当我按下按钮btnlocation时，它应转到Mapsactivity
但它给了我错误：
java.lang.NoClassDefFoundError
我还像往常一样在清单中添加MapsActivity ..但为什么会出现这个错误？我需要解决方案。任何人都可以帮助我...
package com.mamun.tasktest;
import android.app.AlertDialog;
import android.app.Dialog;
import android.app.Fragment;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.location.LocationManager;
import android.os.Bundle;
import android.provider.Settings;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.Toast;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.GooglePlayServicesUtil;
public class FragmentB extends Fragment implements OnClickListener {
private Button btnLocation;
private LocationManager manager;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.frag_b, null, false);
btnLocation = (Button) view.findViewById(R.id.btnLocation);
btnLocation.setOnClickListener(this);
manager = (LocationManager)getActivity().getSystemService(Context.LOCATION_SERVICE);
if (!manager.isProviderEnabled(LocationManager.GPS_PROVIDER)) {
AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
builder.setTitle("GPS is currently disabled");
builder.setMessage("Please enable GPS for better view of your location.\nWould you like to change these settings now?");
builder.setPositiveButton("Yes",
new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
Intent i = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
startActivity(i);
}
});
builder.setNegativeButton("No",
new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
getActivity();
}
});
builder.create().show();
}
return view;
}
@Override
public void onClick(View v) {
if(isMapAvailalble()){
/////////////////////////////
/*
// */
//////////////////////////
Intent in = new Intent(getActivity(),MapsActivity.class);
startActivity(in);
}
}
/*Intent intent = new Intent("android.location.GPS_ENABLED_CHANGE"); intent.putExtra("enabled", false);
sendBroadcast(intent);*/
//if googleplayservis or play store is not available/updated or user recoverable problem occured.
public boolean isMapAvailalble()
{
// to test if there is no googleplayservise
//int resultcode=ConnectionResult.SERVICE_MISSING;
int resultcode = GooglePlayServicesUtil.isGooglePlayServicesAvailable(getActivity());
if(ConnectionResult.SUCCESS==resultcode)
{
return true;
}
else if(GooglePlayServicesUtil.isUserRecoverableError(resultcode))
{
Dialog d = GooglePlayServicesUtil.getErrorDialog(resultcode, getActivity(), 1);
d.show();
}
else
{
Toast.makeText(getActivity()," Google Map API is not supported in your device",Toast.LENGTH_LONG).show();
}
return false;
}
/*public void turnGPSOn()
{
Intent intent = new Intent("android.location.GPS_ENABLED_CHANGE");
intent.putExtra("enabled", true);
((Context) this.ctx).sendBroadcast(intent);
@SuppressWarnings("deprecation")
String provider = Settings.Secure.getString(((Context) ctx).getContentResolver(), Settings.Secure.LOCATION_PROVIDERS_ALLOWED);
if(!provider.contains("gps")){ //if gps is disabled
final Intent poke = new Intent();
poke.setClassName("com.android.settings", "com.android.settings.widget.SettingsAppWidgetProvider");
poke.addCategory(Intent.CATEGORY_ALTERNATIVE);
poke.setData(Uri.parse("3"));
((Context) this.ctx).sendBroadcast(poke);
}*/
}
Manifest.xml 文件：
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.mamun.tasktest"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="11"
android:targetSdkVersion="16" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="com.google.android.providers.gsf.permission.READ_GSERVICES" />
<uses-permission android:name="com.mamun.tasktest.permission.MAPS_RECEIVE" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-library android:name="com.google.android.maps"/>
<permission
android:name="com.mamun.tasktest.permission.MAPS_RECEIVE"
android:protectionLevel="signature" >
</permission>
<uses-feature
android:glEsVersion="0x00020000"
android:required="true" />
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name="com.mamun.tasktest.MainActivity"
android:label="@string/app_name"
android:screenOrientation="portrait" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<meta-data
android:name="com.google.android.maps.v2.API_KEY"
android:value="AIzaSyCgGng3iaqbTxJ3B_lYemZBEqXOonUtFEI" />
<meta-data
android:name="com.google.android.gms.version"
android:value="@integer/google_play_services_version" />
<activity android:name="MapsActivity"></activity>
</application>
</manifest>
MapsActivity
package com.mamun.tasktest;
import java.io.IOException;
import java.util.ArrayList;
import android.app.Activity;
import android.graphics.Canvas;
import android.graphics.Point;
import android.location.Address;
import android.location.Geocoder;
import android.location.Location;
import android.location.LocationManager;
import android.os.AsyncTask;
import android.os.Bundle;
import android.view.MotionEvent;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.GooglePlayServicesClient;
import com.google.android.gms.location.LocationClient;
import com.google.android.gms.location.LocationListener;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.MapFragment;
import com.google.android.gms.maps.MapView;
import com.google.android.gms.maps.model.BitmapDescriptorFactory;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;
import com.google.android.maps.MapActivity;
public class MapsActivity<GeoPoint, OverlayItem> extends MapActivity implements
GooglePlayServicesClient.ConnectionCallbacks,
GooglePlayServicesClient.OnConnectionFailedListener, LocationListener {
MapView mapView;
com.google.android.maps.GeoPoint p;
private LocationManager manager;
private TextView tvAddress;
private Button btnSearch;
private EditText etSearch;
private LocationClient locationClient;
private GoogleMap googleMap;
private MapFragment mapFragment;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.map);
manager = (LocationManager) getSystemService(LOCATION_SERVICE);
tvAddress = (TextView) findViewById(R.id.tvaddress);
btnSearch = (Button) findViewById(R.id.btnSearch);
etSearch = (EditText) findViewById(R.id.etSearch);
mapFragment = (MapFragment) getFragmentManager().findFragmentById(
R.id.maps);
googleMap = mapFragment.getMap();
locationClient = new LocationClient(this, this, this);
}
public void onSearch(View v) {
// Getting user input location
String location = etSearch.getText().toString();
if (location != null && !location.equals("")) {
new GeocoderTask().execute(location);
}
}
@Override
protected void onResume() {
// TODO Auto-generated method stub
super.onResume();
locationClient.connect();
}
@Override
protected void onPause() {
// TODO Auto-generated method stub
super.onPause();
locationClient.disconnect();
}
@Override
public void onLocationChanged(Location location) {
// TODO Auto-generated method stub
}
@Override
public void onConnectionFailed(ConnectionResult result) {
}
@Override
public void onConnected(Bundle connectionHint) {
try {
Location currentLocation = locationClient.getLastLocation();
double lat = currentLocation.getLatitude();
double lng = currentLocation.getLongitude();
// txtLocation.setText(lat + ", " + lng);
Geocoder geocoder = new Geocoder(this);
ArrayList<Address> address = (ArrayList<Address>) geocoder
.getFromLocation(currentLocation.getLatitude(),
currentLocation.getLongitude(), 5);
Address addr = address.get(0);
String currentAddress = (addr.getAddressLine(0) + "-"
+ addr.getAdminArea() + "-" + addr.getLocality() + "-"
+ addr.getPostalCode() + "-" + addr.getCountryCode());
MarkerOptions options = new MarkerOptions();
options.position(new LatLng(lat, lng));
options.title(currentAddress);
options.snippet("Current location");
options.icon(BitmapDescriptorFactory
