在Android中使用ROS

[weijiz]

由于ROS提供了Android的对应的开发库，我们可以方便的在Android中开发相应的ROS客户端程序。下面介绍一下在Android中使用ROS库的方法。

1. 开发环境配置

Android的开发一般使用Android Studio. 其ROS相关的配置方式可以有两种。一种是在ROS环境中使用，另一种是给普通的Android App添加上ROS的依赖库。第二种方式可以在开发机器没有安装ROS的条件下进行开发。由于我使用Windows系统开发Android，所以这里使用第二种方式。

1.创建Android App项目

首先在Android Studio中创建一个普通的Android App

设置好项目名称后点击Next

继续点击Next

选择Empty Activity后点击Next

然后点击Finish

等待项目Sync完成。

2.修改build.gradle文件

项目Sync完成之后，在项目左侧的文件列表内会有两个build.gradle文件。其中一个是Project的，另一个是Module的。

首先修改Project的build.gradle文件

把文件中的

buildscript {
    repositories {
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:2.2.3'

        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

修改为

buildscript {
  apply from: "https://github.com/rosjava/android_core/raw/kinetic/buildscript.gradle"
}

然后在文件中添加

subprojects {
    apply plugin: 'ros-android'

    afterEvaluate { project ->
        android {
            // Exclude a few files that are duplicated across our dependencies and
            // prevent packaging Android applications.
            packagingOptions {
                exclude "META-INF/LICENSE.txt"
                exclude "META-INF/NOTICE.txt"
            }
        }
    }
}

然后修改Module的build.gradle，在dependencies 中添加ros依赖

...
dependencies {
    ...
    // You now now add any rosjava dependencies, like so:
    compile 'org.ros.android_core:android_10:[0.3,0.4)'
}
...

同时把dependencies 中的 全部implementation修改为compile。注意修改时的大小写。

把文件中的compileSdkVersion版本设置为25
targetSdkVersion也设置为25
把 com.android.support:appcompat-v7:27.1.1也修改成25的版本

最后修改完成的文件如下面所示

apply plugin: 'com.android.application'

android {
    compileSdkVersion 25
    defaultConfig {
        applicationId "org.bwbot.rostest"
        minSdkVersion 15
        targetSdkVersion 25
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    compile 'com.android.support:appcompat-v7:25.4.0'
    compile 'com.android.support.constraint:constraint-layout:1.1.3'
    testCompile 'junit:junit:4.12'
    androidTestCompile 'com.android.support.test:runner:1.0.2'
    androidTestCompile 'com.android.support.test.espresso:espresso-core:3.0.2'
    compile 'org.ros.android_core:android_10:[0.3,0.4)'
}

3.修改AndroidManifest.xml文件

此时如果编译项目会出现下面的错误

Manifest merger failed : Attribute application@icon value=(@mipmap/ic_launcher) from AndroidManifest.xml:7:9-43
	is also present at [org.ros.android_core:android_10:0.3.3] AndroidManifest.xml:19:9-36 value=(@mipmap/icon).
	Suggestion: add 'tools:replace="android:icon"' to <application> element at AndroidManifest.xml:5:5-19:19 to override.

此时需要修改AndroidManifest.xml文件在application项目中做如下修改

<application xmlns:tools="http://schemas.android.com/tools"
        tools:replace="android:icon"
        ...

为了能够正常使用还需要给app添加网络权限。在AndroidManifest.xml文件中添加

<uses-permission android:name="android.permission.INTERNET"/>

最后的AndroidManifest.xml文件如下

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="org.bwbot.rostest">
    <uses-permission android:name="android.permission.INTERNET"/>
    <application
        xmlns:tools="http://schemas.android.com/tools"
        tools:replace="android:icon"
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>
</manifest>

