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我想使用编辑文本在我的列表中搜索，但是当我尝试在编辑文本中输入内容时，应用程序停止并在控制台中显示以下错误。

02-08 09:46:23.675: E/AndroidRuntime(3759): FATAL EXCEPTION: main
02-08 09:46:23.675: E/AndroidRuntime(3759): java.lang.NullPointerException
02-08 09:46:23.675: E/AndroidRuntime(3759):     at com.example.search.MainActivity$JSONfunctions.onTextChanged(MainActivity.java:142)
02-08 09:46:23.675: E/AndroidRuntime(3759):     at android.widget.TextView.sendOnTextChanged(TextView.java:7092)
02-08 09:46:23.675: E/AndroidRuntime(3759):     at android.widget.TextView.handleTextChanged(TextView.java:7151)
02-08 09:46:23.675: E/AndroidRuntime(3759):     at android.widget.TextView$ChangeWatcher.onTextChanged(TextView.java:8794)
02-08 09:46:23.675: E/AndroidRuntime(3759):     at android.text.SpannableStringBuilder.sendTextChanged(SpannableStringBuilder.java:962)
02-08 09:46:23.675: E/AndroidRuntime(3759):     at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:496)
02-08 09:46:23.675: E/AndroidRuntime(3759):     at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:435)
02-08 09:46:23.675: E/AndroidRuntime(3759):     at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:30)
02-08 09:46:23.675: E/AndroidRuntime(3759):     at android.text.method.QwertyKeyListener.onKeyDown(QwertyKeyListener.java:222)
02-08 09:46:23.675: E/AndroidRuntime(3759):     at android.text.method.TextKeyListener.onKeyDown(TextKeyListener.java:136)
02-08 09:46:23.675: E/AndroidRuntime(3759):     at android.widget.TextView.doKeyDown(TextView.java:5246)
02-08 09:46:23.675: E/AndroidRuntime(3759):     at android.widget.TextView.onKeyDown(TextView.java:5065)
02-08 09:46:23.675: E/AndroidRuntime(3759):     at android.view.KeyEvent.dispatch(KeyEvent.java:2609)
02-08 09:46:23.675: E/AndroidRuntime(3759):     at android.view.View.dispatchKeyEvent(View.java:7198)
02-08 09:46:23.675: E/AndroidRuntime(3759):     at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1359)
02-08 09:46:23.675: E/AndroidRuntime(3759):     at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1359)
02-08 09:46:23.675: E/AndroidRuntime(3759):     at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1359)
02-08 09:46:23.675: E/AndroidRuntime(3759):     at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1359)
02-08 09:46:23.675: E/AndroidRuntime(3759):     at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchKeyEvent(PhoneWindow.java:1920)
02-08 09:46:23.675: E/AndroidRuntime(3759):     at com.android.internal.policy.impl.PhoneWindow.superDispatchKeyEvent(PhoneWindow.java:1395)
02-08 09:46:23.675: E/AndroidRuntime(3759):     at android.app.Activity.dispatchKeyEvent(Activity.java:2370)
02-08 09:46:23.675: E/AndroidRuntime(3759):     at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchKeyEvent(PhoneWindow.java:1847)
02-08 09:46:23.675: E/AndroidRuntime(3759):     at android.view.ViewRootImpl.deliverKeyEventPostIme(ViewRootImpl.java:3701)
02-08 09:46:23.675: E/AndroidRuntime(3759):     at android.view.ViewRootImpl.handleImeFinishedEvent(ViewRootImpl.java:3651)
02-08 09:46:23.675: E/AndroidRuntime(3759):     at android.view.ViewRootImpl$ViewRootHandler.handleMessage(ViewRootImpl.java:2818)
02-08 09:46:23.675: E/AndroidRuntime(3759):     at android.os.Handler.dispatchMessage(Handler.java:99)
02-08 09:46:23.675: E/AndroidRuntime(3759):     at android.os.Looper.loop(Looper.java:137)
02-08 09:46:23.675: E/AndroidRuntime(3759):     at android.app.ActivityThread.main(ActivityThread.java:5039)
02-08 09:46:23.675: E/AndroidRuntime(3759):     at java.lang.reflect.Method.invokeNative(Native Method)
02-08 09:46:23.675: E/AndroidRuntime(3759):     at java.lang.reflect.Method.invoke(Method.java:511)
02-08 09:46:23.675: E/AndroidRuntime(3759):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
02-08 09:46:23.675: E/AndroidRuntime(3759):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
02-08 09:46:23.675: E/AndroidRuntime(3759):     at dalvik.system.NativeStart.main(Native Method)

