1. 4// This header defines the standard ROS classes .
2. 5#include<ros / ros.h>
3. 6
4. 7int main (int argc ,char** argv ){
5. 8// Initialize the ROS system .
6. 9 ros::init ( argc , argv ," hello _ros ");
7. 10
8. 11// Establ ish this program as a ROS node .
9. 12 ros::NodeHandle nh ;
10. 13
11. 14// Send some output as a log message .
12. 15 ROS_INFO_STREAM(" Hello , ? ROS! ");
13. 16}

1. 1// This program publishes randomly−generated velocity
2. 2// messages for turtlesim .
3. 3#include<ros / ros.h>
4. 4#include<geometry_msgs /Twist. h>// For geometry_msgs:: Twist
5. 5#include<stdlib.h>// For rand() and RAND_MAX
6. 6
7. 7int main (int argc ,char** argv ){
8. 8// Initialize the ROS system and become a node .
9. 9 ros::init ( argc , argv ," publish _ velocity ");
10. 10 ros::NodeHandle nh ;
11. 11
12. 12// Create a publisher obj ect .
13. 13 ros::Publisher pub = nh . advertise <geometry_msgs::Twist>(
14. 14" turtle1 /cmd_vel",1000);
15. 15
16. 16// Seed the random number generator .
17. 17 srand ( time (0));
18. 18
19. 19// Loop at 2Hz until the node is shut down.
20. 20 ros::Raterate(2);
21. 21while( ros::ok ()){
22. 22// Create and fill in the message . The other four
23. 23// fields , which are ignored by turtl esim , default to 0.
24. 24 geometry_msgs ::Twist msg ;
25. 25 msg . linear . x =double( rand ())/double(RAND_MAX);
26. 26 msg.angular.z =2*double( rand ())/double(RAND_MAX)−1;
27. 27
28. 28// Publish the message .
29. 29 pub . publish ( msg );
30. 30
31. 31// Send a message to rosout with the details .
32. 32 ROS_INFO_STREAM("Sending random velocity command : "
33. 33<<" linear="<< msg.linear.x
34. 34<<" angular="<< msg.angular.z);
35. 35
36. 36// Wait untilit‘s time for another iteration .
37. 37 rate.sleep ();
38. 38}
39. 39}
40. 表3

1. 1// This program subscribes to turtle1/pose and shows its
2. 2// messages on the screen .
3. 3#include<ros / ros.h>
4. 4#include<turtlesim /Pose.h>
5. 5#include<iomanip>// for std::setprecision and std::fixed
6. 6
7. 7// A callback function . Executed each time a new pose
8. 8// message arrives .
9. 9void poseMessageReceived (const turtlesim::Pose& msg ){
10. 10 ROS_INFO_STREAM( std::setprecision (2)<< std::fixed
11. 11<<" position =("<< msg . x <<" , "<< msg . y <<" ) "
12. 12<<" *direction="<< msg . theta );
13. 13}
14. 14
15. 15int main (int argc ,char** argv ){
16. 16// Initialize the ROS system and become a node .
17. 17 ros::init ( argc , argv ," subscribe_to _pose ");
18. 18 ros::NodeHandle nh ;
19. 19
20. 20// Create a subscri ber obj ect .
21. 21 ros::Subscriber sub = nh.subscribe (" turtle1/pose ",1000,
22. 22&poseMessageReceived );
23. 23
24. 24// Let ROS take over .
25. 25 ros::spin ();
26. 26}