此时项目已经可以成功编译了。

2. 写一个简单的消息发布程序

MainActivity.java内容如下

package org.bwbot.rostest;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;

import org.ros.android.RosActivity;
import org.ros.concurrent.CancellableLoop;
import org.ros.namespace.GraphName;
import org.ros.node.ConnectedNode;
import org.ros.node.Node;
import org.ros.node.NodeConfiguration;
import org.ros.node.NodeMain;
import org.ros.node.NodeMainExecutor;
import org.ros.node.topic.Publisher;

import java.net.URI;

import std_msgs.String;

public class MainActivity extends RosActivity {

    protected MainActivity() {
        super("ros_test", "ros_test", URI.create("http://192.168.0.23:11311")); // 这里是ROS_MASTER_URI
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    @Override
    protected void init(NodeMainExecutor nodeMainExecutor) {
        NodeConfiguration nodeConfiguration = NodeConfiguration.newPublic(getRosHostname());
        nodeConfiguration.setMasterUri(getMasterUri());
        nodeMainExecutor.execute(new NodeMain() {
            @Override
            public GraphName getDefaultNodeName() {
                return GraphName.of("ros_test");
            }

            @Override
            public void onStart(ConnectedNode connectedNode) {
                final Publisher<std_msgs.String> pub =  connectedNode.newPublisher("/test", String._TYPE);
                connectedNode.executeCancellableLoop(new CancellableLoop() {
                    @Override
                    protected void loop() throws InterruptedException {
                        std_msgs.String msg = pub.newMessage();
                        msg.setData("hello world");
                        pub.publish(msg);
                        Thread.sleep(1000);
                    }
                });
            }

            @Override
            public void onShutdown(Node node) {

            }

            @Override
            public void onShutdownComplete(Node node) {

            }

            @Override
            public void onError(Node node, Throwable throwable) {

            }
        }, nodeConfiguration);
    }
}

编译后，在手机上运行App。然后再运行的ROS的主机上打印/test话题

可以看到消息已经成功发送出来了。

本项目已经发布到 Github

3. 注意事项

1. compileSdkVersion 版本问题
   由于在新版本的Android中，com.android.support:appcompat-v7软件包移除了一些组件。而这些组件ROS的库使用到了。所以在Android SDK > 25的版本中无法使用Android ROS. 所以我们要在配置文件中修改SDK版本。

2. Android模拟器网络
   Android模拟器默认是有NAT转换，所以使用虚拟机是无法访问到局域网内的ROS Master的。开发时建议使用实际的手机。

4. 如何使用自定义的消息类型

使用自己定义的消息需要首先生成消息的jar库文件，然后导入项目依赖。

下面以小强的galileo_serial_server里面的消息为例。

首先安装rosjava相关的依赖包

sudo apt-get install ros-kinetic-genjava
sudo apt-get install ros-kinetic-rosjava*

然后catkin_make具有相关消息的软件包

catkin_make -DCATKIN_WHITELIST_PACKAGES="galileo_serial_server"

可以看到其输出如下

WARNING: Package name "NLlinepatrol_planner" does not follow the naming conventions. It should start with a lower case letter and only contain lower case letters, digits, underscores, and dashes.
[ 73%] Built target galileo_serial_server_generate_messages_java
Scanning dependencies of target galileo_serial_server_node
[ 78%] Building CXX object galileo_serial_server/CMakeFiles/galileo_serial_server_node.dir/src/galileo_serial_server_node.cpp.o
[ 84%] Building CXX object galileo_serial_server/CMakeFiles/galileo_serial_server_node.dir/src/galileo_serial_server.cpp.o
[ 89%] Building CXX object galileo_serial_server/CMakeFiles/galileo_serial_server_node.dir/src/AsyncSerial.cpp.o
[ 94%] Compiling Java code for galileo_serial_server
[100%] Linking CXX executable /home/xiaoqiang/Documents/ros/devel/lib/galileo_serial_server/galileo_serial_server_node
[100%] Built target galileo_serial_server_node
warning: [options] bootstrap class path not set in conjunction with -source 1.7
1 warning
Uploading: org/ros/rosjava_messages/galileo_serial_server/1.0.0/galileo_serial_server-1.0.0.jar to repository remote at file:/home/xiaoqiang/Documents/ros/devel/share/maven/
Transferring 2K from remote
Uploaded 2K
[100%] Built target galileo_serial_server_generate_messages_java_gradle
Scanning dependencies of target galileo_serial_server_generate_messages
[100%] Built target galileo_serial_server_generate_messages

