Question

Events类

package org.examples.events;

import android.app.ListActivity;
import android.content.ContentValues;
import android.widget.SimpleCursorAdapter;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.widget.TextView;
import static org.examples.events.Constants.TABLE_NAME;
import static org.examples.events.Constants.TITLE;
import static org.examples.events.Constants.TIME;
import static android.provider.BaseColumns._ID;

public class Events extends ListActivity {
private EventsData events;

@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    events = new EventsData(this);
    try {
        addEvent("Hello Tarun");
        Cursor cursor = getEvent();
        showEvent(cursor);

    } finally {
        events.close();
    }
}

// Insert data into the database
// similar things can be done for delete or update
private void addEvent(String string) {
    SQLiteDatabase db = events.getWritableDatabase();
    ContentValues values = new ContentValues();
    values.put(TIME, System.currentTimeMillis());
    values.put(TITLE, string);
    db.insertOrThrow(TABLE_NAME, null, values);
}

// GET THE LIST OF EVENTS FROM DATABASE
private static String[] FROM = { _ID, TIME, TITLE };
private static String ORDER_BY = TIME + "DESC";

private Cursor getEvent() {
    // PERFORM A MANAGED QUERY. THE ACTIVITY WILL HANDLE CLOSING AND
    // REQUERING THE DATABASE WHEN NEEDED
    SQLiteDatabase db = events.getReadableDatabase();
    Cursor cursor = db.rawQuery("SELECT * from " +TABLE_NAME, null);
    //Cursor cursor = db.query(TABLE_NAME, FROM, null, null, null, null, ORDER_BY);
    //Cursor c = sampleDB.rawQuery("SELECT * FROM " +TABLE_NAME, null);
    startManagingCursor(cursor);
    return cursor;
}

// STUFF THEM ALL INTO A BIG STRINGS
// THE ADAPTER ACTS AS THE GO BETWEEN THE DATA SOURCE AND THE VIEW
public static int[] TO = { R.id.rowid, R.id.time, R.id.title };

private void showEvent(Cursor cursor) {
    SimpleCursorAdapter adapter = new SimpleCursorAdapter(this,
            R.layout.item, cursor, FROM, TO);
    setListAdapter(adapter);
}

}

EventsData类为

package org.examples.events;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import static org.examples.events.Constants.TABLE_NAME;
import static org.examples.events.Constants.TITLE;
import static org.examples.events.Constants.TIME;
import static android.provider.BaseColumns._ID;

public class EventsData extends SQLiteOpenHelper {
public static final String DATABASE_NAME = "events.db";

public static final int DATABASE_VERSION = 1;
public static final String CREATE_TABLE = "CREATE TABLE events (" +Constants._ID+
        " INT AUTO_INCREMENT PRIMARY KEY," +
        " time INTEGER, title TEXT NOT NULL); ";

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

@Override
public void onCreate(SQLiteDatabase db) {
    db.execSQL(CREATE_TABLE);
}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    db.execSQL("drop table if exists" + TABLE_NAME);
    onCreate(db);

}

}

和常数如下

package org.examples.events;
import android.provider.BaseColumns;;

public interface Constants extends BaseColumns{
public static final String TABLE_NAME = " events ";


// coloumns in the table
public static final String TIME = " time ";
public static final String TITLE = " title ";
public static final String _ID = " _id ";
}

Answer 1

<{1>}中的

，您有一个Events

import

而不是被覆盖的

android.provider.BaseColumns._ID;

错误：由以下引起：java.lang.IllegalArgumentException：列'_id'不存在

1 个答案: