Question

我需要在我的Android应用程序上使用SQLite数据库但是当我尝试打开它时，它崩溃了，我无法弄清楚为什么。我过去一小时在网上看了一下，但是找不到任何帮助。

以下是代码：

public class PrivDB {

public static final String KEY_ROWID = "_id";
public static final String KEY_LEVEL = "level";
public static final String KEY_LOCKED = "locked";
public static final String KEY_SEQUENCE = "sequence";
public static final String KEY_TRIES = "tries";

private static final String DATABASE_NAME = "patdb";
private static final String DATABASE_TABLE = "tablename";
private static final int DATABASE_VERSION = 1;

private DbHelper ourHelper;
private Context ourContext;
private SQLiteDatabase ourDatabase;

private static class DbHelper extends SQLiteOpenHelper {

    public DbHelper(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
        // TODO Auto-generated constructor stub
    }

    @Override
    public void onCreate(SQLiteDatabase arg0) {
        // TODO Auto-generated method stub
        arg0.execSQL("CREATE TABLE " + DATABASE_TABLE + " ("+
                    KEY_ROWID + " INTEGER PRIMARY KEY AUTOINCREMENT, "+
                    KEY_LEVEL + " STRING NOT NULL, " +
                    KEY_LOCKED + " INTEGER NOT NULL, " +
                    KEY_SEQUENCE + " INTEGER NOT NULL, "+
                    KEY_TRIES + " INTEGER NOT NULL);");
    }

    @Override
    public void onUpgrade(SQLiteDatabase arg0, int arg1, int arg2) {
        // TODO Auto-generated method stub
        arg0.execSQL("DROP TABLE IF EXISTS " + DATABASE_TABLE);
        onCreate(arg0);
    }

}

public PrivDB (Context c) {
    ourContext = c;
}

public PrivDB open() throws SQLException {
    ourHelper = new DbHelper(ourContext);
    ourDatabase = ourHelper.getWritableDatabase();
    return this;
}

public void close(){
    ourHelper.close();
}

public long createEntry (String level, int locked, int sequence, int tries){
    ContentValues cv = new ContentValues();
    cv.put(KEY_LEVEL, level);
    cv.put(KEY_LOCKED, locked);
    cv.put(KEY_SEQUENCE, sequence);
    cv.put(KEY_TRIES, tries);
    return ourDatabase.insert(DATABASE_TABLE, null, cv);
}

public String getData() {
    String[] columns = new String[]{KEY_ROWID, KEY_LEVEL, KEY_LOCKED, KEY_SEQUENCE, KEY_TRIES};
    Cursor c = ourDatabase.query(DATABASE_TABLE, columns, null, null, null, null, null);
    String result = "";

    int iRow = c.getColumnIndex(KEY_ROWID);
    int iLevel = c.getColumnIndex(KEY_LEVEL);
    int iLocked = c.getColumnIndex(KEY_LOCKED);
    int iSequence = c.getColumnIndex(KEY_SEQUENCE);
    int iTries = c.getColumnIndex(KEY_TRIES);

    for(c.moveToFirst(); !c.isAfterLast(); c.moveToNext()){
        result = result + c.getString(iRow) + " " + c.getString(iLevel) + " " + c.getString(iLocked) + " " 
                + c.getString(iSequence) + c.getString(iTries) + "\n";
    }

    return result;
}

public int getLocked(String s) throws SQLException {
    String[] columns = new String[]{KEY_ROWID, KEY_LEVEL, KEY_LOCKED, KEY_SEQUENCE, KEY_TRIES};
    Cursor c = ourDatabase.query(DATABASE_TABLE, columns, KEY_LEVEL + "=" + s, null, null, null, null);
    if(c != null){
        c.moveToFirst();
        int locked = c.getInt(2);
        return locked;
    }
    return (Integer) null;
}

public void updateEntry(String s, int locked, int tries) throws SQLException {
    ContentValues cvUpdate = new ContentValues();
    cvUpdate.put(KEY_LOCKED, locked);
    cvUpdate.put(KEY_TRIES, tries);
    ourDatabase.update(DATABASE_TABLE, cvUpdate, KEY_LEVEL + "=" + s, null);
}

}

以及我如何调用数据库：

public class Stats extends Activity {

TextView tv;

@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.stats);
    tv = (TextView) findViewById(R.id.tvStats);
    PrivDB info = new PrivDB(this);
    info.open();
    String data = info.getData();
    info.close();
    tv.setText(data);
}

