如何保持应用程序在后台运行？继续收集数据？ [英] how to keep application running in background? keep collecting data?
本文介绍了如何保持应用程序在后台运行？继续收集数据？的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
UPDATED AT BOTTOM
UPDATED AT BOTTOM
我写了一个记录用户位置，当前速度，平均速度和最高速度的应用程序。我想知道如何让应用程序执行以下操作：
I have written an application that logs the users position, current speed, average speed and top speed. I would like to know how to make the application do the following things:
- 防止屏幕在屏幕上打开时关闭
- 如果用户打开另一个应用程序或返回主屏幕，获取呼叫等，则应用程序应继续收集数据
（或者最好只写入所有数据到每个位置更新的数据库？并且可能有一个按钮来表示何时开始和停止收集数据？）
我写的代码。 （如果你愿意可以随意使用它，如果你有任何建议我如何改进它我非常开放建设性的批评：D）
here is the code that I have written. (feel free to use it if you want and if you have any recommendations on how I might improve it I am very open to constructive criticism :D )
package Hartford.gps;
import java.math.BigDecimal;
import android.app.Activity;
import android.content.Context;
import android.location.Criteria;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.widget.TextView;
public class GPSMain extends Activity implements LocationListener {
LocationManager locationManager;
LocationListener locationListener;
//text views to display latitude and longitude
TextView latituteField;
TextView longitudeField;
TextView currentSpeedField;
TextView kmphSpeedField;
TextView avgSpeedField;
TextView avgKmphField;
//objects to store positional information
protected double lat;
protected double lon;
//objects to store values for current and average speed
protected double currentSpeed;
protected double kmphSpeed;
protected double avgSpeed;
protected double avgKmph;
protected double totalSpeed;
protected double totalKmph;
//counter that is incremented every time a new position is received, used to calculate average speed
int counter = 0;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
run();
}
@Override
public void onResume() {
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 1, this);
super.onResume();
}
@Override
public void onPause() {
locationManager.removeUpdates(this);
super.onPause();
}
private void run(){
final Criteria criteria = new Criteria();
criteria.setAccuracy(Criteria.ACCURACY_FINE);
criteria.setSpeedRequired(true);
criteria.setAltitudeRequired(false);
criteria.setBearingRequired(false);
criteria.setCostAllowed(true);
criteria.setPowerRequirement(Criteria.POWER_LOW);
//Acquire a reference to the system Location Manager
locationManager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);
// Define a listener that responds to location updates
locationListener = new LocationListener() {
public void onLocationChanged(Location newLocation) {
counter++;
//current speed fo the gps device
currentSpeed = round(newLocation.getSpeed(),3,BigDecimal.ROUND_HALF_UP);
kmphSpeed = round((currentSpeed*3.6),3,BigDecimal.ROUND_HALF_UP);
//all speeds added together
totalSpeed = totalSpeed + currentSpeed;
totalKmph = totalKmph + kmphSpeed;
//calculates average speed
avgSpeed = round(totalSpeed/counter,3,BigDecimal.ROUND_HALF_UP);
avgKmph = round(totalKmph/counter,3,BigDecimal.ROUND_HALF_UP);
//gets position
lat = round(((double) (newLocation.getLatitude())),3,BigDecimal.ROUND_HALF_UP);
lon = round(((double) (newLocation.getLongitude())),3,BigDecimal.ROUND_HALF_UP);
latituteField = (TextView) findViewById(R.id.lat);
longitudeField = (TextView) findViewById(R.id.lon);
currentSpeedField = (TextView) findViewById(R.id.speed);
kmphSpeedField = (TextView) findViewById(R.id.kmph);
avgSpeedField = (TextView) findViewById(R.id.avgspeed);
avgKmphField = (TextView) findViewById(R.id.avgkmph);
latituteField.setText("Current Latitude: "+String.valueOf(lat));
longitudeField.setText("Current Longitude: "+String.valueOf(lon));
currentSpeedField.setText("Current Speed (m/s): "+String.valueOf(currentSpeed));
kmphSpeedField.setText("Cuttent Speed (kmph): "+String.valueOf(kmphSpeed));
avgSpeedField.setText("Average Speed (m/s): "+String.valueOf(avgSpeed));
avgKmphField.setText("Average Speed (kmph): "+String.valueOf(avgKmph));
}
//not entirely sure what these do yet
public void onStatusChanged(String provider, int status, Bundle extras) {}
public void onProviderEnabled(String provider) {}
public void onProviderDisabled(String provider) {}
};
// Register the listener with the Location Manager to receive location updates
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 1, locationListener);
}
//Method to round the doubles to a max of 3 decimal places
public static double round(double unrounded, int precision, int roundingMode)
{
BigDecimal bd = new BigDecimal(unrounded);
BigDecimal rounded = bd.setScale(precision, roundingMode);
return rounded.doubleValue();
}
@Override
public void onLocationChanged(Location location) {
// TODO Auto-generated method stub
}
@Override
public void onProviderDisabled(String provider) {
// TODO Auto-generated method stub
}
@Override
public void onProviderEnabled(String provider) {
// TODO Auto-generated method stub
}
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
// TODO Auto-generated method stub
}
}
两个问题解答了解答 Marco Grassi 和 Marcovena 。
BOTH PROBLEMS SOLVED THANKS TO ANSWERS FROM Marco Grassi AND Marcovena.
