android 自带gps定位Location相关知识
16lz
2021-01-23
android自带gps定位功能相信大家都不会太陌生了,都有所涉及。简单的写了一个示例程序,获取经纬度还有其它相关数据的代码,还有其他相关的知识,比如直接跳转到打开系统gps设置的界面。还有一个bug的处理,异常信息:Incomplete location object, missing timestamp or accuracy
1、获取location 示例程序
package com.example.locationexample;import android.location.Location;import android.location.LocationListener;import android.location.LocationManager;import android.os.Build;import android.os.Bundle;import android.os.SystemClock;import android.util.Log;import android.widget.TextView;import android.annotation.TargetApi;import android.app.Activity;import android.content.Context;public class MainActivity extends Activity {LocationManager mLocationManager;Location mlocation;TextView mTextView;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);mTextView = (TextView)findViewById(R.id.textView1);getLocation();//mlocation.setElapsedRealtimeNanos(SystemClock.elapsedRealtimeNanos());//mLocationManager.setTestProviderLocation(LocationManager.GPS_PROVIDER, mlocation);}public Location getLocation(){mLocationManager = (LocationManager)getSystemService(Context.LOCATION_SERVICE);mlocation = mLocationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);if (mlocation == null) {mlocation = mLocationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);}mLocationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 100, 0, mLocationListener);return mlocation;}LocationListener mLocationListener = new LocationListener() {@TargetApi(17)@Overridepublic void onLocationChanged(Location mlocal) {if(mlocal == null) return;String strResult = "getAccuracy:" + mlocal.getAccuracy() + "\r\n"+ "getAltitude:" + mlocal.getAltitude() + "\r\n"+ "getBearing:" + mlocal.getBearing() + "\r\n"+ "getElapsedRealtimeNanos:" + String.valueOf(mlocal.getElapsedRealtimeNanos()) + "\r\n"+ "getLatitude:" + mlocal.getLatitude() + "\r\n"+ "getLongitude:" + mlocal.getLongitude() + "\r\n"+ "getProvider:" + mlocal.getProvider()+ "\r\n"+ "getSpeed:" + mlocal.getSpeed() + "\r\n"+ "getTime:" + mlocal.getTime() + "\r\n";Log.i("Show", strResult);if (mTextView != null) {mTextView.setText(strResult);}}@Overridepublic void onProviderDisabled(String arg0) {}@Overridepublic void onProviderEnabled(String arg0) {}@Overridepublic void onStatusChanged(String provider, int event, Bundle extras) {}};}
在这里提醒一下,最好activity销毁时候onDestroy(),移除mLocationManager这个变量。
权限如下:
还有重点看这行代码参数mLocationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 100, 0, mLocationListener);
LocationManager.GPS_PROVIDER是gps提供,100是时间,多久刷新一次,0是距离,如果你不动的话,测试最好写0
mLocationListener是接口啦,数据就是那里来的。
2、异常
如果你使用mLocationManager.setTestProviderLocation(LocationManager.GPS_PROVIDER, mlocation);这行代码报出下面的堆栈错误信息
java.lang.IllegalArgumentException: Incomplete location object, missing timestamp or accuracy? Location[gps 23.126704,113.365648 acc=1 et=?!? alt=-7.422 vel=0.008333334 bear=237.76]
解决办法:
方法一:
主要是这句,location.setElapsedRealtimeNanos(SystemClock.elapsedRealtimeNanos());,其实加上这句就可以了。
例如:
@SuppressLint("NewApi") private Location getLoc(String provider) { Location location = new Location(provider); location.setLatitude(lat); location.setLongitude(lng); location.setAltitude(altitude); location.setBearing(bearing); location.setSpeed(speed); location.setAccuracy(accuracy); location.setTime(System.currentTimeMillis()); location.setElapsedRealtimeNanos(SystemClock.elapsedRealtimeNanos()); return location; }
主要是这句,location.setElapsedRealtimeNanos(SystemClock.elapsedRealtimeNanos());,其实加上这句就可以了。如下 mlocation.setElapsedRealtimeNanos(SystemClock.elapsedRealtimeNanos());mLocationManager.setTestProviderLocation(LocationManager.GPS_PROVIDER, mlocation);
方法二,加上下面的反射调用:
try { Method method = Location.class.getMethod("makeComplete"); if (method != null) { method.invoke(localLocation); } } catch (NoSuchMethodException e) { e.printStackTrace(); } catch (Exception e) { e.printStackTrace(); }
方法二使用,是借鉴android系统源码的反射作用
源码如下:
/** * Helper to fill incomplete fields. * * Used to assist in backwards compatibility with * Location objects received from applications. * * @see #isComplete * @hide */ public void makeComplete() { if (mProvider == null) mProvider = "?"; if (!mHasAccuracy) { mHasAccuracy = true; mAccuracy = 100.0f; } if (mTime == 0) mTime = System.currentTimeMillis(); if (mElapsedRealtimeNanos == 0) mElapsedRealtimeNanos = SystemClock.elapsedRealtimeNanos(); }
建议使用第一个方法。
3、是否已打开自身GPS
//获取是否已打开自身GPSpublic boolean isGpsEnable() {String providers = Settings.Secure.getString(mContext.getContentResolver(), Settings.Secure.LOCATION_PROVIDERS_ALLOWED);if (providers.contains(LocationManager.GPS_PROVIDER)) {return true;} else {return false;}}
4、直接跳转到系统设置gps界面
Intent callGPSSettingIntent = new Intent(android.provider.Settings.ACTION_LOCATION_SOURCE_SETTINGS);this.startActivity(callGPSSettingIntent);
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