}

当我打开Stats类时，应用程序崩溃，但如果我将info.open()注释掉info.close()，那么它可以正常工作（但显然没有任何反应）。

更新

这是log cat输出：

01-09 13:16:32.786: E/AndroidRuntime(517): FATAL EXCEPTION: main
01-09 13:16:32.786: E/AndroidRuntime(517): java.lang.RuntimeException: Unable to start activity     ComponentInfo{com.docime.vamoose.patternz/com.docime.vamoose.patternz.Stats}:     java.lang.StringIndexOutOfBoundsException
01-09 13:16:32.786: E/AndroidRuntime(517):  at     android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
01-09 13:16:32.786: E/AndroidRuntime(517):  at     android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
01-09 13:16:32.786: E/AndroidRuntime(517):  at     android.app.ActivityThread.access$2300(ActivityThread.java:125)
01-09 13:16:32.786: E/AndroidRuntime(517):  at     android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
01-09 13:16:32.786: E/AndroidRuntime(517):  at     android.os.Handler.dispatchMessage(Handler.java:99)
01-09 13:16:32.786: E/AndroidRuntime(517):  at android.os.Looper.loop(Looper.java:123)
01-09 13:16:32.786: E/AndroidRuntime(517):  at android.app.ActivityThread.main(ActivityThread.java:4627)
01-09 13:16:32.786: E/AndroidRuntime(517):  at java.lang.reflect.Method.invokeNative(Native     Method)
01-09 13:16:32.786: E/AndroidRuntime(517):  at java.lang.reflect.Method.invoke(Method.java:521)
01-09 13:16:32.786: E/AndroidRuntime(517):  at     com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
01-09 13:16:32.786: E/AndroidRuntime(517):  at     com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
01-09 13:16:32.786: E/AndroidRuntime(517):  at dalvik.system.NativeStart.main(Native Method)
01-09 13:16:32.786: E/AndroidRuntime(517): Caused by: java.lang.StringIndexOutOfBoundsException
01-09 13:16:32.786: E/AndroidRuntime(517):  at     android.app.ContextImpl.validateFilePath(ContextImpl.java:1579)
01-09 13:16:32.786: E/AndroidRuntime(517):  at     android.app.ContextImpl.openOrCreateDatabase(ContextImpl.java:539)
01-09 13:16:32.786: E/AndroidRuntime(517):  at     android.content.ContextWrapper.openOrCreateDatabase(ContextWrapper.java:203)
01-09 13:16:32.786: E/AndroidRuntime(517):  at     android.database.sqlite.SQLiteOpenHelper.getWritableDatabase(SQLiteOpenHelper.java:98)
01-09 13:16:32.786: E/AndroidRuntime(517):  at     com.docime.vamoose.patternz.PrivDB.open(PrivDB.java:60)
01-09 13:16:32.786: E/AndroidRuntime(517):  at     com.docime.vamoose.patternz.Stats.onCreate(Stats.java:18)
01-09 13:16:32.786: E/AndroidRuntime(517):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
01-09 13:16:32.786: E/AndroidRuntime(517):  at             android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
01-09 13:16:32.786: E/AndroidRuntime(517):  ... 11 more

Answer 1

您永远不会传递DATABASE_TABLE名称或在代码中指定。这就是它崩溃的原因。

private static final String DATABASE_TABLE = "TABLE_NAME";

更新：请更新您的onCreate()。 SQLite suport TEXT instedOf String

@Override
public void onCreate(SQLiteDatabase arg0) {
    // TODO Auto-generated method stub
    arg0.execSQL("CREATE TABLE " + DATABASE_TABLE + " ( "+
                KEY_ROWID + " INTEGER PRIMARY KEY AUTOINCREMENT, "+
                KEY_LEVEL + " TEXT NOT NULL, " +
                KEY_LOCKED + " INTEGER NOT NULL, " +
                KEY_SEQUENCE + " INTEGER NOT NULL, "+
                KEY_TRIES + " INTEGER NOT NULL);");
 }

您传递上下文但不使用静态变量保存它的另一个重要事项。您应该使用以下

private static Context ourContext;

public PrivDB (Context c) {
    this.ourContext = c;
}

但最重要的是，因为你正面临错误/异常

引起：java.lang.StringIndexOutOfBoundsException，

这Thrown when the a string is indexed with a value less than zero, or greater than or equal to the size of the array

我会要求您检查以下内容 - java.lang.StringIndexOutOfBoundsException: index=0 length=0 in get sqlite database

Answer 2

将STRING更改为下面的TEXT

arg0.execSQL("CREATE TABLE " + DATABASE_TABLE + " ("+
                KEY_ROWID + " INTEGER PRIMARY KEY AUTOINCREMENT, "+
                KEY_LEVEL + " STRING NOT NULL, " +
                KEY_LOCKED + " INTEGER NOT NULL, " +
                KEY_SEQUENCE + " INTEGER NOT NULL, "+
                KEY_TRIES + " INTEGER NOT NULL);");

NOTE :更改后，请在数据库版本中添加一个

Answer 3

我认为您的信息指向null 试试这段代码：

if (null != info) 
{
    info.open();
    String data = info.getData();
    info.close();
}else
Log.d("App Name", "Info is null");

getData（）函数还有一件事就是读取数据库所以你应该在阅读模式下打开数据库。

ourDatabase = ourHelper.getWritableDatabase(); To
ourDatabase = ourHelper.getReadableDatabase();

Answer 4

 @Override
public void onCreate(SQLiteDatabase arg0) {
    // TODO Auto-generated method stub
    arg0.execSQL("CREATE TABLE " + DATABASE_TABLE + " ("+
                KEY_ROWID + " INTEGER PRIMARY KEY AUTOINCREMENT, "+
                KEY_LEVEL + " STRING NOT NULL, " +
                KEY_LOCKED + " INTEGER NOT NULL, " +
                KEY_SEQUENCE + " INTEGER NOT NULL, "+
                KEY_TRIES + " INTEGER NOT NULL);");
}

此行KEY_TRIES + " INTEGER NOT NULL);");有两个;。您的表格是否已创建/填充？

SQLite数据库在打开时崩溃

4 个答案: