显示java.lang.NullPointerException AllSuggestionsActivity.onTextChanged（AllSuggestionsActivity.this.adapter.getFilter（）过滤器（CS）。） [英] java.lang.NullPointerException AllSuggestionsActivity.onTextChanged (AllSuggestionsActivity.this.adapter.getFilter().filter(cs);)

查看：253
本文介绍了显示java.lang.NullPointerException AllSuggestionsActivity.onTextChanged（AllSuggestionsActivity.this.adapter.getFilter（）过滤器（CS）。）的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我得到一个错误（显示java.lang.NullPointerException ），当我执行code为的ListView 与的EditText 在该行过滤

AllSuggestionsActivity.this.adapter.getFilter（）过滤器（CS）;

好心帮。

 公共类AllSuggestionsActivity扩展ListActivity {    的EditText inputSearch;
    ListView的lstList;    //进度对话框
    私人ProgressDialog pDialog;    ArrayAdapter＆LT;串GT;适配器= NULL;    //创建JSON解析器对象
    JSONParser jParser =新JSONParser（）;    ArrayList的＆LT;＆HashMap的LT;字符串，字符串＆GT;＆GT; suggestionsList;    // URL获得所有建议列表
    私人静态字符串url_all_suggestions =htt​​p://10.0.2.2/JKUAT-M-SUGGESTION-BOX/get_all_suggestions.php;    // JSON节点名称
    私有静态最后弦乐TAG_SUCCESS =成功;
    私有静态最后弦乐TAG_SUGGESTIONS =建议;
    私有静态最后弦乐TAG_SID =SID;
    私有静态最后弦乐TAG_SUBJECT =主题;    //建议JSONArray
    JSONArray建议= NULL;    @覆盖
    公共无效的onCreate（捆绑savedInstanceState）{
        super.onCreate（savedInstanceState）;
        的setContentView（R.layout.all_suggestions）;        inputSearch =（EditText上）findViewById（R.id.inputSearch）;
        lstList =（ListView控件）findViewById（android.R.id.list）;
        //为哈希映射的ListView
        suggestionsList =新的ArrayList＆LT;＆HashMap的LT;字符串，字符串＆GT;＆GT;（）;        //在后台线程加载建议
        新LoadAllSuggestions（）执行（）;        //获取列表视图
        ListView控件LV = getListView（）;        / **
         *启用搜索过滤器
         * * /
        inputSearch.addTextChangedListener（新TextWatcher（）{            @覆盖
            公共无效onTextChanged（CharSequence的CS，INT ARG1，ARG2 INT，INT ARG3）{
                //当用户更改文本
                。AllSuggestionsActivity.this.adapter.getFilter（）过滤器（CS）;
            }            @覆盖
            公共无效beforeTextChanged（CharSequence的为arg0，ARG1 INT，INT ARG2，
                    INT ARG3）{
                // TODO自动生成方法存根            }            @覆盖
            公共无效afterTextChanged（编辑为arg0）{
                // TODO自动生成方法存根
            }
        }）;
        //在选课单建议
        //启动编辑建议画面
        lv.setOnItemClickListener（新OnItemClickListener（）{            @覆盖
            公共无效onItemClick（适配器视图＆LT;＆GT;母公司，观景，
                    INT位置，长的id）{
                //从选定的ListItem得到的值
                字符串SID =（（的TextView）view.findViewById（R.id.sid））的getText（）。
                        的ToString（）;                //开始新意图
                在意向=新意图（getApplicationContext（）
                        EditSuggestionActivity.class）;
                //发送到SID下一个活动
                in.putExtra（TAG_SID，SID）;                //开始新的活动，期待一些回响应
                startActivityForResult（在100）;
            }
        }）;    }    //从编辑建议活动响应
    @覆盖
    保护无效的onActivityResult（INT申请code，INT结果code，意图数据）{
        super.onActivityResult（要求code，结果code，数据）;
        //如果结果code 100
        如果（结果code == 100）{
            //如果结果code 100接收
            //意味着用户编辑/删除的建议
            //重新载入该画面
            意向意图= getIntent（）;
            完（）;
            startActivity（意向）;
        }    }    / **
     *背景异步任务以通过HTTP请求负载的所有建议
     * * /
    类LoadAllSuggestions扩展的AsyncTask＆LT;字符串，字符串，字符串＆GT; {        / **
         *启动后台线程显示进度对话框之前
         * * /
        @覆盖
        在preExecute保护无效（）{
            super.on preExecute（）;
            pDialog =新ProgressDialog（AllSuggestionsActivity.this）;
            pDialog.setMessage（加载所有的建议，请稍候......）;
            pDialog.setIndeterminate（假）;
            pDialog.setCancelable（假）;
            pDialog.show（）;
        }        / **
         *让所有的网址建议
         * * /
        @覆盖
        保护字符串doInBackground（字符串参数... args）{
            //大厦参数
            清单＆LT;＆的NameValuePair GT; PARAMS =新的ArrayList＆LT;＆的NameValuePair GT;（）;
            // URL从获取JSON字符串
            JSONObject的JSON = jParser.makeHtt prequest（url_all_suggestions，
                    GET，则params）;            //检查JSON效应初探日志的猫
            Log.d（所有建议：json.toString（））;            尝试{
                //检查成功TAG
                INT成功= json.getInt（TAG_SUCCESS）;                如果（成功== 1）{
                    发现//建议
                    //获取建议的数组
                    建议= json.getJSONArray（TAG_SUGGESTIONS）;                    //通过所有循环的建议
                    的for（int i = 0; I＆LT; suggestions.length（）;我++）{
                        JSONObject的C = suggestions.getJSONObject（I）                        //存储在变量中的每个JSON项目
                        字符串ID = c.getString（TAG_SID）;
                        字符串主题= c.getString（TAG_SUBJECT）;                        //创建新的HashMap
                        HashMap的＆LT;字符串，字符串＆GT;地图=新的HashMap＆LT;字符串，字符串＆GT;（）;                        //将每个子节点的HashMap键=＆GT;值
                        map.put（TAG_SID，身份证）;
                        map.put（TAG_SUBJECT，学科）;                        //添加HashList到ArrayList的
                        suggestionsList.add（地图）;
                    }
                }其他{
                    //没有发现任何建议
                    意图I =新意图（getApplicationContext（）
                            MainScreenActivity.class）;
                    //关闭所有previous活动
                    i.addFlags（Intent.FLAG_ACTIVITY_CLEAR_TOP）;
                    startActivity（ⅰ）;
                }
            }赶上（JSONException E）{
                e.printStackTrace（）;
            }            返回null;
        }        / **
         *在完成后台任务之后辞退进度对话框
         * ** /
        @覆盖
        保护无效onPostExecute（字符串FILE_URL）{
            //让所有建议后关闭该对话框
            pDialog.dismiss（）;
            //从后台线程更新界面
            runOnUiThread（新的Runnable（）{
                @覆盖
                公共无效的run（）{
                    / **
                     *更新解析JSON数据到ListView控件
                     * * /
                    ListAdapter适配器=新SimpleAdapter（
                            AllSuggestionsActivity.this，suggestionsList，
                            R.layout.list_item，新的String [] {TAG_SID，
                                    TAG_SUBJECT}，新的INT [] {R.id.sid，
                                    R.id.subject}）;
                    //更新列表视图
                    setListAdapter（适配器）;
                }
            }）;
        }
    }
}

XML code为ListView：

 ＆LT;？XML版本=1.0编码=UTF-8＆GT？;＆LT;滚动型
    的xmlns：机器人=htt​​p://schemas.android.com/apk/res/android
    机器人：layout_width =FILL_PARENT
    机器人：layout_height =FILL_PARENT
    机器人：fillViewport =真正的＆GT;    ＆LT; LinearLayout中的xmlns：机器人=htt​​p://schemas.android.com/apk/res/android
        机器人：layout_width =FILL_PARENT
        机器人：layout_height =FILL_PARENT
        机器人：方向=垂直＆GT;    ＆LT;的EditText
        机器人：ID =@ + ID / inputSearch
        机器人：layout_width =match_parent
        机器人：layout_height =WRAP_CONTENT
        机器人：layout_marginTop =5DP
        机器人：EMS =10
        机器人：MAXLINES =1
        机器人：提示=搜索＆GT;
        ＆LT; requestFocus的/＆GT;
    ＆所述; /的EditText＆GT  - →;        ＆LT;！ - 主要的ListView
             总是给值id作为列表（@android：ID /列表）
         - ＆GT;
        ＆LT; ListView控件
            机器人：ID =@机器人：ID /列表
            机器人：layout_width =FILL_PARENT
            机器人：layout_height =WRAP_CONTENT/＆GT;    ＆LT; / LinearLayout中＆GT;
    在此输入code＆LT; /滚动型＆GT;


