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我想在Android應用程序中引用SQLite數據庫文件。我將它從eclipse推到模擬器上的SDcard中,然後運行安裝在手機內存中的應用程序。該代碼用於基於查詢的數據檢索。在Android模擬器上從SDcard讀數據庫
我正在使用下面的類文件。
public class ExternalStorageReadOnlyOpenHelper {
private SQLiteDatabase database;
private File dbFile;
private SQLiteDatabase.CursorFactory factory;
public static final String KEY_ROWID1= "_id";
public static final String KEY_num1= "num1";
public static final String KEY_words1 = "words1";
private static final String DATABASE_TABLE1 = "dictionary";
public ExternalStorageReadOnlyOpenHelper(
String dbFileName) {
// this.factory = factory;
if (!Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
throw new AndroidRuntimeException(
"External storage (SD-Card) not mounted");
}
File appDbDir = new File(
Environment.getExternalStorageDirectory(),
"SMSconfApp1");
if (!appDbDir.exists()) {
appDbDir.mkdirs();
}
this.dbFile = new File(appDbDir, dbFileName);
}
public boolean databaseFileExists() {
return dbFile.exists();
}
private void open() {
if (dbFile.exists()) {
database = SQLiteDatabase.openDatabase(
dbFile.getAbsolutePath(),
factory,
SQLiteDatabase.OPEN_READONLY);
}
}
public void close() {
if (database != null) {
database.close();
database = null;
}
}
public SQLiteDatabase getReadableDatabase() {
return getDatabase();
}
private SQLiteDatabase getDatabase() {
if (database==null) {
open();
}
return database;
}
public String getID(String pqr, SQLiteDatabase db) throws SQLException
{
String data="";
Cursor mCursor =
db.query(true, DATABASE_TABLE1, new String[] {
KEY_ROWID1,
KEY_num1,
KEY_words1
},
KEY_words1 + "=?",
new String[]{pqr},
null,
null,
null,
null);
if (mCursor != null) {
mCursor.moveToFirst();
if (mCursor.moveToFirst()){
do{
data = mCursor.getString(1);
// do what ever you want here
}while(mCursor.moveToNext());
}
mCursor.close();
}
return data;
}
}
我的活動如下:
public class SDcardDemo extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
TextView tv= new TextView(this);
setContentView(R.layout.main);
SQLiteDatabase db;
String DBFile="SMSconfApp1";
String number=null;
// ExternalStorageReadOnlyOpenHelper.open();
ExternalStorageReadOnlyOpenHelper obj= new ExternalStorageReadOnlyOpenHelper(DBFile);
if(obj.databaseFileExists())
{
db=obj.getReadableDatabase();
number=obj.getID("hi", db);
obj.close();
}
tv.setText(number);
setContentView(tv);
}
}
當我運行它不會顯示從數據庫檢索的任何應用程序。我沒有看到代碼中出了什麼問題。任何幫助?
您是否看到任何異常在 db = obj.getReadableDatabase(); ? – 2011-03-22 06:50:23
@Shamit Verma:抱歉,遲到的答覆.. M仍然不是很適合eclipse中的調試應用程序。但是,我做了它,我可以得到它的問題,如果(obj.databaseFileExists()) – 2011-03-22 17:43:34
@Shamit Verma:這種情況變得錯誤。控制cuming出循環。 appdbdir = \ MNT \ SD卡\ SMSconfApp1。 – 2011-03-22 17:46:59