定位(1):获取位置

1.User Location能做什么？

获取用户的位置；3颗卫星确定位置

追踪用户的移动；

2.User Location的关键API

Location Manager：用于管理Android的用户定位服务；

Location Providers：提供多种定位方式供开发者选择；

GPS卫星进行定位：

需要在AndroidManifest.xml中声明权限：android.permission.ACCESS_FINE_LOCATION

NETWORD定位：

声明权限：android.permission.ACCESS_FINE_LOCATION

或

android.permission.ACCESS_COARSE_LOCATION(较粗糙)

3.获取用户的当前的位置步骤

在androidmanifest.xml文件中声明权限；

获取LocationManager对象；

选择LocationProvider对象；

绑定LocationListtener，当用户位置改变则触发函数；

 

e.g.

在AndroidManifest.xml中声明权限：android.permission.ACCESS_FINE_LOCATION

    </application>
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
</manifest>

 

main.xml中是一个按钮：

<Button 
        android:id="@+id/locationButton"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="绑定监听器"/>

 

mainActivity.java其中步骤

获取LocationManager对象；

选择LocationProvider对象；

绑定LocationListtener；

package com.example.locate;

import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.app.Activity;
import android.content.Context;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class MainActivity extends Activity {
	private Button button=null;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        button=(Button)findViewById(R.id.locationButton);
        button.setOnClickListener(new ButtonListener());//给button设置监听器
    }
    
    //实现ButtonListener
    private class ButtonListener implements OnClickListener
    {

		@Override
		public void onClick(View arg0) 
		{
			// 得到LocationManager对象
			LocationManager locationmanager=
					(LocationManager)MainActivity.this.getSystemService(Context.LOCATION_SERVICE);
//getSystemService用户得到一些系统服务,其返回值是oboject，所以要对其进行转型(LocationManager)
			//为locationmanager绑定了监听器，参数：使用的定位方式，间隔最小时间，最小距离，监听器
			locationmanager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, new TextLocationListener());
		}
    }
    //locationlistener共包含了四个方法，
    private class TextLocationListener implements  LocationListener{

		@Override
		//location对象代表当前位置，可以从中获取经度和纬度
		public void onLocationChanged(Location location) {
			// TODO Auto-generated method stub
			System.out.println(location.getLongitude());
			System.out.println(location.getLatitude());	
		}

		@Override
		/*Called when the provider is disabled by the user. 
		If requestLocationUpdates is called on an already disabled provider, 
		this method is called immediately.*/
		public void onProviderDisabled(String provider) {
			
		}
		@Override
		//Called when the provider is enabled by the user.
		public void onProviderEnabled(String provider) {
	
		}
		@Override
		/*Called when the provider status changes. 
		This method is called when a provider is unable to fetch a location or 
		if the provider has recently become available after a period of unavailability.*/
		public void onStatusChanged(String provider, int status, Bundle extras) {
			// TODO Auto-generated method stub	
		}	
    }
}

 

 

 

4.使用用DDMS模拟定位

打开DDMS中的：

 
 

点击send则会打印出

 

改变其longitude和latitude：重新打印信息改变