新代码：
package Hartford.gps;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.os.PowerManager;
import android.widget.TextView;
public class GPSMain extends Activity {
//text views to display latitude and longitude
static TextView latituteField;
static TextView longitudeField;
static TextView currentSpeedField;
static TextView kmphSpeedField;
static TextView avgSpeedField;
static TextView avgKmphField;
static TextView topSpeedField;
static TextView topKmphField;
//objects to store positional information
protected static double lat;
protected static double lon;
//objects to store values for current and average speed
protected static double currentSpeed;
protected static double kmphSpeed;
protected static double avgSpeed;
protected static double avgKmph;
protected static double totalSpeed;
protected static double totalKmph;
protected static double topSpeed=0;
protected static double topKmph=0;
//counter that is incremented every time a new position is received, used to calculate average speed
static int counter = 0;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
PowerManager powerManager = (PowerManager)getSystemService(Context.POWER_SERVICE);
PowerManager.WakeLock wL = powerManager.newWakeLock(PowerManager.SCREEN_BRIGHT_WAKE_LOCK,"My Tag");
wL.acquire();
startService(new Intent(this, Calculations.class));
latituteField = (TextView) findViewById(R.id.lat);
longitudeField = (TextView) findViewById(R.id.lon);
currentSpeedField = (TextView) findViewById(R.id.speed);
kmphSpeedField = (TextView) findViewById(R.id.kmph);
avgSpeedField = (TextView) findViewById(R.id.avgspeed);
avgKmphField = (TextView) findViewById(R.id.avgkmph);
topSpeedField = (TextView) findViewById(R.id.topspeed);
topKmphField = (TextView) findViewById(R.id.topkmph);
}
static void run(){
latituteField.setText("Current Latitude: "+String.valueOf(lat));
longitudeField.setText("Current Longitude: "+String.valueOf(lon));
currentSpeedField.setText("Current Speed (m/s): "+String.valueOf(currentSpeed));
kmphSpeedField.setText("Cuttent Speed (kmph): "+String.valueOf(kmphSpeed));
avgSpeedField.setText("Average Speed (m/s): "+String.valueOf(avgSpeed));
avgKmphField.setText("Average Speed (kmph): "+String.valueOf(avgKmph));
topSpeedField.setText("Top Speed (m/s): "+String.valueOf(topSpeed));
topKmphField.setText("Top Speed (kmph): "+String.valueOf(topKmph));
}
}
p>
and
package Hartford.gps;
import java.math.BigDecimal;
import android.app.Service;
import android.content.Context;
import android.content.Intent;
import android.location.Criteria;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.os.IBinder;
import android.util.Log;
import android.widget.Toast;
public class Calculations extends Service implements LocationListener {
static LocationManager locationManager;
LocationListener locationListener;
private static final String TAG = "Calculations";
@Override
public IBinder onBind(Intent intent) {
// TODO Auto-generated method stub
return null;
}
@Override
public void onCreate() {
Toast.makeText(this, "My Service Created", Toast.LENGTH_LONG).show();
Log.d(TAG, "onCreate");
run();
}
private void run(){
final Criteria criteria = new Criteria();
criteria.setAccuracy(Criteria.ACCURACY_FINE);
criteria.setSpeedRequired(true);
criteria.setAltitudeRequired(false);
criteria.setBearingRequired(false);
criteria.setCostAllowed(true);
criteria.setPowerRequirement(Criteria.POWER_LOW);
//Acquire a reference to the system Location Manager
locationManager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);
// Define a listener that responds to location updates
locationListener = new LocationListener() {
public void onLocationChanged(Location newLocation) {
GPSMain.counter++;
//current speed for the GPS device
GPSMain.currentSpeed = round(newLocation.getSpeed(),3,BigDecimal.ROUND_HALF_UP);
GPSMain.kmphSpeed = round((GPSMain.currentSpeed*3.6),3,BigDecimal.ROUND_HALF_UP);
if (GPSMain.currentSpeed>GPSMain.topSpeed) {
GPSMain.topSpeed=GPSMain.currentSpeed;
}
if (GPSMain.kmphSpeed>GPSMain.topKmph) {
GPSMain.topKmph=GPSMain.kmphSpeed;
}
//all speeds added together
GPSMain.totalSpeed = GPSMain.totalSpeed + GPSMain.currentSpeed;
GPSMain.totalKmph = GPSMain.totalKmph + GPSMain.kmphSpeed;
//calculates average speed
