谷歌地图Android应用程序崩溃说nullPointerException

时间：2015-09-06 15:02:33

标签： java android google-maps

我正在尝试制作一个有微调器，按钮和谷歌地图的简单应用程序..一切正常。我最近在我的应用程序中添加了谷歌地图..谷歌地图显示正常..问题是什么时候我按下“开始”按钮从微调器中选择的值保存在变量中，使用位置管理器保存当前位置，并添加到谷歌地图中，​​用于从先前的locarion到新的.. 但是根据logcat它在谷歌地图上说NullPointerException。 请看一下：

MainActivity.java 

package com.example.akshay.bus;

import android.content.Context;
import android.graphics.Color;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.Spinner;
import android.widget.Toast;

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.maps.model.PolylineOptions;

import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity implements View.OnClickListener, AdapterView.OnItemSelectedListener {
    Button start;
    public static final String URL = "http://www.akshay.site90.net/sendnote.php";
    Context context = MainActivity.this;
    Spinner spinner;
    int ROUTE;
    Double LAT, LONG;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        start = (Button) findViewById(R.id.button_START);
        start.setOnClickListener(this);
        spinner = (Spinner) findViewById(R.id.SPINNER_ROUTE);
        List<String> route = new ArrayList<String>();
        route.add("Jagadhari");
        route.add("Yamunanagar");
        route.add("Radaur");
        route.add("Workshop");
        ArrayAdapter<String> adapter = new ArrayAdapter<String>(MainActivity.this, android.R.layout.simple_spinner_item, route);
        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        spinner.setAdapter(adapter);
        spinner.setOnItemSelectedListener(MainActivity.this);

    }

    @Override
    public void onClick(View v) {

        LocationManager locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);

       /* googleMap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map)).getMap();*/

        locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 5000, 0, new LocationListener() {
            @Override
            public void onLocationChanged(Location location) {
                LAT = location.getLatitude();
                LONG = location.getLongitude();
                Log.e("====LOCATION UPDATE====", "LAT==" + String.valueOf(LAT) + "LONG==" + String.valueOf(LONG));
                LatLng mylatlng = new LatLng(LAT, LONG);
                LatLng prev = null;
                int flag = 0;
                if (flag == 0) {
                    prev = mylatlng;
                    flag = 1;
                }
                GoogleMap googleMap = null;
                if (googleMap == null)
                {
                    googleMap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map)).getMap();
                }
                CameraUpdate update = CameraUpdateFactory.newLatLngZoom(mylatlng, 13);
                googleMap.animateCamera(update);
                googleMap.addPolyline((new PolylineOptions()).add(prev, mylatlng).width(6).color(Color.BLUE).visible(true));
               /* List<Double> LAT = new ArrayList<Double>();
                LAT.add(location.getLatitude());
                List<Double>LONG = new ArrayList<Double>();
                LONG.add(location.getLongitude());*/


                prev = mylatlng;
                mylatlng = null;
            }

            @Override
            public void onStatusChanged(String provider, int status, Bundle extras) {

            }

            @Override
            public void onProviderEnabled(String provider) {

            }

            @Override
            public void onProviderDisabled(String provider) {

            }
        });
        new BackgroundTask(URL, context, ROUTE).execute();
    }

    @Override
    public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
        switch (parent.getItemAtPosition(position).toString()) {
            case "Jagadhari":
                ROUTE = 401;
                Toast.makeText(MainActivity.this, String.valueOf(ROUTE), Toast.LENGTH_SHORT).show();
                break;
            case "Yamunanagar":
                ROUTE = 402;
                Toast.makeText(MainActivity.this, String.valueOf(ROUTE), Toast.LENGTH_SHORT).show();
                break;
            case "Radaur":
                ROUTE = 403;
                Toast.makeText(MainActivity.this, String.valueOf(ROUTE), Toast.LENGTH_SHORT).show();
                break;
            case "Workshop":
                ROUTE = 404;
                Toast.makeText(MainActivity.this, String.valueOf(ROUTE), Toast.LENGTH_SHORT).show();
                break;


        }
    }

    @Override
    public void onNothingSelected(AdapterView<?> parent) {

    }
}

acivity_main.xml 

<LinearLayout 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"
    xmlns:name="http://schemas.android.com/apk/res-auto"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:orientation="vertical"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity"
    android:weightSum="5">

