Android开发--用户定位服务--UserLocation

2013-01-28 08:32:26 我来说两句作者：BruceZhang

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[java]

用户定位介绍：

User Location的作用：

1.获取用户的位置

2.追踪用户的移动

User Location的关键API

1.Location Manager：用于管理Android的用户定位服务

2.Location Providers：提供多种定位方式供开发者选择。

<1>GPS Provider

<2>Network Provider

<3>Passive

定位方式的分类：

1.GPS定位：使用GPS卫星进行定位，需要在AndroidManifest.xml当中声明如下权限：

android.permission.ACCESS_FINE_LOCATION

2.NETWORK定位：使用信号接收塔和WIFI接入点进行定位，需要在AndroidManifest.xml当中声明如下权限：

android.permission.ACCESS_FINE_LOCATION

或

android.permission.ACCESS_COARSE_LOCATION

以上两种定位方式的区别是GPS定位精度更高，但同时也更耗电

获取用户的当前位置：

1.在AndroidManifest.xml当中声明相应的权限；

2.获取LocationManager对象；

3.选择LocationProvider；

4.绑定LocationListener对象。

LocationListener有四个方法：

1.onLocationChanged(Location location)：当设备的位置发生改变时调用

我们可以调用location.getLongitude()和location.getLatitude()来得到设备所处的经度和纬度

2.onProviderDisabled(String provider)：当提供数据Provider禁用时调用

3.onProviderEnabled(String provider)：当提供数据的Provider使用时调用

4.onStatusChanged(String provider,int status,Bundle extras)：当状态改变时

我们需要实现LocationListener的以上四个方法：

[java]

private class TestLocationListener implements LocationListener{

@Override

public void onLocationChanged(Location location){

System.out.println(location.getLongitude());

System.out.println(location.getLatitude());

}

@Override

public void onProviderDisabled(String provider){

// do something you need

}

@Override

public void onProviderEnabled(String provider){

// do something you need

}

@Override

public void onStatusChanged(String provider,int status,Bundle extras){

// do something you need

}

}

测试当前设备的LocationProvider

由于一般的设备存在不止一种定位方法，所以在这里给出查找定位服务的方法：

[java]

List<String> providers=locationManager.getAllProviders();

for(Iterator<String> iterator=providers.iterator();iterator.hasNext();){

String string=(String)iterator.next();

Log.d("BruceZhang", string+" ");

由于有多个Provider，那么就需要做出选择，在这里给出选择最好的Provider的方法：

此时需要用到一个类--Criteria

下面是在Android SDK文档上给出的解释：

A class indicating the application criteria for selecting a location provider. Providers maybe ordered according to accuracy, power usage, ability to report altitude, speed, and bearing, and monetary cost.

它提供了一系列的方法，设置用户的需求，并最终给出用户所需要的最佳的Provider，下面是文档上对设置条件的解释：

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void setAccuracy(int accuracy)

Indicates the desired accuracy for latitude and longitude.

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void setAltitudeRequired(boolean altitudeRequired)

Indicates whether the provider must provide altitude information.

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void setBearingAccuracy(int accuracy)

Indicates the desired bearing accuracy.

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void setBearingRequired(boolean bearingRequired)

Indicates whether the provider must provide bearing information.

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void setCostAllowed(boolean costAllowed)

Indicates whether the provider is allowed to incur monetary cost.

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void setHorizontalAccuracy(int accuracy)

Indicates the desired horizontal accuracy (latitude and longitude).

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void setPowerRequirement(int level)

Indicates the desired maximum power level.

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void setSpeedAccuracy(int accuracy)

Indicates the desired speed accuracy.

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void setSpeedRequired(boolean speedRequired)

Indicates whether the provider must provide speed information.

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void setVerticalAccuracy(int accuracy)

Indicates the desired vertical accuracy (altitude).

追踪用户的位置：

对用户的位置进行更新用到的方法和解释如下：

[java]

// public void requestLocationUpdates (String provider,

// long minTime, float minDistance, LocationListener listener)

// Added in API level 1

// Register for location updates using the named provider, and a pending intent.

// Parameters

// provider the name of the provider with which to register

// minTime minimum time interval between location updates, in milliseconds

// minDistance minimum distance between location updates, in meters

// listener a LocationListener whose onLocationChanged(Location) method will be called for each location update

locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0,

0, new TestLocationListener());

下面，给出一个例子，实现用户的定位，取得支持的LocationProvider，根据条件获取最佳的Provider：

一下是实现的源代码：

[java]

public class MainActivity extends Activity {

private Button button;

private Button button2;

private Button button3;

private Button button4;

private LocationManager locationManager;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

button=(Button)findViewById(R.id.button1);

button2=(Button)findViewById(R.id.button2);

button3=(Button)findViewById(R.id.button3);

button4=(Button)findViewById(R.id.button4);

button.setOnClickListener(new ButtonListener());

button2.setOnClickListener(new ProviderButtonListener());

button3.setOnClickListener(new BestProviderButtonListener());

button4.setOnClickListener(new MyLocation());

locationManager=(LocationManager)MainActivity.this.

getSystemService(Context.LOCATION_SERVICE);

}

private class ButtonListener implements OnClickListener{

@Override

public void onClick(View v) {

// TODO Auto-generated method stub

// LocationManager locationManager=(LocationManager)MainActivity.this.

// getSystemService(Context.LOCATION_SERVICE);

* 各个参数的意义：

* 1.定义当前所使用的Location Provider

* 2.位置更新一次的最小时间间隔

* 3.位置更新的最小距离

* 4.绑定监听器--位置发生变化会调用其中的方法

Log.d("BruceZhang", "Bond Success");

// public void requestLocationUpdates (String provider,

// long minTime, float minDistance, LocationListener listener)

// Added in API level 1

// Register for location updates using the named provider, and a pending intent.

// Parameters

// provider the name of the provider with which to register

// minTime minimum time interval between location updates, in milliseconds

// minDistance minimum distance between location updates, in meters

// listener a LocationListener whose onLocationChanged(Location) method will be called for each location update

locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0,

0, new TestLocationListener());

}

private class ProviderButtonListener implements OnClickListener{

@Override

public void onClick(View v) {

// TODO Auto-generated method stub

List<String> providers=locationManager.getAllProviders();

for(Iterator<String> iterator=providers.iterator();iterator.hasNext();){

String string=(String)iterator.next();

Log.d("BruceZhang", string+" ");

}

private class BestProviderButtonListener implements OnClickListener{

@Override

public void onClick(View v) {

// TODO Auto-generated method stub

Criteria criteria=new Criteria();

criteria.setAccuracy(Criteria.ACCURACY_FINE);

criteria.setPowerRequirement(Criteria.POWER_LOW);

criteria.setAltitudeRequired(false);

criteria.setSpeedRequired(false);

criteria.setCostAllowed(false);

//第二个参数设置为false时，不管当前的那个provider是否可用，都需要进行查找，并根据条件设为最优

String provider=locationManager.getBestProvider(criteria, false);

Log.d("BruceZhang", "The best provider is:"+provider);

}

private class MyLocation implements OnClickListener{

@Override

public void onClick(View v) {

// TODO Auto-generated method stub

//对用用户定位服务主要是中间两个参数的设置

locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 5000,

2000, new TestLocationListener());

}

private class TestLocationListener implements LocationListener{

//这个函数的参数是用户当前的位置

@Override

public void onLocationChanged(Location arg0) {

// TODO Auto-generated method stub

// Toast.makeText(MainActivity.this, "您当前的经度是："+arg0.getLongitude()+" ，"+

// "您当前的纬度是："+arg0.getLatitude(),

// Toast.LENGTH_SHORT).show();

Log.d("BruceZhang", arg0.getLongitude()+"");

Log.d("BruceZhang", arg0.getLatitude()+"");

}

@Override

public void onProviderDisabled(String arg0) {

// TODO Auto-generated method stub

}

@Override

public void onProviderEnabled(String arg0) {

// TODO Auto-generated method stub

}

@Override www.2cto.com

public void onStatusChanged(String arg0, int arg1, Bundle arg2) {

// TODO Auto-generated method stub

}

@Override

public boolean onCreateOptionsMenu(Menu menu) {

// Inflate the menu; this adds items to the action bar if it is present.

getMenuInflater().inflate(R.menu.activity_main, menu);

return true;

}