解决方案

请找到解决错误：

 公共类AllSuggestionsActivity扩展ListActivity {SimpleAdapter适配器;的EditText inputSearch;//进度对话框
私人ProgressDialog pDialog;//创建JSON解析器对象
JSONParser jParser =新JSONParser（）;ArrayList的＆LT;＆HashMap的LT;字符串，字符串＆GT;＆GT; suggestionsList;// URL获得所有建议列表
私人静态字符串url_all_suggestions =htt​​p://10.0.2.2/JKUAT-M-SUGGESTION-BOX/get_all_suggestions.php;// JSON节点名称
私有静态最后弦乐TAG_SUCCESS =成功;
私有静态最后弦乐TAG_SUGGESTIONS =建议;
私有静态最后弦乐TAG_SID =SID;
私有静态最后弦乐TAG_SUBJECT =主题;//建议JSONArray
JSONArray建议= NULL;@覆盖
公共无效的onCreate（捆绑savedInstanceState）{
    super.onCreate（savedInstanceState）;
    的setContentView（R.layout.all_suggestions）;    //为哈希映射的ListView
    suggestionsList =新的ArrayList＆LT;＆HashMap的LT;字符串，字符串＆GT;＆GT;（）;    //在后台线程加载建议
    新LoadAllSuggestions（）执行（）;    //获取列表视图
    ListView控件LV = getListView（）;    //在选课单建议
    //启动编辑建议画面
    lv.setOnItemClickListener（新OnItemClickListener（）{        @覆盖
        公共无效onItemClick（适配器视图＆LT;＆GT;母公司，观景，
                INT位置，长的id）{
            //从选定的ListItem得到的值
            字符串SID =（（的TextView）view.findViewById（R.id.sid））的getText（）。
                    的ToString（）;            //开始新意图
            在意向=新意图（getApplicationContext（）
                    EditSuggestionActivity.class）;
            //发送到SID下一个活动
            in.putExtra（TAG_SID，SID）;            //开始新的活动，期待一些回响应
            startActivityForResult（在100）;
        }
    }）;}//从编辑建议活动响应
@覆盖
保护无效的onActivityResult（INT申请code，INT结果code，意图数据）{
    super.onActivityResult（要求code，结果code，数据）;
    //如果结果code 100
    如果（结果code == 100）{
        //如果结果code 100接收
        //意味着用户编辑/删除的建议
        //重新载入该画面
        意向意图= getIntent（）;
        完（）;
        startActivity（意向）;
    }}/ **
 *背景异步任务以通过HTTP请求负载的所有建议
 * * /
类LoadAllSuggestions扩展的AsyncTask＆LT;字符串，字符串，字符串＆GT; {    / **
     *启动后台线程显示进度对话框之前
     * * /
    @覆盖
    在preExecute保护无效（）{
        super.on preExecute（）;
        pDialog =新ProgressDialog（AllSuggestionsActivity.this）;
        pDialog.setMessage（加载所有的建议，请稍候......）;
        pDialog.setIndeterminate（假）;
        pDialog.setCancelable（假）;
        pDialog.show（）;
    }    / **
     *让所有的网址建议
     * * /
    @覆盖
    保护字符串doInBackground（字符串参数... args）{
        //大厦参数
        清单＆LT;＆的NameValuePair GT; PARAMS =新的ArrayList＆LT;＆的NameValuePair GT;（）;
        // URL从获取JSON字符串
        JSONObject的JSON = jParser.makeHtt prequest（url_all_suggestions，
                GET，则params）;        //检查JSON效应初探日志的猫
        Log.d（所有建议：json.toString（））;        尝试{
            //检查成功TAG
            INT成功= json.getInt（TAG_SUCCESS）;            如果（成功== 1）{
                发现//建议
                //获取建议的数组
                建议= json.getJSONArray（TAG_SUGGESTIONS）;                //通过所有循环的建议
                的for（int i = 0; I＆LT; suggestions.length（）;我++）{
                    JSONObject的C = suggestions.getJSONObject（I）                    //存储在变量中的每个JSON项目
                    字符串ID = c.getString（TAG_SID）;
                    字符串主题= c.getString（TAG_SUBJECT）;                    //创建新的HashMap
                    HashMap的＆LT;字符串，字符串＆GT;地图=新的HashMap＆LT;字符串，字符串＆GT;（）;                    //将每个子节点的HashMap键=＆GT;值
                    map.put（TAG_SID，身份证）;
                    map.put（TAG_SUBJECT，学科）;                    //添加HashList到ArrayList的
                    suggestionsList.add（地图）;
                }
            }其他{
                //没有发现任何建议
                意图I =新意图（getApplicationContext（）
                        MainScreenActivity.class）;
                //关闭所有previous活动
                i.addFlags（Intent.FLAG_ACTIVITY_CLEAR_TOP）;
                startActivity（ⅰ）;
            }
        }赶上（JSONException E）{
            e.printStackTrace（）;
        }        返回null;
    }    / **
     *在完成后台任务之后辞退进度对话框
     * ** /
    @覆盖
    保护无效onPostExecute（字符串FILE_URL）{
        //让所有建议后关闭该对话框
        pDialog.dismiss（）;
        //从后台线程更新界面
        runOnUiThread（新的Runnable（）{
            @覆盖
            公共无效的run（）{
                / **
                 *更新解析JSON数据到ListView控件
                 * * /                适配器=新SimpleAdapter（
                        AllSuggestionsActivity.this，suggestionsList，
                        R.layout.list_item，新的String [] {TAG_SID，
                                TAG_SUBJECT}，新的INT [] {R.id.sid，
                                R.id.subject}）;
                //更新列表视图
                setListAdapter（适配器）;                / **
                 *启用搜索过滤器
                 * * /
                inputSearch =（EditText上）findViewById（R.id.inputSearch）;                inputSearch.addTextChangedListener（新TextWatcher（）{                    @覆盖
                    公共无效onTextChanged（CharSequence的CS，INT ARG1，ARG2 INT，INT ARG3）{
                        //当用户更改文本
                        。AllSuggestionsActivity.this.adapter.getFilter（）过滤器（CS）;
                    }                    @覆盖
                    公共无效beforeTextChanged（CharSequence的为arg0，ARG1 INT，INT ARG2，
                            INT ARG3）{
                        // TODO自动生成方法存根                    }                    @覆盖
                    公共无效afterTextChanged（编辑为arg0）{
                        // TODO自动生成方法存根
                    }
                }）;
            }
        }）;
    }
}

}

xml文件保持完好

I am getting an error (java.lang.NullPointerException) when I execute the code for the ListView with EditText for filtering at the line

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

kindly help.

public class AllSuggestionsActivity extends ListActivity {

    EditText inputSearch;
    ListView lstList;

    // Progress Dialog
    private ProgressDialog pDialog;

    ArrayAdapter<String> adapter = null;

    // Creating JSON Parser object
    JSONParser jParser = new JSONParser();

    ArrayList<HashMap<String, String>> suggestionsList;

    // url to get all suggestions list
    private static String url_all_suggestions = "http://10.0.2.2/JKUAT-M-SUGGESTION-BOX/get_all_suggestions.php";

    // JSON Node names
    private static final String TAG_SUCCESS = "success";
    private static final String TAG_SUGGESTIONS = "suggestions";
    private static final String TAG_SID = "sid";
    private static final String TAG_SUBJECT = "subject";

    // suggestions JSONArray
    JSONArray suggestions = null;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.all_suggestions);

        inputSearch = (EditText) findViewById(R.id.inputSearch);
        lstList = (ListView) findViewById(android.R.id.list);


        // Hashmap for ListView
        suggestionsList = new ArrayList<HashMap<String, String>>();

        // Loading suggestions in Background Thread
        new LoadAllSuggestions().execute();

        // Get listview
        ListView lv = getListView();

        /**
         * Enabling Search Filter
         * */
        inputSearch.addTextChangedListener(new TextWatcher() {

            @Override
            public void onTextChanged(CharSequence cs, int arg1, int arg2, int arg3) {
                // When user changed the Text
                AllSuggestionsActivity.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                          
            }
        });


        // on seleting single suggestion
        // launching Edit Suggestion Screen
        lv.setOnItemClickListener(new OnItemClickListener() {

            @Override
            public void onItemClick(AdapterView<?> parent, View view,
                    int position, long id) {
                // getting values from selected ListItem
                String sid = ((TextView) view.findViewById(R.id.sid)).getText()
                        .toString();

                // Starting new intent
                Intent in = new Intent(getApplicationContext(),
                        EditSuggestionActivity.class);
                // sending sid to next activity
                in.putExtra(TAG_SID, sid);

                // starting new activity and expecting some response back
                startActivityForResult(in, 100);
            }
        });

    }

    // Response from Edit Suggestion Activity
    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        // if result code 100
        if (resultCode == 100) {
            // if result code 100 is received
            // means user edited/deleted suggestion
            // reload this screen again
            Intent intent = getIntent();
            finish();
            startActivity(intent);
        }

