2010.12.10(3)——— android MapView 以及 Unable to instantiate activity ComponentInf

2010.12.10(3)——— android MapView 以及  Unable to instantiate activity ComponentInfo问题


清单文件：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="com.huitu"
      android:versionCode="1"
      android:versionName="1.0">
    <application android:icon="@drawable/icon" android:label="@string/app_name">
    	<uses-library android:name="com.google.android.maps" /> 
        <activity android:name=".MainActivity"
                  android:label="@string/app_name">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
	
    </application>
    <uses-permission android:name="android.permission.INTERNET" />  

    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>      
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
    
    <uses-sdk android:minSdkVersion="8" />

</manifest> 

注意
1、要加入包

<uses-library android:name="com.google.android.maps" /> 

2、要加入权限

<uses-permission android:name="android.permission.INTERNET" />  
    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>      
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>

layout文件：

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

    <com.google.android.maps.MapView
        android:layout_width="fill_parent"
       	android:layout_height="fill_parent"
        android:id="@+id/mapview"
        android:clickable="true"
        android:enabled="true"
        android:apiKey="0yhxK-DcK-8qhPG14wiKUL-zAkHqPDDVkk5W1hw"
        />
    
    
    <LinearLayout
    android:id="@+id/zoomview"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignBottom="@id/mapview"
    android:layout_centerHorizontal="true"
/>

</RelativeLayout>

android:apiKey="0yhxK-DcK-8qhPG14wiKUL-zAkHqPDDVkk5W1hw"

就是你申请的map api key

LinearLayout 是用来实现Zoom功能的


MainActivity

import java.util.List;

import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.graphics.drawable.Drawable;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.view.KeyEvent;
import android.widget.LinearLayout;
import android.widget.Toast;
import android.widget.ZoomControls;

import com.google.android.maps.GeoPoint;
import com.google.android.maps.MapActivity;
import com.google.android.maps.MapController;
import com.google.android.maps.MapView;
import com.google.android.maps.Overlay;
import com.google.android.maps.OverlayItem;

public class MainActivity extends MapActivity {
	private LinearLayout linearLayout;
	private MapView mapView;
	private ZoomControls mZoom;
	private LocationManager locationManager;
	
	private List<Overlay> mapOverlays;
	private Drawable drawable;
	private MyPositionItemizedOverlay itemizedOverlay;
	
	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);
		
		linearLayout = (LinearLayout) findViewById(R.id.zoomview);
		mapView = (MapView) findViewById(R.id.mapview);
		mZoom = (ZoomControls) mapView.getZoomControls();
		linearLayout.addView(mZoom);
		
		
		mapOverlays = mapView.getOverlays();
		drawable = this.getResources().getDrawable(R.drawable.red);
		itemizedOverlay = new MyPositionItemizedOverlay(drawable);
		
		
		
		
		locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
		String provider = LocationManager.GPS_PROVIDER;
		//Location location = locationManager.getLastKnownLocation(provider);
		
		
		LocationListener ll = new LocationListener(){
			public void onLocationChanged(Location location) {
				double lat=0.0;
				double lng = 0.0;
				if (location != null) {
					 lat = location.getLatitude();
					 lng = location.getLongitude();
				}else{
					lat = 39.92;
					lng = 116.46;
				}
				Toast.makeText(MainActivity.this, lat+"==="+lng, 0).show();
				GeoPoint point = new GeoPoint((int) (lat * 1E6), (int) (lng * 1E6));
				
				MapController controller = mapView.getController();
				controller.animateTo(point);
				controller.setZoom(21);
				
				OverlayItem overlayitem = new OverlayItem(point, "", "");
				itemizedOverlay.addOverlay(overlayitem);
				mapOverlays.add(itemizedOverlay);
			}
			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);

	}


	@Override
	public boolean onKeyDown(int keyCode, KeyEvent event) {

		// 按下键盘上返回按钮
		if (keyCode == KeyEvent.KEYCODE_BACK) {

			new AlertDialog.Builder(this)
					.setMessage("确定退出系统吗？")
					.setNegativeButton("取消",
							new DialogInterface.OnClickListener() {
								public void onClick(DialogInterface dialog,
										int which) {
								}
							})
					.setPositiveButton("确定",
							new DialogInterface.OnClickListener() {
								public void onClick(DialogInterface dialog,
										int whichButton) {
									finish();
								}
							}).show();

			return true;
		} else {
			return super.onKeyDown(keyCode, event);
		}
	}

	@Override
	protected void onDestroy() {
		super.onDestroy();
		// 或者下面这种方式
		//System.exit(0);
		//建议用这种
		android.os.Process.killProcess(android.os.Process.myPid());
	}
	


	protected boolean isRouteDisplayed() {
		return false;
	}
	
	


}

注意：
1、一定要实现MapActivity 并且 一定要重写

protected boolean isRouteDisplayed() {
		return false;
	}

这个方法


这个实现 当坐标变化时 会在地图上显示新的位置



Unable to instantiate activity ComponentInfo问题

这个问题 就是我上面写的注意 你只要都注意的 应该就不会出这个问题了

但是 其实 说出来 怕你们笑话 我遇到这个问题 折磨了我 好几个小时 最后的原因 让人哭笑不得

<uses-library android:name="com.google.android.maps" /> 

我写成了

<

users-library android:name="com.google.android.maps" /> 

看清楚了 uses -------users


凌乱了。。。。。杯具了。。。