1回答

• 

  慕梦前来

  2020-06-08 21:21:48

  操作方法：1. 把原数据库包括在项目源码的 res/raw 目录下，然后建立一个DBManager类，代码如下：

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  package com.android.ImportDatabase; import java.io.File;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.IOException;import java.io.InputStream; import android.content.Context;import android.database.sqlite.SQLiteDatabase;import android.os.Environment;import android.util.Log; public class DBManager {    private final int BUFFER_SIZE = 400000;    public static final String DB_NAME = "countries.db"; //保存的数据库文件名    public static final String PACKAGE_NAME = "com.android.ImportDatabase";    public static final String DB_PATH = "/data"            + Environment.getDataDirectory().getAbsolutePath() + "/"            + PACKAGE_NAME;  //在手机里存放数据库的位置     private SQLiteDatabase database;    private Context context;     DBManager(Context context) {        this.context = context;    }     public void openDatabase() {        this.database = this.openDatabase(DB_PATH + "/" + DB_NAME);    }     private SQLiteDatabase openDatabase(String dbfile) {        try {            if (!(new File(dbfile).exists())) {　　//判断数据库文件是否存在，若不存在则执行导入，否则直接打开数据库                InputStream is = this.context.getResources().openRawResource(                        R.raw.countries); //欲导入的数据库                FileOutputStream fos = new FileOutputStream(dbfile);                byte[] buffer = new byte[BUFFER_SIZE];                int count = 0;                while ((count = is.read(buffer)) > 0) {                    fos.write(buffer, 0, count);                }                fos.close();                is.close();            }            SQLiteDatabase db = SQLiteDatabase.openOrCreateDatabase(dbfile,                    null);            return db;        } catch (FileNotFoundException e) {            Log.e("Database", "File not found");            e.printStackTrace();        } catch (IOException e) {            Log.e("Database", "IO exception");            e.printStackTrace();        }        return null;    }

  
  

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