Could not find Class exception Android

Question

I am working with two seperate classes one of which has some buttons and the other opens google maps and I am doing an overlay on it. If anyone could see the problem with my intent to open the Map.class let me know. I will throw in my error messages and code.

package com.state.park;




import java.util.ArrayList;
import java.util.List;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.Point;
import android.graphics.Paint.Style;
import android.graphics.drawable.Drawable;
import android.widget.LinearLayout;
import com.google.android.maps.GeoPoint;
import com.google.android.maps.ItemizedOverlay;
import com.google.android.maps.OverlayItem;
import com.google.android.maps.MapActivity;
import com.google.android.maps.MapView;
import com.google.android.maps.Projection;


import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
public class Map extends MapActivity {

    private MapView mapView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.map);

        mapView = (MapView) findViewById(R.id.mapview);

        mapView.setBuiltInZoomControls(true);

        mapView.setClickable(true);

        Drawable marker = getResources().getDrawable(R.drawable.icon);
        marker.setBounds(0, 0, marker.getIntrinsicWidth(), marker.getIntrinsicHeight());

        InterestingLocations funPlaces = new InterestingLocations(marker);
        mapView.getOverlays().add(funPlaces);
        GeoPoint pt = funPlaces.getCenter();
        mapView.getController().setCenter(pt);
        mapView.getController().setZoom(15);
    }

    @Override
    protected boolean isRouteDisplayed() {
        // TODO Auto-generated method stub
        return false;
    }

    class InterestingLocations extends ItemizedOverlay{

        private List<OverlayItem> locations = new ArrayList<OverlayItem>();

        private Drawable marker;
        private GeoPoint p1, p2 ,p3;
        private Paint paint;
        public InterestingLocations(Drawable defaultMarker) {
            super(defaultMarker);

            marker = defaultMarker;

             p1 = new GeoPoint((int)(34.044125 * 1000000) , (int)(-77.912636 * 1000000));
             p2 = new GeoPoint((int)(34.046544 * 1000000) , (int) (-77.918043 * 1000000));
             p3 = new GeoPoint((int) (34.041992 * 1000000) , (int)(-77.921476 * 1000000));



            locations.add(new OverlayItem(p1 , "special1" , "special1"));
            locations.add(new OverlayItem(p2 , "special2" , "special12"));
            locations.add(new OverlayItem(p3 , "special3" , "special3"));
            // TODO Auto-generated constructor stub
            populate();
        }

        public void draw(Canvas canvas, MapView mapView , boolean shadow){
             super.draw(canvas, mapView, shadow);

             boundCenterBottom(marker);

             Point from = new Point();
             Point to = new Point();

             paint = new Paint();

                paint.setColor(Color.BLACK);
                paint.setStrokeWidth(2);
                paint.setStyle(Style.FILL);

             Path path = new Path();        
              Projection proj = mapView.getProjection();       
              proj.toPixels(p1,from );       
              proj.toPixels(p2, to);     
              path.moveTo(from.x, from.y);     
              path.lineTo(to.x,to.y);      
              canvas.drawLine(from.x, from.y, to.x, to.y, paint); 



        }

        @Override
        protected OverlayItem createItem(int i) {
            // TODO Auto-generated method stub
            return locations.get(i);
        }

        @Override
        public int size() {
            // TODO Auto-generated method stub
            return locations.size();
        }   


    }
}

---

package com.state.park;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class CBHome extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        Button POI = (Button)findViewById(R.id.poi);

        POI.setOnClickListener(new View.OnClickListener(){

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub

                Intent i = new Intent(CBHome.this , Map.class);

                CBHome.this.startActivity(i);

            }



        });

    }



}

---

03-31 17:15:51.882: ERROR/dalvikvm(1033): Could not find class 'com.state.park.Map', referenced from method com.state.park.CBHome$1.onClick
03-31 17:15:55.133: ERROR/AndroidRuntime(1033): FATAL EXCEPTION: main
03-31 17:15:55.133: ERROR/AndroidRuntime(1033): java.lang.NoClassDefFoundError: com.state.park.Map
03-31 17:15:55.133: ERROR/AndroidRuntime(1033):     at com.state.park.CBHome$1.onClick(CBHome.java:25)
03-31 17:15:55.133: ERROR/AndroidRuntime(1033):     at android.view.View.performClick(View.java:2408)
03-31 17:15:55.133: ERROR/AndroidRuntime(1033):     at android.view.View$PerformClick.run(View.java:8816)
03-31 17:15:55.133: ERROR/AndroidRuntime(1033):     at android.os.Handler.handleCallback(Handler.java:587)
03-31 17:15:55.133: ERROR/AndroidRuntime(1033):     at android.os.Handler.dispatchMessage(Handler.java:92)
03-31 17:15:55.133: ERROR/AndroidRuntime(1033):     at android.os.Looper.loop(Looper.java:123)
03-31 17:15:55.133: ERROR/AndroidRuntime(1033):     at android.app.ActivityThread.main(ActivityThread.java:4627)
03-31 17:15:55.133: ERROR/AndroidRuntime(1033):     at java.lang.reflect.Method.invokeNative(Native Method)
03-31 17:15:55.133: ERROR/AndroidRuntime(1033):     at java.lang.reflect.Method.invoke(Method.java:521)
03-31 17:15:55.133: ERROR/AndroidRuntime(1033):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
03-31 17:15:55.133: ERROR/AndroidRuntime(1033):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
03-31 17:15:55.133: ERROR/AndroidRuntime(1033):     at dalvik.system.NativeStart.main(Native Method)

Answer 1

It may be one of the following reasons in order of probability (and therefore inverse order of rarity)

1. AndroidManifest.xml problems. <activity> tags, <uses-library android:name="com.google.android.maps" /> declaration in the <application> section, etc.
2. Setup problems: adding the maps.jar files manually as well as setting the project type to use Google APIs. This cause problems for some reason.
3. Finally, you calling activity may be inheriting some class that causes this problem. I had the same problem calling a MapActivity from a class that used the droidFu API. The calling activity used droidFu's BetterActivity inheritance. I only got the map to work after I changed the MapActivity to BetterMapActivity from the droidFu API.

Answer 2

Had the same problem and solved by adding this into AndroidManifest.xml between application tags

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