    }

    /**
     * Background Async Task to Load all suggestion by making HTTP Request
     * */
    class LoadAllSuggestions extends AsyncTask<String, String, String> {

        /**
         * Before starting background thread Show Progress Dialog
         * */
        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            pDialog = new ProgressDialog(AllSuggestionsActivity.this);
            pDialog.setMessage("Loading all suggestions. Please wait.......");
            pDialog.setIndeterminate(false);
            pDialog.setCancelable(false);
            pDialog.show();
        }

        /**
         * getting All suggestions from url
         * */
        @Override
        protected String doInBackground(String... args) {
            // Building Parameters
            List<NameValuePair> params = new ArrayList<NameValuePair>();
            // getting JSON string from URL
            JSONObject json = jParser.makeHttpRequest(url_all_suggestions,
                    "GET", params);

            // Check your log cat for JSON reponse
            Log.d("All Suggestions: ", json.toString());

            try {
                // Checking for SUCCESS TAG
                int success = json.getInt(TAG_SUCCESS);

                if (success == 1) {
                    // suggestions found
                    // Getting Array of Suggestions
                    suggestions = json.getJSONArray(TAG_SUGGESTIONS);

                    // looping through All Suggestions
                    for (int i = 0; i < suggestions.length(); i++) {
                        JSONObject c = suggestions.getJSONObject(i);

                        // Storing each json item in variable
                        String id = c.getString(TAG_SID);
                        String subject = c.getString(TAG_SUBJECT);

                        // creating new HashMap
                        HashMap<String, String> map = new HashMap<String, String>();

                        // adding each child node to HashMap key => value
                        map.put(TAG_SID, id);
                        map.put(TAG_SUBJECT, subject);

                        // adding HashList to ArrayList
                        suggestionsList.add(map);
                    }
                } else {
                    // no suggestions found
                    Intent i = new Intent(getApplicationContext(),
                            MainScreenActivity.class);
                    // Closing all previous activities
                    i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
                    startActivity(i);
                }
            } catch (JSONException e) {
                e.printStackTrace();
            }

            return null;
        }

        /**
         * After completing background task Dismiss the progress dialog
         * **/
        @Override
        protected void onPostExecute(String file_url) {
            // dismiss the dialog after getting all suggestions
            pDialog.dismiss();
            // updating UI from Background Thread
            runOnUiThread(new Runnable() {
                @Override
                public void run() {
                    /**
                     * Updating parsed JSON data into ListView
                     * */
                    ListAdapter adapter = new SimpleAdapter(
                            AllSuggestionsActivity.this, suggestionsList,
                            R.layout.list_item, new String[] { TAG_SID,
                                    TAG_SUBJECT }, new int[] { R.id.sid,
                                    R.id.subject });
                    // updating listview
                    setListAdapter(adapter);
                }
            });
        }
    }
}

xml code for the listview:

<?xml version="1.0" encoding="utf-8"?>

<ScrollView
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:fillViewport="true">    

    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:orientation="vertical">

    <EditText
        android:id="@+id/inputSearch"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="5dp"
        android:ems="10"
        android:maxLines="1"
        android:hint="Search" >
        <requestFocus />
    </EditText>-->

        <!-- Main ListView 
             Always give id value as list(@android:id/list)
        -->
        <ListView
            android:id="@android:id/list"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"/>

    </LinearLayout>


    enter code here

</ScrollView>

解决方案

Kindly find solution to the error:

public class AllSuggestionsActivity extends ListActivity {

SimpleAdapter adapter;

EditText inputSearch;

// Progress Dialog
private ProgressDialog pDialog;

// Creating JSON Parser object
JSONParser jParser = new JSONParser();

ArrayList<HashMap<String, String>> suggestionsList;

// url to get all suggestions list
private static String url_all_suggestions = "http://10.0.2.2/JKUAT-M-SUGGESTION-BOX/get_all_suggestions.php";

// JSON Node names
private static final String TAG_SUCCESS = "success";
private static final String TAG_SUGGESTIONS = "suggestions";
private static final String TAG_SID = "sid";
private static final String TAG_SUBJECT = "subject";

// suggestions JSONArray
JSONArray suggestions = null;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.all_suggestions);

    // Hashmap for ListView
    suggestionsList = new ArrayList<HashMap<String, String>>();

    // Loading suggestions in Background Thread
    new LoadAllSuggestions().execute();

