我正在尝试将谷歌地图添加到我的应用中。 logcat窗口显示以下错误: 引起:java.lang.NullPointerException,位于android.app.Activity.performCreate(Activity.java:5104)的com.example.mymaps.MainActivity.onCreate(MainActivity.java:27) 在android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)。
如何删除此错误?
Main xml:
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity" >
<fragment
android:id="@+id/map"
android:layout_width="match_parent"
android:layout_height="match_parent"
class="com.google.android.gms.maps.MapFragment" />
</RelativeLayout>
主Java import android.app.Activity; import android.os.Bundle; import android.view.Menu;
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.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;
public class MainActivity extends Activity {
static final LatLng HAMBURG = new LatLng(53.558, 9.927);
static final LatLng KIEL = new LatLng(53.551, 9.993);
private GoogleMap map;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
map = ((MapFragment) getFragmentManager().findFragmentById(R.id.map))
.getMap();
Marker hamburg = map.addMarker(new MarkerOptions().position(HAMBURG)
.title("Hamburg"));
Marker kiel = map.addMarker(new MarkerOptions()
.position(KIEL)
.title("Kiel")
.snippet("Kiel is cool")
.icon(BitmapDescriptorFactory
.fromResource(R.drawable.ic_launcher)));
// Move the camera instantly to hamburg with a zoom of 15.
map.moveCamera(CameraUpdateFactory.newLatLngZoom(HAMBURG, 15));
// Zoom in, animating the camera.
map.animateCamera(CameraUpdateFactory.zoomTo(10), 2000, null);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
}
LogCat窗口:
08-13 23:32:27.279:E / AndroidRuntime(1010):致命异常:主要 08-13 23:32:27.279:E / AndroidRuntime(1010):java.lang.RuntimeException:无法启动活动ComponentInfo {com.example.mymaps / com.example.mymaps.MainActivity}:java.lang.NullPointerException 08-13 23:32:27.279:E / AndroidRuntime(1010):在android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180) 08-13 23:32:27.279:E / AndroidRuntime(1010):在android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230) 08-13 23:32:27.279:E / AndroidRuntime(1010):在android.app.ActivityThread.access $ 600(ActivityThread.java:141) 08-13 23:32:27.279:E / AndroidRuntime(1010):在android.app.ActivityThread $ H.handleMessage(ActivityThread.java:1234) 08-13 23:32:27.279:E / AndroidRuntime(1010):在android.os.Handler.dispatchMessage(Handler.java:99) 08-13 23:32:27.279:E / AndroidRuntime(1010):在android.os.Looper.loop(Looper.java:137) 08-13 23:32:27.279:E / AndroidRuntime(1010):在android.app.ActivityThread.main(ActivityThread.java:5039) 08-13 23:32:27.279:E / AndroidRuntime(1010):at java.lang.reflect.Method.invokeNative(Native Method) 08-13 23:32:27.279:E / AndroidRuntime(1010):at java.lang.reflect.Method.invoke(Method.java:511) 08-13 23:32:27.279:E / AndroidRuntime(1010):at com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run(ZygoteInit.java:793) 08-13 23:32:27.279:E / AndroidRuntime(1010):at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560) 08-13 23:32:27.279:E / AndroidRuntime(1010):at dalvik.system.NativeStart.main(Native Method) 08-13 23:32:27.279:E / AndroidRuntime(1010):引起:java.lang.NullPointerException 08-13 23:32:27.279:E / AndroidRuntime(1010):at com.example.mymaps.MainActivity.onCreate(MainActivity.java:27) 08-13 23:32:27.279:E / AndroidRuntime(1010):在android.app.Activity.performCreate(Activity.java:5104) 08-13 23:32:27.279:E / AndroidRuntime(1010):在android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080) 08-13 23:32:27.279:E / AndroidRuntime(1010):在android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144) 08-13 23:32:27.279:E / AndroidRuntime(1010):... 11更多
答案 0 :(得分:0)
可能是由于播放服务问题。所以在使用map之前null检查map对象,这样它会自动要求在设备中下载map。请尝试回复
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
map = ((MapFragment) getFragmentManager().findFragmentById(R.id.map))
.getMap();
if(map!=null){
Marker hamburg = map.addMarker(new MarkerOptions().position(HAMBURG)
.title("Hamburg"));
Marker kiel = map.addMarker(new MarkerOptions()
.position(KIEL)
.title("Kiel")
.snippet("Kiel is cool")
.icon(BitmapDescriptorFactory
.fromResource(R.drawable.ic_launcher)));
// Move the camera instantly to hamburg with a zoom of 15.
map.moveCamera(CameraUpdateFactory.newLatLngZoom(HAMBURG, 15));
// Zoom in, animating the camera.
map.animateCamera(CameraUpdateFactory.zoomTo(10), 2000, null);
}
}
答案 1 :(得分:0)
首先使用此方法检查谷歌地图null
或not null
:
If(gMap!=null)
是否必须直接从URL下载标记图标表单URL(或)将标记图像添加到标记信息窗口。可以获得网络主线程异常。
null
,因此您可能会在Google地图中获得空指针异常解决方案:
在onCreate
方法
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);