Android obtains basic three-axis knowledge

Android obtains basic three-axis knowledge

 

 

Basic knowledge

 

 

Rotation Angle around the Z axis: Azimuth, I call it the north-facing corner (the north-facing direction of the compass)

Rotation Angle around the X axis: Pitch.

Rotation Angle around the Y axis: Roll, I call it the left and right corner.

 

Solution 1: Magnetic Field Sensor + acceleration sensor (recommended)

Step 1: Obtain sensor system services

Private SensorManager sensorManager; initialize protected void onCreate (Bundle savedInstanceState) {sensorManager = (SensorManager) getSystemService (Context. SENSOR_SERVICE );}

Step 2: Initialize the three-axis variable of acceleration and the three-axis variable of the Magnetic Field Sensor

 

 

private float[] accelerometerValues;private float[] magnetFieldValues;

 

Step 3: rewrite the listener

Private final SensorEventListener sensorEventListener = new SensorEventListener () {@ SuppressWarnings (deprecation) @ Overridepublic void onSensorChanged (SensorEvent event) {// method stub automatically generated by TODO if (event. sensor. getType () = Sensor. TYPE_ACCELEROMETER) {accelerometerValues = event. values;} if (event. sensor. getType () = Sensor. TYPE_MAGNETIC_FIELD) {magnetFieldValues = event. values ;}}

Step 4: register the sensor to the listener

@ Override protected void onCreate (Bundle savedInstanceState) {super. onCreate (savedInstanceState); setContentView (R. layout. main);/* Get the system's sensor Service */sensorManager = (SensorManager) getSystemService (Context. SENSOR_SERVICE); getSensorService ();}

private void getSensorService() {//int rate=SensorManager.SENSOR_DELAY_FASTEST;int rate=SensorManager.SENSOR_DELAY_NORMAL;Sensor accelerometerSensor = sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);sensorManager.registerListener(sensorEventListener,accelerometerSensor, rate);Sensor magnetSensor = sensorManager.getDefaultSensor(Sensor.TYPE_MAGNETIC_FIELD);sensorManager.registerListener(sensorEventListener, magnetSensor,rate);}

Step 5: Obtain the current direction (MS at a scheduled time)

 

@ Overrideprotected void onCreate (Bundle savedInstanceState) {super. onCreate (savedInstanceState); setContentView (R. layout. main);/* Get the system's sensor Service */sensorManager = (SensorManager) getSystemService (Context. SENSOR_SERVICE); getSensorService (); Timer updateTimer = new Timer (gForceUpdate); updateTimer. scheduleAtFixedRate (new TimerTask () {@ Overridepublic void run () {// method stub automatically generated by TODO if (accelerometerValues! = Null & magnetFieldValues! = Null) {float [] values = new float [3]; float [] R = new float [9]; SensorManager. getRotationMatrix (R, null, accelerometerValues, magnetFieldValues); SensorManager. getOrientation (R, values); values [0] = (float) Math. toDegrees (values [0]); // values [1] = (float) Math. toDegrees (values [1]); // values [2] = (float) Math. toDegrees (values [2]); // left and right corner/* Insert the three-axis direction into the database */}}, 0,200 );}

 

Solution 2: Use discarded virtual orientation Sensors

 

Step 1: Obtain sensor system services

 

Private SensorManager sensorManager; initialize protected void onCreate (Bundle savedInstanceState) {sensorManager = (SensorManager) getSystemService (Context. SENSOR_SERVICE );}

 

Step 2: Initialize the direction variable

 

 

private float x_orientation = -999;private float y_orientation = -999;private float z_orientation = -999;

Step 3: rewrite the listener

 

 

Private final SensorEventListener sensorEventListener = new SensorEventListener () {@ SuppressWarnings (deprecation) @ Overridepublic void onSensorChanged (SensorEvent event) {// method stub automatically generated by TODO if (event. sensor. getType () = Sensor. TYPE_ORIENTATION) {orientationValues = event. values; z_orientation = event. values [0]; // north-facing corner x_orientation = event. values [1]; // y_orientation = event. values [2]; // left and right corner }}@ Overridepublic void onAccuracyChanged (Sensor sensor, int accuracy) {// method stub automatically generated by TODO }};

 

Step 4: register the Sensor

 

@ Override protected void onCreate (Bundle savedInstanceState) {super. onCreate (savedInstanceState); setContentView (R. layout. main);/* Get the system's sensor Service */sensorManager = (SensorManager) getSystemService (Context. SENSOR_SERVICE); getSensorService ();}

 

private void getSensorService() {//     int rate=SensorManager.SENSOR_DELAY_FASTEST;       int rate=SensorManager.SENSOR_DELAY_NORMAL;       @SuppressWarnings(deprecation)       Sensor orientationSensor = sensorManager              .getDefaultSensor(Sensor.TYPE_ORIENTATION);       sensorManager.registerListener(sensorEventListener,orientationSensor,              rate);    }

 

Step 5: Get the current direction-set the direction for MS

@ Overrideprotected void onCreate (Bundle savedInstanceState) {super. onCreate (savedInstanceState); setContentView (R. layout. main);/* Get the system's sensor Service */sensorManager = (SensorManager) getSystemService (Context. SENSOR_SERVICE); getSensorService (); Timer updateTimer = new Timer (gForceUpdate); updateTimer. scheduleAtFixedRate (new TimerTask () {@ Overridepublic void run () {// method stub automatically generated by TODO if (x_orientation! =-999 & y_orientation! =-999 & z_orientation! =-999) {/* Insert the three-axis direction to the database */}}, 0,200 );}

Note: You need to register the sensor in onResume () and cancel the sensor listening in onDestroy (), onDestroy (), and onPause ().

@ Overrideprotected void onResume () {// method stub automatically generated by TODO super. onResume (); getSensorService () ;}@ Overrideprotected void onDestroy () {// TODO Auto-generated method stubsuper. onDestroy (); sensorManager. unregisterListener (sensorEventListener) ;}@ Overrideprotected void onPause () {// method stub automatically generated by TODO super. onPause (); sensorManager. unregisterListener (sensorEventListener) ;}@ Overrideprotected void onDestroy () {// TODO Auto-generated method stubsuper. onDestroy (); sensorManager. unregisterListener (sensorEventListener );}