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

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：

layout文件：

 

<?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>

Activity文件：

 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);
		}
	}
	
	
}