从数据库中读取数据并在android中的GridView中显示它

how we can read data from database and show them in grid in android? i see codes like this :

我们如何从数据库中读取数据并在android中的网格中显示它们？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","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));
    }
}

same way i want to show data from sqlite DB.

同样的方式我想显示来自sqlite DB的数据。

2 个解决方案

#1

hello this is just demo sample of your need. please check it may help you.

你好，这只是你需要的演示样本。请检查它可能会对你有所帮助。

Your Main Activity class

您的主要活动课程

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();
            }
        });
    }
}

Contact java class

联系java类

package com.Sqlite_grid_view;

import java.util.ArrayList;

public class Contact {



    //private variables
    int _id;
    String _name;
    String _phone_number;

    // Empty constructor
    public Contact(){

    }
    // constructor
    public Contact(int id, String name, String _phone_number){
        this._id = id;
        this._name = name;
        this._phone_number = _phone_number;
    }

    // constructor
    public Contact(String name, String _phone_number){
        this._name = name;
        this._phone_number = _phone_number;
    }
    // getting ID
    public int getID(){
        return this._id;
    }

    // setting id
    public void setID(int id){
        this._id = id;
    }

    // getting name
    public String getName(){
        return this._name;
    }

    // setting name
    public void setName(String name){
        this._name = name;
    }

    // getting phone number
    public String getPhoneNumber(){
        return this._phone_number;
    }

    // setting phone number
    public void setPhoneNumber(String phone_number){
        this._phone_number = phone_number;
    }
}

Database Helper Class:

数据库助手类：

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();
    }

}

your layout file with grid view : main.xml

你的布局文件有网格视图：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>

in last your manifest file:

最后你的清单文件：

<?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>

Best Luck!!

好运！！

#2

You should use CursorLoader and SimpleCursorAdapter. This is the most efficient way of doing this kind of things.

您应该使用CursorLoader和SimpleCursorAdapter。这是做这种事情的最有效方式。

You can read about loaders usage here and see some simple example here.

您可以在这里阅读有关装载机的使用情况，并在此处查看一些简单示

The only thing you may have some difficulties with is that default CursorLoader can query cursor only from ContentProvider, but you can use SimpleCursorLoader mentioned in this question

您可能遇到一些困难的唯一问题是默认的CursorLoader只能从ContentProvider查询游标，但您可以使用此问题中提到的SimpleCursorLoader