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我目前正在創建一個Android GoogleMaps應用程序，並在聯機服務器上的數據庫中存儲了一個位置列表。我拉他們通過成功，現在我想使用操作欄searchview創建一個用戶可以搜索的列表視圖，它會更改當前加載的數據，只顯示鏈接到當前選定的位置。runnable ListViewAdapter導致「無法轉換爲android.content.Context」錯誤
但是當我嘗試將ArrayList更改爲可運行時由於我調用它的位置而將ListViewAdapter代碼更改爲適配器時，我遇到無法轉換爲android.content.Context的錯誤。我的主要活動代碼如下：
TownSelector ts;
ListView townList;
ListViewAdapter townAdapter; <---set variable for adapter here
String[] townID;
String[] townName;
ArrayList<TownSelector> arraylist = new ArrayList<TownSelector>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//setContentView(R.layout.search);
setUpMapIfNeeded();
// Hashmap for ListView
locationList = new ArrayList<HashMap<String, String>>();
// Locate the ListView in listview_main.xml
townList = (ListView) findViewById(R.id.listview);
}
class LoadAllInfo extends AsyncTask<String, String, String> {
protected String doInBackground(String... args) {
// Building Parameters
List<NameValuePair> paramsLocations = new ArrayList<NameValuePair>();
// getting JSON string from URL
JSONObject jsonLocations = jParser.makeHttpRequest(url_all_locations, "GET", paramsLocations);
//Get all offer
if(jsonLocations != null)
{
// Check your log cat for JSON reponse
Log.d("All Locations: ", jsonLocations.toString());
try {
// Checking for SUCCESS TAG
int success = jsonLocations.getInt(TAG_SUCCESS);
if (success == 1) {
// products found
// Getting Array of Offers
locations = jsonLocations.getJSONArray(TAG_LOCATIONS);
// looping through All Offers
for (int i = 0; i < locations.length(); i++) {
JSONObject c = locations.getJSONObject(i);
// Storing each json item in variable
String id = c.getString(TAG_LID);
String locationName = c.getString(TAG_LNAME);
// creating new HashMap
HashMap<String, String> locationsListMap = new HashMap<String, String>();
// adding each child node to HashMap key => value
locationsListMap.put(TAG_LID, id);
locationsListMap.put(TAG_LNAME, locationName);
// adding HashList to ArrayList
locationList.add(locationsListMap);
}
}
} catch (JSONException e) {
e.printStackTrace();
}
}
return null;
}
protected void onPostExecute(String file_url) {
// dismiss the dialog after getting all products
pDialog.dismiss();
// updating UI from Background Thread
runOnUiThread(new Runnable() {
public void run() {
/**
* Updating parsed JSON data into map marker
* */
//TODO setMapMarkers
townID = new String[locationList.size()];
townName = new String[locationList.size()];
for(int l = 0; l <= (locationList.size() - 1); l++)
{
Log.d("Hello", "location loop");
Log.d("Hello", locationList.get(l).toString().split("Location_ID=")[1].split(",")[0]);
townID[l] = locationList.get(l).toString().split("Location_ID=")[1].split(",")[0];
Log.d("Hello", locationList.get(l).toString().split("Location_Name=")[1].split(",")[0].replace("}",""));
townName[l] = locationList.get(l).toString().split("Location_Name=")[1].split(",")[0].replace("}","");
}
for (int i = 0; i < townID.length; i++)
{
ts = new TownSelector(townID[i], townName[i]);
// Binds all strings into an array
arraylist.add(ts);
}
// Pass results to ListViewAdapter Class
townAdapter = new ListViewAdapter(this, arraylist); <--Create new instant of adapter here
// Binds the Adapter to the ListView