GPSMain.avgSpeed = round(GPSMain.totalSpeed/GPSMain.counter,3,BigDecimal.ROUND_HALF_UP);
GPSMain.avgKmph = round(GPSMain.totalKmph/GPSMain.counter,3,BigDecimal.ROUND_HALF_UP);
//gets position
GPSMain.lat = round(((double) (newLocation.getLatitude())),3,BigDecimal.ROUND_HALF_UP);
GPSMain.lon = round(((double) (newLocation.getLongitude())),3,BigDecimal.ROUND_HALF_UP);
GPSMain.run();
}
//not entirely sure what these do yet
public void onStatusChanged(String provider, int status, Bundle extras) {}
public void onProviderEnabled(String provider) {}
public void onProviderDisabled(String provider) {}
};
// Register the listener with the Location Manager to receive location updates
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 1, locationListener);
}
//Method to round the doubles to a max of 3 decimal places
public static double round(double unrounded, int precision, int roundingMode)
{
BigDecimal bd = new BigDecimal(unrounded);
BigDecimal rounded = bd.setScale(precision, roundingMode);
return rounded.doubleValue();
}
public void onLocationChanged(Location location) {
// TODO Auto-generated method stub
}
public void onProviderDisabled(String provider) {
// TODO Auto-generated method stub
}
public void onProviderEnabled(String provider) {
// TODO Auto-generated method stub
}
public void onStatusChanged(String provider, int status, Bundle extras) {
// TODO Auto-generated method stub
}
}
UPDATE FOR shababhsiddique
UPDATE FOR shababhsiddique
import java.math.BigDecimal;
import java.text.DecimalFormat;
import java.text.NumberFormat;
import android.app.Service;
import android.content.Context;
import android.content.Intent;
import android.location.Criteria;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.os.IBinder;
import android.util.Log;
import android.widget.Toast;
public class Calculations extends Service{
static LocationManager locationManager;
static LocationListener locationListener;
private static long timerTime = 1;
private static float timerFloatValue = 1.0f;
private Context context;
private int counter = 0;
@Override
public IBinder onBind(Intent intent) {return null;}
@Override
public void onCreate() {
context = this;
update();
}
protected void update(){
final Criteria criteria = new Criteria();
criteria.setAccuracy(Criteria.ACCURACY_FINE);
criteria.setSpeedRequired(true);
criteria.setAltitudeRequired(false);
criteria.setBearingRequired(false);
criteria.setCostAllowed(true);
criteria.setPowerRequirement(Criteria.POWER_LOW);
//Acquire a reference to the system Location Manager
locationManager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);
// Define a listener that responds to location updates
locationListener = new LocationListener() {
public void onLocationChanged(Location newLocation) {
counter++;
if(GPSMain.GPSHasStarted==0){
GPSMain.previousLocation = newLocation;
//gets position
GPSMain.lat = round(((double) (GPSMain.previousLocation.getLatitude())),3,BigDecimal.ROUND_HALF_UP);
GPSMain.lon = round(((double) (GPSMain.previousLocation.getLongitude())),3,BigDecimal.ROUND_HALF_UP);
GPSMain.startingLocation = GPSMain.previousLocation;
GPSMain.routeLat.add(Double.toString(GPSMain.startingLocation.getLatitude()));
GPSMain.routeLon.add(Double.toString(GPSMain.startingLocation.getLongitude()));
GPSMain.startTime = System.currentTimeMillis();
GPSMain.GPSHasStarted++;
Toast.makeText(context, "GPS Connection Established", Toast.LENGTH_LONG).show();
startService(new Intent(context, AccelerometerReader.class));
Toast.makeText(context, "Accelerometer Calculating", Toast.LENGTH_LONG).show();
Toast.makeText(context, "Have A Safe Trip!", Toast.LENGTH_LONG).show();
}
//gets position
GPSMain.lat = round(((double) (newLocation.getLatitude())),3,BigDecimal.ROUND_HALF_UP);
GPSMain.lon = round(((double) (newLocation.getLongitude())),3,BigDecimal.ROUND_HALF_UP);
if (newLocation.distanceTo(GPSMain.previousLocation)>2.0f){
GPSMain.distanceBetweenPoints = GPSMain.distanceBetweenPoints + newLocation.distanceTo(GPSMain.previousLocation);
}
//current speed for the GPS device
GPSMain.mpsSpeed = newLocation.getSpeed();
if (GPSMain.mpsSpeed>GPSMain.topMps) {GPSMain.topMps=GPSMain.mpsSpeed;}
//store location in order to calculate distance during next iteration.
