如何比较反对我的数据库中的值? [英] How do I compare values against my database?
问题描述
在我的申请,我从插入谷歌用户访问应用程序软件包名称播放,并将其保存在数据库中。我只显示,从安装的应用程序,包名称是数据库应用程序。
该值成功插入到数据库中,但是当我在 PlayStoreApps
类在这一行比较如果(arraylist.equals(p.packageName ))
:
公共类PlayStoreApps扩展活动实现OnItemClickListener { 私有静态最终布尔INCLUDE_SYSTEM_APPS = FALSE;
数据库处理器分贝;
私人的ListView mAppsList;
私人AppListAdapter mAdapter;
私人列表<应用> MAPPS; DB =新数据库处理器(本); 私人列表<应用> loadInstalledApps(布尔includeSysApps){
清单<应用>应用=新的ArrayList<应用>(); //包管理器包含所有安装的应用程序的信息
软件包管理系统软件包管理系统= getPackageManager(); 清单< PackageInfo>包= packageManager.getInstalledPackages(0);
名单的ArrayList = db.getAllApps(); 的for(int i = 0; I< packs.size();我++){
PackageInfo p值= packs.get(ⅰ);
ApplicationInfo applicationInfo = p.applicationInfo; 如果(arraylist.equals(p.packageName)){
//如果((p.packageName).equals(数组列表))
应用程序=新的App();
app.setTitle(p.applicationInfo.loadLabel(软件包管理系统)的ToString());
app.setPackageName(p.packageName);
app.setVersionName(p.versionName);
app.setVersion code(p.version code);
CharSequence的描述= p.applicationInfo.loadDescription(软件包管理系统);
app.setDescription(说明!= NULL?
description.toString():);
apps.add(应用);
}
}
返回应用程序;
} 公共类搜索扩展活动{
/ **当第一次创建活动调用。 * /
数据库处理器分贝;
的WebView网络;
@覆盖
公共无效的onCreate(捆绑savedInstanceState){
super.onCreate(savedInstanceState);
的setContentView(R.layout.search);
DB =新数据库处理器(本); 串ID = url.substring(标准。长度(),url.indexOf(与&));
db.addContact(新联系(ID)); Log.d(读,读所有联系人..);
清单<联系与GT;接触= db.getAllContacts(); 对于(联系CN:触点){
字符串日志=ID:+ cn.getID()+,名称:+ cn.getName(); //字符串日志=ID:+ cn.getID()+,名称:+ cn.getName()+,电话:+ cn.getPhoneNumber();
//写入联系人登录
Log.d(姓名,日志);
} view.loadUrl(URL); 返回true;
}公共类数据库处理器扩展SQLiteOpenHelper { 私有静态最终诠释DATABASE_VERSION = 1; 私有静态最后弦乐DATABASE_NAME =contactsManager; 私有静态最后弦乐TABLE_CONTACTS =接触; 私有静态最后弦乐KEY_ID =ID;
私有静态最后弦乐KEY_NAME =名; 公共数据库处理器(上下文的背景下){
超(背景下,DATABASE_NAME,空,DATABASE_VERSION);
} //创建表
@覆盖
公共无效的onCreate(SQLiteDatabase DB){
//字符串CREATE_CONTACTS_TABLE =CREATE TABLE+ TABLE_CONTACTS +(+ KEY_ID +INTEGER PRIMARY KEY,+ KEY_NAME +TEXT+ KEY_PH_NO +TEXT+); 字符串CREATE_CONTACTS_TABLE =CREATE TABLE+ TABLE_CONTACTS +(+ KEY_ID +INTEGER PRIMARY KEY,+ KEY_NAME +TEXT+独特的+); db.execSQL(CREATE_CONTACTS_TABLE);
} //数据库升级
@覆盖
公共无效onUpgrade(SQLiteDatabase分贝,INT oldVersion,诠释静态网页){
如果存在//删除旧的表
db.execSQL(DROP TABLE IF EXISTS+ TABLE_CONTACTS); //再次创建表
的onCreate(DB);
} / **
*所有CRUD(创建,读取,更新,删除)操作
* / //添加新联系人
无效的addContact(联系方式联系我们){
SQLiteDatabase分贝= this.getWritableDatabase(); ContentValues值=新ContentValues();
values.put(KEY_NAME,contact.getName()); // 联系人姓名
// values.put(KEY_PH_NO,contact.getPhoneNumber()); // 联系电话 //插入行
db.insert(TABLE_CONTACTS,空,价值);
db.close(); //关闭数据库连接
} //获取单触点
联系getContact(INT ID){
SQLiteDatabase分贝= this.getReadableDatabase(); 光标光标= db.query(TABLE_CONTACTS,新的String [] {KEY_ID,KEY_NAME},KEY_ID +=?,新的String [] {将String.valueOf(ID)},NULL,NULL,NULL,NULL);
如果(指针!= NULL)
cursor.moveToFirst(); 联系方式联系我们=新的联系人(的Integer.parseInt(cursor.getString(0)),cursor.getString(1));
//返回接触
返回接触;
} //获取所有联系人
公开名单<联系与GT; getAllContacts(){
清单<联系与GT; contactList =新的ArrayList<联系与GT;();
//选择所有查询
字符串selectQuery =SELECT * FROM+ TABLE_CONTACTS; SQLiteDatabase分贝= this.getWritableDatabase();
光标光标= db.rawQuery(selectQuery,NULL); //通过所有行循环,并增加列表
如果(cursor.moveToFirst()){
做{
联系方式联系我们=新的联系人();
contact.setID(的Integer.parseInt(cursor.getString(0)));
contact.setName(cursor.getString(1));
//contact.setPhoneNumber(cursor.getString(2));
//添加联系人名单
contactList.add(接触);
}而(cursor.moveToNext());
} //返回联系人列表
返回contactList;
} //更新单触点
公众诠释updateContact(联系方式联系我们){
SQLiteDatabase分贝= this.getWritableDatabase(); ContentValues值=新ContentValues();
values.put(KEY_NAME,contact.getName());
// values.put(KEY_PH_NO,contact.getPhoneNumber()); //更新行
返回db.update(TABLE_CONTACTS,价值观,KEY_ID +=?,新的String [] {将String.valueOf(contact.getID())});
} //删除单个联系人
公共无效deleteContact(联系方式联系我们){
SQLiteDatabase分贝= this.getWritableDatabase();
db.delete(TABLE_CONTACTS,KEY_ID +=?,新的String [] {将String.valueOf(contact.getID())});
db.close();
} 公众诠释deleteContact(){
尝试{
SQLiteDatabase分贝= this.getWritableDatabase();
返回db.delete(TABLE_CONTACTS,NULL,NULL);
}赶上(例外五){
e.printStackTrace();
}
返回0;
} //获取联系人计数
公众诠释getContactsCount(){
字符串countQuery =SELECT * FROM+ TABLE_CONTACTS;
SQLiteDatabase分贝= this.getReadableDatabase();
光标光标= db.rawQuery(countQuery,NULL);
cursor.close(); //返回计数
返回cursor.getCount();
} 公众的ArrayList<串GT; getAllApps(){ 字符串selectQuery =SELECT * FROM+ TABLE_CONTACTS;
ArrayList的<串GT;应用=新的ArrayList<串GT;();
SQLiteDatabase分贝= this.getWritableDatabase();
光标光标= db.rawQuery(selectQuery,NULL); //通过所有行循环,并增加列表
如果(cursor.moveToFirst()){
做{
apps.add(cursor.getString(cursor.getColumnIndex(KEY_NAME)));
}而(cursor.moveToNext());
} //返回列表
返回应用程序;
}
}
首先:不使用非通用列表
在你的 loadInstalledApps
方法,您可以使用这一行:
列表的ArrayList = db.getAllApps();
由于 getAllApps
返回的ArrayList<弦乐>
你的列表
应该是类型列表与LT;弦乐方式>
二:你不能在列表中像你想做什么比较项目:
如果(arraylist.equals(p.packageName)
你基本上想看看是否在的ArrayList
对象等于字符串
。苹果与桔子比较不顺利要么...
第三:在code比较,而不是在SQL比较实在是太慢了performancewise,应该肯定是可以避免的,尤其是在移动操作系统的,因为这是内存和CPU的浪费
如果你真的想在code进行比较,你可以做这样的:
如果(arraylist.contains(p.packageName)){
// 做一点事
应用程序=新的App();
app.setTitle(p.applicationInfo.loadLabel(软件包管理系统)的ToString());
app.setPackageName(p.packageName);
app.setVersionName(p.versionName);
app.setVersion code(p.version code);
CharSequence的描述= p.applicationInfo.loadDescription(软件包管理系统);
app.setDescription(说明!= NULL?
description.toString():);
apps.add(应用);
}
不过,我不会推荐这条道路。
In my application, I'm inserting the user visit apps package name from Google Play and save it in a database. I display only that apps from install apps that package name are in database.
The values insert successfully into the database, but when I compare in the PlayStoreApps
class at this line if (arraylist.equals(p.packageName))
:
public class PlayStoreApps extends Activity implements OnItemClickListener {
private static final boolean INCLUDE_SYSTEM_APPS = false;
DatabaseHandler db;
private ListView mAppsList;
private AppListAdapter mAdapter;
private List<App> mApps;
db = new DatabaseHandler(this);
private List<App> loadInstalledApps(boolean includeSysApps) {
List<App> apps = new ArrayList<App>();
// the package manager contains the information about all installed apps
PackageManager packageManager = getPackageManager();
List<PackageInfo> packs = packageManager.getInstalledPackages(0);
List arraylist = db.getAllApps();
for (int i = 0; i < packs.size(); i++) {
PackageInfo p = packs.get(i);
ApplicationInfo applicationInfo = p.applicationInfo;
if (arraylist.equals(p.packageName)) {
// if ( (p.packageName).equals(arraylist))
App app = new App();
app.setTitle(p.applicationInfo.loadLabel(packageManager).toString());
app.setPackageName(p.packageName);
app.setVersionName(p.versionName);
app.setVersionCode(p.versionCode);
CharSequence description = p.applicationInfo.loadDescription(packageManager);
app.setDescription(description != null ?
description.toString() : "");
apps.add(app);
}
}
return apps;
}
public class Search extends Activity {
/** Called when the activity is first created. */
DatabaseHandler db;
WebView web;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.search);
db = new DatabaseHandler(this);
String id= url.substring(Standard .length(), url.indexOf("&"));
db.addContact(new Contact(id));
Log.d("Reading: ", "Reading all contacts..");
List<Contact> contacts = db.getAllContacts();
for (Contact cn : contacts) {
String log = "Id: "+cn.getID()+" ,Name: " + cn.getName() ;
// String log = "Id: "+cn.getID()+" ,Name: " + cn.getName() + " ,Phone: " + cn.getPhoneNumber();
// Writing Contacts to log
Log.d("Name: ", log);
}
view.loadUrl(url);
return true;
}
public class DatabaseHandler extends SQLiteOpenHelper {
private static final int DATABASE_VERSION = 1;
private static final String DATABASE_NAME = "contactsManager";
private static final String TABLE_CONTACTS = "contacts";
private static final String KEY_ID = "id";
private static final String KEY_NAME = "name";
public DatabaseHandler(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
// Creating Tables
@Override
public void onCreate(SQLiteDatabase db) {
// String CREATE_CONTACTS_TABLE = "CREATE TABLE " + TABLE_CONTACTS + "("+ KEY_ID + " INTEGER PRIMARY KEY," + KEY_NAME + " TEXT,"+ KEY_PH_NO + " TEXT" + ")";
String CREATE_CONTACTS_TABLE = "CREATE TABLE " + TABLE_CONTACTS + "("+ KEY_ID + " INTEGER PRIMARY KEY," + KEY_NAME + " TEXT" + " UNIQUE " + ")";
db.execSQL(CREATE_CONTACTS_TABLE);
}
// Upgrading database
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// Drop older table if existed
db.execSQL("DROP TABLE IF EXISTS " + TABLE_CONTACTS);
// Create tables again
onCreate(db);
}
/**
* All CRUD(Create, Read, Update, Delete) Operations
*/
// Adding new contact
void addContact(Contact contact) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_NAME, contact.getName()); // Contact Name
// values.put(KEY_PH_NO, contact.getPhoneNumber()); // Contact Phone
// Inserting Row
db.insert(TABLE_CONTACTS, null, values);
db.close(); // Closing database connection
}
// Getting single contact
Contact getContact(int id) {
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.query(TABLE_CONTACTS, new String[] { KEY_ID, KEY_NAME }, KEY_ID + "=?", new String[] { String.valueOf(id) }, null, null, null, null);
if (cursor != null)
cursor.moveToFirst();
Contact contact = new Contact(Integer.parseInt(cursor.getString(0)), cursor.getString(1));
// return contact
return contact;
}
// Getting All Contacts
public List<Contact> getAllContacts() {
List<Contact> contactList = new ArrayList<Contact>();
// Select All Query
String selectQuery = "SELECT * FROM " + TABLE_CONTACTS;
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
// looping through all rows and adding to list
if (cursor.moveToFirst()) {
do {
Contact contact = new Contact();
contact.setID(Integer.parseInt(cursor.getString(0)));
contact.setName(cursor.getString(1));
//contact.setPhoneNumber(cursor.getString(2));
// Adding contact to list
contactList.add(contact);
} while (cursor.moveToNext());
}
// return contact list
return contactList;
}
// Updating single contact
public int updateContact(Contact contact) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_NAME, contact.getName());
// values.put(KEY_PH_NO, contact.getPhoneNumber());
// updating row
return db.update(TABLE_CONTACTS, values, KEY_ID + " = ?", new String[] { String.valueOf(contact.getID()) });
}
// Deleting single contact
public void deleteContact(Contact contact) {
SQLiteDatabase db = this.getWritableDatabase();
db.delete(TABLE_CONTACTS, KEY_ID + " = ?", new String[] { String.valueOf(contact.getID()) });
db.close();
}
public int deleteContact() {
try {
SQLiteDatabase db = this.getWritableDatabase();
return db.delete(TABLE_CONTACTS, null, null);
} catch (Exception e) {
e.printStackTrace();
}
return 0;
}
// Getting contacts Count
public int getContactsCount() {
String countQuery = "SELECT * FROM " + TABLE_CONTACTS;
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(countQuery, null);
cursor.close();
// return count
return cursor.getCount();
}
public ArrayList<String> getAllApps() {
String selectQuery = "SELECT * FROM "+TABLE_CONTACTS;
ArrayList<String> apps = new ArrayList<String>();
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
// looping through all rows and adding to list
if (cursor.moveToFirst()) {
do {
apps.add(cursor.getString(cursor.getColumnIndex(KEY_NAME)));
} while (cursor.moveToNext());
}
// return list
return apps;
}
}
First of: don't use non-generic Lists
.
In your loadInstalledApps
method, you use this line:
List arraylist = db.getAllApps();
As the getAllApps
returns an ArrayList<String>
your List
should be of type List<String>
.
Second: You can't compare items in a list like what you're trying to do:
if(arraylist.equals(p.packageName)
You're essentially trying to see if the ArrayList
object is equal to a String
. Comparing apples with oranges doesn't go well either...
Third: Comparing in code instead of comparing in SQL is really slow performancewise and should definately be avoided, especially on mobile OS's, as this is a waste of memory and CPU.
If you really want to compare in code, you can do it like this:
if(arraylist.contains(p.packageName)) {
// Do something
App app = new App();
app.setTitle(p.applicationInfo.loadLabel(packageManager).toString());
app.setPackageName(p.packageName);
app.setVersionName(p.versionName);
app.setVersionCode(p.versionCode);
CharSequence description = p.applicationInfo.loadDescription(packageManager);
app.setDescription(description != null ?
description.toString() : "");
apps.add(app);
}
But I wouldn't recommend this path.
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