为字典应用程序创建数据库

Question

我开始学习开发Android应用程序。我想在android中开发一个本地语言字典。我的问题是如何创建一个数据库，可以存储词汇（文本），音频（发音）以及图片？提前致谢。

Answer 1

为避免出现内存问题，您可以将音频和图像文件存储在SD卡中，并将文件的名称保存到数据库中。当您需要这些文件时，只需从数据库中获取详细信息并从SD卡播放/显示。根据我的知识，这是最好的方法。

Answer 2

正常的SQLite数据库足以让你的应用程序存储诸如音频，图片等的东西。 要清楚的是，如果您要创建原生应用程序，最好使用SD卡来存储图像和音频文件，由此您可以根据需要检索文件。

Answer 3

SQLite将是一个合理的解决方案。

如果您需要连接到网络数据库，我建议在MySQL数据库托管的服务器上使用PHP脚本。

下面是什么一个SQLite数据库看起来像一些示例代码：

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 = "android_api"; 

    // Login table name 
    private static final String TABLE_LOGIN = "login"; 

    // Login Table Columns names 
    private static final String KEY_ID = "id"; 
    private static final String KEY_NAME = "name"; 
    public static final String KEY_EMAIL = "email"; 
    private static final String KEY_UID = "uid"; 
    private static final String KEY_CREATED_AT = "created_at"; 

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

    // Creating Tables 
    @Override 
    public void onCreate(SQLiteDatabase db) { 
     String CREATE_LOGIN_TABLE = "CREATE TABLE " + TABLE_LOGIN + "(" 
       + KEY_ID + " INTEGER PRIMARY KEY," 
       + KEY_NAME + " TEXT," 
       + KEY_EMAIL + " TEXT UNIQUE," 
       + KEY_UID + " TEXT," 
       + KEY_CREATED_AT + " TEXT" + ")"; 
     db.execSQL(CREATE_LOGIN_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_LOGIN); 

     // Create tables again 
     onCreate(db); 
    } 

    /** 
    * Storing user details in database 
    * */ 
    public void addUser(String name, String email, String uid, String created_at) { 
     SQLiteDatabase db = this.getWritableDatabase(); 

     ContentValues values = new ContentValues(); 
     values.put(KEY_NAME, name); // Name 
     values.put(KEY_EMAIL, email); // Email 
     values.put(KEY_UID, uid); // Email 
     values.put(KEY_CREATED_AT, created_at); // Created At 

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

    public void addUser(String email) { 
     SQLiteDatabase db = this.getWritableDatabase(); 

     ContentValues values = new ContentValues(); 
     values.put(KEY_EMAIL, email); // Email 

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

    public String getUser() { 
     SQLiteDatabase db = this.getWritableDatabase(); 
     ContentValues values = new ContentValues(); 

     String user = values.getAsString(KEY_EMAIL); 
     Log.v("DBH", user); 
     db.close(); 
     return user;   
    } 

    /** 
    * Getting user data from database 
    * */ 
    public HashMap<String, String> getUserDetails(){ 
     HashMap<String,String> user = new HashMap<String,String>(); 
     String selectQuery = "SELECT * FROM " + TABLE_LOGIN; 

     SQLiteDatabase db = this.getReadableDatabase(); 
     Cursor cursor = db.rawQuery(selectQuery, null); 
     // Move to first row 
     cursor.moveToFirst(); 
     if(cursor.getCount() > 0){ 
      user.put("name", cursor.getString(1)); 
      user.put("email", cursor.getString(2)); 
      user.put("uid", cursor.getString(3)); 
      user.put("created_at", cursor.getString(4)); 
     } 
     cursor.close(); 
     db.close(); 
     // return user 
     return user; 
    } 

    /** 
    * Getting user login status 
    * return true if rows are there in table 
    * */ 
    public int getRowCount() { 
     String countQuery = "SELECT * FROM " + TABLE_LOGIN; 
     SQLiteDatabase db = this.getReadableDatabase(); 
     Cursor cursor = db.rawQuery(countQuery, null); 
     int rowCount = cursor.getCount(); 
     db.close(); 
     cursor.close(); 

     // return row count 
     return rowCount; 
    } 

    public String returnRows() { 
     String response = ""; 
     String countQuery = "SELECT * FROM " + TABLE_LOGIN; 
     SQLiteDatabase db = this.getReadableDatabase(); 
     for (int j = 0; j < getRowCount(); j++) { 
      Cursor cursor = db.rawQuery(countQuery, null); 
      response += cursor.getColumnName(j); 
     } 
     Log.v("LT", response); 
     return response; 
    } 

    /** 
    * Re crate database 
    * Delete all tables and create them again 
    * */ 
    public void resetTables(){ 
     SQLiteDatabase db = this.getWritableDatabase(); 
     // Delete All Rows 
     db.delete(TABLE_LOGIN, null, null); 
     db.close(); 
    }