2010.12.10(4)——— android 1000范围内的数据以及两点之间的距离-优快云博客

本文介绍了一个安卓应用程序，该程序能够在手机上显示用户当前位置附近1000米范围内的工程项目信息。通过GPS获取用户的地理位置，并利用经纬度计算与各工程的距离。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

2010.12.10(4)——— android 1000范围内的数据以及两点之间的距离

项目中需要在手机上显示一定范围内的工程信息在网上找了好久没找到合适的只好自己想了

思路：
首先得到当前经纬度坐标传到后台
然后后台根据当前位置和数据库中工程的经纬度比较如果两点之间的距离 <= 1000米就显示在手机上

难点：

主要是计算两点之间的距离这个网上例子很多如下：

public class MapDistance {
	private static double EARTH_RADIUS = 6378.137;
	private static double rad(double d)
	{
	   return d * Math.PI / 180.0;
	}
	public static double GetDistance(double lat1, double lng1, double lat2, double lng2)
	{
	   double radLat1 = rad(lat1);
	   double radLat2 = rad(lat2);
	   double a = radLat1 - radLat2;
	   double b = rad(lng1) - rad(lng2);
	   double s = 2 * Math.asin(Math.sqrt(Math.pow(Math.sin(a/2),2) + 
	    Math.cos(radLat1)*Math.cos(radLat2)*Math.pow(Math.sin(b/2),2)));
	   s = s * EARTH_RADIUS;
	   s = Math.round(s * 10000) / 10000;
	   return s;
	}
}

这个就是服务器端的主要代码了

android端完整代码如下：

[b]layout文件：[/b]

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >

   <LinearLayout
	    android:orientation="horizontal"
	    android:layout_width="fill_parent"
	    android:layout_height="40dip"
	    >
       <Spinner
		    android:layout_width="wrap_content"
			android:layout_height="fill_parent"
		    android:id="@+id/sp_jl"
		   	/>
	</LinearLayout>
    <LinearLayout
     	android:orientation="horizontal"
    	android:layout_width="fill_parent"
    	android:layout_height="wrap_content"
    	>
		<TextView
			  android:layout_width="20dip"
			  android:layout_height="wrap_content"
			  android:text="序号"
			  android:textColor="#f0f4f9"
			  />
		<TextView
			  android:layout_width="100dip"
			  android:layout_height="wrap_content"
			  android:text="工程名称"
			  android:textColor="#ffffff"
			  />
		<TextView
			  android:layout_width="100dip"
			  android:layout_height="wrap_content"
			  android:text="建设单位"
			  android:textColor="#ffffff"
			  />
		<TextView
			  android:layout_width="50dip"
			  android:layout_height="wrap_content"
			  android:text="施工状态"
			  android:textColor="#ffffff"
			  />
		<TextView
			  android:layout_width="fill_parent"
			  android:layout_height="wrap_content"
			  android:text="建设性质"
			  android:textColor="#ffffff"
			  />
    </LinearLayout>
    <ListView 
	    android:layout_width="fill_parent" 
	    android:layout_height="wrap_content" 
	    android:id="@+id/dis_listview"
	    />
</LinearLayout>

[b]Activity文件：[/b]

 package com.huitu.project;

import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;

import com.huitu.pojo.GCXX2;
import com.huitu.service.GCXXService;
import com.huitu.util.JSONUtil;

import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Context;
import android.content.Intent;
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.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.Spinner;
import android.widget.AdapterView.OnItemClickListener;

public class GCXXForLatLng extends Activity {

	private Spinner sp_jl;
	private ListView listView;
	private String flat;

	private ProgressDialog pd;
	private Handler mProgressHandler;
	private SimpleAdapter adapter;
	private MyThread mt ;

	private LocationManager locationManager;
	private String lat;
	private String lng;
	private String jl;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		// TODO Auto-generated method stub
		super.onCreate(savedInstanceState);
		setContentView(R.layout.gcxxforlatlng);

		pd = new ProgressDialog(this);
		pd.setIndeterminate(true);
		pd.setMessage("加载数据...");
		pd.setCancelable(true);
		pd.show();
		mProgressHandler = new Handler() {
            @Override
            public void handleMessage(Message msg) {
            	int length = msg.getData().getInt("length");
            	switch (length){
            	case 1 :
            		pd.dismiss();
            		break;
            	case 2 :
            		listView.setAdapter(adapter);
        			listView.setOnItemClickListener(new ItemClickListen());
        			break;
            	}

            }
        };

        Intent intent = this.getIntent();
        flat = intent.getStringExtra("flat");

		sp_jl = (Spinner)findViewById(R.id.sp_jl);
		listView = (ListView)findViewById(R.id.dis_listview);

		String[] jls = {"500","1000","2000"};
		ArrayAdapter arr_jl = new ArrayAdapter<String>(this,
				android.R.layout.simple_spinner_item, jls);
		arr_jl.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
		sp_jl.setAdapter(arr_jl);
		sp_jl.setPrompt("请选择查询距离");
		// 默认选择1000米
		sp_jl.setSelection(1, true);
		sp_jl.setOnItemSelectedListener(new Spinner.OnItemSelectedListener() {

			public void onItemSelected(AdapterView<?> arg0, View arg1,
					int arg2, long arg3) {
				// TODO Auto-generated method stub
				pd.show();
				jl = (String) sp_jl.getSelectedItem();
				mt = new MyThread();
				mt.start();
			}
			public void onNothingSelected(AdapterView<?> arg0) {
				// TODO Auto-generated method stub

			}

		});

		locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
		String provider = LocationManager.GPS_PROVIDER;
		Location location = locationManager.getLastKnownLocation(provider);
		pd.show();
		lat = location.getLatitude()+"";
		lng = location.getLongitude()+"";
		jl = "1000";
		mt = new MyThread();
		mt.start();

		LocationListener ll = new LocationListener(){
			public void onLocationChanged(Location location) {
				pd.show();
				lat = location.getLatitude()+"";
				lng = location.getLongitude()+"";
				mt = new MyThread();
				mt.start();
			}
			public void onProviderDisabled(String provider) {
			}

			public void onProviderEnabled(String provider) {
			}

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

		locationManager.requestLocationUpdates(provider, 500, 5,
				ll);
	}

	private final class ItemClickListen implements OnItemClickListener{

		public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
			 ListView lv = (ListView)parent;
			 HashMap<String, Object> map = (HashMap<String, Object>)lv.getItemAtPosition(position);
			 String GCBM = map.get("GCBM").toString();
			 Intent intent = null;
			 if(flat.equals("0")){
				 intent = new Intent(GCXXForLatLng.this,XZJLListActivity.class);
			 }else{
				 intent = new Intent(GCXXForLatLng.this,XZJL_UploadActivity.class);
			 }
			 Bundle bundle = new Bundle();
			 bundle.putString("GCBM", GCBM);
			 intent.putExtras(bundle);
			 startActivity(intent);
		}    	
    }

	private void updateView(String lat,String lng,String jl){
		try {
			String json = GCXXService.query(lat,lng,jl);
			System.out.println(json);
			List<GCXX2> list = JSONUtil.parseJSON_GCXX2_list(json);
			List<HashMap<String, Object>> data = new ArrayList<HashMap<String, Object>>();
			// String[]sta={"无证","有证"};
			// String s;
			for (GCXX2 bean : list) {
				HashMap<String, Object> item = new HashMap<String, Object>();
				item.put("RN", bean.getRowId());
				item.put("GCMC", bean.getXMMC());
				item.put("JSDWMC", bean.getJSDWMC());
				item.put("GCZT_NAME", bean.getGCZT_NAME());
				item.put("STATUES", bean.getSTATUES());
				item.put("GCXZ", bean.getGCXZNAME());

				item.put("GCBM", bean.getGCBM());

				data.add(item);
			}
			adapter = new SimpleAdapter(GCXXForLatLng.this, data,
					R.layout.gcxxitem, new String[] { "RN", "GCMC", "JSDWMC",
							"GCZT_NAME",  "GCXZ" }, new int[] {
							R.id.gcxx_rn, R.id.gcmc, R.id.jsdw, R.id.gczt,
							 R.id.jsxz });
			// ll.setVisibility(View.VISIBLE);

			Message msg = new Message();
			msg.getData().putInt("length", 2);
			mProgressHandler.sendMessage(msg);
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}

	private class MyThread extends Thread {
		public void run(){
			updateView(lat,lng,jl);
			Message msg = new Message();
			msg.getData().putInt("length", 1);
			mProgressHandler.sendMessage(msg);
		}
	}


}