百度地图API开发的定位APK

之前看过Location的app及framework代码，下面贴个简单的定位程序，以供大家交流，使用百度地图SDK开发的，引用了百度地图的so库文件。

效果图如下：

package com.baidumap.location;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ProgressBar;
import android.widget.TextView;

import com.baidu.R;
import com.baidu.location.BDLocation;
import com.baidu.location.BDLocationListener;
import com.baidu.location.LocationClient;
import com.baidu.location.LocationClientOption;

public class BaiduMapActivity extends Activity {
	private static final String TAG = "BaiduMapActivity";
	public static final String KEY_LATITUDE = "Latitude";
	public static final String KEY_LONGITUDE = "Longitude";
	private static final int MSG_REQUEST_LOCATION = 1;
	private static final int MSG_TIME_DELAYED = 2000;
	private LocationClient mLocClient = null;
	private TextView mLocInfo;
	private Button mLocBtn;
	private ProgressBar mProgressView = null;
	private double mLatitude;
	private double mLongitude;
	private MyLocationListenner mLocListener = new MyLocationListenner();
	
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        mLocBtn = (Button)findViewById(R.id.location_btn);
        mLocInfo = (TextView)findViewById(R.id.location_info);
		mProgressView = (ProgressBar) findViewById(R.id.progress_bar);
        mProgressView.setVisibility(View.VISIBLE);
        mProgressView.setIndeterminate(true);
        
        mLocClient = new LocationClient(this);
        mLocClient.registerLocationListener(mLocListener);
        mLocClient.start();
        
        // send message to update location
        sendMsgUpdateLocation();
        
        mLocBtn.setOnClickListener(new OnClickListener() {
			
			@Override
			public void onClick(View v) {
				// click the button and show the webview activity.
				requestCurrentLocation();

				Log.d(TAG, "onClick: mLatitude = " + mLatitude + " " + "mLongitude = " + mLongitude);
				Bundle bundle = new Bundle();
				bundle.putDouble(KEY_LATITUDE, mLatitude);
				bundle.putDouble(KEY_LONGITUDE, mLongitude);					
				Intent intent = new Intent(BaiduMapActivity.this, WebViewActivity.class);
				intent.putExtras(bundle);
				startActivity(intent);
			}
		});
        
    }
    
    public Handler mMsgHandler = new Handler() {

		@Override
		public void handleMessage(Message msg) {
			// TODO Auto-generated method stub
			super.handleMessage(msg);
			
			Log.d(TAG, "handleMessage: msg.what = " + msg.what);
			switch(msg.what) {
			case MSG_REQUEST_LOCATION:
				requestCurrentLocation();
				break;
		    default:
		    	break;
			}
		}
    	
    };
    
    public void sendMsgUpdateLocation() {
        Message msg = mMsgHandler.obtainMessage(MSG_REQUEST_LOCATION);
        mMsgHandler.sendMessageDelayed(msg, MSG_TIME_DELAYED);
    }
    
    public void requestCurrentLocation() {
    	Log.d(TAG, "requestCurrentLocation()");
        try {
        	if (mLocClient != null && mLocClient.isStarted()) {
        		Log.d(TAG, "requestCurrentLocation()->requestLocation()");
				setLocationOption();
				mLocClient.requestLocation();
        	}
        } catch(Exception err) {
        	Log.d(TAG, "error = " + err);
        }    	
    }
    
    /**
	 * show the TextView
	 */
	public void showAddressInfo(String location) {
		try {
			if (mLocInfo != null) {
				mLocInfo.setText(location);
			}
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
	
	 /**
	 * Location Listener
	 */
	public class MyLocationListenner implements BDLocationListener {
		@Override
		public void onReceiveLocation(BDLocation location) {
			Log.d(TAG, "MyLocationListenner: onReceiveLocation");

			if (location == null) {
				return;
			}
			
			String address = location.getAddrStr();
			Log.d(TAG, "MyLocationListenner: onReceiveLocation, address = " + address);
			
			if(address == null) {
				mLocClient.requestLocation();
			}
			
			mLatitude = location.getLatitude();
			mLongitude = location.getLongitude();
			String newLine = "\n";
			StringBuffer sb = new StringBuffer(256);
			sb.append(getString(R.string.time));
			sb.append(location.getTime());
			sb.append(newLine + getString(R.string.error_code));
			sb.append(location.getLocType());
			sb.append(newLine + getString(R.string.Longitude));
			sb.append(location.getLongitude());			
			sb.append(newLine + getString(R.string.Latitude));
			sb.append(location.getLatitude());
			sb.append(newLine + getString(R.string.radius));
			sb.append(location.getRadius());
			
			Log.d(TAG, "MyLocationListenner: onReceiveLocation, getLocType = " + location.getLocType());
			if (location.getLocType() == BDLocation.TypeGpsLocation) {
				sb.append(newLine + getString(R.string.speed));
				sb.append(location.getSpeed());
				sb.append(newLine + getString(R.string.satellite));
				sb.append(location.getSatelliteNumber());
			} else if (location.getLocType() == BDLocation.TypeNetWorkLocation) {			
				sb.append(newLine + getString(R.string.address));
				sb.append(location.getAddrStr());
			}

			sb.append(newLine + getString(R.string.version));
			sb.append(mLocClient.getVersion());
			sb.append(newLine + getString(R.string.flag));
			sb.append(location.isCellChangeFlag());
			
			// show the details
			showAddressInfo(sb.toString());
			
			// address is null, send message to update the textview
			if(address == null) {
				sendMsgUpdateLocation();
			} else {
				mProgressView.setIndeterminate(false);
		                mProgressView.setVisibility(View.GONE);				
			}
		}
		
		public void onReceivePoi(BDLocation poiLocation) {
			if (poiLocation == null){
				return ; 
			}
			
