Question

我有这样的问题。我有一个ListView，首先我使用适配器从SQLIte数据库填充它。然后我实现搜索，并希望将新的搜索数据放入此ListView（方法doMySearch），但我得到相同的结果 - 数据未更新。可以做些什么来解决它？这是代码：

package com.example.citycode;

import android.app.SearchManager;
import android.content.Context;
import android.content.Intent;
import android.database.Cursor;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.util.Log;
import android.view.Menu;
import android.widget.ListView;
import android.widget.SearchView;
import android.widget.SimpleCursorAdapter;

public class MainActivity extends ActionBarActivity {

  ListView lvData,lvData1;
  DBHelper db;
  SimpleCursorAdapter scAdapter;
  Cursor cursor;
  Cursor cursor1;

  final String LOG_TAG = "myLogs";
  final String LOG_TAG1 = "myLogs1";

  /** Called when the activity is first created. */
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    // открываем подключение к БД
    db = new DBHelper(this);
    db.open();

    // Get the intent, verify the action and get the query
    Intent intent = getIntent();
    if (Intent.ACTION_SEARCH.equals(intent.getAction())) {
      String query = intent.getStringExtra(SearchManager.QUERY);
      doMySearch(query);
    }

    // получаем курсор
    cursor = db.getAllData();
    startManagingCursor(cursor);

    // Формируем столбцы сопоставления
    String[] from = new String[] { DBHelper.COLUMN_r_name, DBHelper.COLUMN_region, DBHelper.COLUMN_code};
    int[] to = new int[] { R.id.city_name, R.id.region_name, R.id.city_code };

    // создааем адаптер и настраиваем список
    scAdapter = new SimpleCursorAdapter(this, R.layout.item, cursor, from, to);
    lvData = (ListView) findViewById(R.id.listdata);
    lvData.setAdapter(scAdapter);
  }

  public void doMySearch(String query) {
        lvData1 = (ListView) findViewById(R.id.listdata);
        //Ищем совпадения
        Log.d(LOG_TAG, "Before get the C");
        cursor1 = db.fetchRecordsByQuery(query);
        Log.d(LOG_TAG, "After get the C");
        String t = Integer.toString(cursor1.getCount());
        Log.d(LOG_TAG, t);
        startManagingCursor(cursor1);
        String[] from = new String[] { DBHelper.COLUMN_r_name, DBHelper.COLUMN_region, DBHelper.COLUMN_code};
        int[] to = new int[] { R.id.city_name, R.id.region_name, R.id.city_code };
        SimpleCursorAdapter scAdapter1;

        scAdapter = new SimpleCursorAdapter(this,
                R.layout.item, cursor1, from, to);

        Log.d(LOG_TAG, "Setting the adapter");
        //Обновляем адаптер
        logCursor(cursor1);
        lvData1.setAdapter(scAdapter);
        Log.d(LOG_TAG, "Adapter was set");
      }

//вывод в лог данных из курсора
 void logCursor(Cursor c) {
   if (c != null) {
     if (c.moveToFirst()) {
       String str;
       do {
         str = "";
         for (String cn : c.getColumnNames()) {
           str = str.concat(cn + " = " + c.getString(c.getColumnIndex(cn)) + "; ");
         }
         Log.d(LOG_TAG1, str);
       } while (c.moveToNext());
     }
   } else
     Log.d(LOG_TAG1, "Cursor is null");
 }



     @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);

        // Associate searchable configuration with the SearchView
        SearchManager searchManager =
               (SearchManager) getSystemService(Context.SEARCH_SERVICE);
        SearchView searchView =
                (SearchView) menu.findItem(R.id.action_settings).getActionView();
        searchView.setSearchableInfo(
                searchManager.getSearchableInfo(getComponentName()));

        return true;
    }


  protected void onDestroy() {
    super.onDestroy();
    // закрываем подключение при выходе
    db.close();
  }

}

Answer 1

你试过scAdapter.notifyDataSetChanged();吗？只要您希望视图反映数据中的更新，这就是常见的调用。

Answer 2

目前，您将通过调用db.getAllData()覆盖搜索结果。

由于doMySearch几乎与onCreate相同，请尝试删除doMySearch并添加以下代码（替换onCreate，添加onNewIntent和{ {1}}，执行搜索或以其他方式加载所有数据。

loadData

Answer 3

尝试删除lvData1并使用lvData中的doMySearch，然后删除：

lvData1 = (ListView) findViewById(R.id.listdata);

findViewById中你已经onCreated了。

Answer 4

您可以尝试这样，

           runOnUiThread(new Runnable() {
                public void run() {
                    scAdapter.notifyDataSetChanged()
                }
            });

尝试这个，我评论了一些行“//评论Tharaka”并添加了一些行“// DO Tharaka”

public class MainActivity extends ActionBarActivity {

  ListView lvData,lvData1;
  DBHelper db;
  SimpleCursorAdapter scAdapter;
  Cursor cursor;
  Cursor cursor1;

  final String LOG_TAG = "myLogs";
  final String LOG_TAG1 = "myLogs1";

  /** Called when the activity is first created. */
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    // открываем подключение к БД
    db = new DBHelper(this);
    db.open();

    // Get the intent, verify the action and get the query
    Intent intent = getIntent();
    if (Intent.ACTION_SEARCH.equals(intent.getAction())) {
      String query = intent.getStringExtra(SearchManager.QUERY);
      doMySearch(query);
    }

    // получаем курсор
    cursor = db.getAllData();
    startManagingCursor(cursor);

    // Формируем столбцы сопоставления
    // Comment Tharaka String[] from = new String[] { DBHelper.COLUMN_r_name, DBHelper.COLUMN_region, DBHelper.COLUMN_code};
    // Comment Tharaka int[] to = new int[] { R.id.city_name, R.id.region_name, R.id.city_code };

    // создааем адаптер и настраиваем список
    // Comment Tharaka scAdapter = new SimpleCursorAdapter(this, R.layout.item, cursor, from, to);
    // Comment Tharaka lvData = (ListView) findViewById(R.id.listdata);
    // Comment Tharaka lvData.setAdapter(scAdapter);
  }

  public void doMySearch(String query) {
        lvData1 = (ListView) findViewById(R.id.listdata);
        //Ищем совпадения
        Log.d(LOG_TAG, "Before get the C");
        cursor1 = db.fetchRecordsByQuery(query);
        Log.d(LOG_TAG, "After get the C");
        String t = Integer.toString(cursor1.getCount());
        Log.d(LOG_TAG, t);
        startManagingCursor(cursor1);
        String[] from = new String[] { DBHelper.COLUMN_r_name, DBHelper.COLUMN_region, DBHelper.COLUMN_code};
        int[] to = new int[] { R.id.city_name, R.id.region_name, R.id.city_code };
        SimpleCursorAdapter scAdapter1;

        scAdapter = new SimpleCursorAdapter(this,
                R.layout.item, cursor1, from, to);

        //DO Tharaka
        lvData.setAdapter(scAdarpter);
        Log.d(LOG_TAG, "Setting the adapter");
        //Обновляем адаптер
        logCursor(cursor1);
        lvData1.setAdapter(scAdapter);
        Log.d(LOG_TAG, "Adapter was set");
      }

//вывод в лог данных из курсора
 void logCursor(Cursor c) {
   if (c != null) {
     if (c.moveToFirst()) {
       String str;
       do {
         str = "";
         for (String cn : c.getColumnNames()) {
           str = str.concat(cn + " = " + c.getString(c.getColumnIndex(cn)) + "; ");
         }
         Log.d(LOG_TAG1, str);
       } while (c.moveToNext());
     }
   } else
     Log.d(LOG_TAG1, "Cursor is null");
 }



     @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);

        // Associate searchable configuration with the SearchView
        SearchManager searchManager =
               (SearchManager) getSystemService(Context.SEARCH_SERVICE);
        SearchView searchView =
                (SearchView) menu.findItem(R.id.action_settings).getActionView();
        searchView.setSearchableInfo(
                searchManager.getSearchableInfo(getComponentName()));

        return true;
    }


  protected void onDestroy() {
    super.onDestroy();
    // закрываем подключение при выходе
    db.close();
  }

}

无法使用适配器更新ListView

4 个答案: