我的应用程序在nexus 6中打开后会一直崩溃。问题在于getMapAsync（）。
public class MainActivity extends AppCompatActivity implements OnMapReadyCallback {
GoogleMap mMap; //member variable
private static final int ERROR_DIALOG_REQUEST = 9001; //constant to request certain king of dialog box definition from google play services lib
private static final double
AJAX_LAT = 43.851063,
AJAX_LNG = -79.019737;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (servicesOK()) {
setContentView(R.layout.activity_main);
if (initMap()) {
Toast.makeText(this, "Ready to map!", Toast.LENGTH_SHORT).show();
gotoLocation(AJAX_LAT, AJAX_LNG, 13);
//as of now user must grand permissions to app from phone settings
try {
mMap.setMyLocationEnabled(true);
} catch (SecurityException e) {
Toast.makeText(this, "My Location not enabled!", Toast.LENGTH_SHORT).show();
}
} else {
Toast.makeText(this, "Map not connected!", Toast.LENGTH_SHORT).show();
}
} else {
Toast.makeText(this, "Services not OK!", Toast.LENGTH_SHORT).show();
}
}
//get a reference to the map object
public boolean initMap() {
if (mMap == null) {
MapFragment mapFragment = (MapFragment) getFragmentManager().findFragmentById(R.id.map); mapFragment.getMapAsync(this);
}
return (mMap != null);
}
@Override
public void onMapReady(GoogleMap googleMap) {
mMap = googleMap;
}
//check to see if the google services are ok
public boolean servicesOK() {
GoogleApiAvailability googleAPI = GoogleApiAvailability.getInstance();
int isAvailable = googleAPI.isGooglePlayServicesAvailable(this);
// handle 3 different possibility
if (isAvailable == ConnectionResult.SUCCESS) { //everything ok, user can make mapping request
return true;
} else if (googleAPI.isUserResolvableError(isAvailable)) { //error user can do something about
Dialog dialog = googleAPI.getErrorDialog(this, isAvailable, ERROR_DIALOG_REQUEST);
dialog.show(); //google play services lib delivers correct dialog box telling user what to do
} else { //something wrong, user cant do anything about
Toast.makeText(this, "Can't connect to mapping service", Toast.LENGTH_SHORT).show();
}
return false;
}
}
以下是我得到的错误
Process: com.example.suhail.onmyway, PID: 27425
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.suhail.onmyway/com.example.suhail.onmyway.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void com.google.android.gms.maps.MapFragment.getMapAsync(com.google.android.gms.maps.OnMapReadyCallback)' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2416)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
at android.app.ActivityThread.-wrap11(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5417)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void com.google.android.gms.maps.MapFragment.getMapAsync(com.google.android.gms.maps.OnMapReadyCallback)' on a null object reference
at com.example.suhail.onmyway.MainActivity.initMap(MainActivity.java:89)
at com.example.suhail.onmyway.MainActivity.onCreate(MainActivity.java:47)
at android.app.Activity.performCreate(Activity.java:6251)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1107)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2369)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
at android.app.ActivityThread.-wrap11(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5417)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
我在activity_main.xml中有一个按钮，一旦点击就会打开另一个包含片段的布局
答案 0 :(得分：0)
将setContentView放在if块之外 它从第89行坠毁 这条线的代码是什么？
------------更新------------
使用它：
GoogleMap map = ((WorkaroundMapFragment) getSupportFragmentManager().findFragmentById(R.id.map)).getMap();
final LatLng GOOGLE_MAP_POSITION = new LatLng(lat, lng);
Log.d("GOOGLE_MAP", "lat : " + lat + " , lng : " + lng);
if (map != null) {
map.clear();
map.setMapType(GoogleMap.MAP_TYPE_NORMAL);
Marker marker = map.addMarker(new MarkerOptions().position(GOOGLE_MAP_POSITION)
.title("Title")
.snippet("Content Goes Here")
.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_RED)));
}
MapsInitializer.initialize(this);
// Move the camera instantly to target with a zoom of 14.
map.moveCamera(CameraUpdateFactory.newLatLngZoom(GOOGLE_MAP_POSITION, 50));
// Zoom in, animating the camera, Change 14 to Zoom in And Zoom Out
map.animateCamera(CameraUpdateFactory.zoomTo(14), 2000, null);
int resultCode = GooglePlayServicesUtil.isGooglePlayServicesAvailable(getApplicationContext());
if (resultCode == ConnectionResult.SUCCESS){
Log.e("DETAIL_ACTIVITY", "Google Play Services Util Available SUCCESS : "+resultCode);
}else{
Log.e("DETAIL_ACTIVITY", "Google Play Services Util Available Problem : "+resultCode);
GooglePlayServicesUtil.getErrorDialog(resultCode, this, 1);
}
另外WorkaroundMapFragment是一个自定义类，可让您在ScrollView中使用map
使用它check it out。
答案 1 :(得分：0)
可能您的mapFragment为空，也不正确getMapAsync用法，您必须在收到地图后才使用所有属于地图的内容，因此您必须在调用此回调后才采取行动：< / p>
@Override
public void onMapReady(GoogleMap googleMap) {
mMap = googleMap;
}
在runnable中添加所有下一个初始化并在
之后调用它mMap = googleMap;
答案 2 :(得分：0)
您必须将此添加到activity_main.xml
<fragment
android:name="com.google.android.gms.maps.MapFragment"
android:id="@+id/map"
android:layout_width="match_parent"
android:layout_height="match_parent"/>