我想知道是否有人可以帮助我。
我收到一条错误消息,说column_one
不存在。
但是我将其包含在DBHandler中。
我已经查看了其他一些答案,这些答案可能是由于缺少空格或逗号引起的,但我似乎找不到它。
DBHandler.java
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.database.Cursor;
import android.content.Context;
import android.content.ContentValues;
public class DBHandler extends SQLiteOpenHelper {
private static final int DATABASE_VERSION = 1;
private static final String DATABASE_NAME = "Database.db";
public static final String TABLE_TEST = "test";
public static final String COLUMN_ID = "_id";
public static final String COLUMN_ONE = "one";
public static final String COLUMN_TWO = "two";
public DBHandler(Context context, String name, SQLiteDatabase.CursorFactory factory, int version) {
super(context, DATABASE_NAME, factory, DATABASE_VERSION);
}
public void onCreate(SQLiteDatabase db) {
String query = "CREATE TABLE " + TABLE_TEST + "(" +
COLUMN_ID + " INTEGER PRIMARY KEY AUTOINCREMENT," +
COLUMN_ONE + " TEXT," +
COLUMN_TWO + " TEXT" + ");";
db.execSQL(query);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXISTS " + TABLE_TEST);
onCreate(db);
}
public void addTest(Test test){
ContentValues values = new ContentValues();
values.put(COLUMN_ONE, test.get_one());
values.put(COLUMN_TWO, test.get_two());
SQLiteDatabase db = getWritableDatabase();
db.insert(TABLE_TEST, null, values);
db.close();
}
}
Test.java
public class Test {
private int _id;
private String _one;
private String _two;
public Test(){
}
public Test(int id){
this._id = id;
}
public Test(String one, String two){
this._one = one;
this._two = two;
}
public int get_id() {
return _id;
}
public void set_id(int _id) {
this._id = _id;
}
public String get_one() {
return _one;
}
public void set_one(String _one) {
this._one = _one;
}
public String get_two() {
return _two;
}
public void set_two(String _two) {
this._two = _two;
}
我的主活动非常长,并且有多个其他项目,所以这里很重要(在代码前面声明了dbHandler)
Test test = new Test ("Test One", "Test Two");
dbHandler.addTest(test);
如果有人可以看一下我的代码,我将不胜感激。
编辑:logcat
08-12 09:39:00.358 2305-2305/com.test.test E/SQLiteLog﹕ (1) table test has no column named one
08-12 09:39:00.380 2305-2305/com.test.test E/SQLiteDatabase﹕ Error inserting one=Random two=Random
android.database.sqlite.SQLiteException: table test has no column named one (code 1): , while compiling: INSERT INTO test(one,two) VALUES (?,?)
at android.database.sqlite.SQLiteConnection.nativePrepareStatement(Native Method)
at android.database.sqlite.SQLiteConnection.acquirePreparedStatement(SQLiteConnection.java:889)
at android.database.sqlite.SQLiteConnection.prepare(SQLiteConnection.java:500)
at android.database.sqlite.SQLiteSession.prepare(SQLiteSession.java:588)
at android.database.sqlite.SQLiteProgram.<init>(SQLiteProgram.java:58)
at android.database.sqlite.SQLiteStatement.<init>(SQLiteStatement.java:31)
at android.database.sqlite.SQLiteDatabase.insertWithOnConflict(SQLiteDatabase.java:1469)
at android.database.sqlite.SQLiteDatabase.insert(SQLiteDatabase.java:1341)
at com.test.test.DBHandler.addTest(DBHandler.java:54)
at com.test.test.MainActivity.onClick(MainActivity.java:58)
at android.view.View.performClick(View.java:4780)
at android.view.View$PerformClick.run(View.java:19866)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5257)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
最佳答案
表名未初始化为字符串
public static final String TABLE_TEST = test
您实际上是在将String初始化为另一个(空)对象变量。
您需要双引号字符串,使其成为字符串:
public static final String TABLE_TEST = "test"
现在,卸载并重新安装您的应用程序。
该数据库将被删除,因此在下一次运行时将重新创建该数据库。
或者,增加DATABASE_VERSION常数的值。
这样,将触发
onUpgrade()
方法,删除该表并重新创建它。