    <Spinner
        android:layout_weight="1"
        android:id="@+id/SPINNER_ROUTE"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"></Spinner>

    <Button
        android:layout_weight="1"
        android:id="@+id/button_START"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:text="Start" />
    <fragment

        android:name="com.google.android.gms.maps.MapFragment"
        android:layout_width="fill_parent"
        android:layout_height="700dp"
        android:id="@+id/map">

    </fragment>



</LinearLayout>

logcat的：

09-06 20:24:38.780    8112-8196/com.example.akshay.bus E/BufferQueue﹕ [unnamed-8112-0] dequeueBuffer: min undequeued buffer count (2) exceeded (dequeued=2 undequeudCount=1)
09-06 20:24:38.790    8112-8196/com.example.akshay.bus E/BufferQueue﹕ [unnamed-8112-0] dequeueBuffer: min undequeued buffer count (2) exceeded (dequeued=2 undequeudCount=1)
09-06 20:24:38.790    8112-8196/com.example.akshay.bus E/BufferQueue﹕ [unnamed-8112-0] dequeueBuffer: min undequeued buffer count (2) exceeded (dequeued=2 undequeudCount=1)
09-06 20:24:38.790    8112-8196/com.example.akshay.bus E/BufferQueue﹕ [unnamed-8112-0] dequeueBuffer: min undequeued buffer count (2) exceeded (dequeued=2 undequeudCount=1)
09-06 20:24:38.790    8112-8196/com.example.akshay.bus E/BufferQueue﹕ [unnamed-8112-0] dequeueBuffer: min undequeued buffer count (2) exceeded (dequeued=2 undequeudCount=1)
09-06 20:24:38.790    8112-8196/com.example.akshay.bus E/BufferQueue﹕ [unnamed-8112-0] dequeueBuffer: min undequeued buffer count (2) exceeded (dequeued=2 undequeudCount=1)
09-06 20:24:38.790    8112-8196/com.example.akshay.bus E/BufferQueue﹕ [unnamed-8112-0] dequeueBuffer: min undequeued buffer count (2) exceeded (dequeued=2 undequeudCount=1)
09-06 20:24:38.800    8112-8196/com.example.akshay.bus E/BufferQueue﹕ [unnamed-8112-0] dequeueBuffer: min undequeued buffer count (2) exceeded (dequeued=2 undequeudCount=1)
09-06 20:24:53.984    8112-8112/com.example.akshay.bus E/ViewRootImpl﹕ sendUserActionEvent() mView == null
09-06 20:24:57.288    8112-8112/com.example.akshay.bus E/ViewRootImpl﹕ sendUserActionEvent() mView == null
09-06 20:25:31.111    8112-8112/com.example.akshay.bus E/====LOCATION UPDATE====﹕ LAT==30.13956043766201LONG==77.25664889705503
09-06 20:25:31.121    8112-8112/com.example.akshay.bus E/AndroidRuntime﹕ FATAL EXCEPTION: main
    Process: com.example.akshay.bus, PID: 8112
    java.lang.NullPointerException
            at com.example.akshay.bus.MainActivity$1.onLocationChanged(MainActivity.java:79)
            at android.location.LocationManager$ListenerTransport._handleMessage(LocationManager.java:279)
            at android.location.LocationManager$ListenerTransport.access$000(LocationManager.java:208)
            at android.location.LocationManager$ListenerTransport$1.handleMessage(LocationManager.java:224)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:146)
            at android.app.ActivityThread.main(ActivityThread.java:5602)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:515)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1283)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1099)
            at dalvik.system.NativeStart.main(Native Method)

1 个答案:

答案 0 :(得分：0)

我发现了我的错误

在activity_main.xml

中

应该是这样的

<fragment

        android:name="com.google.android.gms.maps.SupportMapFragment"
        android:layout_width="fill_parent"
        android:layout_height="700dp"
        android:id="@+id/map">

我写过这个

    android:name="com.google.android.gms.maps.MapFragment"
    android:layout_width="fill_parent"
    android:layout_height="700dp"
    android:id="@+id/map">
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