.defaultMarker(BitmapDescriptorFactory.HUE_AZURE));
if (googleMap != null) {
googleMap.moveCamera(CameraUpdateFactory.newLatLngZoom(
new LatLng(lat, lng), 14.0f));
googleMap.addMarker(options);
} else {
Toast.makeText(getApplicationContext(), "Map is null",
Toast.LENGTH_LONG).show();
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
@Override
public void onDisconnected() {
// TODO Auto-generated method stub
}
// An AsyncTask class for accessing the GeoCoding Web Service
private class GeocoderTask extends
AsyncTask<String, Void, ArrayList<Address>> {
@Override
protected ArrayList<Address> doInBackground(String... locationName) {
// Creating an instance of Geocoder class
Geocoder geocoder = new Geocoder(getBaseContext());
ArrayList<Address> addresses = null;
try {
// Getting a maximum of 3 Address that matches the input text
addresses = (ArrayList<Address>) geocoder.getFromLocationName(
locationName[0], 3);
} catch (IOException e) {
e.printStackTrace();
}
return addresses;
}
@Override
protected void onPostExecute(ArrayList<Address> addresses) {
if (addresses == null || addresses.size() == 0) {
Toast.makeText(getBaseContext(), "No Location found",
Toast.LENGTH_SHORT).show();
return;
}
// Clears all the existing markers on the map
googleMap.clear();
// 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
LatLng latLng;
latLng = new LatLng(address.getLatitude(),
address.getLongitude());
String addressText = String.format(
"%s, %s",
address.getMaxAddressLineIndex() > 0 ? address
.getAddressLine(0) : "", address
.getCountryName());
MarkerOptions markerOptions = new MarkerOptions();
// markerOptions = new MarkerOptions();
markerOptions.position(latLng);
markerOptions.title(addressText);
googleMap.addMarker(markerOptions);
// Locate the first location
if (i == 0)
googleMap.animateCamera(CameraUpdateFactory
.newLatLng(latLng));
}
}
}
class MapOverlay extends com.google.android.maps.Overlay {
@Override
public void draw(Canvas canvas, com.google.android.maps.MapView mapView,
boolean shadow) {
// TODO Auto-generated method stub
super.draw(canvas, mapView, shadow);
Point screenPts = new Point();
mapView.getProjection().toPixels(p, screenPts);
}
@Override
public boolean onTouchEvent(MotionEvent e,
com.google.android.maps.MapView mapView) {
// TODO Auto-generated method stub
if (e.getAction() == 1) {
com.google.android.maps.GeoPoint p = mapView.getProjection().fromPixels(
(int) e.getX(), (int) e.getY());
Toast.makeText(
getBaseContext(),
"Lat: " + p.getLatitudeE6() / 1E6 + ", Lon: "
+ p.getLongitudeE6() / 1E6, Toast.LENGTH_SHORT)
.show();
}
return false;
}
}
@Override
protected boolean isRouteDisplayed() {
// TODO Auto-generated method stub
return false;
}
}
答案 0 :(得分：1)
将Activity添加到manifest.xml，因为如果您的Activity位于不同的套餐中，则需要提供所有路径。
<activity
android:name="com.mamun.tasktest.MapsActivity"
android:label="MapActivity" >
</activity>
和/或您的Activity属于同一个套餐，然后添加
<activity android:name=".MapsActivity"></activity>
有关更多信息，请访问：http://developer.android.com/guide/topics/manifest/manifest-intro.html
答案 1 :(得分：0)
这是不正确的：
<activity android:name="MapsActivity"></activity>
您需要提供完整或相对的路径：
<activity android:name="com.mamun.tasktest.MapsActivity"></activity>
或
<activity android:name=".MapsActivity"></activity>
答案 2 :(得分：0)
在清单
中替换此标记 <activity android:name="MapsActivity"></activity>
by：
<activity android:name=".MapsActivity"></activity>
您应该在声明活动时指定完整的包裹名称。
请参阅此链接以供参考： - Add a new activity to the AndroidManifest?
答案 3 :(得分：0)
您只是忘记在MapsActivity之前放置 DOt（。）。所以，没有那个点（。）你的类路径看起来像......
com.mamun.tasktestMapsActivity.java
但是，它应该是......
com.mamun.tasktest.MapsActivity.java
现在，更改Manifest ...
<activity android:name="MapsActivity"></activity>
为...
<activity android:name=".MapsActivity"></activity>
答案 4 :(得分：0)
我得到了解决方案....行“”应该在应用程序内部而不是直接在manifest上。如下所示....