从输出中可以看出，消息的jar包已经生成到了/home/xiaoqiang/Documents/ros/devel/share/maven/文件夹中

把此jar文件复制到Android项目中的 app\libs文件夹中。

右键点击app,在弹出的菜单中点击Open Module Settings

选择dependencies页面，然后点击右侧加号

选择jar dependencies,然后选择jar文件点击确认就可以了

这样就可以在程序中使用自定义的消息了。

5. ROS Android的程序设计模式

在ROS Android库中，ROS的相关操作都是异步的(通过回调的方式)，比如创建节点，发布和订阅消息。这个在使用中会比较麻烦。比如我们需要实现点击一个按钮就发布一个消息的功能。就需要把这个发布消息的程序封装成一个类，然后继承CancellableLoop。在loop中发布消息。同时提供一个发布消息的方法给别人调用。
比如下面的方法

public class GalileoCommander extends CancellableLoop {

    private Publisher<galileo_serial_server.GalileoNativeCmds> pub;
    private ConnectedNode node;
    private Queue<byte[]> cmdList;

    public GalileoCommander(ConnectedNode connectedNode){
        node = connectedNode;
        cmdList = new LinkedBlockingQueue<>(100);
        pub = connectedNode.newPublisher("/test", GalileoNativeCmds._TYPE);
    }

    public void sendCmds(byte[] cmds){
        if(!cmdList.offer(cmds)){
            cmdList.poll();
            cmdList.offer(cmds);
        }
    }

    @Override
    protected void loop() throws InterruptedException {
        byte[] cmd = cmdList.poll();
        if(cmd == null){
            Thread.sleep(1);
        }else{
            galileo_serial_server.GalileoNativeCmds galileo_cmd =  pub.newMessage();
            galileo_cmd.setLength(cmd.length);
            pub.publish(galileo_cmd);
        }
    }
}

使用时

nodeMainExecutor.execute(new NodeMain() {
    @Override
    public GraphName getDefaultNodeName() {
        return GraphName.of("test_node");
    }

    @Override
    public void onStart(ConnectedNode connectedNode) {
        galileoCommander = new GalileoCommander(connectedNode);
        connectedNode.executeCancellableLoop(galileoCommander);
    }
}, nodeConfiguration)

这是我目前想到的比较好的模式，如果有其他更好的方法也欢迎交流。

[BITLiuYu]

我的系统是Ubuntu，所有的设置也是按照您的教程做的，但是run的时候就立即闪退。
其中，修改app的build.gradle时出现错误：

Error:Conflict with dependency 'com.google.code.findbugs:jsr305' in project ':app'. Resolved versions for app (1.3.9) and test app (2.0.1) differ. See http://g.co/androidstudio/app-test-app-conflict for details.

按照网上的方式，进行修改，在Android节点下添加:

configurations.all {
resolutionStrategy.force 'com.google.code.findbugs:jsr305:1.3.9'
}

不知道是否会影响

我的build.gradle为：

apply plugin: 'com.android.application'

android {
compileSdkVersion 25
//buildToolsVersion '25.0.0'
defaultConfig {
applicationId "com.example.rostest"
minSdkVersion 15
targetSdkVersion 25
versionCode 1
versionName "1.0"
testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
productFlavors {
}

configurations.all {
    resolutionStrategy.force 'com.google.code.findbugs:jsr305:1.3.9'
}

}

dependencies {
compile fileTree(include: ['*.jar'], dir: 'libs')
androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
exclude group: 'com.android.support', module: 'support-annotations'
})
compile 'com.android.support:appcompat-v7:25.+'
compile 'com.android.support.constraint:constraint-layout:1.0.2'
testCompile 'junit:junit:4.12'

