我有一个基本上只绘制地图上的点的Android应用程序。 这些地图是由完全不同的课程确定的。 我最初编写这个类作为自己的程序(它读取一个CSV文件并挑选出点并在数组中返回它们的经度和纬度)。获取Android活动运行非活动代码
因此,我所做的是将这个类添加到我的Android应用程序。我希望应用程序在某个时刻调用该类的方法,该方法将生成数组,并将其返回,然后使用此新数组在地图上绘制点。至于抓住阵列并确定每个纬度和经度,我可以做到。
然而,当我的Android应用程序的主类,我声明:
String[][] bump = ReadCsv.getArray(fileToUse);
,我的程序将强制关闭。 (ReadCsv是我在程序中放置的类的名称 - getArray是类中唯一的方法,它返回一个数组[] [])。
有没有人认为他们看到我的问题是什么?也许有其他解决方案是可能的?
的logcat的是: 07-27 15:19:25.105:ERROR/AndroidRuntime(12214):致命异常:主 07-27 15:19:25.105:ERROR/AndroidRuntime(12214):java.lang中。 RuntimeException:无法启动活动ComponentInfo {net.learn2develop.GoogleMaps/net.learn2develop.GoogleMaps.MapsActivity}:java.lang.NullPointerException 07-27 15:19:25.105:错误/ AndroidRuntime(12214):在android.app。 ActivityThread.performLaunchActivity(ActivityThread.java:2663) 07-27 15:19:25.105:ERROR/AndroidRuntime(12214):at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679) 07-27 15:19: 25.105:错误/ AndroidRuntime(12214):在android.app.ActivityThread.access $ 2300(ActivityThread.java:125) 07-27 15 :19:25.105:错误/ AndroidRuntime(12214):在android.app.ActivityThread $ H.handleMessage(ActivityThread.java:2033) 07-27 15:19:25.105:错误/ AndroidRuntime(12214):在android.os .Handler.dispatchMessage(Handler.java:99) 07-27 15:19:25.105:ERROR/AndroidRuntime(12214):at android.os.Looper.loop(Looper.java:123) 07-27 15:19 :25.105:错误/ AndroidRuntime(12214):在android.app.ActivityThread.main(ActivityThread.java:4627) 07-27 15:19:25.105:错误/ AndroidRuntime(12214):在java.lang.reflect.Method .invokeNative(Native Method) 07-27 15:19:25.105:ERROR/AndroidRuntime(12214):at java.lang.reflect.Method.invoke(Method.java:521) 07-27 15:19:25.105:错误/ AndroidRuntime(12214):at com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run(ZygoteInit.java:858) 07-27 15:19: 25.105:错误/ AndroidRuntime(12214):在com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 07-27 15:19:25.105:错误/ AndroidRuntime(12214):在dalvik.system。 NativeStart.main(本地方法) 07:27:15:19:25.105:错误/ AndroidRuntime(12214):导致:java.lang.NullPointerException 07-27 15:19:25.105:错误/ AndroidRuntime(12214):at net.learn2develop.GoogleMaps.MapsActivity.onCreate(MapsActivity.java:86) 07-27 15:19:25.105:ERROR/AndroidRuntime(12214):at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) 07 -27 15:19:25.105:错误/ AndroidRuntime(12214):在android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627) 07-27 15:19:25.105:错误/ AndroidRuntime(12214):...11多
而且我的代码是:
package net.learn2develop.GoogleMaps;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.util.List;
import java.util.StringTokenizer;
import com.google.android.maps.GeoPoint;
import com.google.android.maps.MapActivity;
import com.google.android.maps.MapController;
import com.google.android.maps.MapView;
import com.google.android.maps.Overlay;
import com.google.android.maps.MapView.LayoutParams;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Point;
import android.os.Bundle;
import android.view.View;
import android.widget.LinearLayout;
public class MapsActivity extends MapActivity
{
MapView mapView;
MapController mc;
GeoPoint p;
GeoPoint p2;
GeoPoint p99;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
mapView = (MapView) findViewById(R.id.mapView);
LinearLayout zoomLayout = (LinearLayout)findViewById(R.id.zoom);
@SuppressWarnings("deprecation")
View zoomView = mapView.getZoomControls();
mapView.setSatellite(true);
zoomLayout.addView(zoomView,
new LinearLayout.LayoutParams(
