使用edittext作为搜索视图出错

Question

我有这个listview:

private EditText mySearchView;
private ListView listView;
ArrayAdapter<String> adapter;
@Override
        public void onComplete(List<Profile> friends) {
            runOnUiThread(new Runnable() {
                @Override
                public void run() {
                    mSpinner.setVisibility(View.GONE);
                    mSpinner.clearAnimation();
                }
                });
            // populate list
            List<String> values = new ArrayList<String>();
            for (Profile profile : friends) {
                //profile.getInstalled();
                values.add(profile.getName());
            }

            mySearchView = (EditText) findViewById(R.id.searchText);
            listView = (ListView) findViewById(R.id.list);
            listView.setOnItemClickListener(new OnItemClickListener() {
                @Override
                public void onItemClick(AdapterView<?> av, final View view, final int i, long i2) {
                  Animation pushLeftIn = AnimationUtils.loadAnimation(CallActivity.this, R.anim.jump_no_fade);
                  view.startAnimation(pushLeftIn);
            }
            });
            ArrayAdapter<String> adapter = new ArrayAdapter<String>(getApplicationContext(), R.layout.list_items2, values);
            adapter.sort(new Comparator<String>() {
                @Override
                public int compare(String lhs, String rhs) {
                    return lhs.compareTo(rhs);    
                }
            });
            mySearchView.addTextChangedListener(new TextWatcher() {
                @Override
                public void onTextChanged(CharSequence cs, int arg1, int arg2, int arg3) {
                    // When user changed the Text
                    CallActivity.this.adapter.getFilter().filter(cs);   
                }
                @Override
                public void beforeTextChanged(CharSequence arg0, int arg1, int arg2,
                        int arg3) {
                    // TODO Auto-generated method stub
                }
                @Override
                public void afterTextChanged(Editable arg0) {
                    // TODO Auto-generated method stub                          
                }
            });
            mFriendsList.setAdapter(adapter);
        }
    };

我试过设置一个链接到edittext的文本观察器，为了使用edittext来过滤列表视图，它似乎在代码中没有错误，但是当我打开应用程序并在edittext中键入第一个字符时，它崩溃了，我得到这个LogCat错误:

05-05 17:09:45.794: E/AndroidRuntime(6732): FATAL EXCEPTION: main
05-05 17:09:45.794: E/AndroidRuntime(6732): java.lang.NullPointerException
05-05 17:09:45.794: E/AndroidRuntime(6732):     at com.example.test.CallActivity$1$4.onTextChanged(CallActivity.java:133)
05-05 17:09:45.794: E/AndroidRuntime(6732):     at android.widget.TextView.sendOnTextChanged(TextView.java:7407)
05-05 17:09:45.794: E/AndroidRuntime(6732):     at android.widget.TextView.handleTextChanged(TextView.java:7469)
05-05 17:09:45.794: E/AndroidRuntime(6732):     at android.widget.TextView$ChangeWatcher.onTextChanged(TextView.java:9218)
05-05 17:09:45.794: E/AndroidRuntime(6732):     at android.text.SpannableStringBuilder.sendTextChanged(SpannableStringBuilder.java:962)
05-05 17:09:45.794: E/AndroidRuntime(6732):     at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:496)
05-05 17:09:45.794: E/AndroidRuntime(6732):     at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:435)
05-05 17:09:45.794: E/AndroidRuntime(6732):     at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:30)
05-05 17:09:45.794: E/AndroidRuntime(6732):     at android.view.inputmethod.BaseInputConnection.replaceText(BaseInputConnection.java:676)
05-05 17:09:45.794: E/AndroidRuntime(6732):     at android.view.inputmethod.BaseInputConnection.setComposingText(BaseInputConnection.java:435)
05-05 17:09:45.794: E/AndroidRuntime(6732):     at com.android.internal.view.IInputConnectionWrapper.executeMessage(IInputConnectionWrapper.java:333)
05-05 17:09:45.794: E/AndroidRuntime(6732):     at com.android.internal.view.IInputConnectionWrapper$MyHandler.handleMessage(IInputConnectionWrapper.java:77)
05-05 17:09:45.794: E/AndroidRuntime(6732):     at android.os.Handler.dispatchMessage(Handler.java:99)
05-05 17:09:45.794: E/AndroidRuntime(6732):     at android.os.Looper.loop(Looper.java:137)
05-05 17:09:45.794: E/AndroidRuntime(6732):     at android.app.ActivityThread.main(ActivityThread.java:4867)
05-05 17:09:45.794: E/AndroidRuntime(6732):     at java.lang.reflect.Method.invokeNative(Native Method)
05-05 17:09:45.794: E/AndroidRuntime(6732):     at java.lang.reflect.Method.invoke(Method.java:511)
05-05 17:09:45.794: E/AndroidRuntime(6732):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1007)
05-05 17:09:45.794: E/AndroidRuntime(6732):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:774)
05-05 17:09:45.794: E/AndroidRuntime(6732):     at dalvik.system.NativeStart.main(Native Method)

关于为什么会发生这种情况或者我如何修改代码使其工作的任何提示?

Answer 1

在onCreate()中，初始化成员变量adapter而不是局部变量。改变这个

ArrayAdapter<String> adapter = new ArrayAdapter<String>(getApplicationContext(), R.layout.list_items2, values);

adapter = new ArrayAdapter<String>(getApplicationContext(), R.layout.list_items2, values);

Answer 2

你确定你总是在getFilter方法中返回一个非空过滤器吗?

将这一行分隔成组件，以查看NullPointerException发生的确切位置。变化:

CallActivity.this.adapter.getFilter().filter(cs);

ArrayAdapter<String> myAdapter = CallActivity.this.adapter;
Filter filter = myAdapter.getFilter();
filter.filter(cs);