代码，错误选择表，我需要显示数据表列表视图，但要运行APP，错误到**＆＃34;没有这样的表：main（code1）:,编译时：SELECT * FROM main"**.
package sam.app.shiftroid;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import android.os.Bundle;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.Intent;
import android.content.SharedPreferences;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;
import android.database.sqlite.SQLiteOpenHelper;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListAdapter;
import android.widget.ListView;
public class MainActivity extends Activity {
//=======================database=========================
DBOpenHelper myDbHelper;
SQLiteDatabase db;
ListAdapter adapter;
ArrayList<HashMap<String, String>> data;
//=====================end =================================
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button b = (Button) findViewById(R.id.btnClose);
Button btnSave = (Button) findViewById(R.id.btnSave);
//========================== db =========================
try
{
ListView lst=(ListView) findViewById(R.id.listView1);
Load_Database();
db = myDbHelper.getReadableDatabase();
Cursor c = db.rawQuery("SELECT * FROM main", null);
data = new ArrayList<HashMap<String, String>>();
for (; c.moveToNext();) {
HashMap<String, String> map = new HashMap<String, String>();
String id = c.getString(c.getColumnIndex("a"));
String name = c.getString(c.getColumnIndex("aa"));
map.put("a", id);
map.put("aa", name);
data.add(map);
}
adapter = new list_view(this, data);
lst.setAdapter(adapter);
}
catch (SQLiteException e) {
AlertDialog.Builder dialog = new AlertDialog.Builder(MainActivity.this);
dialog.setTitle("پرکردن تکست ها");
dialog.setMessage("\n"+String.valueOf(e.toString()+"ست کردن متن"));
dialog.setIcon(R.drawable.ic_launcher);
dialog.show();
}
//====================== end ==============================
b.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
startActivity(new Intent(MainActivity.this, RegShift.class));
}
});
btnSave.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
try{
AlertDialog.Builder dialog = new AlertDialog.Builder(MainActivity.this);
dialog.setTitle("پرکردن تکست ها");
dialog.setMessage("\n"+String.valueOf("ست کردن متن"));
dialog.setIcon(R.drawable.ic_launcher);
dialog.show();
}
catch (Exception e) {
AlertDialog.Builder dialog = new AlertDialog.Builder(MainActivity.this);
dialog.setTitle("پرکردن تکست ها");
dialog.setMessage("\n"+String.valueOf(e.toString()+"ست کردن متن"));
dialog.setIcon(R.drawable.ic_launcher);
dialog.show();
}
}
});
Button b2 = (Button) findViewById(R.id.button3);
b2.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
try
{
EditText etLName = (EditText) findViewById(R.id.editText1);
Intent intent = new Intent(MainActivity.this, SaveWork.class);
intent.putExtra("lname", etLName.getText().toString());
startActivity(intent);
}
catch (Exception e) {
AlertDialog.Builder dialog = new AlertDialog.Builder(MainActivity.this);
dialog.setTitle("اموزش AlertDialog");
dialog.setMessage(e.toString());
dialog.setIcon(R.drawable.ic_launcher);
dialog.show();
}
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
private void Load_Database() throws Error {
myDbHelper = new DBOpenHelper(MainActivity.this);
try {
myDbHelper.createDataBase();
} catch (IOException ioe) {
throw new Error("Unable to create database");
}
try {
myDbHelper.openDataBase();
} catch (SQLException sqle) {
throw sqle;
}
}
}
帮帮我
答案 0 :(得分：0)
这是myDBhelper
enter code here
package sam.app.shiftroid;
public class DBOpenHelper extends SQLiteOpenHelper {
String DB_PATH = null;
public static String DB_NAME = "db_shift1";
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 DBOpenHelper(Context context) {
super(context, DB_NAME, null, 2);
this.myContext = context;
DB_PATH = "/data/data/" + context.getPackageName() + "/" + "databases/";
}
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");
}
}
}
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;
// SQLiteDatabase.NO_LOCALIZED_COLLATORS
myDataBase = SQLiteDatabase.openDatabase(myPath, null,
SQLiteDatabase.OPEN_READONLY
| SQLiteDatabase.NO_LOCALIZED_COLLATORS
| SQLiteDatabase.CREATE_IF_NECESSARY);
}
@Override
public synchronized void close() {
if (myDataBase != null)
myDataBase.close();
super.close();
}
// return cursor
public Cursor query(String table, String[] columns, String selection,
String[] selectionArgs, String groupBy, String having,
String orderBy) {
return myDataBase.query("pwp_singers", null, null, null, null, null,
null);
}
@Override
public void onCreate(SQLiteDatabase db) {
// TODO Auto-generated method stub
String CREATE_BOOK_TABLE = "CREATE TABLE main ( " +
"id INTEGER PRIMARY KEY AUTOINCREMENT, " +
"title TEXT, "+
"author TEXT )";
// create books table
db.execSQL(CREATE_BOOK_TABLE);
}
@Override
public void onUpgrade(SQLiteDatabase arg0, int arg1, int arg2) {
// TODO Auto-generated method stub
}
}