我正在尝试制作我的第一款Android应用.我注意到,SQLiteOpenHelper.onCreate()
如果数据库不存在,则不会调用该方法来创建表.但是,onCreate()
即使我尝试调试,该方法也无法正常工作.
请查看下面的代码,并给我任何建议.任何帮助将不胜感激.
public class NameToPinyinActivity extends Activity {
DatabaseOpenHelper helper = null;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.nametopinyin);
Button searchButton = (Button) findViewById(R.id.search);
searchButton.setOnClickListener(new ButtonClickListener());
helper = new DatabaseOpenHelper(NameToPinyinActivity.this);
}
public class DatabaseOpenHelper extends SQLiteOpenHelper {
/** DB Name */
private static final String DB_NAME = "pinyin";
/** CREATE TABLE SQL */
private static final String CREATE_TABLE_SQL = "CREATE TABLE UNICODE_PINYIN"
+ "(ID INTEGER PRIMARY KEY AUTOINCREMENT, "
+ "UNICODE TEXT NOT NULL, PINYIN …
Run Code Online (Sandbox Code Playgroud) springframework.beans.BeanUtils
复制对象非常有用,我经常使用"ignoreProperties"选项.但是,有时我只想复制特定对象(基本上,与"忽略属性"相反).有谁知道我该怎么做?任何帮助将不胜感激.
import org.springframework.beans.BeanUtils;
public class Sample {
public static void main(String[] args) {
DemoADto demoADto = new DemoADto();
demoADto.setName("Name of Demo A");
demoADto.setAddress("Address of Demo A");
DemoBDto demoBDto = new DemoBDto();
// This is "ignoreProperties" option
// But I want to know how I can copy only name field by using BeanUtils or something.
BeanUtils.copyProperties(demoADto, demoBDto, new String[] {"address"});
System.out.println(demoBDto.getName());
System.out.println(demoBDto.getAddress());
}
}
public class DemoADto {
private String name;
private String address;
public String getName() {
return name; …
Run Code Online (Sandbox Code Playgroud) 我没有任何想法.你能给我任何线索(比如参考站点).任何帮助将不胜感激.
Model1: GROUP(id, name)
Model2: USER_GROUP_CMB(id, user_id, group_id)
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预期的SQL语句:
SELECT *
FROM groups AS g LEFT OUTER JOIN user_group_cmbs AS cmb
ON g.id = cmb.group_id
WHERE cmb.user_id = 1
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我尝试在下面建立协会,但我不知道在此之后该怎么办.
class Group < ActiveRecord::Base
has_many :user_group_cmb
end
class UserGroupCmb < ActiveRecord::Base
has_many :group
end
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Rails版本:3.1.1
我的目标是比较两列并添加结果列.R使用ifelse,但我需要知道熊猫的方式.
[R
> head(mau.payment)
log_month user_id install_month payment
1 2013-06 1 2013-04 0
2 2013-06 2 2013-04 0
3 2013-06 3 2013-04 14994
> mau.payment$user.type <-ifelse(mau.payment$install_month == mau.payment$log_month, "install", "existing")
> head(mau.payment)
log_month user_id install_month payment user.type
1 2013-06 1 2013-04 0 existing
2 2013-06 2 2013-04 0 existing
3 2013-06 3 2013-04 14994 existing
4 2013-06 4 2013-04 0 existing
5 2013-06 6 2013-04 0 existing
6 2013-06 7 2013-04 0 existing
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熊猫
>>> maupayment
user_id log_month install_month
1 …
Run Code Online (Sandbox Code Playgroud) 我试图了解Spring MVC的架构.但是,我完全被@SessionAttributes的行为搞糊涂了.
请看下面的SampleController,它是由SuperForm类处理post方法.事实上,只是SuperForm类的字段只能像我预期的那样绑定.
但是,在我将@SessionAttributes放入Controller后,处理方法作为SubAForm进行绑定.任何人都可以解释我在这个绑定中发生了什么.
-------------------------------------------------------
@Controller
@SessionAttributes("form")
@RequestMapping(value = "/sample")
public class SampleController {
@RequestMapping(method = RequestMethod.GET)
public String getCreateForm(Model model) {
model.addAttribute("form", new SubAForm());
return "sample/input";
}
@RequestMapping(method = RequestMethod.POST)
public String register(@ModelAttribute("form") SuperForm form, Model model) {
return "sample/input";
}
}
-------------------------------------------------------
public class SuperForm {
private Long superId;
public Long getSuperId() {
return superId;
}
public void setSuperId(Long superId) {
this.superId = superId;
}
}
-------------------------------------------------------
public class SubAForm extends SuperForm {
private Long subAId;
public Long …
Run Code Online (Sandbox Code Playgroud) 有时候,我找到了一些类名,包括感知,如ApplicationContextAware
和MessageSourceAware
(春季).这个Aware有什么特别的含义还是一个着名的规则?
我正在尝试使用来自GCE(Google Compute Engine)实例的Google Cloud SQL over SSL.我的问题是我无法通过SSL连接到Cloud SQL实例.
mysql命令正常工作.我可以使用认证文件连接到Cloud SQL实例.
mysql -uroot -p -h [IP Address] --ssl-ca=/home/user/.cert/server-ca.pem --ssl-cert=/home/user/.cert/client-cert.pem --ssl-key=/home/user/.cert/client-key.pem
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但是,当我从PHP程序访问时,我收到了警告和致命错误.
<?php
$pdo = new PDO('mysql:host=[IP Address];dbname=testdb', 'root', 'test', array(
PDO::MYSQL_ATTR_SSL_KEY =>'/home/user/.cert/client-key.pem',
PDO::MYSQL_ATTR_SSL_CERT=>'/home/user/.cert/client-cert.pem',
PDO::MYSQL_ATTR_SSL_CA =>'/home/user/.cert/server-ca.pem'
)
);
$stmt = $pdo->query("SHOW TABLES;");
$row = $stmt->fetch(PDO::FETCH_ASSOC);
print_r($row);
?>?
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PHP Warning: PDO::__construct(): Peer certificate CN=`[GCP project name]:[Cloud SQL instance name]' did not match expected CN=`[IP Address]' in /tmp/mysql.php on line 7
Fatal error: Uncaught exception 'PDOException' with message 'SQLSTATE[HY000] [2002] ' in /tmp/mysql.php on …
Run Code Online (Sandbox Code Playgroud) 我想在用户进入某个区域时发布通知.但是,由于同样的两个CLLocationManagerDelegate方法,我很困惑.我该如何正确使用这两种方法?
有人说如果应用程序在该区域开始,则需要"didDetermineState"方法来开始区域观察.
谢谢,
- (void)locationManager:(CLLocationManager *)manager
didEnterRegion:(CLRegion *)region
{
[self sendNotification:@"didEnterRegion"];
}
- (void)locationManager:(CLLocationManager *)manager
didDetermineState:(CLRegionState)state
forRegion:(CLRegion *)region
{
switch (state) {
case CLRegionStateInside:
[self sendNotification:@"didEnterRegion"];
break;
case CLRegionStateOutside:
break;
case CLRegionStateUnknown:
break;
default:
break;
}
}
Run Code Online (Sandbox Code Playgroud) 我使用一个名为"ECOTree"的梦幻般的javascript组织树生成器,但是当我放置时绘图不起作用<!DOCTYPE html>
.盒子中的标签没有正确放入盒子中.
您可以在下面的网站上的sample1.htm中看到错误.任何人都可以建议我如何解决. http://www.codeproject.com/script/Articles/ViewDownloads.aspx?aid=16192
(为了遵循我的项目规则,我必须定义<!DOCTYPE html>
)
我正在寻找一种从应用程序ID获取应用程序图标的方法.你知道怎么做吗?请分享方式.谢谢.
例如Instagram,我正在寻找的id是:id389801252
https://itunes.apple.com/jp/app/instagram/id389801252?mt=8
我想得到这个图片: