单击地图标记时 Android 地图应用程序强制关闭

Question

我正在构建一个谷歌地图应用程序，在地图上标记几个点。我目前正在尝试在单击标记时显示对话框。现在，标记出现在正确的位置，但是当我单击它们时，整个应用程序意外停止/被迫关闭。有人对出了什么问题以及我应该如何解决它有任何建议吗？

MyMapsActivity.java 类：

package net.learn2develop.MyGoogleMapsNew;


import java.util.List;

import android.graphics.drawable.Drawable;
import android.os.Bundle;

import com.google.android.maps.GeoPoint;
import com.google.android.maps.MapActivity;
import com.google.android.maps.MapView;
import com.google.android.maps.Overlay;
import com.google.android.maps.OverlayItem;

public class MyMapsActivity extends MapActivity {
    /** Called when the activity is first created. */

 public MyItemOverlay itemoverlay;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        MapView mapView = (MapView) findViewById(R.id.mapview);
        //MapView = new MapView(this, "example_Maps_ApiKey_String");
        mapView.setBuiltInZoomControls(true);

        List<Overlay> mapOverlays = mapView.getOverlays();
        Drawable drawable = this.getResources().getDrawable(R.drawable.androidmarker);
        itemoverlay = new MyItemOverlay(drawable);

        GeoPoint point1 = new GeoPoint(19240000,-99120000);
        OverlayItem overlayitem1 = new OverlayItem(point1, "Hola, Mundo!", "I'm in Mexico City!");

        GeoPoint point2 = new GeoPoint(35410000, 139460000);
        OverlayItem overlayitem2 = new OverlayItem(point2, "Sekai, konichiwa!", "I'm in Japan!");

        GeoPoint point3 = new GeoPoint(39000000, -77000000);
        OverlayItem overlayitem3 = new OverlayItem(point3, "","");


        itemoverlay.addOverlay(overlayitem1);
        itemoverlay.addOverlay(overlayitem2);
        itemoverlay.addOverlay(overlayitem3);

        mapOverlays.add(itemoverlay);

    }

    protected boolean isRouteDisplayed() {
        return false;
    }
}

MyItemOverlay 类：

package net.learn2develop.MyGoogleMapsNew;

import java.util.ArrayList;

import android.app.AlertDialog;
import android.content.Context;
import android.graphics.drawable.Drawable;

import com.google.android.maps.ItemizedOverlay;
import com.google.android.maps.OverlayItem;

public class MyItemOverlay extends ItemizedOverlay {

 private ArrayList<OverlayItem> mOverlays = new ArrayList<OverlayItem>();
 private Context mContext;

 public MyItemOverlay(Drawable defaultMarker) {
  super(boundCenterBottom(defaultMarker));
  // TODO Auto-generated constructor stub
 }

 public MyItemOverlay(Drawable defaultMarker, Context context) {
    super(defaultMarker);
    mContext = context;
 }
 @Override
 protected boolean onTap(int index) {
   OverlayItem item = mOverlays.get(index);
   AlertDialog.Builder dialog = new AlertDialog.Builder(mContext);
   dialog.setTitle(item.getTitle());
   dialog.setMessage(item.getSnippet());
   dialog.show();
   return true;
 }

/* protected boolean onTap(int index) {
        OverlayItem item = mOverlays.get(index);
        AlertDialog.Builder dialog = new AlertDialog.Builder(mContext);
        dialog.setTitle(item.getTitle());
        dialog.setMessage(item.getSnippet());
        dialog.setPositiveButton("Yes", new OnClickListener() {    
            @Override
            public void onClick(DialogInterface dialog, int which) {
                dialog.dismiss();
            }
        });
        dialog.show();
        return true;
    }
}*/


// @Override
 /*protected OverlayItem createItem(int arg0) {
  // TODO Auto-generated method stub
  return null;
 }*/

 /*@Override
 public int size() {
  // TODO Auto-generated method stub
  return 0;
 }*/

 @Override
 public int size() {
   return mOverlays.size();
 }

 public void addOverlay(OverlayItem overlay) {
     mOverlays.add(overlay);
     populate();
 }
 @Override
 protected OverlayItem createItem(int i) {
   return mOverlays.get(i);
 }


}

AndroidManifest.xml 文件

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="net.learn2develop.MyGoogleMapsNew"
      android:versionCode="1"
      android:versionName="1.0">
      <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
    <application android:icon="@drawable/icon" android:label="@string/app_name">
  <uses-library android:name="com.google.android.maps" />
         <activity android:name=".MyMapsActivity"
                  android:label="@string/app_name">
             <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
         </activity>


    </application>

    <uses-permission 
        xmlns:android="http://schemas.android.com/apk/res/android" 
        android:name="android.permission.INTERNET">
    </uses-permission>

    <uses-permission 
        xmlns:android="http://schemas.android.com/apk/res/android" 
        android:name="android.permission.ACCESS_COARSE_LOCATION">
    </uses-permission>
    <uses-sdk android:minSdkVersion="3" />

</manifest>

Answer 1

更改

itemoverlay = new MyItemOverlay(drawable);

为

itemoverlay = new MyItemOverlay(drawable, this);

MyMapsActivity.java

Answer 2

在 MyMapsActivity.java 中，您需要更改：（

itemoverlay = new MyItemOverlay(drawable);

如 Bobby P 提到的）并将

itemoverlay = new MyItemOverlay(drawable, this);

MyItemOverlay.java 中的第二个构造函数从： 更改

public MyItemOverlay(Drawable defaultMarker, Context context) 
{ 
   super(defaultMarker); 
   mContext = context; 
} 

为：

public MyItemOverlay(Drawable defaultMarker, Context context) 
{ 
   super(boundCenterBottom(defaultMarker)); 
   mContext = context; 
}