LayoutParams.WRAP_CONTENT,
LayoutParams.WRAP_CONTENT));
mapView.displayZoomControls(true);
mc = mapView.getController();
String coordinates[] = {"42.30936432", "-71.12162781"};
double lat = Double.parseDouble(coordinates[0]);
double lng = Double.parseDouble(coordinates[1]);
p = new GeoPoint(
(int) (lat * 1E6),
(int) (lng * 1E6));
mc.animateTo(p);
mc.setZoom(8);
//---Add a location marker---
MapOverlay mapOverlay = new MapOverlay();
List<Overlay> listOfOverlays = mapView.getOverlays();
//listOfOverlays.clear();
listOfOverlays.add(mapOverlay);
// -- my own point ---
String coordinates2[] = {"42.20", "-71.20"};
double lat2 = Double.parseDouble(coordinates2[0]);
double lng2 = Double.parseDouble(coordinates2[1]);
p2 = new GeoPoint(
(int) (lat2 * 1E6),
(int) (lng2 * 1E6));
MapOverlay mapOverlay2 = new MapOverlay();
List<Overlay> listOfOverlays2 = mapView.getOverlays();
listOfOverlays2.add(mapOverlay2);
// Add points from ReadCsv.java
File fileToUse = new File("/Users/csrobot/Desktop/Training4.csv");
String[][] bump = ReadCsv.getArray(fileToUse);
for(int i = 0; i < bump.length; i++) {
String coordinates99[] = {bump[i][0], bump[i][1]};
double lat99 = Double.parseDouble(coordinates99[0]);
double lng99 = Double.parseDouble(coordinates99[1]);
p99 = new GeoPoint(
(int) (lat99 * 1E6),
(int) (lng99 * 1E6));
MapOverlay mapOverlay99 = new MapOverlay();
List<Overlay> listOfOverlays99 = mapView.getOverlays();
listOfOverlays99.add(mapOverlay99);
}
mapView.invalidate();
}
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(p, screenPts);
//---add the marker---
Bitmap bmp = BitmapFactory.decodeResource(
getResources(), R.drawable.redpin);
canvas.drawBitmap(bmp, screenPts.x, screenPts.y-44, null);
// --make my own point---
Point screenPts2 = new Point();
mapView.getProjection().toPixels(p2, screenPts2);
Bitmap bmp2 = BitmapFactory.decodeResource(
getResources(), R.drawable.redpin);
canvas.drawBitmap(bmp2, screenPts2.x, screenPts2.y-44, null);
return true;
}
}
static class ReadCsv {
public static String[][] getArray(File file) {
try {
//
// Code That I know Works is Here
//
return arrayOfBumps;
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch(Exception e) {
// System.out.println("The following error occurred "+e);
}
return null;
}
}
@Override
protected boolean isRouteDisplayed() {
return false;
}
}
编辑:拉维布哈特
private class MapPoint extends AsyncTask <String[][], String, String> {
@Override
protected String doInBackground(String[][]... <<What goes here...? >>) {
String << what am i making to return? >> = null;
try {
InputStream is = getAssets().open("Training4.csv");
BufferedReader reader = new BufferedReader(new InputStreamReader(is));
bump = getArray(reader);
if(bump == null){
setContentView(R.layout.deleteme);
} else {
for(int i = 0; i < bump.length; i++) {
String coordinates99[] = {bump[i][0], bump[i][1]};
double lat99 = Double.parseDouble(coordinates99[0]);
double lng99 = Double.parseDouble(coordinates99[1]);
p99 = new GeoPoint(
(int) (lat99 * 1E6),
(int) (lng99 * 1E6));
MapOverlay mapOverlay99 = new MapOverlay();
List<Overlay> listOfOverlays99 = mapView.getOverlays();
listOfOverlays99.add(mapOverlay99);
}
}
} catch (IOException e) {
e.printStackTrace();
}
return << do I really need to return something? if so, what? >>;
}
@Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
mapView.refreshDrawableState();
}
}
每当应用程序“强行关闭”时,它通常会在logcat中提供一些错误信息。请将这些信息包含在您的帖子中,否则,任何人都会猜测问题出在哪里。 –