使用过滤器搜索listview

时间：2018-01-30 11:32:51

标签： java android listview

我在android studio中有一个项目，它从在线数据库加载数据并将这些数据放在listview中。列表视图上方有一个EditText，我想在列表视图中搜索我在里面写的值。我试图让this tutorial适应我的但我得到很多错误和崩溃，我无法解决因为我是一个菜鸟。你能帮助我让教程适应我的项目吗？下面是没有搜索过滤器的代码。如果你想我可以上传我的尝试与错误。提前谢谢！

AllStudents.java：

public class AllStudents extends AppCompatActivity {
ListView StudentListView;
ProgressBar progressBar;
String HttpUrl = "http://sissy-nickels.000webhostapp.com/AllStudentData.php";
List<String> IdList = new ArrayList<>();
String LessonName;
HttpParse httpParse = new HttpParse();
ProgressDialog pDialog;
String FinalJSonObject;
HashMap<String,String> ResultHash = new HashMap<>();
String ParseResult ;
List<Student> studentList;

@Override
public void onBackPressed()
{
    super.onBackPressed();
    startActivity(new Intent(AllStudents.this, AddStudent.class));
    finish();

}

@Override
protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_allstudents);

    StudentListView = (ListView)findViewById(R.id.listview2);

    progressBar = (ProgressBar)findViewById(R.id.progressBar);

    LessonName = getIntent().getStringExtra("Lesson");

    HttpWebCall(LessonName);





    //Adding ListView Item click Listener.
    StudentListView.setOnItemClickListener(new AdapterView.OnItemClickListener()
    {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {

            // TODO Auto-generated method stub

            Intent intent = new Intent(AllStudents.this,SingleStudent.class);

            // Sending ListView clicked value using intent.
            intent.putExtra("ListViewValue", IdList.get(position).toString());

            startActivity(intent);


            //Finishing current activity after open next activity.
            finish();



        }
    });


}
public void HttpWebCall(final String LessonName){

    class HttpWebCallFunction extends AsyncTask<String,Void,String> {

        @Override
        protected void onPreExecute() {
            super.onPreExecute();

            pDialog = ProgressDialog.show(AllStudents.this,"Loading Data",null,true,true);
        }

        @Override
        protected void onPostExecute(String httpResponseMsg) {

            super.onPostExecute(httpResponseMsg);

            pDialog.dismiss();

            //Storing Complete JSon Object into String Variable.
            FinalJSonObject = httpResponseMsg ;

            //Parsing the Stored JSOn String to GetHttpResponse Method.
            new GetHttpResponse(AllStudents.this).execute();

        }

        @Override
        protected String doInBackground(String... params) {

            ResultHash.put("LessonName",params[0]);

            ParseResult = httpParse.postRequest(ResultHash, HttpUrl);

            return ParseResult;
        }
    }

    HttpWebCallFunction httpWebCallFunction = new HttpWebCallFunction();

    httpWebCallFunction.execute(LessonName);
}

// JSON parse class started from here.
private class GetHttpResponse extends AsyncTask<Void, Void, Void>
{
    public Context context;


    public GetHttpResponse(Context context)
    {
        this.context = context;
    }

    @Override
    protected void onPreExecute()
    {
        super.onPreExecute();
    }

    @Override
    protected Void doInBackground(Void... arg0)
    {

        try
        {
                if(FinalJSonObject != null)
                {
                    JSONArray jsonArray = null;

                    try {
                        jsonArray = new JSONArray(FinalJSonObject);

                        JSONObject jsonObject;

                        Student student;

                        studentList = new ArrayList<Student>();

                        for(int i=0; i<jsonArray.length(); i++)
                        {
                            jsonObject = jsonArray.getJSONObject(i);

                            student = new Student();

                            // Adding Student Id TO IdList Array.
                            IdList.add(jsonObject.getString("id").toString());

                            //Adding Student Name.
                            student.StudentName = jsonObject.getString("Regnum").toString();


                            studentList.add(student);

                        }
                    }
                    catch (JSONException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                }

        }
        catch (Exception e)
        {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return null;
    }

    @Override
    protected void onPostExecute(Void result)

    {
        progressBar.setVisibility(View.GONE);

        StudentListView.setVisibility(View.VISIBLE);

        ListAdapter adapter = new ListAdapter(studentList, context);

        StudentListView.setAdapter(adapter);
        adapter.notifyDataSetChanged();

    }
}}

ListAdapter.java 

public class ListAdapter extends BaseAdapter {
Context context;
List<Student> valueList=null;



public ListAdapter(List<Student> listValue, Context context)
{
    this.context = context;
    this.valueList = listValue;

    if(valueList==null){
        valueList = new ArrayList<>();
    }

}

@Override
public int getCount()
{
    return this.valueList.size();
}

@Override
public Object getItem(int position)
{
    return this.valueList.get(position);
}

@Override
public long getItemId(int position)
{
    return position;
}

@Override
public View getView(int position, View convertView, ViewGroup parent)
{
    ViewItem viewItem;
    convertView = null;

    if(convertView == null)
    {

        viewItem = new ViewItem();

        LayoutInflater layoutInfiater = (LayoutInflater)this.context.getSystemService(Activity.LAYOUT_INFLATER_SERVICE);

        convertView = layoutInfiater.inflate(R.layout.listviewitem, null);

        viewItem.TextViewStudentName = (TextView)convertView.findViewById(R.id.textView1);

        convertView.setTag(viewItem);

    }
    else
    {
        viewItem = (ViewItem) convertView.getTag();
    }

    viewItem.TextViewStudentName.setText(valueList.get(position).StudentName);


    return convertView;
}}class ViewItem{    TextView TextViewStudentName;}

Student.java：

public class Student {
public String StudentName ;}

listview.xml 

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@drawable/gradient"
android:padding="15dp">

<TextView
    android:id="@+id/textView1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:padding="10dp"
    android:textColor="@android:color/holo_blue_dark"
    android:textSize="24dp" />

avtivity_allstudents.xml 

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/activity_show_all_students"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.djale.login_register.AllStudents"
android:background="@drawable/gradient"
>

<EditText
    android:id="@+id/search"
    android:layout_width="250dp"
    android:layout_height="30dp"
    android:layout_alignParentEnd="true"
    android:layout_alignParentStart="true"
    android:background="#11000000"
    android:ems="10"
    android:drawableLeft="@drawable/ic_search_black_24dp"
    android:hint=" Search by reg. number"
    android:inputType="textPersonName"
    android:textColorHint="@android:color/holo_blue_dark"
    android:textSize="18sp" />

<ListView
    android:id="@+id/listview2"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_alignParentStart="true"
    android:layout_below="@+id/search" />

<ProgressBar
    android:id="@+id/progressBar"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_centerInParent="true"
    android:visibility="visible"
    />

2 个答案:

答案 0 :(得分：1)

你可以这样做：

search=(EditText)findviewById(R.id.search);
 search.addTextChangedListener(new TextWatcher() {
            @Override
            public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {

            }

            @Override
            public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {

            }

            @Override
            public void afterTextChanged(Editable editable) {

                searchList=new ArrayList<>();

                for(studentList name: String){

                    if(name.toLowerCase().contains(editable.toString().toLowerCase())){
                        searchList.add(name);
                    }
                }
//clear data in adapter
//add searchList to your adapter
            }
        });

答案 1 :(得分：0)

您可以将TextChangedListener添加到搜索框（EditText）。在onTextChanged()中，过滤列表＆amp;相应地更新ListView。

在AllStudents.java中，尝试进行以下更改：

public class AllStudents extends AppCompatActivity {
    .....

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        ....

        StudentListView.setOnItemClickListener(...)


        // add TextChangedListener to search box.
        // It listens for user's entered text & filter students' list by name
        EditText searchEditText = (EditText) findViewById(R.id.search);

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

            // when text is entered in search box, filter list by search text
            @Override
            public void onTextChanged(CharSequence cs, int start, int before, int count) {
                filterStudents(cs);
            }

            @Override
            public void afterTextChanged(Editable s) {
            }
        });
    }


    // check student's name whether contain text entered in search box
    private void filterStudents (CharSequence cs) {
        List<Student> filteredList = new ArrayList<>();

        if (TextUtils.isEmpty(cs)) {
            // no text is entered for search, do nothing
            return;
        }

        // build new student list which filtered by search text. 
        for (Student student : studentList) {
            if (student.StudentName.contains(cs)) {
                filteredList.add(student);
            }
        }

        // show filtered list in listview
        ListAdapter adapter = new ListAdapter(filteredList, this);

        StudentListView.setAdapter(adapter);
        adapter.notifyDataSetChanged();
    }
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