Question

**编辑：我将使用listview而不是Gridview。 **

我已经学习了Android几个星期和最后几天我一直在努力在网格视图中获取我的SQL数据。我一直在搜索许多主题，但我似乎无法找到适合我的问题的答案。这是我到目前为止的代码：

package com.example.myfirstapp;

import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.EditText;
import android.widget.GridView;
import android.widget.TextView;
import android.widget.Toast;

import java.util.ArrayList;


public class DisplayMessageActivity extends AppCompatActivity {

    public static ArrayList<String> ArrayofName = new ArrayList<String>();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_display_message);

        SQLiteDatabase db = mDbHelper.getReadableDatabase();
        String selectQuery = "SELECT * FROM " + MainActivity.FeedReaderContract.FeedEntry.TABLE_NAME;

        Cursor cursor = db.rawQuery(selectQuery, null);
        {
            // looping through all rows and adding to list
            if (cursor.moveToFirst()) {
                do {
                    String id = cursor.getString(cursor.getColumnIndex("_ID"));
                    String title = cursor.getString(cursor.getColumnIndex("title"));
                    String subtitle = cursor.getString(cursor.getColumnIndex("subtitle"));

                    String name = id +"\n" + title +"\n"+ subtitle;
                    DisplayMessageActivity.ArrayofName.add(name);

                } while (cursor.moveToNext());
            }
        }
        GridView 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 AdapterView.OnItemClickListener() {
            public void onItemClick(AdapterView<?> parent, View v,
                                    int position, long id) {
                Toast.makeText(getApplicationContext(),
                        ((TextView) v).getText(), Toast.LENGTH_SHORT).show();
            }
        });



    }

    private static final String TEXT_TYPE = " TEXT";
    private static final String COMMA_SEP = ",";
    private static final String SQL_CREATE_ENTRIES =
            "CREATE TABLE " + MainActivity.FeedReaderContract.FeedEntry.TABLE_NAME + " (" +
                    MainActivity.FeedReaderContract.FeedEntry._ID + " INTEGER PRIMARY KEY," +
                    MainActivity.FeedReaderContract.FeedEntry.COLUMN_NAME_TITLE + TEXT_TYPE + COMMA_SEP +
                    MainActivity.FeedReaderContract.FeedEntry.COLUMN_NAME_SUBTITLE + TEXT_TYPE + " )";

    private static final String SQL_DELETE_ENTRIES = "DROP TABLE IF EXISTS '" + MainActivity.FeedReaderContract.FeedEntry.TABLE_NAME + "'";

    public class FeedReaderDbHelper extends SQLiteOpenHelper {
        // If you change the database schema, you must increment the database version.
        public static final int DATABASE_VERSION = 1;
        public static final String DATABASE_NAME = "FeedReader.db";


        public FeedReaderDbHelper(Context context) {
            super(context, DATABASE_NAME, null, DATABASE_VERSION);
        }

        public void onCreate(SQLiteDatabase db) {
            db.execSQL(SQL_CREATE_ENTRIES);
        }

        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
            // This database is only a cache for online data, so its upgrade policy is
            // to simply to discard the data and start over
            db.execSQL(SQL_DELETE_ENTRIES);
            onCreate(db);

        }
    }
    DisplayMessageActivity.FeedReaderDbHelper mDbHelper = new FeedReaderDbHelper(this);

    public void Test (View view) {
        SQLiteDatabase db = mDbHelper.getReadableDatabase();

        // Define a projection that specifies which columns from the database you will actually use after this query.
        String[] projection = {MainActivity.FeedReaderContract.FeedEntry._ID, MainActivity.FeedReaderContract.FeedEntry.COLUMN_NAME_TITLE, MainActivity.FeedReaderContract.FeedEntry.COLUMN_NAME_SUBTITLE};

        // Filter results WHERE "title" = 'My Title'
        String selection = MainActivity.FeedReaderContract.FeedEntry.COLUMN_NAME_TITLE + " = ?";
        String[] selectionArgs = {"A"};

        // How you want the results sorted in the resulting Cursor
        String sortOrder = MainActivity.FeedReaderContract.FeedEntry.COLUMN_NAME_SUBTITLE + " DESC";

