在文本更改事件检查与指定获得NPE

Question

您可以在下面的代码中使用Row Adapter类以listview格式显示来自服务器的指定名称。当我使用指定名称搜索时，它显示空指针异常。

任何人都可以帮助我

的java

 img_Search.addTextChangedListener(new TextWatcher() {
                @Override
                public void beforeTextChanged(CharSequence s, int start, int count, int after) {

                }

                @Override
                public void onTextChanged(CharSequence s, int start, int before, int count) {
                    if(count>=1) {
                        InputMethodManager imm = (InputMethodManager) getActivity().getApplicationContext().getSystemService(Context.INPUT_METHOD_SERVICE);
                        imm.hideSoftInputFromWindow(img_Search.getWindowToken(), 0);
                    }
                    else if(count>=2) {
                        InputMethodManager imm = (InputMethodManager) getActivity().getApplicationContext().getSystemService(Context.INPUT_METHOD_SERVICE);
                        imm.hideSoftInputFromWindow(img_Search.getWindowToken(), 0);
                    }
                    else if(count>=3) {
                        InputMethodManager imm = (InputMethodManager) getActivity().getApplicationContext().getSystemService(Context.INPUT_METHOD_SERVICE);
                        imm.hideSoftInputFromWindow(img_Search.getWindowToken(), 0);
                    }
                    else if(count>=4) {
                        InputMethodManager imm = (InputMethodManager) getActivity().getApplicationContext().getSystemService(Context.INPUT_METHOD_SERVICE);
                        imm.hideSoftInputFromWindow(img_Search.getWindowToken(), 0);
                    }
                    else if(count>=5) {
                        InputMethodManager imm = (InputMethodManager) getActivity().getApplicationContext().getSystemService(Context.INPUT_METHOD_SERVICE);
                        imm.hideSoftInputFromWindow(img_Search.getWindowToken(), 0);
                    }
                    final List<LeadResult.Users> allUsers = list;
                    final List<LeadResult.Users> searchResultUsers = new ArrayList<LeadResult.Users>();


                    for (int i = 0; i < allUsers.size(); i++) {

                        if (allUsers.get(i).getDESIGNATION().toLowerCase().startsWith((s.toString()).toLowerCase())) {
                            searchResultUsers.add(allUsers.get(i));

                        }


                    }
                    RowAdapter row = new RowAdapter(getActivity(), searchResultUsers);
                    users.setAdapter(row);
                }

                @Override
                public void afterTextChanged(Editable s) {


                }
            });

logcat的

    java.lang.NullPointerException
            at info.androidhive.slidingmenu.ContactFragment$3.onTextChanged(ContactFragment.java:242)
            at android.widget.TextView.sendOnTextChanged(TextView.java:7079)
            at android.widget.TextView.handleTextChanged(TextView.java:7138)
            at android.widget.TextView$ChangeWatcher.onTextChanged(TextView.java:8732)
            at android.text.SpannableStringBuilder.sendTextChanged(SpannableStringBuilder.java:962)
            at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:496)
            at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:435)
            at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:30)
            at android.text.method.QwertyKeyListener.onKeyDown(QwertyKeyListener.java:222)
            at android.text.method.TextKeyListener.onKeyDown(TextKeyListener.java:136)
            at android.widget.TextView.doKeyDown(TextView.java:5240)
            at android.widget.TextView.onKeyDown(TextView.java:5059)
            at android.view.KeyEvent.dispatch(KeyEvent.java:2609)
            at android.view.View.dispatchKeyEvent(View.java:7086)
            at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1358)
            at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1358)
            at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1358)
            at android.widget.ScrollView.dispatchKeyEvent(ScrollView.java:350)
            at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1358)
            at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1358)
            at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1358)
            at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1358)
            at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1358)
            at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1358)
            at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchKeyEvent(PhoneWindow.java:1892)
            at com.android.internal.policy.impl.PhoneWindow.superDispatchKeyEvent(PhoneWindow.java:1369)
            at android.app.Activity.dispatchKeyEvent(Activity.java:2356)
            at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchKeyEvent(PhoneWindow.java:1819)
            at android.view.ViewRootImpl.deliverKeyEventPostIme(ViewRootImpl.java:3575)
            at android.view.ViewRootImpl.handleImeFinishedEvent(ViewRootImpl.java:3545)
            at android.view.ViewRootImpl$ViewRootHandler.handleMessage(ViewRootImpl.java:2795)
            at android.os.Handler.dispatchMessage(Handler.java:99)
            at android.os.Looper.loop(Looper.java:137)
            at android.app.ActivityThread.main(ActivityThread.java:4745)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:511)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
            at dalvik.system.NativeStart.main(Native Method)