Question

朋友们，我已经创建了一个数据库。现在我想在其中添加一个新事件，但通过＆＃34; INSERT INTO＆＃34; 我不想使用＆＃34; contentvalues＆＃34;。

这是我的代码部分提前谢谢。

protected static final int DATABASE_VERSION = 1;
protected static final String DATABSE_NAME = "eventDB.db";
protected static final String TABLE_EVENTS = "Events";

public static final String COLUMN_ID = "id";
public static final String COLUMN_EVENTNAME = "eventname";

String insertQuery = " INSERT INTO " + TABLE_EVENTS + "("
            + COLUMN_EVENTNAME + ")" + " VALUES ( ' "
            + eventname + " ' )";

    mDatabase.execSQL(insertQuery);

这是错误日志

    09-21 15:20:15.992: E/AndroidRuntime(828): java.lang.IllegalStateException: Could not execute method of the activity
09-21 15:20:15.992: E/AndroidRuntime(828):  at android.view.View$1.onClick(View.java:3633)
09-21 15:20:15.992: E/AndroidRuntime(828):  at android.view.View.performClick(View.java:4240)
09-21 15:20:15.992: E/AndroidRuntime(828):  at android.view.View$PerformClick.run(View.java:17721)
09-21 15:20:15.992: E/AndroidRuntime(828):  at android.os.Handler.handleCallback(Handler.java:730)
09-21 15:20:15.992: E/AndroidRuntime(828):  at android.os.Handler.dispatchMessage(Handler.java:92)
09-21 15:20:15.992: E/AndroidRuntime(828):  at android.os.Looper.loop(Looper.java:137)
09-21 15:20:15.992: E/AndroidRuntime(828):  at android.app.ActivityThread.main(ActivityThread.java:5103)
09-21 15:20:15.992: E/AndroidRuntime(828):  at java.lang.reflect.Method.invokeNative(Native Method)
09-21 15:20:15.992: E/AndroidRuntime(828):  at java.lang.reflect.Method.invoke(Method.java:525)
09-21 15:20:15.992: E/AndroidRuntime(828):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
09-21 15:20:15.992: E/AndroidRuntime(828):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
09-21 15:20:15.992: E/AndroidRuntime(828):  at dalvik.system.NativeStart.main(Native Method)
09-21 15:20:15.992: E/AndroidRuntime(828): Caused by: java.lang.reflect.InvocationTargetException
09-21 15:20:15.992: E/AndroidRuntime(828):  at java.lang.reflect.Method.invokeNative(Native Method)
09-21 15:20:15.992: E/AndroidRuntime(828):  at java.lang.reflect.Method.invoke(Method.java:525)
09-21 15:20:15.992: E/AndroidRuntime(828):  at android.view.View$1.onClick(View.java:3628)
09-21 15:20:15.992: E/AndroidRuntime(828):  ... 11 more
09-21 15:20:15.992: E/AndroidRuntime(828): Caused by: android.database.CursorIndexOutOfBoundsException: Index 0 requested, with a size of 0
09-21 15:20:15.992: E/AndroidRuntime(828):  at android.database.AbstractCursor.checkPosition(AbstractCursor.java:424)
09-21 15:20:15.992: E/AndroidRuntime(828):  at android.database.AbstractWindowedCursor.checkPosition(AbstractWindowedCursor.java:136)
09-21 15:20:15.992: E/AndroidRuntime(828):  at android.database.AbstractWindowedCursor.getInt(AbstractWindowedCursor.java:68)
09-21 15:20:15.992: E/AndroidRuntime(828):  at com.database.DBManager.cursorToEvent(DBManager.java:96)
09-21 15:20:15.992: E/AndroidRuntime(828):  at com.database.DBManager.addEvent(DBManager.java:55)
09-21 15:20:15.992: E/AndroidRuntime(828):  at com.database.MainActivity.addClick(MainActivity.java:55)
09-21 15:20:15.992: E/AndroidRuntime(828):  ... 14 more
09-21 15:38:20.721: E/AndroidRuntime(887): FATAL EXCEPTION: main
09-21 15:38:20.721: E/AndroidRuntime(887): java.lang.IllegalStateException: Could not execute method of the activity
09-21 15:38:20.721: E/AndroidRuntime(887):  at android.view.View$1.onClick(View.java:3633)
09-21 15:38:20.721: E/AndroidRuntime(887):  at android.view.View.performClick(View.java:4240)
09-21 15:38:20.721: E/AndroidRuntime(887):  at android.view.View$PerformClick.run(View.java:17721)
09-21 15:38:20.721: E/AndroidRuntime(887):  at android.os.Handler.handleCallback(Handler.java:730)
09-21 15:38:20.721: E/AndroidRuntime(887):  at android.os.Handler.dispatchMessage(Handler.java:92)
09-21 15:38:20.721: E/AndroidRuntime(887):  at android.os.Looper.loop(Looper.java:137)
09-21 15:38:20.721: E/AndroidRuntime(887):  at android.app.ActivityThread.main(ActivityThread.java:5103)
09-21 15:38:20.721: E/AndroidRuntime(887):  at java.lang.reflect.Method.invokeNative(Native Method)
09-21 15:38:20.721: E/AndroidRuntime(887):  at java.lang.reflect.Method.invoke(Method.java:525)
09-21 15:38:20.721: E/AndroidRuntime(887):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
09-21 15:38:20.721: E/AndroidRuntime(887):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
09-21 15:38:20.721: E/AndroidRuntime(887):  at dalvik.system.NativeStart.main(Native Method)
09-21 15:38:20.721: E/AndroidRuntime(887): Caused by: java.lang.reflect.InvocationTargetException
09-21 15:38:20.721: E/AndroidRuntime(887):  at java.lang.reflect.Method.invokeNative(Native Method)
09-21 15:38:20.721: E/AndroidRuntime(887):  at java.lang.reflect.Method.invoke(Method.java:525)
09-21 15:38:20.721: E/AndroidRuntime(887):  at android.view.View$1.onClick(View.java:3628)
09-21 15:38:20.721: E/AndroidRuntime(887):  ... 11 more
09-21 15:38:20.721: E/AndroidRuntime(887): Caused by: android.database.CursorIndexOutOfBoundsException: Index 0 requested, with a size of 0
09-21 15:38:20.721: E/AndroidRuntime(887):  at android.database.AbstractCursor.checkPosition(AbstractCursor.java:424)
09-21 15:38:20.721: E/AndroidRuntime(887):  at android.database.AbstractWindowedCursor.checkPosition(AbstractWindowedCursor.java:136)
09-21 15:38:20.721: E/AndroidRuntime(887):  at android.database.AbstractWindowedCursor.getInt(AbstractWindowedCursor.java:68)
09-21 15:38:20.721: E/AndroidRuntime(887):  at com.database.DBManager.cursorToEvent(DBManager.java:96)
09-21 15:38:20.721: E/AndroidRuntime(887):  at com.database.DBManager.addEvent(DBManager.java:55)
09-21 15:38:20.721: E/AndroidRuntime(887):  at com.database.MainActivity.addClick(MainActivity.java:55)
09-21 15:38:20.721: E/AndroidRuntime(887):  ... 14 more

