从数据库中读取数据并在android的GridView中显示
我们如何从数据库中读取数据并在android的网格中显示它们? 我看到这样的代码:从数据库中读取数据并在android的GridView中显示,android,database,grid,Android,Database,Grid,我们如何从数据库中读取数据并在android的网格中显示它们? 我看到这样的代码: public class DataAdapter extends BaseAdapter { Context mContext; private String [] id = {"S001","S002","S003","S004","S005","S006","S007"}; private String [] name={"Rohit","Rahul","Ravi","Amit","A
public class DataAdapter extends BaseAdapter
{
Context mContext;
private String [] id = {"S001","S002","S003","S004","S005","S006","S007"};
private String [] name={"Rohit","Rahul","Ravi","Amit","Arun","Anil","Kashif"};
private LayoutInflater mInflater;
public DataAdapter(Context c)
{
mContext=c;
mInflater = LayoutInflater.from(c);
}
public int getCount()
{
return id.length;
}
public Object getItem(int position)
{
return position;
}
public long getItemId(int position)
{
return position;
}
public View getView(int position, View convertView, ViewGroup parent)
{
ViewHolder holder=null;
// convertView=null;
if(convertView==null)
{
convertView = mInflater.inflate(R.layout.customgrid,
parent,false);
holder = new ViewHolder();
holder.txtId=(TextView)convertView.findViewById(R.id.txtId);
holder.txtId.setPadding(100, 10,10 , 10);
holder.txtName=(TextView)convertView.findViewById(R.id.txtName);
holder.txtName.setPadding(100, 10, 10, 10);
if(position==0)
{
convertView.setTag(holder);
}
}
else
{
holder = (ViewHolder) convertView.getTag();
}
// holder.txtId.setText(id[position]);
holder.txtId.setText(id[position]);
holder.txtName.setText(name[position]);
return convertView;
}
static class ViewHolder
{
TextView txtId;
TextView txtName;
}
}
//------------main---------------------------------------------
public class GridViewDataActivity extends Activity {
EditText name;
GridView gridview;
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
gridview = (GridView) findViewById(R.id.gridview);
gridview.setAdapter(new DataAdapter(this));
}
}
与我希望显示sqlite DB中的数据的方式相同。您应该使用和。这是做这类事情最有效的方法
您可以阅读装载机的用法,并查看一些简单的示例
您可能遇到的唯一问题是默认的
CursorLoader
只能从ContentProvider
查询光标,但您可以使用问题中提到的SimpleCursorLoader
,您好这只是您需要的演示示例。请检查一下,也许对你有帮助
你的主要活动课
package com.Sqlite_grid_view;
import java.util.ArrayList;
import java.util.List;
import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ArrayAdapter;
import android.widget.GridView;
import android.widget.TextView;
import android.widget.Toast;
public class AndroidSQLiteTutorialActivity extends Activity {
private GridView gridView;
public static ArrayList<String> ArrayofName = new ArrayList<String>();
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
DatabaseHandler db = new DatabaseHandler(this);
/**
* CRUD Operations
* */
// Inserting Contacts
Log.d("Insert: ", "Inserting ..");
db.addContact(new Contact("Ravi", "91"));
db.addContact(new Contact("Srinivas", "99"));
db.addContact(new Contact("Tommy", "95"));
db.addContact(new Contact("Karthik", "93"));
// Reading all contacts
Log.d("Reading: ", "Reading all contacts..");
List<Contact> contacts = db.getAllContacts();
for (Contact cn : contacts) {
String log = "Id: "+cn.getID()+" ,Name: " + cn.getName() + " ,Phone: " + cn.getPhoneNumber();
// Writing Contacts to log
Log.d("Name: ", log);
}
db.getAllContacts();
gridView = (GridView) findViewById(R.id.gridView1);
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
android.R.layout.simple_list_item_1, ArrayofName);
gridView.setAdapter(adapter);
gridView.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View v,
int position, long id) {
Toast.makeText(getApplicationContext(),
((TextView) v).getText(), Toast.LENGTH_SHORT).show();
}
});
}
}
数据库帮助程序类:
package com.Sqlite_grid_view;
import java.util.ArrayList;
import java.util.List;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
public class DatabaseHandler extends SQLiteOpenHelper {
// All Static variables
// Database Version
private static final int DATABASE_VERSION = 1;
// Database Name
private static final String DATABASE_NAME = "contactsManager";
// Contacts table name
private static final String TABLE_CONTACTS = "contacts";
// Contacts Table Columns names
private static final String KEY_ID = "id";
private static final String KEY_NAME = "name";
private static final String KEY_PH_NO = "phone_number";
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" + ")";
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_PH_NO }, 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), cursor.getString(2));
// 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));
String name = cursor.getString(1) +"\n"+ cursor.getString(2);
AndroidSQLiteTutorialActivity.ArrayofName.add(name);
// 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();
}
// 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();
}
}
package com.Sqlite\u grid\u视图;
导入java.util.ArrayList;
导入java.util.List;
导入android.content.ContentValues;
导入android.content.Context;
导入android.database.Cursor;
导入android.database.sqlite.SQLiteDatabase;
导入android.database.sqlite.SQLiteOpenHelper;
公共类DatabaseHandler扩展了SQLiteOpenHelper{
//所有静态变量
//数据库版本
私有静态最终int数据库_VERSION=1;
//数据库名称
私有静态最终字符串数据库\u NAME=“contactsManager”;
//联系人表名称
专用静态最终字符串表\u CONTACTS=“CONTACTS”;
//联系人表列名称
私有静态最终字符串密钥\u ID=“ID”;
私有静态最终字符串键\u NAME=“NAME”;
专用静态最终字符串密钥\u PH\u NO=“电话号码”;
公共数据库处理程序(上下文){
super(上下文、数据库名称、null、数据库版本);
}
//创建表
@凌驾
public void onCreate(SQLiteDatabase db){
字符串CREATE_CONTACTS_TABLE=“CREATE TABLE”+TABLE_CONTACTS+”(“
+键ID+“整数主键”+“键名称+”文本
+键号+“文本”+”;
execSQL(创建联系人表);
}
//升级数据库
@凌驾
public void onUpgrade(SQLiteDatabase db,int-oldVersion,int-newVersion){
//删除旧表(如果存在)
db.execSQL(“如果存在删除表”+表_联系人);
//再次创建表
onCreate(db);
}
/**
*所有CRUD(创建、读取、更新、删除)操作
*/
//添加新联系人
无效添加联系人(联系人联系人){
SQLiteDatabase db=this.getWritableDatabase();
ContentValues=新的ContentValues();
value.put(KEY_NAME,contact.getName());//contact NAME
value.put(键号,contact.getPhoneNumber());//联系电话
//插入行
db.插入(表_触点,空,值);
db.close();//关闭数据库连接
}
//获得单一联系
联系人getContact(int-id){
SQLiteDatabase db=this.getReadableDatabase();
Cursor Cursor=db.query(TABLE_CONTACTS,新字符串[]{KEY_ID,
密钥名称,密钥号,密钥ID+“=?”,
新字符串[]{String.valueOf(id)},null,null,null,null);
如果(光标!=null)
cursor.moveToFirst();
Contact Contact=新联系人(Integer.parseInt(cursor.getString(0)),
cursor.getString(1),cursor.getString(2));
//回接
回接;
}
//获取所有联系人
公共列表getAllContacts(){
List contactList=new ArrayList();
//选择所有查询
String selectQuery=“SELECT*FROM”+表格\联系人;
SQLiteDatabase db=this.getWritableDatabase();
Cursor Cursor=db.rawQuery(selectQuery,null);
//循环遍历所有行并添加到列表
if(cursor.moveToFirst()){
做{
触点=新触点();
setID(Integer.parseInt(cursor.getString(0));
contact.setName(cursor.getString(1));
contact.setPhoneNumber(cursor.getString(2));
字符串名称=cursor.getString(1)+“\n”+cursor.getString(2);
AndroidSQLiteTutorialActivity.ArrayofName.add(名称);
//将联系人添加到列表中
联系人列表。添加(联系人);
}while(cursor.moveToNext());
}
//返回联系人列表
返回联系人列表;
}
//更新单个联系人
public int updateContact(联系人){
SQLiteDatabase db=this.getWritableDatabase();
ContentValues=新的ContentValues();
value.put(KEY_NAME,contact.getName());
value.put(键号,contact.getPhoneNumber());
//更新行
返回db.update(表联系人、值、键ID+“=?”,
新字符串[]{String.valueOf(contact.getID())};
}
//删除单个联系人
公共联系人(联系人){
SQLiteDatabase db=this.getWritableDatabase();
db.delete(表触点,键ID+“=?”,
新字符串[]{String.valueOf(contact.getID())};
db.close();
}
//获取联系人计数
public int getcontactscont(){
String countQuery=“SELECT*FROM”+表\u联系人;
SQLiteDatabase db=this.getReadableDatabase();
Cursor Cursor=db.rawQuery(countQuery,null);
cursor.close();
//返回计数
返回cursor.getCount();
}
}
带有网格视图的布局文件:main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="fill_parent"
android:layout_height="fill_parent">
<GridView android:layout_height="wrap_content" android:id="@+id/gridView1"
android:layout_width="match_parent" android:numColumns="3"></GridView>
</LinearLayout>
在最后一个清单文件中:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.Sqlite_grid_view"
android:versionCode="1"
android:versionName="1.0">
<uses-sdk android:minSdkVersion="4" />
<application
android:icon="@drawable/icon"
android:label="sqlite test" >
<activity
android:label="@string/app_name"
android:name=".AndroidSQLiteTutorialActivity" >
<intent-filter >
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
祝你好运 选中此项在此处添加您的所有代码!并给出关于设计的想法。意思是你从数据库中得到了什么类型的数据,以及如何显示它。。它可能会起作用。但同时从数据库表加载所有信息是一种非常糟糕的做法。当您100%确定一定数量的数据行永远不会重新生成时,这可能是可以接受的
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.Sqlite_grid_view"
android:versionCode="1"
android:versionName="1.0">
<uses-sdk android:minSdkVersion="4" />
<application
android:icon="@drawable/icon"
android:label="sqlite test" >
<activity
android:label="@string/app_name"
android:name=".AndroidSQLiteTutorialActivity" >
<intent-filter >
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>