我从MainActivity
向服务器发送请求,然后我在GETLLRD
类中获得响应。
我想将ArrayList<ItemDTO>
传递给我已经在manifest.xml中注册的Map
活动,但我得到了下面的错误。我怎么能传递一个自定义数组列表到Map
活动,并从onPostExecute
方法在AsyncTask类启动它?我试过在ItemDTO
类中使用Serializable
。
谢谢你的帮助。
错误:
07-06 17:06:18.039: E/AndroidRuntime(24568): FATAL EXCEPTION: AsyncTask #1
07-06 17:06:18.039: E/AndroidRuntime(24568): Process: com.bustracker, PID: 24568
07-06 17:06:18.039: E/AndroidRuntime(24568): java.lang.RuntimeException: An error occured while executing doInBackground()
07-06 17:06:18.039: E/AndroidRuntime(24568): at android.os.AsyncTask$3.done(AsyncTask.java:300)
07-06 17:06:18.039: E/AndroidRuntime(24568): at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355)
07-06 17:06:18.039: E/AndroidRuntime(24568): at java.util.concurrent.FutureTask.setException(FutureTask.java:222)
07-06 17:06:18.039: E/AndroidRuntime(24568): at java.util.concurrent.FutureTask.run(FutureTask.java:242)
07-06 17:06:18.039: E/AndroidRuntime(24568): at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
07-06 17:06:18.039: E/AndroidRuntime(24568): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
07-06 17:06:18.039: E/AndroidRuntime(24568): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
07-06 17:06:18.039: E/AndroidRuntime(24568): at java.lang.Thread.run(Thread.java:818)
07-06 17:06:18.039: E/AndroidRuntime(24568): Caused by: java.lang.ArrayIndexOutOfBoundsException: length=0; index=0
07-06 17:06:18.039: E/AndroidRuntime(24568): at com.bustracker.GetLLRD$MyAsyncTask.doInBackground(GetLLRD.java:62)
07-06 17:06:18.039: E/AndroidRuntime(24568): at com.bustracker.GetLLRD$MyAsyncTask.doInBackground(GetLLRD.java:1)
07-06 17:06:18.039: E/AndroidRuntime(24568): at android.os.AsyncTask$2.call(AsyncTask.java:288)
07-06 17:06:18.039: E/AndroidRuntime(24568): at java.util.concurrent.FutureTask.run(FutureTask.java:237)
07-06 17:06:18.039: E/AndroidRuntime(24568): ... 4 more
<<p> GetLLRD类/strong> public class GetLLRD {
Context mContext;
public void post_selected(String json, Context context) {
new MyAsyncTask().execute(json);
context = this.mContext;
}
class MyAsyncTask extends AsyncTask<String, Integer, ArrayList<ItemDTO>> {
@Override
protected ArrayList<ItemDTO> doInBackground(String... params) {
.
.
.
.
Gson gson = new Gson();
Type listType = new TypeToken<List<ItemDTO>>() {
}.getType();
ArrayList<ItemDTO> data = gson.fromJson(sb.toString(), listType);
for (ItemDTO itemDTO : data) {
double latitude = itemDTO.getLatitude();
double longitude = itemDTO.getLongitude();
int route = itemDTO.getRoute();
String direction = itemDTO.getDirection();
System.out.println(latitude + ", " + longitude + ", "
+ ", " + route + ", " + direction);
}
.
.
.
.
return data;
}
protected void onPostExecute(ArrayList<ItemDTO> result) {
new Handler().postDelayed(new Runnable() {
@Override
public void run() {
new MyAsyncTask().execute();
System.out.println("The method onPostExcute() in GETLLRD class was invoked again");
}
}, 1*30 * 1000);
if (result != null && !result.isEmpty()) {
Intent intent = new Intent(mContext, Map.class);
intent.putExtra("list",result);
mContext.startActivity(intent);
}else{
Log.e("123", "Avoiding null pointer, the dat is null in the GETLLRD class!!!");
}
}
}
}
MapDataJSON类与内部类ItemDTo,我需要从JSON字符串,我从服务器获得的数据。
public class MapDataJSON {
ArrayList<ItemDTO> items;
public MapDataJSON(ArrayList<ItemDTO> items) {
super();
this.items = items;
}
public ArrayList<ItemDTO> getItems() {
return items;
}
public void setItems(ArrayList<ItemDTO> items) {
this.items = items;
}
public static class ItemDTO implements Serializable {
private static final long serialVersionUID = 1L;
double latitude;
double longitude;
int route;
String direction;
public ItemDTO(double latitude, double longitude, int route,
String direction) {
super();
this.latitude = latitude;
this.longitude = longitude;
this.route = route;
this.direction = direction;
}
public double getLatitude() {
return latitude;
}
public double getLongitude() {
return longitude;
}
public int getRoute() {
return route;
}
public String getDirection() {
return direction;
}
public void setLatitude(double latitude) {
this.latitude = latitude;
}
public void setLongitude(double longitude) {
this.longitude = longitude;
}
public void setRoute(int route) {
this.route = route;
}
public void setDirection(String direction) {
this.direction = direction;
}
}
}
列表似乎是空的。请检查从服务器获取的数据是否正确:
. lang。ArrayIndexOutOfBoundsException:长度= 0;指数= 0
从文档中,当:
时抛出错误公共类ArrayIndexOutOfBoundsException扩展IndexOutOfBoundsException
表示数组已被使用非法索引访问。指标要么是负的,要么是大于或等于数组的大小。
如果你能调试一下就更好了。
发送可序列化的数据:
intent.putExtra("datalist",(Serializable)yourList);
获取数据:
list = (ArrayList<POJOModel>)intent.getSerializableExtra("datalist");