我正处于我的应用程序开发的最后阶段，但我找不到应用程序崩溃的原因，希望有人在这里可以。它从不同的文件中获取输入，但是当我尝试搜索时，应用程序会挂起一分钟然后崩溃。
根据我的LogCat文件，崩溃前到达的行是
mapV = (MapView) findViewById(R.id.mapView);然后它崩溃了。同样在LogCat中，它在packagename.DisplaySearchOptions上显示了java.lang.NullPointerException。
这是我的代码 -
// All imports
public class DisplaySearchOptions extends MapActivity
{
MapController mControl;
GeoPoint GeoP;
MapView mapV;
EditText numberOfRooms;
int theAvailablePropertiesBedrooms[] = {4, 3, 3, 1, 5};
int theAvailablePropertiesprice[] = {300000, 180000, 200000, 50000, 450000};
double LatHouses[] = {53.426599, 53.425500, 53.425122, 53.413081, 53.416208};
double LongHouses[] = {-7.931568, -7.939915, -7.950454, -7.957041, -7.904963};
double desiredRooms = 0;
double desiredPrice = 0;
class MapOverlay extends com.google.android.maps.Overlay
{
@Override
public boolean draw(Canvas canvas, MapView mapView, boolean shadow, long when) {
super.draw(canvas, mapView, shadow);
// ---translate the GeoPoint to screen pixels---
Point screenPts = new Point();
mapView.getProjection().toPixels(GeoP, screenPts);
// ---add the marker---
Bitmap bmp = BitmapFactory.decodeResource(getResources(), R.drawable.pushpin);
canvas.drawBitmap(bmp, screenPts.x, screenPts.y - 50, null);
return true;
}
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.search_options);
Log.d("Events", "Inside onCreate method");
Button searchBtn = (Button) findViewById(R.id.btnSearch);
Log.d("Events", "Button searchBtn = (Button) findViewById(R.id.btnSearch); LINE REACHED");
mapV = (MapView) findViewById(R.id.mapView);
Log.d("Events", "mapV = (MapView) findViewById(R.id.mapView); LINE REACHED");
mapV.setBuiltInZoomControls(true);
mapV.setSatellite(true);
final List<Overlay> mapOverlays = mapV.getOverlays();
Drawable drawable = this.getResources().getDrawable(R.drawable.ic_launcher);
final HelloItemizedOverlay itemizedoverlay = new HelloItemizedOverlay(drawable, this);
// Starting point on map
double lat = 53.423933100000000000;
double longi = -7.940689799999973000;
GeoP = new GeoPoint((int) (lat * 1E6), (int) (longi * 1E6));
mControl = mapV.getController();
mControl.animateTo(GeoP);
mControl.setZoom(15);
searchBtn.setOnClickListener(new Button.OnClickListener() {
@Override
public void onClick(View v) {
Log.d("Events", "searchBtn.setOnClickListener(new Button.OnClickListener() LINE REACHED");
EditText numberOfRooms = (EditText) findViewById(R.id.numberRoomsnew);
String myEditValue = numberOfRooms.getText().toString();
desiredRooms = Integer.parseInt(myEditValue);
Spinner priceEntered = (Spinner) findViewById(R.id.priceRange);
String myEditValue2 = priceEntered.getSelectedItem().toString();
desiredPrice = Integer.parseInt(myEditValue2);
double roomScoreForHouses[] = { 0, 0, 0, 0, 0 };
double priceScoreForHouses[] = { 0, 0, 0, 0, 0 };
for (int i = 0; i < 5; i++)
{
if (desiredRooms == theAvailablePropertiesBedrooms[i]){
roomScoreForHouses[i] = 1.0;
} else if (desiredRooms == theAvailablePropertiesBedrooms[i] + 1){
roomScoreForHouses[i] = 0.75;
} else if (desiredRooms == theAvailablePropertiesBedrooms[i] - 1){
roomScoreForHouses[i] = 0.75;
} else if (desiredRooms == theAvailablePropertiesBedrooms[i] + 2){
roomScoreForHouses[i] = 0.5;
} else{
roomScoreForHouses[i] = 0;
}
}
// Repeat this for price
for (int i = 0; i < 5; i++)
{
if (desiredPrice >= theAvailablePropertiesprice[i] - 50000 && desiredPrice <= theAvailablePropertiesprice[i] + 50000){
priceScoreForHouses[i] = 1.0;
}
else if (desiredPrice == theAvailablePropertiesprice[i] + 1){
priceScoreForHouses[i] = 0.75;
}
else if (desiredPrice == theAvailablePropertiesprice[i] - 1){
priceScoreForHouses[i] = 0.75;
}
else if (desiredPrice == theAvailablePropertiesprice[i] + 2){
priceScoreForHouses[i] = 0.5;
}
else{
priceScoreForHouses[i] = 0;
}
}
for (int i = 0; i < 5; i++) {
if ((roomScoreForHouses[i] + priceScoreForHouses[i]) > .75)
{
GeoPoint point = new GeoPoint((int) (LatHouses[i] * 1E6),(int) (LongHouses[i] * 1E6));
OverlayItem overlayitem = new OverlayItem(point,"House Information:", "Price:"+ theAvailablePropertiesprice[i]+ " Num Rooms "+ theAvailablePropertiesBedrooms[i]);
itemizedoverlay.addOverlay(overlayitem);
}
mapOverlays.add(itemizedoverlay);
}
}
});
}
@Override
protected boolean isRouteDisplayed() {
// TODO Auto-generated method stub
return false;
}
}
这是我的search_options.xml文件 -
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<!-- Choose number of rooms label -->
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textStyle="bold|italic"
android:text="Choose number of bedrooms:"
