java - 如何在 Android 中使用 My Sqlite 数据库

Question

我在我的应用程序中使用数据库，但我在 SQLite 浏览器中创建数据库，并在我的应用程序中按照此 link 的指南进行了尝试。 ，当我尝试在 Eclipse 中将项目运行到我的手机时，我的应用程序成功调用数据库，但在另一种情况下，我尝试从 Android 中的文件夹 bin 复制我的 apk 应用程序并安装它。当我安装 apk 文件时，我的应用程序错误无法调用数据库..并且再也不会调用数据库..请帮助我..在这里感谢我的代码:

DataBaseHelper.java

public class DataBaseHelper extends SQLiteOpenHelper{

    //The Android's default system path of your application database.
    private static String DB_PATH = "/data/data/com.apps.visitkuningan/databases/";

    private static String DB_NAME = "db_keterangan.sqlite3";

    private SQLiteDatabase myDataBase; 

    private final Context myContext;

    /**
     * Constructor
     * Takes and keeps a reference of the passed context in order to access to the application assets and resources.
     * @param context
     */
    public DataBaseHelper(Context context) {

        super(context, DB_NAME, null, 1);
        this.myContext = context;
    }   

  /**
     * Creates a empty database on the system and rewrites it with your own database.
     * */
    public void createDataBase() throws IOException{

        boolean dbExist = checkDataBase();

        if(dbExist){
            //do nothing - database already exist
        }else{

            //By calling this method and empty database will be created into the default system path
               //of your application so we are gonna be able to overwrite that database with our database.
            this.getReadableDatabase();

            try {

                copyDataBase();

            } catch (IOException e) {

                throw new Error("Error copying database");

            }
        }

    }

    /**
     * Check if the database already exist to avoid re-copying the file each time you open the application.
     * @return true if it exists, false if it doesn't
     */
    private boolean checkDataBase(){

        SQLiteDatabase checkDB = null;

        try{
            String myPath = DB_PATH + DB_NAME;
            checkDB = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);

        }catch(SQLiteException e){

            //database does't exist yet.

        }

        if(checkDB != null){

            checkDB.close();

        }

        return checkDB != null ? true : false;
    }

    /**
     * Copies your database from your local assets-folder to the just created empty database in the
     * system folder, from where it can be accessed and handled.
     * This is done by transfering bytestream.
     * */
    private void copyDataBase() throws IOException{

        //Open your local db as the input stream
        InputStream myInput = myContext.getAssets().open(DB_NAME);

        // Path to the just created empty db
        String outFileName = DB_PATH + DB_NAME;

        //Open the empty db as the output stream
        OutputStream myOutput = new FileOutputStream(outFileName);

        //transfer bytes from the inputfile to the outputfile
        byte[] buffer = new byte[1024];
        int length;
        while ((length = myInput.read(buffer))>0){
            myOutput.write(buffer, 0, length);
        }

        //Close the streams
        myOutput.flush();
        myOutput.close();
        myInput.close();

    }

    public void openDataBase() throws SQLException{

        //Open the database
        String myPath = DB_PATH + DB_NAME;
        myDataBase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);

    }

    @Override
    public synchronized void close() {

            if(myDataBase != null)
                myDataBase.close();

            super.close();

    }

    @Override
    public void onCreate(SQLiteDatabase db) {

    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

    }

        // Add your public helper methods to access and get content from the database.
       // You could return cursors by doing "return myDataBase.query(....)" so it'd be easy
       // to you to create adapters for your views.

}

这是使用查询的代码:

public class KetWisata extends Activity{
    Intent arah;
    String tampilarah;
    String tempat;
    Bundle bundel2 = new Bundle();
    Cursor cur;
    Cursor cur2;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        this.requestWindowFeature(Window.FEATURE_NO_TITLE);
        setContentView(R.layout.ket_data);
        String tampil = getIntent().getExtras().getString("key");
        ImageView img1 = (ImageView) findViewById(R.id.gambar);
        TextView nama = (TextView) findViewById(R.id.nama);
        TextView alamat = (TextView) findViewById(R.id.alamat);
        TextView keterangan = (TextView) findViewById(R.id.keterangan);
        Button arahkan = (Button) findViewById(R.id.arahkan);