//androidTestCompile 'com.android.support.test:runner:1.0.2'
//androidTestCompile 'com.android.support.test.espresso:espresso-core:2.2.2'

compile 'org.ros.android_core:android_10:[0.3,0.4)'

}

[weijiz]

@bitliuyu 在 在Android中使用ROS 中说：

versionName

可以运行例子的Android项目吗？
闪退后Logcat里面的错误是什么？
是不是没有设置网络权限？

[BITLiuYu]

@weijiz 可以运行自带的HelloWorld，但是改为您写的MainActivity就会闪退，URI.create我已经改为自己的ip地址了。logcat错误信息为：
10-15 17:16:56.627 32148-32148/org.bwbot.rostest E/AndroidRuntime: FATAL EXCEPTION: main
Process: org.bwbot.rostest, PID: 32148
java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{org.bwbot.rostest/org.bwbot.rostest.MainActivity}: java.lang.IllegalAccessException: void org.bwbot.rostest.MainActivity.() is not accessible from java.lang.Class<android.app.AppComponentFactory>
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2843)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3048)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1808)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:193)
at android.app.ActivityThread.main(ActivityThread.java:6669)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
Caused by: java.lang.IllegalAccessException: void org.bwbot.rostest.MainActivity.() is not accessible from java.lang.Class<android.app.AppComponentFactory>
at java.lang.Class.newInstance(Native Method)
at android.app.AppComponentFactory.instantiateActivity(AppComponentFactory.java:69)
at android.app.Instrumentation.newActivity(Instrumentation.java:1215)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2831)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3048) 
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78) 
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108) 
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1808) 
at android.os.Handler.dispatchMessage(Handler.java:106) 
at android.os.Looper.loop(Looper.java:193) 
at android.app.ActivityThread.main(ActivityThread.java:6669) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)

[weijiz]

@bitliuyu 在 在Android中使用ROS 中说：

lass<android.app.AppComponentFactory>

从错误看不像是gradle的设置问题。你可以把你的代码发github上，我给你看看。

[BITLiuYu]

@weijiz 这是我上传到github上的代码
https://github.com/BITLiuYu/ROSTest.git
多谢您能帮我看一下

[weijiz]

@bitliuyu 你的程序我可以正常运行额

用的是这个配置

[BITLiuYu]

@weijiz 我的程序也跑通了，是一个设置出了问题，修改过程是：
打开IDE，进入File—>Setting—>Build,Execution,Deployment—>Instant Run
将将enable instant run to hot swap code/resource changes on deploy勾上!

[gongyue666]

请问导入的自建消息,如何在jni中调用呢?

[gongyue666]

@gongyue666 好像是给java用的,如果是给c++用的自建消息应该如何导入呢?

[几何木偶]

