我有一个使用 SQLiteBrowser 创建的数据库，并且我已将此文件复制到 assets 文件夹中。我在数据库中有 1 个表。该表有 2 列 id 和 desc。
我用于执行此操作的代码是
package com.example.ccc;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.HashMap;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;
public class DataBaseHelper extends SQLiteOpenHelper {
//The Android's default system path of your application database.
private static String DB_PATH = "/data/data/com.example.ccc/databases/";
private static String DB_NAME = "db";
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();
copyDataBase();
}
}
/**
* 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;
}
/**
* 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()
{
Log.i("Database", "New database is being copied to device!");
byte[] buffer = new byte[1024];
OutputStream myOutput = null;
int length;
// Open your local db as the input stream
InputStream myInput = null;
try
{
myInput = myContext.getAssets().open(DB_NAME);
// transfer bytes from the inputfile to the
// outputfile
myOutput = new FileOutputStream(DB_PATH + DB_NAME);
while((length = myInput.read(buffer)) > 0)
{
myOutput.write(buffer, 0, length);
}
myOutput.close();
myOutput.flush();
myInput.close();
Log.i("Database", "New database has been copied to device!");
//cmn.mailDetails();
}
catch(IOException e)
{
e.printStackTrace();
}
}
protected Boolean openDataBase()
{
if(checkDataBase())
{
// Open the database
String myPath = DB_PATH + DB_NAME;
try
{
Log.i("Database", "Trying to Open Database!");
if(myDataBase != null)
{
if(!myDataBase.isOpen())
{
Log.i("Database", "Database is closed now opening it!");
myDataBase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READWRITE);
}
else
{
Log.i("Database", "Database is already Open!");
}
Log.i("Database", "Database is Opened successfully in OPEN_READWRITE Mode !");
return true;
}
else
{
myDataBase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READWRITE);
Log.i("Database", "Database is Opened successfully in OPEN_READWRITE Mode !");
return true;
}
}
catch(Exception e)
{
Log.e("Database", "Some error occured while opening Database Error:" + e.getMessage());
myDataBase = null;
return false;
}
}
else
{
copyDataBase();
}
return false;
}
@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 getT(int id)
{
Cursor c = myDataBase.rawQuery("SELECT * FROM TotList WHERE id = '"+id+"'", null);
//Cursor c = myDataBase.rawQuery("SELECT * FROM TotList WHERE id = ?", new String[] {id});
c.moveToFirst();
String s=c.getString(c.getColumnIndex("desc"));
return s;
}
}
在我的活动中，我试图调用 getT() 并显示指定 id 的列内容。为此，我使用的代码是
package com.example.ccc;
import java.io.IOException;
import android.os.Bundle;
import android.app.Activity;
import android.database.SQLException;
import android.view.Menu;
import android.widget.TextView;
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
TextView tv=(TextView)findViewById(R.id.textView1);
DataBaseHelper myDbHelper = new DataBaseHelper(this);
try {
myDbHelper.createDataBase();
} catch (IOException ioe) {
throw new Error("Unable to create database");
}
try {
myDbHelper.openDataBase();
}catch(SQLException sqle){
throw sqle;
}
String s=myDbHelper.getT(1);
tv.setText(s);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
应用程序停止运行并出现以下错误。
10-22 15:12:49.086: E/SQLiteLog(885): (14) cannot open file at line 30176 of [00bb9c9ce4]
10-22 15:12:49.152: E/SQLiteLog(885): (14) os_unix.c:30176: (2) open(/data/data/com.example.ccc/databases/db) -
10-22 15:12:49.388: E/SQLiteDatabase(885): Failed to open database '/data/data/com.example.ccc/databases/db'.
10-22 15:12:49.388: E/SQLiteDatabase(885): android.database.sqlite.SQLiteCantOpenDatabaseException: unknown error (code 14): Could not open database
10-22 15:12:49.388: E/SQLiteDatabase(885): at android.database.sqlite.SQLiteConnection.nativeOpen(Native Method)
10-22 15:12:49.388: E/SQLiteDatabase(885): at android.database.sqlite.SQLiteConnection.open(SQLiteConnection.java:209)
10-22 15:12:49.388: E/SQLiteDatabase(885): at android.database.sqlite.SQLiteConnection.open(SQLiteConnection.java:193)
10-22 15:12:49.388: E/SQLiteDatabase(885): at android.database.sqlite.SQLiteConnectionPool.openConnectionLocked(SQLiteConnectionPool.java:463)
10-22 15:12:49.388: E/SQLiteDatabase(885): at android.database.sqlite.SQLiteConnectionPool.open(SQLiteConnectionPool.java:185)
10-22 15:12:49.388: E/SQLiteDatabase(885): at android.database.sqlite.SQLiteConnectionPool.open(SQLiteConnectionPool.java:177)
10-22 15:12:49.388: E/SQLiteDatabase(885): at android.database.sqlite.SQLiteDatabase.openInner(SQLiteDatabase.java:804)
10-22 15:12:49.388: E/SQLiteDatabase(885): at android.database.sqlite.SQLiteDatabase.open(SQLiteDatabase.java:789)
10-22 15:12:49.388: E/SQLiteDatabase(885): at android.database.sqlite.SQLiteDatabase.openDatabase(SQLiteDatabase.java:694)
10-22 15:12:49.388: E/SQLiteDatabase(885): at android.database.sqlite.SQLiteDatabase.openDatabase(SQLiteDatabase.java:669)
10-22 15:12:49.388: E/SQLiteDatabase(885): at com.example.ccc.DataBaseHelper.checkDataBase(DataBaseHelper.java:69)
10-22 15:12:49.388: E/SQLiteDatabase(885): at com.example.ccc.DataBaseHelper.createDataBase(DataBaseHelper.java:44)
10-22 15:12:49.388: E/SQLiteDatabase(885): at com.example.ccc.MainActivity.onCreate(MainActivity.java:25)
10-22 15:12:49.388: E/SQLiteDatabase(885): at android.app.Activity.performCreate(Activity.java:5104)
10-22 15:12:49.388: E/SQLiteDatabase(885): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
10-22 15:12:49.388: E/SQLiteDatabase(885): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
10-22 15:12:49.388: E/SQLiteDatabase(885): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
10-22 15:12:49.388: E/SQLiteDatabase(885): at android.app.ActivityThread.access$600(ActivityThread.java:141)
10-22 15:12:49.388: E/SQLiteDatabase(885): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
10-22 15:12:49.388: E/SQLiteDatabase(885): at android.os.Handler.dispatchMessage(Handler.java:99)
10-22 15:12:49.388: E/SQLiteDatabase(885): at android.os.Looper.loop(Looper.java:137)
10-22 15:12:49.388: E/SQLiteDatabase(885): at android.app.ActivityThread.main(ActivityThread.java:5041)
10-22 15:12:49.388: E/SQLiteDatabase(885): at java.lang.reflect.Method.invokeNative(Native Method)
10-22 15:12:49.388: E/SQLiteDatabase(885): at java.lang.reflect.Method.invoke(Method.java:511)
10-22 15:12:49.388: E/SQLiteDatabase(885): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
10-22 15:12:49.388: E/SQLiteDatabase(885): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
10-22 15:12:49.388: E/SQLiteDatabase(885): at dalvik.system.NativeStart.main(Native Method)
10-22 15:12:49.856: I/Database(885): New database is being copied to device!
10-22 15:12:49.899: I/Database(885): New database has been copied to device!
10-22 15:12:49.926: I/Database(885): Trying to Open Database!
10-22 15:12:50.056: I/Database(885): Database is Opened successfully in OPEN_READWRITE Mode !
