在Android应用程序读取从SQLite数据库的数据。 [英] Reading data from Sqlite Database in android application.

问题描述

我试图从数据库中读取数据。我在 sqlite的手动导入数据库，现在只想连接在Android应用程序制成，想读的行，并在文本字段显示它们，然而$ C $三我现在用每次要么是使数据库的新的或在该数据库再次创建表，我得到一个运行时错误。

I am trying to read data from a database. I imported the database in the sqlite manually and now just want the connection made in android application and want to read the rows and display them in the text fields, however the code I am using is either making the database new every time or is creating the table again in that database and I get a run time error.

我的code是：

    package com.example.dbexample;

    import java.util.ArrayList;
    import java.util.List;

    import android.content.ContentValues;
    import android.content.Context;
    import android.database.Cursor;
    import android.database.sqlite.SQLiteDatabase;
    import android.database.sqlite.SQLiteOpenHelper;

public class DatabaseHandler extends SQLiteOpenHelper {

    // All Static variables
    // Database Version
    private static final int DATABASE_VERSION = 1;

    // Database Name
    private static final String DATABASE_NAME = "TranslatesManager";

    // Translates table name
    private static final String TABLE_TRANSLATOR = "Words";

    // Translates Table Columns names
    private static final String KEY_ID = "id";
    private static final String KEY_ENGLISHNAME = "Englishname";
    private static final String KEY_URDUNAME = "Urduname";

    public DatabaseHandler(Context context) {
       super(context, DATABASE_NAME, null, DATABASE_VERSION);
    }

    // Creating Tables
    @Override
    public void onCreate(SQLiteDatabase db) {
  /*  String CREATE_TranslateS_TABLE = "CREATE TABLE " + TABLE_TRANSLATOR + "("
               + KEY_ID + " INTEGER PRIMARY KEY," + KEY_ENGLISHNAME + " TEXT,"
               + KEY_URDUNAME + " TEXT" + ")";
      db.execSQL(CREATE_TranslateS_TABLE);
    */
    }

    // Upgrading database
    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        // Drop older table if existed
        // db.execSQL("DROP TABLE IF EXISTS " + TABLE_TRANSLATOR);
        // Create tables again
        //onCreate(db);
    }

 // Adding new Translate
    void addTranslate(Translate Translate) {
        SQLiteDatabase db = this.getWritableDatabase();

        ContentValues values = new ContentValues();
        values.put(KEY_ENGLISHNAME, Translate.getName()); // Translate Name
        values.put(KEY_URDUNAME, Translate.getUrduName()); // Translate Phone

        // Inserting Row
        db.insert(TABLE_TRANSLATOR, null, values);
        db.close(); // Closing database connection
    }

    // Getting single Translate
    Translate getTranslate(int id) {
        SQLiteDatabase db = this.getReadableDatabase();

        Cursor cursor = db.query(TABLE_TRANSLATOR, new String[] { KEY_ID,
                KEY_ENGLISHNAME, KEY_URDUNAME }, KEY_ID + "=?",
                new String[] { String.valueOf(id) }, null, null, null, null);
        if (cursor != null)
            cursor.moveToFirst();

        Translate Translate = new Translate(Integer.parseInt
               (cursor.getString(0)),cursor.getString(1), cursor.getString(2));
        // return Translate
        return Translate;
    }

    // Getting All Translates
    public List<Translate> getAllTranslates() {
        List<Translate> TranslateList = new ArrayList<Translate>();
        // Select All Query
        String selectQuery = "SELECT  * FROM " + TABLE_TRANSLATOR;

        SQLiteDatabase db = this.getWritableDatabase();
        Cursor cursor = db.rawQuery(selectQuery, null);

        // looping through all rows and adding to list
        if (cursor.moveToFirst()) {
            do {
                Translate Translate = new Translate();
                Translate.setID(Integer.parseInt(cursor.getString(0)));
                Translate.setName(cursor.getString(1));
                Translate.setUrduName(cursor.getString(2));
                // Adding Translate to list
                TranslateList.add(Translate);
            } while (cursor.moveToNext());
        }

        // return Translate list
        return TranslateList;
    }

    // Updating single Translate
    public int updateTranslate(Translate Translate) {
        SQLiteDatabase db = this.getWritableDatabase();

        ContentValues values = new ContentValues();
        values.put(KEY_ENGLISHNAME, Translate.getName());
        values.put(KEY_URDUNAME, Translate.getUrduName());

        // updating row
        return db.update(TABLE_TRANSLATOR, values, KEY_ID + " = ?",
                new String[] { String.valueOf(Translate.getID()) });
    }

    // Deleting single Translate
    public void deleteTranslate(Translate Translate) {
        SQLiteDatabase db = this.getWritableDatabase();
        db.delete(TABLE_TRANSLATOR, KEY_ID + " = ?",
                new String[] { String.valueOf(Translate.getID()) });
        db.close();
    }

    // Getting Translates Count
    public int getTranslatesCount() {
        String countQuery = "SELECT  * FROM " + TABLE_TRANSLATOR;
        SQLiteDatabase db = this.getReadableDatabase();
        Cursor cursor = db.rawQuery(countQuery, null);
        cursor.close();

        // return count
        return cursor.getCount();
    }
    }

译者是类。
它只有ID，英文名，urduname领域。

Translator is the class. It has just id, englishname, urduname fields.

请更正此文件或发现错误，让我知道如何刚刚从<$ ​​C $ C> sqlLiteDatabase 读文本框。

Please correct this file or find error so that I know how to just read from sqlLiteDatabase to text boxes.

我的主要活动code是：

my main activity code is :

    protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main_db);
    DatabaseHandler db = new DatabaseHandler(this);             
      // Inserting Translates
          ///  Log.d("Insert: ", "Inserting ..");
    //db.addTranslate(new Translate("Ravi", "9100000000"));
    //db.addTranslate(new Translate("Srinivas", "9199999999"));
    //db.addTranslate(new Translate("Tommy", "9522222222"));
    //db.addTranslate(new Translate("Karthik", "9533333333"));

    // Reading all Translates
    Log.d("Reading: ", "Reading all Translates..");
    List<Translate> Translates = db.getAllTranslates();       

    for (Translate cn : Translates) {
        String log = "Id: "+cn.getID()+" ,Name: " + cn.getName() +
                                                  " ,Phone: " + cn.getUrduName();
            // Writing Translates to log
    Log.d("Name: ", log);
     }
    TextView t1 = (TextView) findViewById(R.id.textView1);
    TextView t2 = (TextView) findViewById(R.id.textView4);
    TextView t3 = (TextView) findViewById(R.id.textView3);

    for (Translate cn : Translates)
    {
        t1.setText(Integer.toString(cn.getID()));
        t2.setText(cn.getName());
        t3.setText(cn.getUrduName());
    }

}

让我知道问题出在哪里吧。

Let me know where the problem is please.

推荐答案

这里的'圣杯'上使用自己的数据库：的http://www.reigndesign.com/blog/using-your-own-sqlite-database-in-android-applications/

Here's the 'Holy Grail' on using your own db : http://www.reigndesign.com/blog/using-your-own-sqlite-database-in-android-applications/

这篇关于在Android应用程序读取从SQLite数据库的数据。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！