4.4.3
1、創建Utils類文件
2、將類加入com.nokia.example.location.tourist包中
3、創建Utils類，編寫字符串顯示的代碼。
/**
* A container class for general purpose utility method(s).
*/
public class Utils
{
/**
* Creates a String presentation of double value that is formatted to have a
* certain number of decimals. Formatted output value does not include any
* rounding rules. Output value is just truncated on the place that is
* defined by received decimals parameter.
*
* @param value -
* double value to be converted.
* @param decimals -
* number of decimals in the String presentation.
* @return a string representation of the argument.
*/
public static String formatDouble(double value, int decimals)
{
String doubleStr = "" + value;
int index = doubleStr.indexOf(".") != -1 ? doubleStr.indexOf(".")
: doubleStr.indexOf(",");
// Decimal point can not be found...
if (index == -1) return doubleStr;
// Truncate all decimals
if (decimals == 0)
{
return doubleStr.substring(0, index);
}
int len = index + decimals + 1;
if (len >= doubleStr.length()) len = doubleStr.length();
double d = Double.parseDouble(doubleStr.substring(0, len));
return String.valueOf(d);
}
}
1、創建ConfigurationProvider文件
2、引入必要的類
package com.nokia.example.location.tourist.model;
import Javax.microedition.location.Criteria;
import Javax.microedition.location.LocationException;
import Javax.microedition.location.LocationProvider;
import Javax.microedition.location.OrIEntation;
import com.nokia.example.location.tourist.ui.ProviderQueryUI;
3、創建處理定位搜索的類
/**
* Model class that handles location providers search.
*/
public class ConfigurationProvider
{
private static ConfigurationProvider INSTANCE = null;
/** Array of free Criterias. */
private static Criteria[] freeCriterias = null;
/** String array of free criteria names. */
private static String[] freeCriteriaNames = null;
/** Array of Criterias that may cause costs */
private static Criteria[] costCriterias = null;
/** String array of non-free criteria names. */
private static String[] costCriteriaNames = null;
/** Reference to ProviderQueryUI vIEwer class. */
private ProviderQueryUI queryUI = null;
/** Selected criteria */
private Criteria criteria = null;
/** Selected location provider */
private LocationProvider provider = null;
4、編寫靜態模塊創建參數結構。用來選擇定位服務的Criteria類是已經確定的。關於這個類和方法的更多信息，參考API定位。
/*
* Static block that constructs the content of free and non-free Criterias.
* This code block is performed before the constructor.
*/
static
{
// 1. Create pre-defined free criterias
freeCriterias = new Criteria[2];
freeCriteriaNames = new String[2];
Criteria crit1 = new Criteria();
crit1.setHorizontalAccuracy(25); //
crit1.setVerticalAccuracy(25); //
crit1.setPreferredResponseTime(Criteria.NO_REQUIREMENT);
crit1.setPreferredPowerConsumption(Criteria.POWER_USAGE_HIGH);
crit1.setCostAllowed(false);
crit1.setSpeedAndCourseRequired(true);
crit1.setAltitudeRequired(true);
crit1.setAddressInfoRequired(true);
freeCriterias[0] = crit1;
freeCriteriaNames[0] = "High details, cost not allowed";
Criteria crit2 = new Criteria();
crit2.setHorizontalAccuracy(Criteria.NO_REQUIREMENT);
crit2.setVerticalAccuracy(Criteria.NO_REQUIREMENT);
crit2.setPreferredResponseTime(Criteria.NO_REQUIREMENT);
crit2.setPreferredPowerConsumption(Criteria.POWER_USAGE_HIGH);
crit2.setCostAllowed(false); // allowed to cost
crit2.setSpeedAndCourseRequired(false);
crit2.setAltitudeRequired(false);
crit2.setAddressInfoRequired(false);
freeCriterias[1] = crit2;
freeCriteriaNames[1] = "Low details and power consumption, cost not
allowed";
編寫靜態模塊構建非免費參數
// 2. Create pre-defined cost criterias
costCriterias = new Criteria[3];
costCriteriaNames = new String[3];
Criteria crit3 = new Criteria();
crit3.setHorizontalAccuracy(25); //
crit3.setVerticalAccuracy(25); //
crit3.setPreferredResponseTime(Criteria.NO_REQUIREMENT);
crit3.setPreferredPowerConsumption(Criteria.NO_REQUIREMENT);
crit3.setCostAllowed(true);
crit3.setSpeedAndCourseRequired(true);
crit3.setAltitudeRequired(true);
crit3.setAddressInfoRequired(true);
costCriterias[0] = crit3;
costCriteriaNames[0] = "High details, cost allowed";
Criteria crit4 = new Criteria();
crit4.setHorizontalAccuracy(500); //
crit4.setVerticalAccuracy(Criteria.NO_REQUIREMENT);
crit4.setPreferredResponseTime(Criteria.NO_REQUIREMENT);
crit4.setPreferredPowerConsumption(Criteria.NO_REQUIREMENT);
crit4.setCostAllowed(true);
crit4.setSpeedAndCourseRequired(true);
crit4.setAltitudeRequired(true);
crit4.setAddressInfoRequired(false);
costCriterias[1] = crit4;
costCriteriaNames[1] = "Medium details, cost allowed";
// Least restrictive criteria (with default values)
Criteria crit5 = null;
costCriterias[2] = crit5;
costCriteriaNames[2] = "Least restrictive criteria";
}
5、為類創建結構
/**
* Private constructor to force using getInstance() method.
*/
private ConfigurationProvider()
{
queryUI = new ProviderQueryUI();
}
6、創建方法，為類提供一個實例。
/**
* Provide singleton instance of this class.
*
* @return static instance of this class.
*/
public static ConfigurationProvider getInstance()
{
if (INSTANCE == null)
{
// Enable use of this class when Location API is supported.
if (isLocationApiSupported())
{
INSTANCE = new ConfigurationProvider();
}
else
{
INSTANCE = null;
}
}
return INSTANCE;
}
7、創建方法，檢測是否支持API。
/**
* Checks whether Location API is supported.
*
* @return a boolean indicating is Location API supported.
*/
public static boolean isLocationApiSupported()
{
String version = System.getProperty("microedition.location.version");
return (version != null && !version.equals("")) ? true : false;
}
public LocationProvider getSelectedProvider()
{
return provider;
}
8、使用預先定義的參數，創建搜索定位服務的方法。getInstance是一個內置的方法，根據已經確定的參數運行LocationProvider。當API定位發生錯誤的時候，程序跳轉至LocationException。getOrIEntation方法返回最終的定位源。
關於該類的更所信息，參考API定位。
/**
*
* @param listener -
* a event listener that listens ProviderStatusLisneter events.
*/
public void autoSearch(ProviderStatusListener listener)
{
try
{
for (int i = 0; i < freeCriterias.length; i++)
{
criteria = freeCriterias[i];
provider = LocationProvider.getInstance(criteria);
if (provider != null)
{
// Location provider found, send a selection event.
listener.providerSelectedEvent();
return;
}
}
if (queryUI.confirmCostProvider())
{
for (int i = 0; i < costCriterias.length; i++)
{
criteria = costCriterias[i];
provider = LocationProvider.getInstance(criteria);
if (provider != null)
{
// Location provider found, send a selection event.
listener.providerSelectedEvent();
return;
}
}
}
else
{
queryUI.showNoFreeServiceFound();
}
}
catch (LocationException le)
{
queryUI.showOutOfService();
}
}
public Orientation getOrIEntation()
{
try
{
return Orientation.getOrIEntation();
}
catch (LocationException e)
{
return null;
}
}
9、創建方法，判斷是否支持Oritation
/**
* Tells whether orIEntation is supported.
*
* @return a boolean indicating is orIEntation supported.
*/
public boolean isOrIEntationSupported()
{
try
{
// Test whether OrIEntation instance can be obtained.
Orientation.getOrIEntation();
return true;
}
catch (LocationException e)
{
return false;
}
}
