读取外部的SQLdatabase步骤

//1：首先要将后缀为db的文件放入工程的资源中res下的raw文件夹//2：外部数据库需要我们先存入手机内存，然后再打开，所以我们要开读写权限//代码部分：

String permissons[] = {android.Manifest.permission.READ_EXTERNAL_STORAGE, android.Manifest.permission.WRITE_EXTERNAL_STORAGE};

String  SdPath = Environment.getExternalStorageDirectory().getPath();//在oncreate中先申请权限

if (hasPermission(permissons)) {
} else {
hasRequse(1, permissons);
}

public boolean hasPermission(String... permission) {
for (String permissiom : permission) {
if (ActivityCompat.checkSelfPermission(this, permissiom) != PackageManager.PERMISSION_GRANTED) {
return false;
}
}
return true;
}

public void hasRequse(int code, String... permission) {
ActivityCompat.requestPermissions(this, permission,code);
}

//3：解读数据，首先将资源文件存入SD卡，然后再从SD卡中打开数据库

    private void initCity() {//打开资源文件获取输入流InputStream in = getResources().openRawResource(R.raw.city);

		//存入SD卡之前一定要先创建路径File file = new File(SdPath + "//sql_database//");file.mkdirs();

		//创建要写入的文件对象File file1=new File(file.getPath(),"city.db");try {FileOutputStream out = new FileOutputStream(file1);byte b[] = new byte[1024];while (in.read(b) != -1) {out.write(b);

		}in.close();out.flush();out.close();} catch (IOException e) {e.printStackTrace();} catch (FileNotFoundException e) {e.printStackTrace();}db = openOrCreateDatabase(file1.getPath(), Context.MODE_PRIVATE, null);Cursor cursor = db.rawQuery(" select * from t_city ", null);Log.i(TAG, "cursor.getCount() === " + cursor.getCount());}

//得到了cursor 您就可以为所欲为了。附件demo：链接：http://pan.baidu.com/s/1bYNiEy 密码：9o19