Sqlite 数据库使用方法_public sqlitedatabase

import android.annotation.SuppressLint;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;

@SuppressLint("DefaultLocale")
public class UserDBHelper extends SQLiteOpenHelper {
   
    private static final String TAG = "UserDBHelper";
    private static final String DB_NAME = "user.db"; // 数据库的名称
    private static final int DB_VERSION = 1; // 数据库的版本号
    private static UserDBHelper mHelper = null; // 数据库帮助器的实例
    private SQLiteDatabase mDB = null; // 数据库的实例
    public static final String TABLE_NAME = "user_info"; // 表的名称

    private UserDBHelper(Context context) {
   
        super(context, DB_NAME, null, DB_VERSION);
    }

    private UserDBHelper(Context context, int version) {
   
        super(context, DB_NAME, null, version);
    }

    // 利用单例模式获取数据库帮助器的唯一实例
    public static UserDBHelper getInstance(Context context, int version) {
   
        if (version > 0 && mHelper == null) {
   

            mHelper = new UserDBHelper(context, version);
        } else if (mHelper == null) {
   
            Log.i("@@@","gouzao2");
            mHelper = new UserDBHelper(context);
        }
        return mHelper;
    }

    // 打开数据库的读连接
    public SQLiteDatabase openReadLink() {
   
        if (mDB == null || !mDB.isOpen()) {
   
            mDB = mHelper.getReadableDatabase();
        }
        return mDB;
    }

    // 打开数据库的写连接
    public SQLiteDatabase openWriteLink() {
   
        if (mDB == null || !mDB.isOpen()) {
   
            mDB = mHelper.getWritableDatabase();
        }
        return mDB;
    }

    // 关闭数据库连接
    public void closeLink() {
   
        if (mDB != null && mDB.isOpen()) {
   
            
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