        // Create the database
        DataBaseHelper myDbHelper = new DataBaseHelper(
                this.getApplicationContext());
        myDbHelper = new DataBaseHelper(this);
        SQLiteDatabase db = myDbHelper.getReadableDatabase();           
        arahkan.setOnClickListener(new OnClickListener() {  
            @Override
            public void onClick(View arg0) {
                startActivity(arah);
            }
        });

        if(tampil.equalsIgnoreCase("wis_balongdalem"))
         {
            img1.setBackgroundResource(R.drawable.wis_balong);
            nama.setText("Balong Dalem");
            tempat="Balong Dalem";
            tampilarah ="Balong Dalem";     
         }
         if(tampil.equalsIgnoreCase("wis_curugbangkong"))
         { 
            img1.setBackgroundResource(R.drawable.wis_bangkong);
            nama.setText("Curug Bangkong");
            tempat="Curug Bangkong";
            tampilarah ="Curug Bangkong";   

         }
         if(tampil.equalsIgnoreCase("wis_buperciberem"))
         {
            img1.setBackgroundResource(R.drawable.wis_ciberem);
            nama.setText("Bumi Perkemahan Cibeureum");
            tempat="Bumi Perkemahan Cibeureum";
            tampilarah ="Bumi Perkemahan Cibeureum";    