    // Get listview
    ListView lv = getListView();

    // on seleting single suggestion
    // launching Edit Suggestion Screen
    lv.setOnItemClickListener(new OnItemClickListener() {

        @Override
        public void onItemClick(AdapterView<?> parent, View view,
                int position, long id) {
            // getting values from selected ListItem
            String sid = ((TextView) view.findViewById(R.id.sid)).getText()
                    .toString();

            // Starting new intent
            Intent in = new Intent(getApplicationContext(),
                    EditSuggestionActivity.class);
            // sending sid to next activity
            in.putExtra(TAG_SID, sid);

            // starting new activity and expecting some response back
            startActivityForResult(in, 100);
        }
    });

}

// Response from Edit Suggestion Activity
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    // if result code 100
    if (resultCode == 100) {
        // if result code 100 is received
        // means user edited/deleted suggestion
        // reload this screen again
        Intent intent = getIntent();
        finish();
        startActivity(intent);
    }

}

/**
 * Background Async Task to Load all suggestion by making HTTP Request
 * */
class LoadAllSuggestions extends AsyncTask<String, String, String> {

    /**
     * Before starting background thread Show Progress Dialog
     * */
    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        pDialog = new ProgressDialog(AllSuggestionsActivity.this);
        pDialog.setMessage("Loading all suggestions. Please wait.......");
        pDialog.setIndeterminate(false);
        pDialog.setCancelable(false);
        pDialog.show();
    }

    /**
     * getting All suggestions from url
     * */
    @Override
    protected String doInBackground(String... args) {
        // Building Parameters
        List<NameValuePair> params = new ArrayList<NameValuePair>();
        // getting JSON string from URL
        JSONObject json = jParser.makeHttpRequest(url_all_suggestions,
                "GET", params);

        // Check your log cat for JSON reponse
        Log.d("All Suggestions: ", json.toString());

        try {
            // Checking for SUCCESS TAG
            int success = json.getInt(TAG_SUCCESS);

            if (success == 1) {
                // suggestions found
                // Getting Array of Suggestions
                suggestions = json.getJSONArray(TAG_SUGGESTIONS);

                // looping through All Suggestions
                for (int i = 0; i < suggestions.length(); i++) {
                    JSONObject c = suggestions.getJSONObject(i);

                    // Storing each json item in variable
                    String id = c.getString(TAG_SID);
                    String subject = c.getString(TAG_SUBJECT);

                    // creating new HashMap
                    HashMap<String, String> map = new HashMap<String, String>();

                    // adding each child node to HashMap key => value
                    map.put(TAG_SID, id);
                    map.put(TAG_SUBJECT, subject);

                    // adding HashList to ArrayList
                    suggestionsList.add(map);
                }
            } else {
                // no suggestions found
                Intent i = new Intent(getApplicationContext(),
                        MainScreenActivity.class);
                // Closing all previous activities
                i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
                startActivity(i);
            }
        } catch (JSONException e) {
            e.printStackTrace();
        }

        return null;
    }

    /**
     * After completing background task Dismiss the progress dialog
     * **/
    @Override
    protected void onPostExecute(String file_url) {
        // dismiss the dialog after getting all suggestions
        pDialog.dismiss();
        // updating UI from Background Thread
        runOnUiThread(new Runnable() {
            @Override
            public void run() {
                /**
                 * Updating parsed JSON data into ListView
                 * */

                adapter = new SimpleAdapter(
                        AllSuggestionsActivity.this, suggestionsList,
                        R.layout.list_item, new String[] { TAG_SID,
                                TAG_SUBJECT }, new int[] { R.id.sid,
                                R.id.subject });
                // updating listview
                setListAdapter(adapter);

                /**
                 * Enabling Search Filter
                 * */
                inputSearch = (EditText) findViewById(R.id.inputSearch);

                inputSearch.addTextChangedListener(new TextWatcher() {

                    @Override
                    public void onTextChanged(CharSequence cs, int arg1, int arg2, int arg3) {
                        // When user changed the Text
                        AllSuggestionsActivity.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                          
                    }
                });
            }
        });
    }
}

}

xml file remains intact

这篇关于显示java.lang.NullPointerException AllSuggestionsActivity.onTextChanged（AllSuggestionsActivity.this.adapter.getFilter（）过滤器（CS）。）的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！

查看全文
相关文章
移动开发最新文章
热门教程
热门工具
登录 关闭
扫码关注1秒登录
发送“验证码”获取 | 15天全站免登陆