Android數(shù)據(jù)庫SD卡創(chuàng)建和圖片存取操作

import android.content.Context; 
import android.database.sqlite.SQLiteDatabase; 
import android.database.sqlite.SQLiteOpenHelper; 
import android.util.Log; 
 
/** 
 * 此類繼承了SQLiteOpenHelper抽象類，是一個(gè)輔助器類，需要 一個(gè)構(gòu)造函數(shù)和重寫兩個(gè)方法。 
 * 
 */ 
public class MySQLiteOpenHelper extends SQLiteOpenHelper { 
  public static final String DATABASE_NAME = "text.db"; // 數(shù)據(jù)庫名 
  public static final int VERSION = 1; // 版本號(hào) 
  public static final String TABLE_NAME = "text"; // 表名 
  public static final String ID = "id"; 
  public static final String IMAGE = "image"; 
 
  public MySQLiteOpenHelper(Context context) { 
    super(context, DATABASE_NAME, null, VERSION); 
  } 
 
  /** 
   * 在數(shù)據(jù)庫第一次生成的時(shí)候會(huì)調(diào)用這個(gè)方法，同時(shí)我們?cè)谶@個(gè)方法里邊生成數(shù)據(jù)庫表 
   */ 
  @Override 
  public void onCreate(SQLiteDatabase db) { 
    // 創(chuàng)建數(shù)據(jù)表的操作 
    String strSQL = "CREATE TABLE " + TABLE_NAME + "(" + ID 
        + " INTEGER PRIMARY KEY AUTOINCREMENT," + IMAGE + " blob not null );"; 
 
    db.execSQL(strSQL); 
  } 
 
  /** 
   * 更新或者升級(jí)數(shù)據(jù)庫的時(shí)候會(huì)自動(dòng)調(diào)用這個(gè)方法，一般我們會(huì)在這個(gè)方法中 刪除數(shù)據(jù)表，然后再創(chuàng)建新的數(shù)據(jù)表操作。 
   */ 
  @Override 
  public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { 
    Log.e("AndyDemo", "onUpgrade"); 
  } 
} 

private Button btn_newTable, btn_addOne, get_Image; 
private TextView tv; 
private ImageView showimage; 
private MySQLiteOpenHelper myOpenHelper; 
private SQLiteDatabase sqlitedb; 
private File path = new File("sdcard/text"); // 數(shù)據(jù)庫文件目錄 
private File f = new File("sdcard/text/text.db"); // 數(shù)據(jù)庫文件 
 
@Override 
public void onCreate(Bundle savedInstanceState) { 
  super.onCreate(savedInstanceState); 
  setContentView(R.layout.main); 
 
  init(); 
 
  // 實(shí)例化默認(rèn)數(shù)據(jù)庫輔助操作對(duì)象 
  myOpenHelper = new MySQLiteOpenHelper(this); 
 
  // SD卡中創(chuàng)建數(shù)據(jù)庫文件 
  if (!path.exists()) { // 判斷目錄是否存在 
    path.mkdirs(); // 創(chuàng)建目錄 
  } 
  if (!f.exists()) { // 判斷文件是否存在 
    try { 
      f.createNewFile(); // 創(chuàng)建文件 
    } catch (IOException e) { 
      e.printStackTrace(); 
    } 
  } 
} 
 
/** 
 * 初始化UI界面 
 */ 
private void init() { 
  tv = (TextView) findViewById(R.id.tv_result); 
  btn_newTable = (Button) findViewById(R.id.newTable); 
  btn_addOne = (Button) findViewById(R.id.addOne); 
  get_Image = (Button) findViewById(R.id.getimage); 
  showimage = (ImageView) findViewById(R.id.showimage); 
  btn_newTable.setOnClickListener(new ClickEvent()); 
  btn_addOne.setOnClickListener(new ClickEvent()); 
  get_Image.setOnClickListener(new ClickEvent()); 
 
} 
 
class ClickEvent implements OnClickListener { 
  @Override 
  public void onClick(View v) { 
    try { 
      // SD卡中創(chuàng)建數(shù)據(jù)庫，實(shí)例化sqlitedb的操作如下 
      sqlitedb = SQLiteDatabase.openOrCreateDatabase(f, null); 
      if (v == btn_newTable) { // 1.新建數(shù)據(jù)表 
        String TABLE_NAME = "text"; 
        String ID = "id"; 
        String IMAGE = "image"; 
        String str_sql2 = "CREATE TABLE " + TABLE_NAME + "(" + ID 
            + " INTEGER PRIMARY KEY AUTOINCREMENT," + IMAGE 
            + " blob not null );"; 
        sqlitedb.execSQL(str_sql2); 
        tv.setText("新建數(shù)據(jù)表成功!"); 
 
      } else if (v == btn_addOne) { // 2.插入一條記錄 
        ContentValues values = new ContentValues(); 
        values.put( 
            MySQLiteOpenHelper.IMAGE, 
            drawableChange(getResources().getDrawable( 
                R.drawable.ic_launcher))); 
        sqlitedb.insert(MySQLiteOpenHelper.TABLE_NAME, null, values); 
        tv.setText("添加新數(shù)據(jù)成功!"); 
      } else if (v == get_Image) { 
        Cursor c = sqlitedb.rawQuery("select * from text", null); 
        c.moveToLast(); 
 
        if (c.isLast()) { 
          byte[] blob = c.getBlob(c 
              .getColumnIndex(MySQLiteOpenHelper.IMAGE)); 
          Bitmap bmp = BitmapFactory.decodeByteArray(blob, 0, 
              blob.length); 
          showimage.setImageBitmap(bmp); 
        } 
        c.close(); 
      } 
    } catch (Exception e) { 
      tv.setText("操作失敗"); 
    } finally { 
      sqlitedb.close(); 
    } 
  } 
} 
 
/** 
 * drawable轉(zhuǎn)化成字節(jié)數(shù)組 
 * 
 * @param drawable 
 * @return 
 */ 
private byte[] drawableChange(Drawable drawable) { 
 
  Bitmap bm = ((BitmapDrawable) drawable).getBitmap(); 
  ByteArrayOutputStream baos = new ByteArrayOutputStream(); 
  bm.compress(Bitmap.CompressFormat.PNG, 100, baos); 
  byte[] date = baos.toByteArray(); 
  return date; 
} 

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" /> 
<uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/>