Google地圖自動完成android

我正在嘗試爲goofle地圖開發自動完成位置。但是，我在開發過程中遇到了一些錯誤。我不知道錯誤的原因是什麼。Google地圖自動完成android

以下是我的代碼。

public class MainActivity extends Activity { 
/** Called when the activity is first created. */ 
ArrayAdapter<String> adapter; 
AutoCompleteTextView textView; 
Object[] arg0 = null; 

@Override 
public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main); 
    adapter = new ArrayAdapter<String>(this, R.layout.item_list); 
    textView = (AutoCompleteTextView) findViewById(R.id.autoCompleteTextView1); 
    adapter.setNotifyOnChange(true); 
    textView.setAdapter(adapter); 
    textView.addTextChangedListener(new TextWatcher() { 

     public void onTextChanged(CharSequence s, int start, int before, 
       int count) { 
      if (count % 3 == 1) { 
       adapter.clear(); 
       // GetPlaces task = new GetPlaces(); 
       // now pass the argument in the textview to the task 
       new GetPlaces().execute(textView.getText().toString()); 
      } 
     } 

     public void beforeTextChanged(CharSequence s, int start, int count, 
       int after) { 
     } 

     public void afterTextChanged(Editable s) { 

     } 
    }); 
} 

class GetPlaces extends AsyncTask<String, Void, ArrayList<String>> { 

    @Override 
    // three dots is java for an array of strings 
    protected ArrayList<String> doInBackground(String... args) { 

     Log.d("gottaGo", "doInBackground"); 

     ArrayList<String> predictionsArr = new ArrayList<String>(); 

     try { 


      URL googlePlaces = new URL(
      // URLEncoder.encode(url,"UTF-8"); 
        "https://maps.googleapis.com/maps/api/place/autocomplete/json?input=" 
          + URLEncoder.encode(arg0[0].toString(), "UTF-8") 
          + "&types=geocode&language=en&sensor=true&key=<API-key here>"); 
      URLConnection tc = googlePlaces.openConnection(); 
      BufferedReader in = new BufferedReader(new InputStreamReader(
        tc.getInputStream())); 

      String line; 
      StringBuffer sb = new StringBuffer(); 
      // take Google's legible JSON and turn it into one big 
      // string. 
      while ((line = in.readLine()) != null) { 
       sb.append(line); 
      } 
      // turn that string into a JSON object 
      JSONObject predictions = new JSONObject(sb.toString()); 
      // now get the JSON array that's inside that object 
      JSONArray ja = new JSONArray(
        predictions.getString("predictions")); 

      for (int i = 0; i < ja.length(); i++) { 
       JSONObject jo = (JSONObject) ja.get(i); 
       // add each entry to our array 
       predictionsArr.add(jo.getString("description")); 
      } 
     } catch (IOException e) { 

      Log.e("YourApp", "GetPlaces : doInBackground", e); 

     } catch (JSONException e) { 

      Log.e("YourApp", "GetPlaces : doInBackground", e); 

     } 

     return predictionsArr; 

    } 

    // then our post 

    @Override 
    protected void onPostExecute(ArrayList<String> result) { 

     Log.d("YourApp", "onPostExecute : " + result.size()); 
     // update the adapter 
     adapter = new ArrayAdapter<String>(getBaseContext(), 
       R.layout.item_list); 
     adapter.setNotifyOnChange(true); 
     // attach the adapter to textview 
     textView.setAdapter(adapter); 

     for (String string : result) { 

      Log.d("YourApp", "onPostExecute : result = " + string); 
      adapter.add(string); 
      adapter.notifyDataSetChanged(); 

     } 

     Log.d("YourApp", 
       "onPostExecute : autoCompleteAdapter" + adapter.getCount()); 

    }

這裏是logcat的錯誤：

10-24 15:10:54.609: E/AndroidRuntime(14346): FATAL EXCEPTION: AsyncTask #1 
10-24 15:10:54.609: E/AndroidRuntime(14346): java.lang.RuntimeException: An error occured while executing doInBackground() 
10-24 15:10:54.609: E/AndroidRuntime(14346): at android.os.AsyncTask$3.done(AsyncTask.java:278) 
10-24 15:10:54.609: E/AndroidRuntime(14346): at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273) 
10-24 15:10:54.609: E/AndroidRuntime(14346): at java.util.concurrent.FutureTask.setException(FutureTask.java:124) 
10-24 15:10:54.609: E/AndroidRuntime(14346): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307) 
10-24 15:10:54.609: E/AndroidRuntime(14346): at java.util.concurrent.FutureTask.run(FutureTask.java:137) 
10-24 15:10:54.609: E/AndroidRuntime(14346): at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:208) 
10-24 15:10:54.609: E/AndroidRuntime(14346): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076) 
10-24 15:10:54.609: E/AndroidRuntime(14346): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569) 
10-24 15:10:54.609: E/AndroidRuntime(14346): at java.lang.Thread.run(Thread.java:856) 
10-24 15:10:54.609: E/AndroidRuntime(14346): Caused by: java.lang.NullPointerException 
10-24 15:10:54.609: E/AndroidRuntime(14346): at com.test.main.MainActivity$GetPlaces.doInBackground(MainActivity.java:76) 
10-24 15:10:54.609: E/AndroidRuntime(14346): at com.test.main.MainActivity$GetPlaces.doInBackground(MainActivity.java:1) 
10-24 15:10:54.609: E/AndroidRuntime(14346): at android.os.AsyncTask$2.call(AsyncTask.java:264) 
10-24 15:10:54.609: E/AndroidRuntime(14346): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)

來源

2012-10-24 Justin

錯誤的來源是明顯MainActivity線76，在那裏正在訪問在第76行一個空對象

來源

2012-10-25 05:12:04

。使用「URLEncoder.encode（args [0] .toString（）」而不是「URLEncoder.encode（arg0 [0] .toString（）」

來源

2013-05-03 06:29:55

它對我很好。 –

Google地圖自動完成android

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