10-22 15:12:50.076: E/SQLiteLog(885): (1) no such table: TotList
10-22 15:12:50.096: D/AndroidRuntime(885): Shutting down VM
10-22 15:12:50.096: W/dalvikvm(885): threadid=1: thread exiting with uncaught exception (group=0x40a71930)
10-22 15:12:50.218: E/AndroidRuntime(885): FATAL EXCEPTION: main
10-22 15:12:50.218: E/AndroidRuntime(885): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.ccc/com.example.ccc.MainActivity}: android.database.sqlite.SQLiteException: no such table: TotList (code 1): , while compiling: SELECT * FROM TotList WHERE id = '1'
10-22 15:12:50.218: E/AndroidRuntime(885): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
10-22 15:12:50.218: E/AndroidRuntime(885): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
10-22 15:12:50.218: E/AndroidRuntime(885): at android.app.ActivityThread.access$600(ActivityThread.java:141)
10-22 15:12:50.218: E/AndroidRuntime(885): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
10-22 15:12:50.218: E/AndroidRuntime(885): at android.os.Handler.dispatchMessage(Handler.java:99)
10-22 15:12:50.218: E/AndroidRuntime(885): at android.os.Looper.loop(Looper.java:137)
10-22 15:12:50.218: E/AndroidRuntime(885): at android.app.ActivityThread.main(ActivityThread.java:5041)
10-22 15:12:50.218: E/AndroidRuntime(885): at java.lang.reflect.Method.invokeNative(Native Method)
10-22 15:12:50.218: E/AndroidRuntime(885): at java.lang.reflect.Method.invoke(Method.java:511)
10-22 15:12:50.218: E/AndroidRuntime(885): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
10-22 15:12:50.218: E/AndroidRuntime(885): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
10-22 15:12:50.218: E/AndroidRuntime(885): at dalvik.system.NativeStart.main(Native Method)
10-22 15:12:50.218: E/AndroidRuntime(885): Caused by: android.database.sqlite.SQLiteException: no such table: TotList (code 1): , while compiling: SELECT * FROM TotList WHERE id = '1'
10-22 15:12:50.218: E/AndroidRuntime(885): at android.database.sqlite.SQLiteConnection.nativePrepareStatement(Native Method)
10-22 15:12:50.218: E/AndroidRuntime(885): at android.database.sqlite.SQLiteConnection.acquirePreparedStatement(SQLiteConnection.java:882)
10-22 15:12:50.218: E/AndroidRuntime(885): at android.database.sqlite.SQLiteConnection.prepare(SQLiteConnection.java:493)
10-22 15:12:50.218: E/AndroidRuntime(885): at android.database.sqlite.SQLiteSession.prepare(SQLiteSession.java:588)
10-22 15:12:50.218: E/AndroidRuntime(885): at android.database.sqlite.SQLiteProgram.<init>(SQLiteProgram.java:58)
10-22 15:12:50.218: E/AndroidRuntime(885): at android.database.sqlite.SQLiteQuery.<init>(SQLiteQuery.java:37)
10-22 15:12:50.218: E/AndroidRuntime(885): at android.database.sqlite.SQLiteDirectCursorDriver.query(SQLiteDirectCursorDriver.java:44)
10-22 15:12:50.218: E/AndroidRuntime(885): at android.database.sqlite.SQLiteDatabase.rawQueryWithFactory(SQLiteDatabase.java:1314)
10-22 15:12:50.218: E/AndroidRuntime(885): at android.database.sqlite.SQLiteDatabase.rawQuery(SQLiteDatabase.java:1253)
10-22 15:12:50.218: E/AndroidRuntime(885): at com.example.ccc.DataBaseHelper.getT(DataBaseHelper.java:208)
10-22 15:12:50.218: E/AndroidRuntime(885): at com.example.ccc.MainActivity.onCreate(MainActivity.java:43)
10-22 15:12:50.218: E/AndroidRuntime(885): at android.app.Activity.performCreate(Activity.java:5104)
10-22 15:12:50.218: E/AndroidRuntime(885): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
10-22 15:12:50.218: E/AndroidRuntime(885): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
10-22 15:12:50.218: E/AndroidRuntime(885): ... 11 more
10-22 15:13:20.548: I/Process(885): Sending signal. PID: 885 SIG: 9
问题出在哪里？我该如何解决？先感谢您