我的MainActivity.java

package com.database;

import java.util.ArrayList;

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.EditText;
import android.widget.ListView;

import com.ajay.database.R;

public class MainActivity extends Activity {

    private DBManager mEvemanager;
    private EditText mName;
    public CustomListAdapter mAdapter;
    public ArrayList<Event> mEvents;
    public ListView mListview;

    public String TAG = "MyActivityTag";

    @Override
    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        setTitle("Attendance Tracker");

        mEvemanager = new DBManager(this);
        // Log.d(TAG, "Back into main after creating object of eventmanager");
        mEvemanager.open();

        mEvents = mEvemanager.getallEvents();
        // Log.d(TAG,
        // "Back into main activity after got events from eventmanager");

        mAdapter = new CustomListAdapter(MainActivity.this, mEvents);
        // Log.d(TAG, "Back into main after creating customadapter");

        mListview = (ListView) findViewById(R.id.listview);
        // Log.d(TAG, "listView reference Created");

        mListview.setAdapter(mAdapter);
        // Log.d(TAG, "Adapter Set");

    }

    public void addClick(View view) {

        Log.d(TAG, "Add button clicked");
        Event event = null;
        mName = (EditText) findViewById(R.id.eventNameText);
        event = mEvemanager.addEvent(mName.getText().toString());
        mAdapter.add(event);
        mAdapter.notifyDataSetChanged();
        mName.setText(null);

    }

    @Override
    protected void onResume() {
        mEvemanager.open();
        super.onResume();
    }

    @Override
    protected void onPause() {
        mEvemanager.close();
        super.onPause();
    }
}

