GPS定位是目前很多手机都有的功能,且非常实用。本文以实例形式讲述了Android中GPS定位的用法。分享给大家供大家参考之用。具体方法如下:
一般在Android中通过GPS获得当前位置,首先要获得一个LocationManager实例,通过该实例的getLastKnownLocation()方法获得第一个的位置,该方法的说明如下:
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void android.location.LocationManager.requestLocationUpdates(String provider, long minTime, float minDistance, LocationListener listener) |
provider即定位方式,可以采用GPS定位(LocationManager.GPS_PROVIDER)或者网络定位(LocationManager.NETWORK_PROVIDER),本文是GPS定位,因此使用LocationManager.GPS_PROVIDER。minTime是位置更新的间隔时间。listener是位置改变的监听器,自己定义一个LocationListener(),重写onLocationChanged(),加入位置改变时的动作。
布局文件如下:
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< LinearLayout xmlns:android = "http://schemas.android.com/apk/res/android" xmlns:tools = "http://schemas.android.com/tools" android:layout_width = "match_parent" android:layout_height = "match_parent" android:orientation = "vertical" android:paddingBottom = "@dimen/activity_vertical_margin" android:paddingLeft = "@dimen/activity_horizontal_margin" android:paddingRight = "@dimen/activity_horizontal_margin" android:paddingTop = "@dimen/activity_vertical_margin" tools:context = ".MainActivity" > < TextView android:id = "@+id/txt_time" style = "@style/my_text" android:layout_width = "fill_parent" android:layout_height = "wrap_content" android:text = "时间:" /> < TextView android:id = "@+id/txt_lat" style = "@style/my_text" android:layout_width = "fill_parent" android:layout_height = "wrap_content" android:text = "经度:" /> < TextView android:id = "@+id/txt_lng" style = "@style/my_text" android:layout_width = "fill_parent" android:layout_height = "wrap_content" android:text = "纬度:" /> </ LinearLayout > |
MainActivity.java文件如下:
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package com.hzhi.my_gps; import java.text.SimpleDateFormat; import java.util.Date; import java.util.Timer; import java.util.TimerTask; import android.location.Criteria; import android.location.Location; import android.location.LocationListener; import android.location.LocationManager; import android.os.Bundle; import android.os.Handler; import android.os.Message; import android.app.Activity; import android.content.Context; import android.view.Menu; import android.widget.TextView; public class MainActivity extends Activity { TextView txt_time; TextView txt_lat; TextView txt_lng; LocationManager lom; Location loc; Double lat; Double lng; SimpleDateFormat formatter = new SimpleDateFormat( "yyyy-MM-dd HH:mm:ss" ); Date now; String str_date; Timer timer; @Override protected void onCreate(Bundle savedInstanceState) { super .onCreate(savedInstanceState); setContentView(R.layout.activity_main); get_con(); get_gps(); timer = new Timer( true ); timer.schedule(task, 0 , 1000 ); } @Override public boolean onCreateOptionsMenu(Menu menu) { // Inflate the menu; this adds items to the action bar if it is present. getMenuInflater().inflate(R.menu.main, menu); return true ; } public void get_gps(){ lom = (LocationManager) getSystemService(Context.LOCATION_SERVICE); loc = lom.getLastKnownLocation(LocationManager.GPS_PROVIDER); if (loc != null ) { lat = loc.getLatitude(); lng = loc.getLongitude(); txt_lat.setText( "纬度:" + String.valueOf(lat)); txt_lng.setText( "经度:" + String.valueOf(lng)); } else { txt_lat.setText( "纬度:未知" ); txt_lng.setText( "经度:未知" ); } Criteria criteria = new Criteria(); criteria.setAccuracy(Criteria.ACCURACY_FINE); criteria.setAltitudeRequired( false ); criteria.setBearingRequired( false ); criteria.setCostAllowed( true ); criteria.setPowerRequirement(Criteria.POWER_LOW); String provider = lom.getBestProvider(criteria, true ); lom.requestLocationUpdates(provider, 1000 , 10 , los); } LocationListener los = new LocationListener(){ public void onLocationChanged(Location location){ if (location != null ) { lat = location.getLatitude(); lng = location.getLongitude(); txt_lat.setText( "纬度:" + String.valueOf(lat)); txt_lng.setText( "经度:" + String.valueOf(lng)); } else { txt_lat.setText( "纬度:未知" ); txt_lng.setText( "经度:未知" ); } }; public void onProviderDisabled(String provider){ }; public void onProviderEnabled(String provider){ }; public void onStatusChanged(String provider, int status, Bundle extras){ }; }; // 获取控件 public void get_con(){ txt_time = (TextView) findViewById(R.id.txt_time); txt_lat = (TextView) findViewById(R.id.txt_lat); txt_lng = (TextView) findViewById(R.id.txt_lng); } Handler handler = new Handler(){ public void handleMessage(Message msg){ switch (msg.what){ case 1 : get_time(); break ; } } }; TimerTask task = new TimerTask(){ public void run() { Message message = new Message(); message.what = 1 ; handler.sendMessage(message); } }; // 获取时间 public void get_time(){ now = new Date(System.currentTimeMillis()); str_date = formatter.format(now); txt_time.setText( "时间:" + str_date); } } |
在AndroidManifest.xml文件中加入权限:
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< uses-permission android:name = "android.permission.ACCESS_FINE_LOCATION" /> |
运行前先打开GPS卫星,运行结果如下图所示:
读者可以在室外信号充足的地方试试,是可以获取GPS位置的。
希望本文所述对大家的Android程序设计有所帮助。