我正在尝试一个我在互联网上获得的项目，但是当我在 Eclipse Juno 上导入它时，activity_main.xml 中的项目无法使用。这是activity_main.xml 代码`
<RelativeLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="horizontal" >
<Button
android:id="@+id/btn_find"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/str_btn_find"
android:layout_alignParentRight="true" />
<EditText
android:id="@+id/et_location"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:inputType="text"
android:hint="@string/hnt_et_location"
android:layout_toLeftOf="@id/btn_find" />
</RelativeLayout>
<com.google.android.maps.MapView
android:id="@+id/map_view"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:apiKey="02XkocQETlvu36mzmDnwYr-A4GTX5mENmESOG8A"
android:clickable="true" />
`
这是 MainActivity.java 的代码
import java.io.IOException;
import java.util.List;
import android.R;
import android.graphics.drawable.Drawable;
import android.location.Address;
import android.location.Geocoder;
import android.os.AsyncTask;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
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 {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Getting reference to btn_find of the layout activity_main
Button btn_find = (Button) findViewById(R.id.btn_find);
// Defining button click event listener for the find button
OnClickListener findClickListener = new OnClickListener() {
@Override
public void onClick(View v) {
// Getting reference to EditText to get the user input location
EditText etLocation = (EditText) findViewById(R.id.et_location);
// Getting user input location
String location = etLocation.getText().toString();
if(location!=null && !location.equals("")){
new GeocoderTask().execute(location);
}
}
};
// Setting button click event listener for the find button
btn_find.setOnClickListener(findClickListener);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
@Override
protected boolean isRouteDisplayed() {
// TODO Auto-generated method stub
return false;
}
// An AsyncTask class for accessing the GeoCoding Web Service
private class GeocoderTask extends AsyncTask<String, Void, List<Address>>{
@Override
protected List<Address> doInBackground(String... locationName) {
// Creating an instance of Geocoder class
Geocoder geocoder = new Geocoder(getBaseContext());
List<Address> addresses = null;
try {
// Getting a maximum of 3 Address that matches the input text
addresses = geocoder.getFromLocationName(locationName[0], 3);
} catch (IOException e) {
e.printStackTrace();
}
return addresses;
}
@Override
protected void onPostExecute(List<Address> addresses) {
// Getting Reference to MapView of the layout activity_main
MapView mapView = (MapView) findViewById(R.id);
// Setting ZoomControls
mapView.setBuiltInZoomControls(true);
// Getting MapController for the MapView
MapController mc = mapView.getController();
// Getting Drawable object corresponding to a resource image
Drawable drawable = getResources().getDrawable(R.drawable.marker);
// Getting Overlays of the map
List<Overlay> overlays = mapView.getOverlays();
// Creating an ItemizedOverlay
LocationOverlay locationOverlay = new LocationOverlay(drawable,getBaseContext());
// Clearing the overlays
overlays.clear();
if(addresses==null || addresses.size()==0){
Toast.makeText(getBaseContext(), "No Location found", Toast.LENGTH_SHORT).show();
// Redraws the map to clear the overlays
mapView.invalidate();
}
// Adding Markers on Google Map for each matching address
for(int i=0;i<addresses.size();i++){
Address address = (Address) addresses.get(i);
// Creating an instance of GeoPoint, to display in Google Map
GeoPoint p = new GeoPoint(
(int)(address.getLatitude()*1E6),
(int)(address.getLongitude()*1E6)
);
String addressText = String.format("%s, %s",
address.getMaxAddressLineIndex() > 0 ? address.getAddressLine(0) : "",
address.getCountryName());
// Creating an OverlayItem to mark the point
OverlayItem overlayItem = new OverlayItem(p, "Location",addressText);
// Adding the OverlayItem in the LocationOverlay
locationOverlay.addOverlay(overlayItem);
// Adding locationOverlay to the overlay
overlays.add(locationOverlay);
// Locate the first location
if(i==0)
mc.animateTo(p);
}
// Redraws the map
mapView.invalidate();
}
}
}`
该错误在“R.layout.activity_main”、“Button btn_find = (Button) findViewById(R.id.btn_find)”之类的行上显示了一些错误。activity_main 和 btn_find 以及另一个 R.id.x 标记为错误。那里有什么问题？谢谢。