android:textSize="18sp" />
<!-- Number of rooms text field -->
<EditText
android:id="@+id/numberRoomsnew"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:hint="No. of rooms"
android:imeActionLabel="launch"
android:inputType="number" />
<!-- Select price range label -->
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textStyle="bold|italic"
android:text="Select your price range:"
android:textSize="18sp" />
<!-- Price range drop down menu -->
<Spinner
android:id="@+id/priceRange"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:prompt="@string/prompt"
android:entries="@array/priceRange" />
<!-- Search button -->
<Button
android:id="@+id/btnSearch"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Search" />
</LinearLayout>
我的清单 -
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.cornboyz.googlemapsC"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="17" />
<uses-permission android:name="android.permission.INTERNET" />
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<uses-library android:name="com.google.android.maps" />
<!-- Launches this screen first -->
<activity
android:name="com.cornboyz.googlemapsC.Splash"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name="com.cornboyz.googlemapsC.ButtonClass"
android:label="@string/app_name" >
<intent-filter>
<action android:name="com.cornboyz.googlemapsC.BUTTONCLASS" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
<activity
android:name="com.cornboyz.googlemapsC.MainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="com.cornboyz.googlemapsC.MAINACTIVITY" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
<activity
android:name="com.cornboyz.googlemapsC.SearchOptions"
android:label="@string/app_name" >
<intent-filter>
<action android:name="com.cornboyz.googlemapsC.SEARCHOPTIONS" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
<activity
android:name="com.cornboyz.googlemapsC.DisplaySearchOptions"
android:label="@string/app_name" >
<intent-filter>
<action android:name="com.cornboyz.googlemapsC.DISPLAYSEARCHOPTIONS" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
<activity
android:name="com.cornboyz.googlemapsC.SearchActivity"
android:label="@string/title_activity_search" >
<intent-filter>
<action android:name="com.cornboyz.googlemapsC.SEARCHACTIVITY" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
</application>
</manifest>
这是我的完整LogCat -
04-23 10:54:31.648: E/AndroidRuntime(1613): FATAL EXCEPTION: main
04-23 10:54:31.648: E/AndroidRuntime(1613): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.cornboyz.googlemapsC/com.cornboyz.googlemapsC.DisplaySearchOptions}: java.lang.NullPointerException
04-23 10:54:31.648: E/AndroidRuntime(1613): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
04-23 10:54:31.648: E/AndroidRuntime(1613): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
04-23 10:54:31.648: E/AndroidRuntime(1613): at android.app.ActivityThread.access$600(ActivityThread.java:141)
04-23 10:54:31.648: E/AndroidRuntime(1613): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
04-23 10:54:31.648: E/AndroidRuntime(1613): at android.os.Handler.dispatchMessage(Handler.java:99)
04-23 10:54:31.648: E/AndroidRuntime(1613): at android.os.Looper.loop(Looper.java:137)
04-23 10:54:31.648: E/AndroidRuntime(1613): at android.app.ActivityThread.main(ActivityThread.java:5041)
04-23 10:54:31.648: E/AndroidRuntime(1613): at java.lang.reflect.Method.invokeNative(Native Method)
04-23 10:54:31.648: E/AndroidRuntime(1613): at java.lang.reflect.Method.invoke(Method.java:511)
04-23 10:54:31.648: E/AndroidRuntime(1613): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
04-23 10:54:31.648: E/AndroidRuntime(1613): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
04-23 10:54:31.648: E/AndroidRuntime(1613): at dalvik.system.NativeStart.main(Native Method)
04-23 10:54:31.648: E/AndroidRuntime(1613): Caused by: java.lang.NullPointerException
04-23 10:54:31.648: E/AndroidRuntime(1613): at com.cornboyz.googlemapsC.DisplaySearchOptions.onCreate(DisplaySearchOptions.java:91)
04-23 10:54:31.648: E/AndroidRuntime(1613): at android.app.Activity.performCreate(Activity.java:5104)
04-23 10:54:31.648: E/AndroidRuntime(1613): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
04-23 10:54:31.648: E/AndroidRuntime(1613): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
04-23 10:54:31.648: E/AndroidRuntime(1613): ... 11 more
答案 0 :(得分：0)
您的search_options布局似乎不包含任何ID为'mapView'的视图
由于您对此布局使用setContentView，因此对于R.id.mapView，findViewById返回null