我的DBManager.java

package com.database;

import java.util.ArrayList;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.util.Log;

public class DBManager {

    private SQLiteDatabase mDatabase;
    private MyDBHandler mDBhandler;

    private String[] allEvents = { MyDBHandler.COLUMN_ID,
            MyDBHandler.COLUMN_EVENTNAME };

    public static final String TAG = "MyActivityTag";

    public DBManager(Context context) {
        // Log.d(TAG, "Eventmanager constructor called");
        mDBhandler = new MyDBHandler(context);
    }

    public void open() throws SQLException {
        mDatabase = mDBhandler.getWritableDatabase();
    }

    public void close() throws SQLException {
        mDBhandler.close();
    }

    public Event addEvent(String eventname) {
        Log.d(TAG, "addEvent method in eventmanager");

        // ContentValues values = new ContentValues();
        // values.put(MyDBHandler.COLUMN_EVENTNAME, eventname);

        String insertQuery = " INSERT INTO " + MyDBHandler.TABLE_EVENTS + "("
                + MyDBHandler.COLUMN_EVENTNAME + ")" + " VALUES ( ' "
                + eventname + " ' )";

        mDatabase.execSQL(insertQuery);

        // long insertId = mDatabase
        // .insert(MyDBHandler.TABLE_EVENTS, null, values);

        Cursor cursor = mDatabase.query(MyDBHandler.TABLE_EVENTS, allEvents,
                MyDBHandler.COLUMN_ID + " = " + 0, null, null, null, null);

        cursor.moveToFirst();

        Event mEvent = cursorToEvent(cursor);

        cursor.close();
        return mEvent;
    }

    public void deleteEvent(String eventname) {
        Log.d(TAG, "in deleteEvent method eventmanager");
        String query = "Select * FROM " + MyDBHandler.TABLE_EVENTS + " WHERE "
                + MyDBHandler.COLUMN_EVENTNAME + " =  \"" + eventname + "\"";
        SQLiteDatabase db = mDBhandler.getWritableDatabase();
        Cursor cursor = db.rawQuery(query, null);
        Event event = new Event();
        if (cursor.moveToFirst()) {
            event.setID(Integer.parseInt(cursor.getString(0)));
            db.delete(MyDBHandler.TABLE_EVENTS, MyDBHandler.COLUMN_ID + " = ?",
                    new String[] { String.valueOf(event.getID()) });
            cursor.close();
        }
        db.close();
    }

    public ArrayList<Event> getallEvents() {
        Log.d(TAG, "getallEvents in eventmanager");
        ArrayList<Event> events = new ArrayList<Event>();

        Cursor cursor = mDatabase.query(MyDBHandler.TABLE_EVENTS, allEvents,
                null, null, null, null, null);

        cursor.moveToFirst();
        while (!cursor.isAfterLast()) {
            Event event = cursorToEvent(cursor);
            events.add(event);
            cursor.moveToNext();
        }
        cursor.close();
        return events;
    }

    private Event cursorToEvent(Cursor cursor) {
        Event event = new Event();
        event.setID(cursor.getInt(0));
        event.setEventName(cursor.getString(1));
        return event;
    }
}

和MyDBHandler.java

package com.database;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;

public class MyDBHandler extends SQLiteOpenHelper {

    protected static final int DATABASE_VERSION = 1;
    protected static final String DATABSE_NAME = "eventDB.db";
    protected static final String TABLE_EVENTS = "Events";

    public static final String COLUMN_ID = "id";
    public static final String COLUMN_EVENTNAME = "eventname";

    public static final String TAG = "MyActivityTag";

    public MyDBHandler(Context context, String name, CursorFactory factory,
            int version) {
        super(context, DATABSE_NAME, factory, DATABASE_VERSION);
    //  Log.d(TAG, "MyDBHandler constructor called with 4 arguments");
    }

    public MyDBHandler(Context context) {
        super(context, DATABSE_NAME, null, DATABASE_VERSION);
    //  Log.d(TAG, "MyDBHandler const called with only context argument");
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        String CREATE_EVENTS_TABLE = " CREATE TABLE " + TABLE_EVENTS + "("
                + COLUMN_ID + " INTEGER PRIMARY KEY," + COLUMN_EVENTNAME
                + " TEXT" + ")";
        db.execSQL(CREATE_EVENTS_TABLE);
        Log.d(TAG, "Table Created in database");
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        db.execSQL("DROP TABLE IF EXISTS " + TABLE_EVENTS);
        onCreate(db);
    }

}

Answer 1

最可能的原因是数据库中的Event表中没有ID为0的行。因此，您的光标为空，并在cursorToEvent

中出错

在Android中的数据库中插入INTO

1 个答案: