我已经有一段时间了。我搜索并尝试了我所见过的一切。我无法宣布这个该死的活动。我有一个MarkerActivity用于在地图上创建标记。单击时，我希望它们打开一个活动并传递一个变量。我已经尝试了所有内容，并继续使用NullPointerException崩溃。代码如下：
清单：
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.tapmap.app.tapmapapp" >
<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="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<meta-data
android:name="com.google.android.gms.version"
android:value="@integer/google_play_services_version" /><meta-data
android:name="com.google.android.gms.version"
android:value="@integer/google_play_services_version" />
<meta-data
android:name="com.google.android.maps.v2.API_KEY"
android:value="AIzaSyAksheZLMAALUfLHKWOsfTFCz7iP_KwpCE" />
<activity
android:name=".MapsActivity"
android:label="@string/title_activity_maps" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name=".BarBrewry"
android:configChanges="orientation|keyboardHidden|screenSize"
android:label="@string/title_activity_bar_brewry"
android:theme="@style/FullscreenTheme" >
</activity>
<activity
android:name=".MarkerActivity"
android:label="@string/title_activity_marker">
</activity>
</application>
</manifest>
Marker.java：
package com.tapmap.app.tapmapapp;
import android.content.Intent;
import android.content.IntentSender;
import android.location.Location;
import android.support.v4.app.FragmentActivity;
import android.os.Bundle;
import android.util.Log;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.location.LocationListener;
import com.google.android.gms.location.LocationRequest;
import com.google.android.gms.location.LocationServices;
import com.google.android.gms.maps.CameraUpdate;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.BitmapDescriptorFactory;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.Marker;
import com.google.android.gms.maps.model.MarkerOptions;
import com.google.android.gms.common.api.GoogleApiClient;
public class MarkerActivity extends android.support.v4.app.FragmentActivity implements GoogleMap.OnMarkerClickListener {
public Marker myMarker;
public LatLng latLng;
public String venueid;
public String venuename;
public String[] taps;
public String address;
public Integer markid;
public void setUpMap() {
MapsActivity.mMap.setOnMarkerClickListener(this);
//googleMap.setOnInfoWindowClickListener(listener);
myMarker = MapsActivity.mMap.addMarker(new MarkerOptions()
.position(latLng)
.title(venuename)
.snippet("Check Taps/Get Directions")
.icon(BitmapDescriptorFactory.fromResource(R.drawable.tmico))
);
}
@Override
public boolean onMarkerClick(final Marker marker) {
Log.i("RetrieveFeedTask", MarkerActivity.this + "Marker Clicked" + MapsActivity.venues.get(markid).venuename);
try {
Intent bar = new Intent(MarkerActivity.this, BarBrewry.class);
// bar.putExtra("venuename", venuename);
//this.startActivity(bar);
} catch(Exception vo) {
Log.i("RetrieveFeedTask", "Error opening: " + vo.getMessage());
}
return true;
}
}
堆栈追踪：
9153-9153/? E/AndroidRuntime﹕ FATAL EXCEPTION: main
java.lang.NullPointerException
at android.content.ContextWrapper.getPackageName(ContextWrapper.java:135)
at android.content.ComponentName.<init>(ComponentName.java:75)
at android.content.Intent.<init>(Intent.java:3662)
at com.tapmap.app.tapmapapp.MarkerActivity.onMarkerClick(MarkerActivity.java:50)
at com.google.android.gms.maps.GoogleMap$10.zza(Unknown Source)
at com.google.android.gms.maps.internal.zzn$zza.onTransact(Unknown Source)
at android.os.Binder.transact(Binder.java:347)
at com.google.android.gms.maps.internal.bd.a(SourceFile:84)
at com.google.maps.api.android.lib6.d.as.b(Unknown Source)
at com.google.maps.api.android.lib6.gmm6.c.e.a(Unknown Source)
at com.google.maps.api.android.lib6.gmm6.n.av.a(Unknown Source)
at com.google.maps.api.android.lib6.gmm6.n.be.a(Unknown Source)
at com.google.maps.api.android.lib6.gmm6.n.bd.a(Unknown Source)
at com.google.maps.api.android.lib6.gmm6.n.bt.d(Unknown Source)
at com.google.maps.api.android.lib6.gmm6.n.ak.onSingleTapConfirmed(Unknown Source)
at com.google.maps.api.android.lib6.gmm6.h.g.onSingleTapConfirmed(Unknown Source)
at com.google.maps.api.android.lib6.gmm6.h.i.handleMessage(Unknown Source)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5103)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
at dalvik.system.NativeStart.main(Native Method)
MapsActivity
package com.tapmap.app.tapmapapp;
import android.content.IntentSender;
import android.location.Location;
import android.support.v4.app.FragmentActivity;
import android.os.Bundle;
import android.util.Log;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.location.LocationListener;
import com.google.android.gms.location.LocationRequest;
import com.google.android.gms.location.LocationServices;
import com.google.android.gms.maps.CameraUpdate;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.common.api.GoogleApiClient;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
public class MapsActivity extends FragmentActivity implements
GoogleApiClient.ConnectionCallbacks,
GoogleApiClient.OnConnectionFailedListener,
LocationListener {
public static GoogleMap mMap; // Might be null if Google Play services APK is not available.