为什么编译总是这个错误？是依赖错了吗？

Caused by: org.gradle.api.resources.ResourceException: Could not get resource 'https://github.com/rosjava/android_core/raw/kinetic/buildscript.gradle'.
	at org.gradle.internal.resource.ResourceExceptions.failure(ResourceExceptions.java:74)
	at org.gradle.internal.resource.ResourceExceptions.getFailed(ResourceExceptions.java:57)
	at org.gradle.api.internal.artifacts.repositories.resolver.DefaultExternalResourceAccessor.resolve(DefaultExternalResourceAccessor.java:67)
	at org.gradle.api.internal.artifacts.repositories.resolver.DefaultExternalResourceAccessor.resolveUri(DefaultExternalResourceAccessor.java:47)
	at org.gradle.internal.resource.transfer.DefaultUriTextResourceLoader.loadUri(DefaultUriTextResourceLoader.java:43)
	at org.gradle.api.internal.plugins.DefaultObjectConfigurationAction.applyScript(DefaultObjectConfigurationAction.java:103)
	at org.gradle.api.internal.plugins.DefaultObjectConfigurationAction.access$000(DefaultObjectConfigurationAction.java:38)
	at org.gradle.api.internal.plugins.DefaultObjectConfigurationAction$1.run(DefaultObjectConfigurationAction.java:68)
	at org.gradle.api.internal.plugins.DefaultObjectConfigurationAction.execute(DefaultObjectConfigurationAction.java:143)
	at org.gradle.api.internal.project.AbstractPluginAware.apply(AbstractPluginAware.java:46)
	at org.gradle.api.internal.project.ProjectScript.apply(ProjectScript.java:34)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:93)
	at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:325)
	at org.gradle.internal.metaobject.BeanDynamicObject$MetaClassAdapter.invokeMethod(BeanDynamicObject.java:479)
	at org.gradle.internal.metaobject.BeanDynamicObject.tryInvokeMethod(BeanDynamicObject.java:191)
	at org.gradle.groovy.scripts.BasicScript$ScriptDynamicObject.tryInvokeMethod(BasicScript.java:130)
	at org.gradle.internal.metaobject.ConfigureDelegate.invokeMethod(ConfigureDelegate.java:78)
	at org.codehaus.groovy.runtime.metaclass.ClosureMetaClass.invokeOnDelegationObjects(ClosureMetaClass.java:430)
	at org.codehaus.groovy.runtime.metaclass.ClosureMetaClass.invokeMethod(ClosureMetaClass.java:369)
	at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1022)
	at org.codehaus.groovy.runtime.callsite.PogoMetaClassSite.callCurrent(PogoMetaClassSite.java:69)

Caused by: org.gradle.internal.resource.transport.http.HttpRequestException: Could not HEAD 'https://github.com/rosjava/android_core/raw/kinetic/buildscript.gradle'.
	at org.gradle.internal.resource.transport.http.HttpClientHelper.performRequest(HttpClientHelper.java:96)
	at org.gradle.internal.resource.transport.http.HttpClientHelper.performRawHead(HttpClientHelper.java:72)
	at org.gradle.internal.resource.transport.http.HttpClientHelper.performHead(HttpClientHelper.java:76)
	at org.gradle.internal.resource.transport.http.HttpResourceAccessor.getMetaData(HttpResourceAccessor.java:65)
	at org.gradle.internal.resource.transfer.DefaultExternalResourceConnector.getMetaData(DefaultExternalResourceConnector.java:63)
	at org.gradle.internal.resource.transfer.AccessorBackedExternalResource.getMetaData(AccessorBackedExternalResource.java:201)
	at org.gradle.internal.resource.BuildOperationFiringExternalResourceDecorator$1.call(BuildOperationFiringExternalResourceDecorator.java:61)
	at org.gradle.internal.resource.BuildOperationFiringExternalResourceDecorator$1.call(BuildOperationFiringExternalResourceDecorator.java:58)
	at org.gradle.internal.progress.DefaultBuildOperationExecutor$CallableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:350)
	at org.gradle.internal.progress.DefaultBuildOperationExecutor$CallableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:340)
	at org.gradle.internal.progress.DefaultBuildOperationExecutor.execute(DefaultBuildOperationExecutor.java:199)
	at org.gradle.internal.progress.DefaultBuildOperationExecutor.call(DefaultBuildOperationExecutor.java:120)
	at org.gradle.internal.resource.BuildOperationFiringExternalResourceDecorator.getMetaData(BuildOperationFiringExternalResourceDecorator.java:58)
	at org.gradle.internal.resource.transfer.DefaultCacheAwareExternalResourceAccessor$1.create(DefaultCacheAwareExternalResourceAccessor.java:102)
	at org.gradle.internal.resource.transfer.DefaultCacheAwareExternalResourceAccessor$1.create(DefaultCacheAwareExternalResourceAccessor.java:82)
	at org.gradle.cache.internal.ProducerGuard$AdaptiveProducerGuard.guardByKey(ProducerGuard.java:97)
	at org.gradle.internal.resource.transfer.DefaultCacheAwareExternalResourceAccessor.getResource(DefaultCacheAwareExternalResourceAccessor.java:82)