Jak przekonwertować rekordy bazy danych na plik csv w systemie Android?

Question

Witam Chcę eksportować moje dane z bazy danych w formacie CSV do mojej aplikacji na Androida. Jak mogę to zrobić? Jakieś ciało mi pomoże? Z góry dziękuję.

Answer 1

Hi zrobić tak ....

package com.my.CSVcreation; 
import java.io.File; 
import java.io.FileWriter; 
import java.io.IOException; 
import android.app.Activity; 
import android.app.ProgressDialog; 
import android.content.Context; 
import android.database.Cursor; 
import android.database.SQLException; 
import android.database.sqlite.SQLiteDatabase; 
import android.os.AsyncTask; 
import android.os.Bundle; 
import android.os.Environment; 
import android.util.Log; 
import android.view.View; 
import android.widget.Button; 
import android.widget.EditText; 
import android.widget.TextView; 
import android.widget.Toast; 

public class CSVCreationActivity extends Activity { 
    TextView empidtxt,empnametxt,empsaltxt; 
    EditText empidet,empnameet,empsalet; 
    Button insetbt,viewbt; 
    SQLiteDatabase myDatabase=null; 
    String DataBase_Name="employeedata"; 
    String Table_Name="employeedetails"; 
    Cursor c1,c2; 

    @Override 
    public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.main); 

    empidtxt=(TextView)findViewById(R.id.tv1); 
    empnametxt=(TextView)findViewById(R.id.tv2); 
    empsaltxt=(TextView)findViewById(R.id.tv3); 

    empidet=(EditText)findViewById(R.id.et1); 
    empnameet=(EditText)findViewById(R.id.et2); 
    empsalet=(EditText)findViewById(R.id.et3); 

    insetbt=(Button)findViewById(R.id.bt1); 
    viewbt=(Button)findViewById(R.id.bt2); 

    try { 
     myDatabase=this.openOrCreateDatabase(DataBase_Name, MODE_PRIVATE, null); 
     System.out.println("databse has been creates....."); 
     myDatabase.execSQL("create table if not exists " + Table_Name + "(empid integer(10),empname varchar(50),empsal integer(10))"); 
     System.out.println("table has been created....."); 
     c1 = myDatabase.rawQuery("select * from " + Table_Name, null); 
     c1.moveToFirst(); 
     int count1 = c1.getCount(); 
     System.out.println("columns --->" + count1); 
     if (count1 == 0) { 
      myDatabase.execSQL("insert into "+Table_Name+ "(empid,empname,empsal)" +"values(101,'asha',20000)"); 
      System.out.println("data base has been inserted....."); 
     } 

     c2 = myDatabase.rawQuery("select * from " + Table_Name, null); 
     c2.moveToFirst(); 
     int count2 = c2.getCount(); 
     System.out.println("columns --->" + count2); 
     final int column1 = c2.getColumnIndex("empid"); 
     final int column2 = c2.getColumnIndex("empname"); 
     final int column3 = c2.getColumnIndex("empsal"); 

     insetbt.setOnClickListener(new View.OnClickListener() {    
      @Override 
      public void onClick(View v) { 
       if (c2 != null) { 
        do { 
         int id = c2.getInt(column1); 
         String name = c2.getString(column2); 
         int salary = c2.getInt(column3); 

         System.out.println("empID --> "+id); 
         System.out.println("empNAME --> "+name); 
         System.out.println("empsalalry --> "+salary); 
        } while(c2.moveToNext()); 
       }         
      } 
     }); 

     viewbt.setOnClickListener(new View.OnClickListener() {    
      @Override 
      public void onClick(View v) { 
       try { 
        new ExportDatabaseCSVTask().execute(""); 
       } catch(Exception ex) { 
        Log.e("Error in MainActivity",ex.toString()); 
       } 
      } 
     }); 
    } 
    catch(SQLException ex) { ex.printStackTrace(); } 
    /*finally { 
     if (myDB != null) { myDB.close(); } 
    }*/ 
} 


public class ExportDatabaseCSVTask extends AsyncTask<String, Void, Boolean> { 
    private final ProgressDialog dialog = new ProgressDialog(CSVCreationActivity.this); 

    @Override 
    protected void onPreExecute() { 
     this.dialog.setMessage("Exporting database..."); 
     this.dialog.show(); 
    } 

    protected Boolean doInBackground(final String... args) { 
     File dbFile = getDatabasePath("myDatabase.db"); 
     System.out.println(dbFile); // displays the data base path in your logcat 
     File exportDir = new File(Environment.getExternalStorageDirectory(), ""); 

     if (!exportDir.exists()) { exportDir.mkdirs(); } 

     File file = new File(exportDir, "myfile.csv"); 
     try { 
      file.createNewFile(); 
      CSVWriter csvWrite = new CSVWriter(new FileWriter(file)); 
      Cursor curCSV = myDatabase.rawQuery("select * from " + Table_Name,null); 
      csvWrite.writeNext(curCSV.getColumnNames()); 
      while(curCSV.moveToNext()) { 
       String arrStr[] ={curCSV.getString(0),curCSV.getString(1),curCSV.getString(2)}; 
       // curCSV.getString(3),curCSV.getString(4)}; 
       csvWrite.writeNext(arrStr); 
      } 
      csvWrite.close(); 
      curCSV.close(); 
      return true; 
     } catch(SQLException sqlEx) { 
      Log.e("MainActivity", sqlEx.getMessage(), sqlEx); 
      return false; 
     } catch (IOException e) { 
      Log.e("MainActivity", e.getMessage(), e); 
      return false; 
     } 
    } 

    protected void onPostExecute(final Boolean success) { 
     if (this.dialog.isShowing()) { this.dialog.dismiss(); } 
     if (success) { 
      Toast.makeText(CSVCreationActivity.this, "Export successful!", Toast.LENGTH_SHORT).show(); 
     } else { 
      Toast.makeText(CSVCreationActivity.this, "Export failed", Toast.LENGTH_SHORT).show(); 
     } 
    } 
} 

I dostaniesz CsvReader i plik CSVWriter z następującej witryny https://code.google.com/p/secrets-for-android/source/checkout. Wszystkiego najlepszego.

Nie zapomnij dodać uprawnienia do pliku manifestu <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>