townList.setAdapter(townAdapter); //This is the line that causes a crash
}
});
}
}
ListViewAdapter代碼：
// Declare Variables
Context mContext;
LayoutInflater inflater;
private List<TownSelector> locationlist = null;
private ArrayList<TownSelector> arraylist;
public ListViewAdapter(Runnable runnable, List<TownSelector> locationlist) {
mContext = (Context) runnable;
this.locationlist = locationlist;
inflater = LayoutInflater.from(mContext);
this.arraylist = new ArrayList<TownSelector>();
this.arraylist.addAll(locationlist);
}
我改變了ListViewAdapter代碼到下面的是找到這個stackflow問題android callback fails in fragment fails cannot be cast to android.content.Context
public ListViewAdapter(Context context,Runnable runnable, List<TownSelector> locationlist) {
mContext = context;
this.runnable = runnable;
this.locationlist = locationlist;
inflater = LayoutInflater.from(mContext);
this.arraylist = new ArrayList<TownSelector>();
this.arraylist.addAll(locationlist);
}
錯誤調用堆棧後：
09-22 03:58:03.467: E/AndroidRuntime(15586): FATAL EXCEPTION: main
09-22 03:58:03.467: E/AndroidRuntime(15586): Process: biz.nickbullcomputing.bevnav, PID: 15586
09-22 03:58:03.467: E/AndroidRuntime(15586): java.lang.ClassCastException: biz.nickbullcomputing.bevnav.MainActivity$LoadAllInfo$1 cannot be cast to android.content.Context
09-22 03:58:03.467: E/AndroidRuntime(15586): at biz.nickbullcomputing.bevnav.ListViewAdapter.<init>(ListViewAdapter.java:25)
09-22 03:58:03.467: E/AndroidRuntime(15586): at biz.nickbullcomputing.bevnav.MainActivity$LoadAllInfo$1.run(MainActivity.java:409)
09-22 03:58:03.467: E/AndroidRuntime(15586): at android.app.Activity.runOnUiThread(Activity.java:4794)
09-22 03:58:03.467: E/AndroidRuntime(15586): at biz.nickbullcomputing.bevnav.MainActivity$LoadAllInfo.onPostExecute(MainActivity.java:376)
09-22 03:58:03.467: E/AndroidRuntime(15586): at biz.nickbullcomputing.bevnav.MainActivity$LoadAllInfo.onPostExecute(MainActivity.java:1)
09-22 03:58:03.467: E/AndroidRuntime(15586): at android.os.AsyncTask.finish(AsyncTask.java:632)
09-22 03:58:03.467: E/AndroidRuntime(15586): at android.os.AsyncTask.access$600(AsyncTask.java:177)
09-22 03:58:03.467: E/AndroidRuntime(15586): at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:645)
09-22 03:58:03.467: E/AndroidRuntime(15586): at android.os.Handler.dispatchMessage(Handler.java:102)
09-22 03:58:03.467: E/AndroidRuntime(15586): at android.os.Looper.loop(Looper.java:157)
09-22 03:58:03.467: E/AndroidRuntime(15586): at android.app.ActivityThread.main(ActivityThread.java:5867)
09-22 03:58:03.467: E/AndroidRuntime(15586): at java.lang.reflect.Method.invokeNative(Native Method)
09-22 03:58:03.467: E/AndroidRuntime(15586): at java.lang.reflect.Method.invoke(Method.java:515)
09-22 03:58:03.467: E/AndroidRuntime(15586): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:858)
09-22 03:58:03.467: E/AndroidRuntime(15586): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:674)
09-22 03:58:03.467: E/AndroidRuntime(15586): at dalvik.system.NativeStart.main(Native Method)
你是如何初始化adapater請mainActivity顯示代碼 – 2014-09-22 03:30:24
@NavinRaj潘迪我在我所創建的適配器變量的代碼編寫了一個名爲'townAdapter '那麼它在哪裏然後intialied和使用 – TaurusDroid 2014-09-22 03:39:37
我的意思是你如何通過你的活動或片段的上下文傳遞到這個適配器 – 2014-09-22 03:41:13