         }
         if(tampil.equalsIgnoreCase("wis_cibulan"))
         {
            img1.setBackgroundResource(R.drawable.wis_cibulan);
            nama.setText("Wisata Cibulan");
            tempat="Cibulan";
            tampilarah ="Cibulan";  
         }
         if(tampil.equalsIgnoreCase("wis_balongcicerem"))
         { 
            img1.setBackgroundResource(R.drawable.wis_situ);
            nama.setText("Situ Cicereum");
            tempat="Situ Ciceureum";
            tampilarah ="Situ Ciceureum";   
         }
         if(tampil.equalsIgnoreCase("wis_balongcigugur"))
         {
             img1.setBackgroundResource(R.drawable.wis_cigugur);
             nama.setText("Wisata Cigugur");
             tempat="Wisata Cigugur";
             tampilarah ="Wisata Cigugur";  
         }
         if(tampil.equalsIgnoreCase("wis_curugcilengkrang"))
         {
             img1.setBackgroundResource(R.drawable.wis_cilengkrang3);
             nama.setText("Lembah Cilengkrang");
             tempat="Lembah Cilengkrang";
             tampilarah ="Lembah Cilengkrang";  
         }
         if(tampil.equalsIgnoreCase("wis_cipari"))
         {           
             img1.setBackgroundResource(R.drawable.wis_cipari2);
             nama.setText("Taman Purbakala Cipari");
             tempat="Taman Purbakala Cipari";
             tampilarah ="Taman Purbakala Cipari";  
         }
         if(tampil.equalsIgnoreCase("wis_balongdarmaloka"))
         {           
             img1.setBackgroundResource(R.drawable.wis_darmaloka2);
             nama.setText("Balong Darmaloka");
             tempat="Balong Darmaloka";
             tampilarah ="Balong Darmaloka";    
         }
         if(tampil.equalsIgnoreCase("wis_linggarjati"))
         {
             img1.setBackgroundResource(R.drawable.wis_linggarjat2i);
             nama.setText("Linggarjati Indah");
             tempat="Linggarjati Indah";
             tampilarah ="Linggarjati Indah";   
         }
         if(tampil.equalsIgnoreCase("wis_guamaria"))
         {
             img1.setBackgroundResource(R.drawable.wis_guamaria);
             nama.setText("Gua Maria");
             tempat="Gua Maria";
             tampilarah ="Gua Maria";   
         }
         if(tampil.equalsIgnoreCase("wis_gedungnaskah"))
         {
             img1.setBackgroundResource(R.drawable.wis_muslinggar2);
             nama.setText("Gedung Perundingan Linggarjati");
             tempat="Gedung Perundingan Linggarjati";
             tampilarah ="Gedung Perundingan Linggarjati";  
         }
         if(tampil.equalsIgnoreCase("wis_buperpalutungan"))
         {
             img1.setBackgroundResource(R.drawable.wis_palutungan2);
             nama.setText("Bumi Perkemahan Palutungan");
             tempat="Bumi Perkemahan Palutungan";
             tampilarah ="Bumi Perkemahan Palutungan";  
         }
         if(tampil.equalsIgnoreCase("wis_buperpaniis"))
         {
             img1.setBackgroundResource(R.drawable.wis_paniis2);
             nama.setText("Bumi Perkemahan Paniis");
             tempat="Bumi Perkemahan Paniis";
             tampilarah ="Bumi Perkemahan Paniis";  
         }
         if(tampil.equalsIgnoreCase("wis_paseban"))
         {
             img1.setBackgroundResource(R.drawable.wis_paseban);
             nama.setText("Gedung Merapat Lima");
             tempat="Gedung Merapat Lima";
             tampilarah ="Gedung Merapat Lima"; 
         }
         if(tampil.equalsIgnoreCase("wis_makamvanbeck"))
         {
             img1.setBackgroundResource(R.drawable.wis_makamvanbeck);
             nama.setText("Situs Makam Van Beck");
             tempat="Situs Makam Van Beck";
             tampilarah ="Situs Makam Van Back";    
         }       
         if(tampil.equalsIgnoreCase("wis_sanggariang"))
         {
             img1.setBackgroundResource(R.drawable.wis_sanggariang2);
             nama.setText("Sanggariang");
             tempat="Sanggariang";
             tampilarah ="Sanggariang"; 
         }       
         if(tampil.equalsIgnoreCase("wis_sangkanurip"))
         {
             img1.setBackgroundResource(R.drawable.wis_sangkanurip);
             nama.setText("Sangkanurip Alami");
             tempat="Sangkanurip Alami";
             tampilarah ="Sangkanurip Alami";   
         }       
         if(tampil.equalsIgnoreCase("wis_curugsidomba"))
         {
             img1.setBackgroundResource(R.drawable.wis_sidomba2);
             nama.setText("Sidomba");
             tempat="Sidomba";
             tampilarah ="Sidomba"; 
         }      
         if(tampil.equalsIgnoreCase("wis_talagaremis"))
         {
             img1.setBackgroundResource(R.drawable.wis_talagaremis2);
             nama.setText("Talagaremis");
             tempat="Talagaremis";
             tampilarah ="Talagaremis"; 
         }   
         if(tampil.equalsIgnoreCase("wis_tngc"))
         {
             img1.setBackgroundResource(R.drawable.wis_tngc);
             nama.setText("Taman Nasional Gunung Ciremai");
             tempat="Taman Nasional Gunung Ciremai";
             tampilarah ="Taman Nasional Gunung Ciremai";   
         }       
         if(tampil.equalsIgnoreCase("wis_wadukdarma"))
         {
             img1.setBackgroundResource(R.drawable.wis_waduk);
             nama.setText("Waduk Darma");
             tempat="Waduk Darma";
             tampilarah ="Waduk Darma"; 
         }       
         if(tampil.equalsIgnoreCase("wis_tirtaagung"))
         {
             img1.setBackgroundResource(R.drawable.wis_tirtaagung);
             nama.setText("Tirta Agung Mas");
             tempat="Tirta Agung Mas";
             tampilarah ="Tirta Agung Mas"; 
         }       
         if(tampil.equalsIgnoreCase("wis_sangkanaqua"))
         {
             img1.setBackgroundResource(R.drawable.wis_sangkanaqua);
             nama.setText("Sangkan Resort Aqua Park");
             tempat="Sangkan Resort Aqua Park";
             tampilarah ="Sangkan Resort Aqua Park";    
         }       
         if(tampil.equalsIgnoreCase("wis_talaganilem"))
         {
             img1.setBackgroundResource(R.drawable.wis_talaganilem);
             nama.setText("Talaga Nilem");
             tempat="Talaga Nilem";
             tampilarah ="Talaga Nilem";    
         }
          cur = db.rawQuery("SELECT keterangan FROM KETERANGAN_WIS WHERE nama_tempat='"  + tempat +  "';", null);
          cur2 = db.rawQuery("SELECT alamat FROM KETERANGAN_WIS WHERE nama_tempat='"  + tempat +  "';", null);
          cur.moveToPosition(0);
          cur2.moveToPosition(0);
          keterangan.append(cur.getString(0));
          alamat.append(cur2.getString(0));
            // Close
          myDbHelper.close();

         bundel2.putString("key", tampilarah);
         arah = new Intent(KetWisata.this, Arahkan.class); 
         arah.putExtras(bundel2);
    }


}

请大家帮帮我..!!

Answer 1

当您从 eclipse 运行到手机时，它将在将其部署到手机之前执行构建。因此，将数据库放入 Assets 后，请在从 bin 复制 apk 文件之前执行构建，否则您将复制在复制数据库之前构建的 apk 文件