sqlite与android交互 (封装)

学android已经有大概一周时间了吧，总感觉自己基础不怎么好，只能通过一点一点积累着敲来巩固平常的知识，有的时候就先不封装的敲一遍，再封装上，有些语句真的记不住，虽然知道他是什么意思，于是乎就反复的敲着，加油吧！少年，下面进入正题吧

　　DBConn.java类主要是将raw写入到DDMS里的data/data/xxx包/下，代码如下：

package com.tp.soft.util;import java.io.File;import java.io.FileOutputStream;import java.io.InputStream;import com.example.dbcity.R;import android.content.Context;import android.database.sqlite.SQLiteDatabase;import android.os.Environment;public class DBConn {    private static String DB_NAME = "test.db";    private static String PACKAGE = "com.example.dbcity";    private static String PATH = "/data" +                Environment.getDataDirectory().getPath()+                File.separator + PACKAGE;    private Context context;    private SQLiteDatabase database;    public DBConn(Context context){        this.context = context;    }        public static final DBConn getInstance(Context context){        DBConn conn = new DBConn(context);        return conn;    }    public SQLiteDatabase getDb(){        database = openDB(PATH + File.separator + DB_NAME);        return database;    }        public SQLiteDatabase openDB(String dbFile){        try{            if(!isExitFile(dbFile)){                InputStream is = context.getResources().openRawResource(R.raw.test);                FileOutputStream fos = new FileOutputStream(dbFile);                byte[] buffer = new byte[1024];                int len = -1;                while((len = is.read(buffer)) != -1){                    fos.write(buffer, 0, len);                }                is.close();                fos.close();            }                        database = SQLiteDatabase.openOrCreateDatabase(dbFile, null);            return database;        }catch (Exception e) {            e.printStackTrace();            return null;        }    }        public boolean isExitFile(String path){        File file = new File(path);        return file.exists();    }}

DBManage.java主要是对数据库的封装，目前只做了个查询，待后期完善吧，代码如下：

package com.tp.soft.util;import java.util.ArrayList;import java.util.List;import android.content.Context;import android.database.Cursor;import android.database.sqlite.SQLiteDatabase;public class DBManage {    private SQLiteDatabase db;        public DBManage(Context context) {        DBConn conn = DBConn.getInstance(context);        db = conn.getDb();    }    public List<String> queryData(String sql, String[] selectionArgs, String property){        Cursor cursor = null;        List<String> list = new ArrayList<String>();        try{            cursor = db.rawQuery(sql, selectionArgs);            while(cursor.moveToNext()){                String str = cursor.getString(cursor.getColumnIndex(property));                list.add(str);            }        }catch (Exception e) {            e.printStackTrace();        }finally{            if(null != cursor){                cursor.close();            }        }        return list;    }    }

主入口就是一个下拉列表的显示，然后就是调用sqlite数据库了，部分代码如下：

proSelect = (Spinner) findViewById(R.id.proSelect);        DBManage dbManage = new DBManage(this);        List<String> proList = dbManage.queryData("select * from au_user", null, "username");        ArrayAdapter<String> arrayAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_gallery_item, proList);        proSelect.setAdapter(arrayAdapter);

总结一句话，其实代码敲多了才去想怎么敲，而不是一点都没敲就去想如何将语句敲到最好我觉得这个是不可能的，菜鸟自学路程。。。

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