2. /**
3. * 写Publisher必须继承NodeMain  重写NodeMain的getDefaultNodeName()
4. */
5. publicclassImuPublisherimplementsNodeMain
6. {
8. privateImuThread imuThread;
9. privateSensorListener sensorListener;
10. privateSensorManager sensorManager;
11. privatePublisher<Imu> publisher;
13. privateclassImuThreadextendsThread
14. {
15. privatefinalSensorManager sensorManager;
16. privateSensorListener sensorListener;
17. privateLooper threadLooper;
19. privatefinalSensor accelSensor;
20. privatefinalSensor gyroSensor;
21. privatefinalSensor quatSensor;
23. privateImuThread(SensorManager sensorManager,SensorListener sensorListener)
24. {
25. this.sensorManager = sensorManager;
26. this.sensorListener = sensorListener;
27. this.accelSensor =this.sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
28. this.gyroSensor =this.sensorManager.getDefaultSensor(Sensor.TYPE_GYROSCOPE);
29. this.quatSensor =this.sensorManager.getDefaultSensor(Sensor.TYPE_ROTATION_VECTOR);
30. }
33. publicvoid run()
34. {
35. Looper.prepare();
36. this.threadLooper =Looper.myLooper();
37. this.sensorManager.registerListener(this.sensorListener,this.accelSensor,SensorManager.SENSOR_DELAY_FASTEST);
38. this.sensorManager.registerListener(this.sensorListener,this.gyroSensor,SensorManager.SENSOR_DELAY_FASTEST);
39. this.sensorManager.registerListener(this.sensorListener,this.quatSensor,SensorManager.SENSOR_DELAY_FASTEST);
40. Looper.loop();
41. }
44. publicvoid shutdown()
45. {
46. this.sensorManager.unregisterListener(this.sensorListener);
47. if(this.threadLooper !=null)
48. {
49. this.threadLooper.quit();
50. }
51. }
52. }
54. privateclassSensorListenerimplementsSensorEventListener
55. {
57. privatePublisher<Imu> publisher;
59. privateImu imu;
61. privateSensorListener(Publisher<Imu> publisher,boolean hasAccel,boolean hasGyro,boolean hasQuat)
62. {
63. this.publisher = publisher;
64. ...
65. this.imu =this.publisher.newMessage();
66. }
68. // @Override
69. publicvoid onSensorChanged(SensorEvent event)
70. {
72. this.imu.getLinearAcceleration().setX(event.values[0]);
73. this.imu.getLinearAcceleration().setY(event.values[1]);
74. this.imu.getLinearAcceleration().setZ(event.values[2]);
76. this.imu.setLinearAccelerationCovariance(tmpCov);
78. this.imu.getAngularVelocity().setX(event.values[0]);
79. this.imu.getAngularVelocity().setY(event.values[1]);
80. this.imu.getAngularVelocity().setZ(event.values[2]);
81. double[] tmpCov ={0.0025,0,0,0,0.0025,0,0,0,0.0025};// TODO Make Parameter
82. this.imu.setAngularVelocityCovariance(tmpCov);
84. this.imu.getOrientation().setW(quaternion[0]);
85. this.imu.getOrientation().setX(quaternion[1]);
86. this.imu.getOrientation().setY(quaternion[2]);
87. this.imu.getOrientation().setZ(quaternion[3]);
88. double[] tmpCov ={0.001,0,0,0,0.001,0,0,0,0.001};// TODO Make Parameter
89. this.imu.setOrientationCovariance(tmpCov);
91. //组装header
92. // Convert event.timestamp (nanoseconds uptime) into system time, use that as the header stamp
93. long time_delta_millis =System.currentTimeMillis()-SystemClock.uptimeMillis();
94. this.imu.getHeader().setStamp(Time.fromMillis(time_delta_millis + event.timestamp/1000000));
95. this.imu.getHeader().setFrameId("/imu");// TODO Make parameter
96. //前面组装消息
97.  
98. //后面发布消息
99. publisher.publish(this.imu);
101. // Create a new message ，清空了this.imu
102. this.imu =this.publisher.newMessage();
104. // Reset times
105. this.accelTime =0;
106. this.gyroTime =0;
107. this.quatTime =0;
108. }
109. }
110. }
113. publicImuPublisher(SensorManager manager)
114. {
115. this.sensorManager = manager;
116. }
118. publicGraphName getDefaultNodeName()
119. { 
120. //节点名称
121. returnGraphName.of("android_sensors_driver/imuPublisher");
122. }
124. publicvoid onError(Node node,Throwable throwable)
125. {
126. }
128. publicvoid onStart(ConnectedNode node)
129. {
130. try
131. {
132. //主题为"android/imu" 消息类型为 "sensor_msgs/Imu" ,是标准类型的消息
133. this.publisher = node.newPublisher("android/imu","sensor_msgs/Imu");
134.    ......
135. this.sensorListener = new SensorListener(publisher, hasAccel, hasGyro, hasQuat);
136. this.imuThread.start();   
137. this.imuThread = new ImuThread(this.sensorManager, sensorListener);
138. }
139. catch(Exception e)
140. {
141. if(node !=null)
142. {
143. node.getLog().fatal(e);
144. }
145. else
146. {
147. e.printStackTrace();
148. }
149. }
150. }
152. //@Override
153. publicvoid onShutdown(Node arg0)
154. {
155. ....
156. }
158. //@Override
159. publicvoid onShutdownComplete(Node arg0)
160. {
161. }
163. }

