Android Pedometer1. Purpose(1) By programming an Android pedometer program using mobile platform,we learnto familiarize the calling methods of mobile platform sensors.(2) Simple mobile apps’ design and implementation.2. Contents(1) Acceleration sensor’s applicationBy using a compiler like Eclipse, write an Android program which could realizethe function listed below.1st? Use the acceleration sensor to measure the mobile’s acceleration in the X,Yand Z axis directions and the scalar value of the total acceleration.2nd? Display the results on the screen.3rd? Record the results in the specified file.The relative position of the mobile’s X,Y and Z axis derections is showed in the picture belowReference Code:package com.practice.cos;import java.io.File;import java.io.FileOutputStream;import java.io.IOException; import java.io.RandomAccessFile;import java.text.DecimalFormat;import android.app.Activity;import android.content.Context;import android.hardware.Sensor;import android.hardware.SensorEvent;import android.hardware.SensorEventListener;import android.hardware.SensorManager;import android.os.Bundle;import android.os.Environment;import android.util.Log;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;import android.widget.TextView;public class PracticeActivity extends Activity implements SensorEventListener,OnClickListener { /** Called when the activity is first created. */ //Create a LOG label private Button mWriteButton, mStopButton; private boolean doWrite = false; private SensorManager sm; private float lowX = 0, lowY = 0, lowZ = 0; private final float FILTERING_VALAUE = 0.1f; private TextView AT,ACT; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); AT = (TextView)findViewById(R.id.AT); ACT = (TextView)findViewById(R.id.onAccuracyChanged); //Create a SensorManager to get the system’s sensor service sm =(SensorManager)getSystemService(Context.SENSOR_SERVICE); /* *Using the most common method to register an event * Parameter1 ：SensorEventListener detectophone * Parameter2 ：Sensor one service could have several Sensorrealizations.Here,We use getDefaultSensor to get the defaulted Sensor * Parameter3 ：Mode We can choose the refresh frequency of thedata change * */ // Register the acceleration sensor sm.registerListener(this, sm.getDefaultSensor(Sensor.TYPE_ACCELEROMETER), SensorManager.SENSOR_DELAY_FASTEST);//Highsampling rate；.SENSOR_DELAY_NORMAL means a lower sampling rate try { FileOutputStream fout = openFileOutput(acc.txt,Context.MODE_PRIVATE); fout.close(); } catch (IOException e) { e.printStackTrace(); } mWriteButton = (Button) findViewById(R.id.Button_Write); mWriteButton.setOnClickListener(this); mStopButton = (Button) findViewById(R.id.Button_Stop); mStopButton.setOnClickListener(this); } public void onPause(){ super.onPause(); } public void onClick(View v) { if (v.getId() == R.id.Button_Write) { doWrite = true; } if (v.getId() == R.id.Button_Stop) { doWrite = false; } } public void onAccuracyChanged(Sensor sensor, int accuracy) { ACT.setText(onAccuracyChanged is detonated); } public void onSensorChanged(SensorEvent event) { String message = new String(); if(event.sensor.getType() == Sensor.TYPE_ACCELEROMETER) { float X = event.values[0]; float Y = event.values[1]; float Z = event.values[2]; //Low-Pass Filter lowX = X * FILTERING_VALAUE + lowX * (1.0f -FILTERING_VALAUE); lowY = Y * FILTERING_VALAUE + lowY * (1.0f -FILTERING_VALAUE); lowZ = Z * FILTERING_VALAUE + lowZ * (1.0f -FILTERING_VALAUE); //High-pass filter float highX = X - lowX; float highY = Y - lowY; float highZ = Z - lowZ; double highA = Math.sqrt(highX * highX + highY * highY + highZ代写mobile platform作业、代做R课程作业、代写programming留学生作业、代做R编程语言作业 帮做H* highZ); DecimalFormat df = new DecimalFormat(#,##0.000); message = df.format(highX) + ; message += df.format(highY) + ; message += df.format(highZ) + ; message += df.format(highA) + \n; AT.setText(message + \n); if (doWrite) { write2file(message); } } } private void write2file(String a){ try { File file = new File(/sdcard/acc.txt);//write the resultinto/sdcard/acc.txt if (!file.exists()){ file.createNewFile();} // Open a random access file stream for reading and writing RandomAccessFile randomFile = newRandomAccessFile(/sdcard/acc.txt, rw); // The length of the file (the number of bytes) long fileLength = randomFile.length(); // Move the file pointer to the end of the file randomFile.seek(fileLength); randomFile.writeBytes(a); randomFile.close(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } }}Layout files android:layout_width=fill_parent android:layout_height=fill_parent android:orientation=vertical > android:id=@+id/AT android:layout_width=wrap_content android:layout_height=wrap_content android:text=@string/AT android:textSize=20dp /> android:id=@+id/onAccuracyChanged android:layout_width=wrap_content android:layout_height=wrap_content android:text=@string/onAccuracyChanged android:textSize=18dp /> android:layout_width=fill_parent android:layout_height=wrap_content > android:id=@+id/Button_Write android:layout_width=90dp android:layout_height=wrap_content android:text=@string/Button_Writeandroid:textSize=20dp/> android:id=@+id/Button_Stop android:layout_width=90dp android:layout_height=wrap_content android:text=@string/Button_Stop android:textSize=20dp/> String Hello World, PracticeActivity! Practice onAccuracyChanged doesn’tdetonate 0 Write Stop (2) Step counting methodThere are many mobile step‐counting methods but the best method is notfound now. A typical acceleration scalar graph is showed below.Self‐designed methods are encouraged in this step and the display of the resultson the screen in real time is required.HintWe can use the threshold filtering method. When the acceleration is higher orlower than the threshold, we can treat it as a step’s beginning or ending. We alsoneed to consider the waveform burr and the acceleration of walking is not a simplesingle‐peak waveform.3. Questions(1) Why we need low pass filtering when we measure the acceleration ?What are the differences made by the filtering? Make a contrast.(2) Can we estimate the stride length using the acceleration oscillogram?(3) What’s the meaning of using super.onPause ?4. Extended problems(1) Suppose a driver uses an Android mobile.Use the GPS data and acceleration datato judge the switch of the moving and rest states and upload the statusinformation to the server.(2) Suppose there are a great number of drivers using the app mentioned in the 1stproblem.How could we judge the traffic light’s color using theseinformation? Design and build a system to realize this functionHintYou can refer the literatureYiran Zhao, Yang Zhang, Tuo Yu, Tianyuan Liu, Xinbing Wang, Xiaohua Tian, XueLiu, “CityDrive: A map-generating and speed-optimizing driving system,” inproceedings of IEEE International Conference on Computer Communications, pp.1986-1994, 2014. 转自：http://www.7daixie.com/2019041830873834.html
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