private GoogleApiClient mGoogleApiClient;
private final static int CONNECTION_FAILURE_RESOLUTION_REQUEST = 9000;
public static final String TAG = MapsActivity.class.getSimpleName();
public static List<MarkerActivity> venues = new ArrayList<MarkerActivity>();
private LocationRequest mLocationRequest;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_maps);
setUpMapIfNeeded();
mGoogleApiClient = new GoogleApiClient.Builder(this)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.addApi(LocationServices.API)
.build();
// Create the LocationRequest object
mLocationRequest = LocationRequest.create()
.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY)
.setInterval(10 * 1000) // 10 seconds, in milliseconds
.setFastestInterval(1 * 1000); // 1 second, in milliseconds
}
@Override
protected void onResume() {
super.onResume();
setUpMapIfNeeded();
mGoogleApiClient.connect();
}
@Override
protected void onPause() {
super.onPause();
if (mGoogleApiClient.isConnected()) {
LocationServices.FusedLocationApi.removeLocationUpdates(mGoogleApiClient, this);
mGoogleApiClient.disconnect();
}
}
/**
* Sets up the map if it is possible to do so (i.e., the Google Play services APK is correctly
* installed) and the map has not already been instantiated.. This will ensure that we only ever
* call {@link #setUpMap()} once when {@link #mMap} is not null.
* <p/>
* If it isn't installed {@link SupportMapFragment} (and
* {@link com.google.android.gms.maps.MapView MapView}) will show a prompt for the user to
* install/update the Google Play services APK on their device.
* <p/>
* A user can return to this FragmentActivity after following the prompt and correctly
* installing/updating/enabling the Google Play services. Since the FragmentActivity may not
* have been completely destroyed during this process (it is likely that it would only be
* stopped or paused), {@link #onCreate(Bundle)} may not be called again so we should call this
* method in {@link #onResume()} to guarantee that it will be called.
*/
private void setUpMapIfNeeded() {
// Do a null check to confirm that we have not already instantiated the map.
if (mMap == null) {
// Try to obtain the map from the SupportMapFragment.
mMap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map))
.getMap();
// Check if we were successful in obtaining the map.
if (mMap != null) {
try {
setUpMap();
} catch(IOException ioe){
//nothing
}
}
}
}
/**
* This is where we can add markers or lines, add listeners or move the camera. In this case, we
* just add a marker near Africa.
* <p/>
* This should only be called once and when we are sure that {@link #mMap} is not null.
*/
private void setUpMap()throws IOException {
mMap.setMyLocationEnabled(true);
Log.i("MapsActivity","calling get locs");
try {
Log.i("RetrieveFeedTask", "Starting Call");
new RetrieveFeedTask().execute("http://fltapmap.com/get-locs.php");
} catch (Exception alle) {
Log.i("RetrieveFeedTask", "Error" + alle.getMessage());
}
}
@Override
public void onConnected(Bundle bundle) {
Log.i(TAG, "Location services connected.");
Location location = LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient);
if (location == null) {
LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient, mLocationRequest, this);
}
else {
handleNewLocation(location);
}
}
private void handleNewLocation(Location location) {
Log.d(TAG, location.toString());
double currentLatitude = location.getLatitude();
double currentLongitude = location.getLongitude();
LatLng latLng = new LatLng(currentLatitude, currentLongitude);
mMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
CameraUpdate zoom=CameraUpdateFactory.zoomTo(10);
mMap.animateCamera(zoom);
}
@Override
public void onConnectionSuspended(int i) {
Log.i(TAG, "Location services suspended. Please reconnect.");
}
@Override
public void onConnectionFailed(ConnectionResult connectionResult) {
if (connectionResult.hasResolution()) {
try {
// Start an Activity that tries to resolve the error
connectionResult.startResolutionForResult(this, CONNECTION_FAILURE_RESOLUTION_REQUEST);
} catch (IntentSender.SendIntentException e) {
e.printStackTrace();
}
} else {
Log.i(TAG, "Location services connection failed with code " + connectionResult.getErrorCode());
}
}
@Override
public void onLocationChanged(Location location) {
handleNewLocation(location);
}
}
BarBrewry现在只是用于测试的bar barebones
package com.tapmap.app.tapmapapp;
import com.tapmap.app.tapmapapp.util.SystemUiHider;
import android.annotation.TargetApi;
import android.app.Activity;
import android.os.Build;
import android.os.Bundle;
import android.os.Handler;
import android.view.MotionEvent;
import android.view.View;
import android.widget.TextView;
public class BarBrewry extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
}
答案 0 :(得分：0)
这是因为你在该行中使用了错误的上下文：
Intent bar = new Intent(MarkerActivity.this, BarBrewry.class);
bar.putExtra("venuename", venuename);
this.startActivity(bar);
this不是内部类中的有效上下文。尝试使用：
MarkerActivity.this.startActivity(bar);
此外，您必须在MarkerActivity中实施onCreate，否则将永远不会存在此活动的实例：
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
...
}
我并不完全知道您希望通过MarkerActivity实现什么目标，但在评论中提到的丹尼尔纽金特，您应该考虑将MarkerActivity与MapsActivity合并。
答案 1 :(得分：0)
也许您需要实现 public void onCreate（Bundle savedInstanceState）方法..