sqlite Connection method:
CreateTable (Type type);
What I had in my hand was a TypeInfo instance which I needed to convert back to the System.Type. I accidentally without thinking used the GetType() method instead of AsType() method which is obvious when you think about it. The clue I got was in the exception message along with the OP message was does System.Runtime have public properties?
var type = table.TypeInfo.AsType();
// var type = table.TypeInfo.GetType(); *WRONG*
connection.CreateTable(type);
I'm currently trying to load and use the Gephi Toolkit from within a .Net 4 C# website.
I have a version of the toolkit jar file compiled against the IKVM virtual machine, which works as expected from a command line application using the following code:
var controller = (ProjectController)Lookup.getDefault().lookup(typeof(ProjectController));
controller.closeCurrentProject();
controller.newProject();
var project = controller.getCurrentProject();
var workspace = controller.getCurrentWorkspace();
The three instances are correctly instantiated in a form similar to org.gephi.project.impl.ProjectControllerImpl#8ddb93.
If however I run the exact same code, with the exact same using statements & references, the very first line loading the ProjectController instance returns null.
I have tried a couple of solutions
Firstly, I have tried ignoring the Lookup.getDefault().lookup(type) call, instead trying to create my own instances:
var controller = new ProjectControllerImpl();
controller.closeCurrentProject();
controller.newProject();
var project = controller.getCurrentProject();
var workspace = controller.getCurrentWorkspace();
This fails at the line controller.newProject();, I think because internally (using reflector) the same Lookup.getDefault().lookup(type) is used in a constructor, returns null and then throws an exception.
Secondly, from here: Lookup in Jython (and Gephi) I have tried to set the %CLASSPATH% to the location of both the toolkit JAR and DLL files.
Is there a reason why the Lookup.getDefault().lookup(type) would not work in a web environment? I'm not a Java developer, so I am a bit out of my depth with the Java side of this.
I would have thought it possible to create all of the instances myself, but haven't been able to find a way to do so.
I also cannot find a way of seeing why the ProjectController load returned null. No exception is thrown, and unless I'm being very dumb, there doesn't appear to be a method to see the result of the attempted load.
Update - Answer
Based on the answer from Jeroen Frijters, I resolved the issue like this:
public class Global : System.Web.HttpApplication
{
public Global()
{
var assembly = Assembly.LoadFrom(Path.Combine(root, "gephi-toolkit.dll"));
var acl = new AssemblyClassLoader(assembly);
java.lang.Thread.currentThread().setContextClassLoader(new MySystemClassLoader(acl));
}
}
internal class MySystemClassLoader : ClassLoader
{
public MySystemClassLoader(ClassLoader parent)
: base(new AppDomainAssemblyClassLoader(typeof(MySystemClassLoader).Assembly))
{ }
}
The code ikvm.runtime.Startup.addBootClassPathAssemby() didn't seem to work for me, but from the provided link, I was able to find a solution that seems to work in all instances.
This is a Java class loader issue. In a command line app your main executable functions as the system class loader and knows how to load assembly dependencies, but in a web process there is no main executable so that system class loader doesn't know how to load anything useful.
One of the solutions is to call ikvm.runtime.Startup.addBootClassPathAssemby() to add the relevant assemblies to the boot class loader.
For more on IKVM class loading issues see http://sourceforge.net/apps/mediawiki/ikvm/index.php?title=ClassLoader
I'm creating a program that uses the CodeProject CoreAudioApi (pretty popular framework for manipulating audio), but the problem is the CoreAudioApi uses system calls that aren't available in any versions of Windows earlier than Vista. If I run a program with CoreAudioApi compiled with it (using a using statement as normal), the program will crash on anything earlier than Vista.
I've created this function to get the version number of the current environment:
win_version = Environment.OSVersion.Version.Major;
That returns the major version number I need. '6' is Vista/7, anything else is not, which is all I need to determine. Utilizing this, I need to determine whether or not to include the CoreAudioApi namespace if the OS is over or equal to '6'. From research, usings need to be compiled with the program, but I've also read about something called Reflection - which might be what I need.
Once I get the CoreAudioApi namespace using'd (sorry for the lack of terminology), the rest is easy. How can I do this?
TL;DR
I need some form of code that would effectively do this:
using System;
using System.Text;
//etc
if(currentWindowsVersion>=6) using CoreAudioApi;
Except control structures won't work outside of a class, and all namespaces are compiled with the program, not controlled individually.
Thanks!
EDIT: So far, I'm using this to load the CoreAudioApi namespace as a compiled assembly:
if(win_version>=6){
CoreAudioApi = Assembly.LoadFrom("CoreAudio.dll");
CoreAudioApi.GetLoadedModules();
CoreAudioApi.GetTypes();
MessageBox.Show("Loaded CoreAudioApi");
}
From here, what I need to do is actually use the types, and methods from the API. My code that works on Windows Vista/7 is this:
public static MMDeviceEnumerator devEnum;
public static MMDevice defaultDevice;
//later in a mute method:
defaultDevice.AudioEndpointVolume.Mute = true/false;
I don't even really need devEnum AFAIK, so really the only important lines are the last two (besides the comment).
I've just tried the following:
Create a new console application project
Add the CoreAudioApi project from CodeProject to the solution
Add a project reference to CoreAudioApi in my console app
Create the following classes:
interface IAudio { void SetVolume(float level); }
class XpAudio : IAudio {
public void SetVolume(float level) {
// I do nothing, but this is where your old-style code would go
}
}
class VistaAudio : IAudio {
public void SetVolume(float level) {
MMDeviceEnumerator devEnum = new MMDeviceEnumerator();
MMDevice defaultDevice = devEnum
.GetDefaultAudioEndpoint(EDataFlow.eRender, ERole.eMultimedia);
defaultDevice.AudioEndpointVolume.MasterVolumeLevel = level;
}
}
class Program {
static void Main(string[] args) {
IAudio setter = Environment.OSVersion.Version.Major >= 6
? (IAudio)new VistaAudio()
: (IAudio)new XpAudio();
float val = float.Parse(Console.ReadLine());
setter.SetVolume(val);
Console.ReadLine();
}
}
This runs on both my server (~ Windows 7) and local (Windows XP) machines. On my XP machine it'll happily take in a value and ignore it; on my server, it throws an exception, (presumably because I don't have a sound output). If I make my XP machine run the CoreAudioApi, I get an exception when I input a value, not before.
The question is, what are you doing differently to make your application break? Are you using CoreAudioApi code at startup?
EDIT: After seeing your edit, if you do this, you shouldn't need to mess about with Assembly.LoadFrom at all. The framework should dynamically load that assembly if (and only if) and when it needs to.
COREAUDIOAPI.dll does not work on XP or earlier, because they cant handle MMDEVICE API (Device Enumeration). I dont know about Vista.
I'm exposing a C# class to COM using these attributes:
[ComVisible(true)]
[ClassInterface(ClassInterfaceType.AutoDual)]
[GuidAttribute("2325EBEB-DB5F-4D29-B220-64845379D9C5")]
[ComSourceInterfaces(typeof(WrapperEvents))]
in this class I have a function:
public void shutdownService()
This function is meant to be called just once from a VB6 client via COM Interop. Everything works fine. But somehow, it's being called more than once. My C# codes doesn't call this function directly. So I'm guessing the problem is in VB6 code. Unfortunately, that's not what the VB6 team thinks.
Is there a way to determine the caller of this function, ie. from my C#code or the VB6 code?
Right now I'm using a simple function to get the stacktrace:
public void LogStack()
{
var trace = new System.Diagnostics.StackTrace();
foreach (var frame in trace.GetFrames())
{
var method = frame.GetMethod();
if (method.Name.Equals("LogStack")) continue;
logger.Debug(string.Format("LogStack: {0}::{1}",
method.ReflectedType != null ? method.ReflectedType.Name : string.Empty, method.Name));
}
}
Obviously, I got somthing like this on the log:
2011-12-23 08:28:40,067 1 DEBUG (null) LogStack: Service::shutdownService
Since the only line of LogStack is the COM exposed function, I assume it's being called from vb6. But that's not enough proof for the VB6 team. Any idea how to really prove where function ?
You can try several things:
set a breakpoint in your code to trigger the debugger, then look at the call stack.
You could do an application dump here from visual studio and send it to them or screenshot the stack.
ex. Debugger.Break
http://www.netsplore.com/PublicPortal/blog.aspx?EntryID=12
Dump with "Savre Dump As"
http://msdn.microsoft.com/en-us/library/d5zhxt22.aspx
Use the com tracing
from a system level see
http://support.microsoft.com/kb/926098
I also recall a tool being installed with visual studio 6 do to this as well