1. publicinterfaceNodeMainextendsNodeListener{
2. GraphName getDefaultNodeName();
3. }

1. //
2. // Source code recreated from a .class file by IntelliJ IDEA
3. // (powered by Fernflower decompiler)
4. //
6. package sensor_msgs;
8. import geometry_msgs.Quaternion;
9. import geometry_msgs.Vector3;
10. import org.ros.internal.message.Message;
11. import std_msgs.Header;
13. publicinterfaceImuextendsMessage{
14. String _TYPE ="sensor_msgs/Imu";
15. String _DEFINITION ="# This is a message to hold data from an IMU (Inertial Measurement Unit)\n#\n# Accelerations should be in m/s^2 (not in g\‘s), and rotational velocity should be in rad/sec\n#\n# If the covariance of the measurement is known, it should be filled in (if all you know is the \n# variance of each measurement, e.g. from the datasheet, just put those along the diagonal)\n# A covariance matrix of all zeros will be interpreted as \"covariance unknown\", and to use the\n# data a covariance will have to be assumed or gotten from some other source\n#\n# If you have no estimate for one of the data elements (e.g. your IMU doesn\‘t produce an orientation \n# estimate), please set element 0 of the associated covariance matrix to -1\n# If you are interpreting this message, please check for a value of -1 in the first element of each \n# covariance matrix, and disregard the associated estimate.\n\nHeader header\n\ngeometry_msgs/Quaternion orientation\nfloat64[9] orientation_covariance # Row major about x, y, z axes\n\ngeometry_msgs/Vector3 angular_velocity\nfloat64[9] angular_velocity_covariance # Row major about x, y, z axes\n\ngeometry_msgs/Vector3 linear_acceleration\nfloat64[9] linear_acceleration_covariance # Row major x, y z \n";
17. Header getHeader();
19. void setHeader(Header var1);
21. Quaternion getOrientation();
23. void setOrientation(Quaternion var1);
25. double[] getOrientationCovariance();
27. void setOrientationCovariance(double[] var1);
29. Vector3 getAngularVelocity();
31. void setAngularVelocity(Vector3 var1);
33. double[] getAngularVelocityCovariance();
35. void setAngularVelocityCovariance(double[] var1);
37. Vector3 getLinearAcceleration();
39. void setLinearAcceleration(Vector3 var1);
41. double[] getLinearAccelerationCovariance();
43. void setLinearAccelerationCovariance(double[] var1);
44. }

rosjava发布者的使用

1. publicGraphName getDefaultNodeName()
2. {
3. //节点名称
4. returnGraphName.of("android_sensors_driver/imuPublisher");
5. }

1. @Override
2. protectedvoid init(NodeMainExecutor nodeMainExecutor)
3. {
4. ...
6. }