GPSMain.previousLocation = newLocation;
if (counter % 20 == 0){
GPSMain.routeLat.add(Double.toString(GPSMain.previousLocation.getLatitude()));
GPSMain.routeLon.add(Double.toString(GPSMain.previousLocation.getLongitude()));
}
}
//not entirely sure what these do yet
public void onStatusChanged(String provider, int status, Bundle extras) {}
public void onProviderEnabled(String provider) {}
public void onProviderDisabled(String provider) {}
};
// Register the listener with the Location Manager to receive location updates
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 2000, 20, locationListener);
}
//Method to round the doubles to a max of 3 decimal places
public static double round(double unrounded, int precision, int roundingMode){
BigDecimal bd = new BigDecimal(unrounded);
BigDecimal rounded = bd.setScale(precision, roundingMode);
return rounded.doubleValue();
}
//formats the time taken in milliseconds into hours minutes and seconds
public static String getTimeTaken(long end, long start){
@SuppressWarnings("unused")
String formattedTime = "", hourHour = "", hourMin = ":", minSec = ":";
long timeTaken = end-start, hour = 0, min = 0, sec = 0;
timerTime = timeTaken;
timeTaken = (end-start)/1000;
if (timeTaken>9 ){
hourHour = "0";
hourMin = ":0";
if (timeTaken>=60){
if (timeTaken>= 3200){
hour = timeTaken/3200;
timeTaken = timeTaken%3200;
if (hour>9){
hourHour = "";
}
}
min = timeTaken/60;
timeTaken = timeTaken%60;
if (min >9){
hourMin = ":";
}
}
sec = timeTaken;
if(sec%60<10){
minSec = ":0";
}
return formattedTime = (hourHour+hour+hourMin+min+minSec+sec);
}
sec = timeTaken;
minSec = ":0";
hourMin = ":0";
hourHour = "0";
return formattedTime = (hourHour+hour+hourMin+min+minSec+sec);
}
public static double averageSpeed(){
//calculates average speed
if (timerTime==0){timerTime=1;}
timerFloatValue = (float) timerTime;
timerFloatValue = timerFloatValue/1000;
return GPSMain.avgMps = GPSMain.distanceBetweenPoints/timerFloatValue;
}
//rounds the float values from the accelerometer
static String roundTwoDecimalFloat(float a){
float b = a/9.8f;
String formattedNum;
NumberFormat nf = new DecimalFormat();
nf.setMaximumFractionDigits(2);
nf.setMinimumFractionDigits(2);
formattedNum = nf.format(b);
return formattedNum;
}
}
推荐答案
1：您必须获取 WakeLock 。有多种类型的wakelock，取决于你是否只需要cpu或屏幕。
Question 1: You must acquire a WakeLock . There are multiple types of wakelock, depending if you want only the cpu on or also the screen.
问题2：你应该在服务，并将图形界面与收集数据分开。如果您正确实施，服务将继续收集数据，直到您停止为止。
Question 2: You should do your collecting data stuff inside a Service and separate the graphical interface from the collecting data. The Service will continue to collect the data until you stop it if you implement it correctly.
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