我只是尝试创建表，在其中插入几条记录，然后尝试从数据库中检索记录...我编码的内容让我向您展示更清晰的图片
package com.example.istudy;
import java.text.ParseException;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import com.example.dbtable.ProfileTable;
import com.example.dbtable.Sem5;
public class DBHandler extends SQLiteOpenHelper {
private static final int VERSION = 1;
private static final String DB_NAME = "iStudy";
private static final String TABLE_NAME1 = "sem5";
private static final String TABLE_NAME2 = "profile";
//columns
private static final String KEY_SUBJ = "sub_name";
private static final String KEY_CHAP = "total_chapters";
private static final String KEY_CHAP_COMPLETED = "chap_completed";
private static final String KEY_CHAP_REMAINING = "chap_remaining";
private static final String KEY_NAME = "name";
private static final String KEY_SEM = "sem";
private static final String KEY_COLG_TIMING = "colg_timing";
private static final String KEY_STUDY_HOURS = "study_hours";
private static final String KEY_TERM_START = "term_start";
private static final String KEY_TERM_END = "term_end";
public DBHandler(Context context) {
super(context, DB_NAME, null, VERSION);
// TODO Auto-generated constructor stub
}
@Override
public void onCreate(SQLiteDatabase db) {
// TODO Auto-generated method stub
String create_table = "CREATE TABLE " + TABLE_NAME1 + " ( " + KEY_SUBJ + " TEXT PRIMARY KEY , " + KEY_CHAP + " INTEGER , " +
KEY_CHAP_COMPLETED + " INTEGER, " + KEY_CHAP_REMAINING + " INTEGER " + " )";
db.execSQL(create_table);
create_table = null;
create_table = "CREATE TABLE " + TABLE_NAME2 + " ( " + KEY_NAME + " TEXT PRIMARY KEY, " + KEY_SEM + " INTEGER , " + KEY_COLG_TIMING + " TEXT ," +
KEY_STUDY_HOURS + " TEXT , " + KEY_TERM_START + " DATE , " + KEY_TERM_END + " DATE )";
db.execSQL(create_table);
insertInSem5Table();
}
private void insertInSem5Table( ){
String[] subName = {"ADBMS","CN","EVS","MP","TCS"};
String insert_Query = "";
SQLiteDatabase db = this.getWritableDatabase();
for (int i = 0; i < subName.length; i++) {
ContentValues values = new ContentValues();
values.put(KEY_SUBJ, subName[i]);
if( !(subName[i].equals("MP")) ){
values.put(KEY_CHAP, 8);
}
else{
values.put(KEY_CHAP, 7);
}
values.put(KEY_CHAP_COMPLETED, 0);
if( !(subName[i].equals("MP")) ){
values.put(KEY_CHAP_COMPLETED, 8);
}
else{
values.put(KEY_CHAP_COMPLETED, 7);
}
db.insert(TABLE_NAME1, null, values);
}
db.close();
}
public List<Sem5> getAllRecordsOfSem5Table( ){
List<Sem5> list = new ArrayList<Sem5>();
String query = "SELECT * FROM " + TABLE_NAME1;
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery(query, null);
if( cursor.moveToFirst() ){
do{
Sem5 sem5 = new Sem5();
sem5.setKEY_SUBJ(cursor.getString(0));
sem5.setKEY_CHAP(Integer.parseInt(cursor.getString(1)));
sem5.setKEY_CHAP_COMPLETED(Integer.parseInt(cursor.getString(2)));
sem5.setKEY_CHAP_REMAINING(Integer.parseInt(cursor.getString(3)));
list.add(sem5);
}while(cursor.moveToNext());
}
return list;
}
public List<ProfileTable> getAllRecordsOfProfileTable( ){
List<ProfileTable> list = new ArrayList<ProfileTable>();
String query = "SELECT * FROM " + TABLE_NAME2;
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery(query, null);
if( cursor.moveToFirst() ){
do{
ProfileTable profileTable = new ProfileTable();
profileTable.setKEY_NAME(cursor.getString(0));
profileTable.setKEY_SEM(Integer.parseInt(cursor.getString(1)));
Date colgTiming = null, studyHrs = null, termStart = null, termEnd = null;
try {
colgTiming = java.text.DateFormat.getInstance().parse(cursor.getString(2));
studyHrs = java.text.DateFormat.getInstance().parse(cursor.getString(3));
termStart = java.text.DateFormat.getInstance().parse(cursor.getString(4));
termEnd = java.text.DateFormat.getInstance().parse(cursor.getString(5));
profileTable.setKEY_COLG_TIMING( colgTiming);
profileTable.setKEY_STUDY_HOURS(studyHrs);
profileTable.setKEY_TERM_START(termStart);
profileTable.setKEY_TERM_END(termEnd);
list.add(profileTable);
} catch (ParseException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}while(cursor.moveToNext());
}
return list;
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO Auto-generated method stub
}
}
使用以下代码调用db方法
public class Profile extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
DBHandler dbHandler = new DBHandler(this);
Log.d("Insert : " , "INserting ...");
List<Sem5> allRecordsOfSem5Table = dbHandler.getAllRecordsOfSem5Table();
}
}
我收到以下错误
06-29 06：55：59.993：E / AndroidRuntime（817）：java.lang.RuntimeException：无法启动活动ComponentInfo {com.example.istudy / com.example.istudy.Profile}：java.lang。 IllegalStateException：递归调用getDatabase
答案 0 :(得分：1)
看看这个：
onCreate(SQLiteDatabase db){
...
insertInSem5Table();
}
......而且这个：
private void insertInSem5Table( ){
....
SQLiteDatabase db = this.getWritableDatabase();
...
您正试图以递归方式获取SQLiteDatabase
尝试：
onCreate(SQLiteDatabase db){
...
insertInSem5Table(db);
}
......而且这个：
private void insertInSem5Table(SQLiteDatabase db ){
....
SQLiteDatabase db = db //this of course is not necessary, just to point out the idea.
...