			String newLine = "\n";
			StringBuffer sb = new StringBuffer(256);
			sb.append(getString(R.string.position_time));
			sb.append(poiLocation.getTime());
			sb.append(newLine + getString(R.string.error_code));
			sb.append(poiLocation.getLocType());
			sb.append(newLine + getString(R.string.Latitude));
			sb.append(poiLocation.getLatitude());
			sb.append(newLine + getString(R.string.Longitude));
			sb.append(poiLocation.getLongitude());
			sb.append(newLine + getString(R.string.radius));
			sb.append(poiLocation.getRadius());
			if (poiLocation.getLocType() == BDLocation.TypeNetWorkLocation) {
				sb.append(newLine + getString(R.string.address));
				sb.append(poiLocation.getAddrStr());
			} 
			if(poiLocation.hasPoi()) {
				sb.append(newLine + getString(R.string.position));
				sb.append(poiLocation.getPoi());
			} else {
				sb.append(newLine + getString(R.string.no_position_info));
			}
		}
	}
	
	private void setLocationOption() {
		Log.d(TAG, "setLocationOption()");
		LocationClientOption option = new LocationClientOption();
		option.setServiceName("com.baidu.location.service_v2.6");
		
		// 返回的定位结果包含地址信息
		option.setAddrType("all");
		// 是否需要POI的电话和地址等详细信息
		option.setPoiExtraInfo(true);  
		   
		// 设置产品线名称。强烈建议您使用自定义的产品线名称，方便我们以后为您提供更高效准确的定位服务。  
		option.setProdName(getString(R.string.location_by_GPS));  
		   
		// 设置GPS，使用gps前提是用户硬件打开gps。默认是不打开gps的。
		option.setOpenGps(true);  
		   
		// 定位的时间间隔，单位：ms 
		// 当所设的整数值大于等于1000（ms）时，定位SDK内部使用定时定位模式。 
		option.setScanSpan(500);  
		   
		// 查询范围，默认值为500，即以当前定位位置为中心的半径大小。
		option.setPoiDistance(500);  
		// 禁用启用缓存定位数据  
		option.disableCache(true);  
		   
		// 坐标系类型，百度手机地图对外接口中的坐标系默认是bd09ll
		option.setCoorType("bd09ll");  
		   
		// 设置最多可返回的POI个数，默认值为3。由于POI查询比较耗费流量，设置最多返回的POI个数，以便节省流量。  
		option.setPoiNumber(3);  
		   
		// 设置定位方式的优先级, GpsFirst NetWorkFirst
		// 当gps可用，而且获取了定位结果时，不再发起网络请求，直接返回给用户坐标。这个选项适合希望得到准确坐标位置的用户。如果gps不可用，再发起网络请求，进行定位。
		option.setPriority(LocationClientOption.GpsFirst);
		mLocClient.setLocOption(option);
	}
}

代码比较简单，主要思路是：

1、在onCreate的时候，让ProgressBar先转一会，创建一个LocationClient，并注册一个BDLocationListener用于监听定位消息；

2、创建一个Handler用于发消息MSG_REQUEST_LOCATION，用于请求获取定位信息，暂时消息以2s后发送，经测试发送太快往往还得不到数据；

3、收到消息后，可能经纬度都得到了，但是地址还未得到。所以如果未获取到地址的话，再发个消息MSG_REQUEST_LOCATION出去；

4、假如收到消息了，将ProgressBar停掉；

5、点屏幕上的Button按钮，将获取的经纬度信息传给WebViewActivity，并用百度地图的链接打开一个网页。WebViewActivity代码如下：

package com.baidumap.location;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.KeyEvent;
import android.webkit.WebView;

import com.baidu.R;

public class WebViewActivity extends Activity {
	private static String TAG = "webViewActivity";
	private String mHtml;
	private WebView mWebView;
	
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.webview);

		// get Bundle from previous activity.
		Intent intent = getIntent();
		Bundle bundle = intent.getExtras();
		Double latitude = bundle.getDouble(BaiduMapActivity.KEY_LATITUDE);
		Double longitude = bundle.getDouble(BaiduMapActivity.KEY_LONGITUDE);
		
		mWebView = (WebView)this.findViewById(R.id.webView);
		// enable javascript
		mWebView.getSettings().setJavaScriptEnabled(true);
		mWebView.addJavascriptInterface(new InJavaScriptLocalObj(), "local_obj");
		// load the web
		mWebView.loadUrl("http://api.map.baidu.com/marker?location=" + latitude + "," + longitude 
				+ "&title=" + getString(R.string.mylocation) + "&output=html");   
	}

	final class InJavaScriptLocalObj {
		public void showSource(String html) {
			try {
				mHtml = html;
				Log.d(TAG, "InJavaScriptLocalObj: showSource, mHtml = " + mHtml);
			} catch (Exception e) {
			}

		}
	}
	
	@Override
	public boolean onKeyDown(int keyCode, KeyEvent event) {
		this.finish();
		return super.onKeyDown(keyCode, event);
	}	 
}

上文代码中提到的R.layout.main以及R.layout.webview如下：

main.xml

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

    <ProgressBar
        android:id="@+id/progress_bar"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        style="?android:attr/progressBarStyleLarge" />
    
    <Button 
        android:id="@+id/location_btn"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="@string/Location"/>
    
    <TextView 
        android:id="@+id/location_info"
        android:layout_below="@id/location_btn"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"/>

</RelativeLayout>

webview.xml

<?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"
    >
    
	<WebView
	    android:id="@+id/webView"
	    android:layout_width="fill_parent" 
	    android:layout_height="fill_parent" />
</LinearLayout>