我已将数据库导入SQLite（testing.sqllite），这是在Firefox插件的SQLliteManager中创建的。我把它放在数据/数据// databases /.
中当我尝试从数据库中检索数据时，我遇到了运行时异常。这是我的代码......
DataBaseHelper.java
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;
import android.database.sqlite.SQLiteOpenHelper;
public class DataBaseHelper extends SQLiteOpenHelper{
public static final String KEY_ROWID = "keyno";
public static final String DESTINATION = "Destination";
public static final String CITY = "City";
public static final String COUNTRY = "Country";
public static final String IMG1 = "Img1";
//The Android's default system path of your application database.
private static String DB_PATH = "/data/data/com.world.destinations/databases/";
private static String DB_NAME = "testing";
private static String DATABASE_TABLE = "Master";
private DataBaseHelper ourHelper;
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;
}
public DataBaseHelper open() throws SQLiteException {
ourHelper = new DataBaseHelper(myContext);
myDataBase = ourHelper.getWritableDatabase();
return this;
}
/**
* 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) {
}
public String getData() {
// TODO Auto-generated method stub
String[] columns = new String[]{KEY_ROWID, DESTINATION, CITY, COUNTRY, PERIOD, TYPE, CURRENCY, ELEVATION, BRIEF, HIGHLIGHTS, IMG_MAIN};
Cursor c = myDataBase.query(DATABASE_TABLE, columns, null, null, null, null, null);
String result = "";
int iRow = c.getColumnIndex(KEY_ROWID);
int iName = c.getColumnIndex(DESTINATION);
int iCity = c.getColumnIndex(CITY);
int iCountry = c.getColumnIndex(COUNTRY);
int iImgmain = c.getColumnIndex(IMG1);
for(c.moveToFirst(); !c.isAfterLast(); c.moveToNext()){
result = result + c.getString(iRow) + " " + c.getString(iName) + " " + c.getString(iCity) + " " + c.getString(iCountry) + " " + c.getString(iImgmain) + "\n";
}
return result;
}
}
这是我的 ShowData.java
import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;
public class ShowData extends Activity{
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
this.setContentView(R.layout.showdata);
TextView tv = (TextView)findViewById(R.id.textView1);
DataBaseHelper info = new DataBaseHelper(this);
info.open();
String data = info.getData();
info.close();
tv.setText(data);
}
}
这是例外......
11-14 20:19:29.099: E/AndroidRuntime(933): FATAL EXCEPTION: main
11-14 20:19:29.099: E/AndroidRuntime(933): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.world.destinations/com.world.destinations.ShowData}: android.database.sqlite.SQLiteException: no such table: Master (code 1): , while compiling: SELECT keyno, Destination, City, Country, Img_Main FROM Master
11-14 20:19:29.099: E/AndroidRuntime(933): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2059)
11-14 20:19:29.099: E/AndroidRuntime(933): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084)
11-14 20:19:29.099: E/AndroidRuntime(933): at android.app.ActivityThread.access$600(ActivityThread.java:130)
11-14 20:19:29.099: E/AndroidRuntime(933): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195)
11-14 20:19:29.099: E/AndroidRuntime(933): at android.os.Handler.dispatchMessage(Handler.java:99)
11-14 20:19:29.099: E/AndroidRuntime(933): at android.os.Looper.loop(Looper.java:137)
11-14 20:19:29.099: E/AndroidRuntime(933): at android.app.ActivityThread.main(ActivityThread.java:4745)
11-14 20:19:29.099: E/AndroidRuntime(933): at java.lang.reflect.Method.invokeNative(Native Method)
11-14 20:19:29.099: E/AndroidRuntime(933): at java.lang.reflect.Method.invoke(Method.java:511)
11-14 20:19:29.099: E/AndroidRuntime(933): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
有人可以在我出错的地方帮助我。非常感激。感谢。
答案 0 :(得分：0)
您正在尝试查询空数据库。
从堆栈跟踪：
SQLiteException：没有这样的表：Master（代码1）:,同时编译：SELECT keyno，Destination，City，Country，Img_Main FROM Master
我的猜测是你把文件放在sd卡上的错误目录中，而SQLite在其他地方创建了一个空数据库。