我的代码：

public class MainActivity extends ListActivity {

     SimpleAdapter adapter;
     ArrayList<HashMap<String, String>> mylist = new ArrayList<HashMap<String, String>>();

        @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
           setContentView(R.layout.list);

        JSONfunctions jsfn=new JSONfunctions();
        jsfn.execute("http://192.168.6.43/employees.php");
    }


    public class JSONfunctions extends AsyncTask<String, Integer, ArrayList<HashMap<String, String>> > implements TextWatcher {


         InputStream is;
         String result ;
         JSONObject jArray;
        ArrayList<HashMap<String, String>> mylist = new ArrayList<HashMap<String, String>>();

        @Override
        protected ArrayList<HashMap<String, String>> doInBackground(String... params)
        {

            try{
/*get jobject from the url
                HttpClient httpclient = new DefaultHttpClient();

                HttpPost httppost = new HttpPost(params[0]);
                HttpResponse response = httpclient.execute(httppost);
                HttpEntity entity = response.getEntity();
                is = entity.getContent();

        }catch(Exception e){
                Log.e("log_tag", "Error in http connection "+e.toString());
        }
        try{
             BufferedReader reader = new BufferedReader(new InputStreamReader(is,"iso-8859-1"),8);
             StringBuilder sb = new StringBuilder();
             String line = null;
             while ((line = reader.readLine()) != null) {
                     sb.append(line + "\n");
             }
             is.close();
             result=sb.toString();

     }catch(Exception e){
             Log.e("log_tag", "Error converting result "+e.toString());
     }

     try{

         jArray = new JSONObject(result);    

       //  MainActivity.dataFromAsyncTask=jArray;
     }catch(JSONException e){
             Log.e("log_tag", "Error parsing data "+e.toString());
     }*/
            try{

                JSONArray  ip = jArray.getJSONArray("Employees");

                for(int i=0;i<ip.length();i++){                     
                    JSONArray e = ip.getJSONArray(i);
                    HashMap<String, String> map = new HashMap<String, String>();    

                    map.put("name", e.getString(0)+" "+e.getString(1)+" "+e.getString(2));
                    //map.put("email id",e.getString(3));
                    //map.put("phone no",e.getString(4));

                    mylist.add(map);        
                } 

            }catch(JSONException e)        {
                 Log.e("log_tag", "Error parsing data "+e.toString());
            }
            return mylist;

                }

                @Override
                protected void onPostExecute(ArrayList<HashMap<String, String>> result)
                {
                    ListAdapter adapter = new SimpleAdapter(MainActivity.this, result , R.layout.activity_main, 
                            new String[] { "name" }, 
                            new int[] { R.id.item_title });
                    MainActivity.this.setListAdapter(adapter);// If Activity extends ListActivity
                    final ListView lv = getListView();
                    lv.setTextFilterEnabled(true);
                    EditText myFilter = (EditText) findViewById(R.id.editText1);
                    myFilter.addTextChangedListener(this);
                }

                @Override
                public void afterTextChanged(Editable s) {
                    // TODO Auto-generated method stub

                }

                @Override
                public void beforeTextChanged(CharSequence s, int start,
                        int count, int after) {
                    // TODO Auto-generated method stub

                }

                @Override
                public void onTextChanged(CharSequence s, int start,
                        int before, int count) {
                    // TODO Auto-generated method stub
                    MainActivity.this.adapter.getFilter().filter(s.toString());

                }



}
}
4

1 回答 1

0

您永远不会初始化您在方法中使用的适配器变量。onTextChanged所以你要么写：

adapter = new SimpleAdapter(MainActivity.this, result , R.layout.activity_main, new String[] { "name" }, new int[] { R.id.item_title });

在方法中，或者您在方法中使用以下代码onPostExecute过滤：ListViewonTextXhanged

@Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
    ((Filterable)MainActivity.this.getListView().getAdapter()).getFilter().filter(s.toString());   
}
于 2013-02-08T10:15:51.260 回答