我是android开发的新手.我在这段代码中使用了一个名为Donors的用户定义数组列表,但它给了我错误.我多次看到这里发布了相同的错误,但仍然找不到我的解决方案.请帮忙.谢谢
05-01 23:45:10.855 1756-3399/com.donateblood.blooddonation E/AndroidRuntime: FATAL EXCEPTION: AsyncTask #2
Process: com.donateblood.blooddonation, PID: 1756
java.lang.RuntimeException: An error occured while executing doInBackground()
at android.os.AsyncTask$3.done(AsyncTask.java:300)
at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355)
at java.util.concurrent.FutureTask.setException(FutureTask.java:222)
at java.util.concurrent.FutureTask.run(FutureTask.java:242)
at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
at java.lang.Thread.run(Thread.java:818)
Caused by: java.lang.indexoutofboundsexception: Invalid index 0, size is 0
at java.util.ArrayList.throwindexoutofboundsexception(ArrayList.java:255)
at java.util.ArrayList.get(ArrayList.java:308)
at com.donateblood.blooddonation.MainGUI.getotherLatLong(MainGUI.java:136)
at com.donateblood.blooddonation.MainGUI$dbAsync.doInBackground(MainGUI.java:89)
at com.donateblood.blooddonation.MainGUI$dbAsync.doInBackground(MainGUI.java:84)
at android.os.AsyncTask$2.call(AsyncTask.java:288)
at java.util.concurrent.FutureTask.run(FutureTask.java:237)
at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
at java.lang.Thread.run(Thread.java:818)
05-01 23:45:11.525 1756-1756/com.donateblood.blooddonation E/WindowManager: android.view.WindowLeaked: Activity com.donateblood.blooddonation.MainGUI has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView{28ea9195 V.E..... R......D 0,0-1026,348} that was originally added here
at android.view.ViewRootImpl.<init>(ViewRootImpl.java:382)
at android.view.WindowManagerGlobal.addView(WindowManagerGlobal.java:261)
at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:69)
at android.app.Dialog.show(Dialog.java:298)
at com.donateblood.blooddonation.MainGUI$dbAsync.onPreExecute(MainGUI.java:100)
at android.os.AsyncTask.executeOnExecutor(AsyncTask.java:587)
at android.os.AsyncTask.execute(AsyncTask.java:535)
at com.donateblood.blooddonation.MainGUI$1.onClick(MainGUI.java:63)
at android.view.View.performClick(View.java:4785)
at android.view.View$PerformClick.run(View.java:19858)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:155)
at android.app.ActivityThread.main(ActivityThread.java:5696)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1028)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:823)
05-01 23:45:47.083 1756-3399/com.donateblood.blooddonation D/Process: killProcess, pid=1756
05-01 23:45:47.083 1756-3399/com.donateblood.blooddonation D/Process: com.android.internal.os.RuntimeInit$UncaughtHandler.uncaughtException:138 java.lang.ThreadGroup.uncaughtException:693 java.lang.ThreadGroup.uncaughtException:690 package com.donateblood.blooddonation;
import android.app.ProgressDialog;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.MenuItem;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Spinner;
import android.widget.Toast;
import com.mongodb.DB;
import com.mongodb.DBCollection;
import com.mongodb.DBCursor;
import com.mongodb.DBObject;
import java.util.ArrayList;
import java.util.List;
import butterknife.ButterKnife;
import butterknife.InjectView;
/**
* Created by YouCaf Iqbal on 4/6/2016.
*/
public class MainGUI extends AppCompatActivity {
public static List<DonorPerson> Donors = new ArrayList<DonorPerson>();
@InjectView(R.id.findppl) Button _findButton;
GPSTracker gps;
private double latitude;
private double longitude;
DB db; String test="";
DBCursor cursor;
DBCollection collection;
Database dataobj = new Database();
ArrayList allPPLlat = new ArrayList();
ArrayList allPPLlong = new ArrayList();
ArrayList allPPLNumbers = new ArrayList();
ArrayList allPPLNames = new ArrayList();
ArrayList allPPLImages = new ArrayList();
ArrayList allPPLEmails = new ArrayList();
ArrayList SelectedPPLlat = new ArrayList();
ArrayList SelectedPPLlong = new ArrayList();
public Spinner mySpinner;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.maingui);
ButterKnife.inject(this);
getSupportActionBar().setdisplayHomeAsUpEnabled(true);
Spinner spinner =(Spinner) findViewById(R.id.spinner);
String[] list = getResources().getStringArray(R.array.blood_type);
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,R.layout.spinner_layout,R.id.txt,list);
spinner.setAdapter(adapter);
_findButton.setonClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
getCurrentLatLong();
dbAsync thrd = new dbAsync();
thrd.execute();
}
//distance=distance(lablat, lablong, curlat, curlong);
});
}
public void getCurrentLatLong(){
gps = new GPSTracker(MainGUI.this);
if (gps.canGetLocation()) {
latitude = gps.getLatitude();
longitude = gps.getLongitude();
}
}
@Override
public boolean onoptionsItemSelected(MenuItem item) {
if(item.getItemId()==android.R.id.home){
finish();
}
return super.onoptionsItemSelected(item);
}
public class dbAsync extends AsyncTask<Void,Void,Void>{
private ProgressDialog pDialog;
@Override
protected Void doInBackground(Void... voids) {
getotherLatLong();
return null;
}
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(MainGUI.this);
pDialog.setMessage("Searching people nearby...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(true);
pDialog.show();
}
@Override
protected void onPostExecute(Void aVoid) {
super.onPostExecute(aVoid);
pDialog.dismiss();
Intent intent = new Intent(getApplicationContext(), PeopleList.class);
startActivity(intent);
// Toast.makeText(getBaseContext(), "Near by latitudes "+SelectedPPLlat, Toast.LENGTH_LONG).show();
// Toast.makeText(getBaseContext(), "Near by longitudes "+SelectedPPLlong, Toast.LENGTH_LONG).show();
}
}
public void getotherLatLong() {
db = dataobj.getconnection();
collection = db.getCollection("UserDetails");
cursor = collection.find();
while (cursor.hasNext()) {
DBObject doc = cursor.next();
// Lats longs used in the next for Loop for calculation distances
allPPLlat.add(doc.get("lat"));
allPPLlong.add(doc.get("long"));
// All these other arraylists are used to store object of a donor person
allPPLEmails.add(doc.get("number").toString());
allPPLNames.add(doc.get("Name").toString());
allPPLImages.add(doc.get("image").toString());
allPPLEmails.add(doc.get("email").toString());
}
for(int i =0;i<allPPLlat.size();i++){
double dist= distance((double)allPPLlat.get(i),(double)allPPLlong.get(i),latitude,longitude);
dist=dist/1000;
if(dist<20){
Donors.add(new DonorPerson(""+allPPLNames.get(i)+"", ""+allPPLEmails.get(i)+"" ,""+allPPLNumbers.get(i)+"" ,""+allPPLImages.get(i)+""));
}
}
}
public double distance(double lat1, double lon1, double lat2, double lon2) {
double R = 6371.0; // km
double dLat = (lat2 - lat1) * Math.PI / 180.0;
double dLon = (lon2 - lon1) * Math.PI / 180.0;
lat1 = lat1 * Math.PI / 180.0;
lat2 = lat2 * Math.PI / 180.0;
double a = Math.sin(dLat / 2.0) * Math.sin(dLat / 2.0) +
Math.sin(dLon / 2.0) * Math.sin(dLon / 2.0) * Math.cos(lat1) * Math.cos(lat2);
double c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));
double d = R * c;
return d * 1000; // return distance in m
}
}解决方法:
在这一部分上：
for(int i =0;i<allPPLlat.size();i++){
double dist= distance((double)allPPLlat.get(i),(double)allPPLlong.get(i),latitude,longitude);
dist=dist/1000;
if(dist<20){
Donors.add(new DonorPerson(""+allPPLNames.get(i)+"", ""+allPPLEmails.get(i)+"" ,""+allPPLNumbers.get(i)+"" ,""+allPPLImages.get(i)+""));
}
}
您正在获取一个空数组的位置0的get,该数组不存在并且抛出您所看到的错误.堆栈跟踪实际上指向您确切的位置.
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