        Cursor c = db.query(
                MainActivity.FeedReaderContract.FeedEntry.TABLE_NAME,  // The table to query
                projection,                               // The columns to return
                selection,                                // The columns for the WHERE clause
                selectionArgs,                            // The values for the WHERE clause
                null,                                     // don't group the rows
                null,                                     // don't filter by row groups
                sortOrder                                 // The sort order
        );

        if (c.getCount()>0) {
            c.moveToFirst();
            int itemId = c.getInt(c.getColumnIndexOrThrow(MainActivity.FeedReaderContract.FeedEntry._ID));
            String strTitel = c.getString(c.getColumnIndexOrThrow(MainActivity.FeedReaderContract.FeedEntry.COLUMN_NAME_TITLE));
            String strSubtitel = c.getString(c.getColumnIndexOrThrow(MainActivity.FeedReaderContract.FeedEntry.COLUMN_NAME_SUBTITLE));

            EditText edtID = (EditText) findViewById(R.id.txtInvoer);
            edtID.setText(Integer.toString(itemId));

            EditText edtTitle = (EditText) findViewById(R.id.txtTitel2);
            edtTitle.setText(strTitel);

            EditText edtSubtitle = (EditText) findViewById(R.id.txtSubtitel2);
            edtSubtitle.setText(strSubtitel);
        } else {
            Toast.makeText(getApplicationContext(), "Geen data in db", Toast.LENGTH_LONG).show();

        }
    }

    public void Vorige (View view) {
        SQLiteDatabase db = mDbHelper.getReadableDatabase();

        String[] projection = {MainActivity.FeedReaderContract.FeedEntry._ID, MainActivity.FeedReaderContract.FeedEntry.COLUMN_NAME_TITLE, MainActivity.FeedReaderContract.FeedEntry.COLUMN_NAME_SUBTITLE};

        String selection = "_ID=?";
        EditText edtGeselecteerdeID = (EditText) findViewById(R.id.txtInvoer);
        int intVolgendeID=Integer.parseInt(edtGeselecteerdeID.getText().toString())-1;
        String strVolgendeID=Integer.toString(intVolgendeID);

        String[] selectionArgs = {strVolgendeID};

        // How you want the results sorted in the resulting Cursor
        String sortOrder = MainActivity.FeedReaderContract.FeedEntry.COLUMN_NAME_SUBTITLE + " DESC";

        Cursor c = db.query(
                MainActivity.FeedReaderContract.FeedEntry.TABLE_NAME,  // The table to query
                projection,                               // The columns to return
                selection,                                // The columns for the WHERE clause
                selectionArgs,                            // The values for the WHERE clause
                null,                                     // don't group the rows
                null,                                     // don't filter by row groups
                sortOrder                                 // The sort order
        );


        if (c.getCount()>0) {
            c.moveToFirst();
            int itemId = c.getInt(c.getColumnIndexOrThrow(MainActivity.FeedReaderContract.FeedEntry._ID));
            String strTitel = c.getString(c.getColumnIndexOrThrow(MainActivity.FeedReaderContract.FeedEntry.COLUMN_NAME_TITLE));
            String strSubtitel = c.getString(c.getColumnIndexOrThrow(MainActivity.FeedReaderContract.FeedEntry.COLUMN_NAME_SUBTITLE));

            EditText edtID = (EditText) findViewById(R.id.txtInvoer);
            edtID.setText(Integer.toString(itemId));

            EditText edtTitle = (EditText) findViewById(R.id.txtTitel2);
            edtTitle.setText(strTitel);

            EditText edtSubtitle = (EditText) findViewById(R.id.txtSubtitel2);
            edtSubtitle.setText(strSubtitel);
        } else {
            Toast.makeText(getApplicationContext(), "Geen data in db", Toast.LENGTH_LONG).show();

        }

    }

    public void Volgende (View view) {
        SQLiteDatabase db = mDbHelper.getReadableDatabase();

        String[] projection = {MainActivity.FeedReaderContract.FeedEntry._ID, MainActivity.FeedReaderContract.FeedEntry.COLUMN_NAME_TITLE, MainActivity.FeedReaderContract.FeedEntry.COLUMN_NAME_SUBTITLE};

        String selection = MainActivity.FeedReaderContract.FeedEntry._ID + " = ?";
        EditText edtGeselecteerdeID = (EditText) findViewById(R.id.txtInvoer);
        int intVolgendeID=Integer.parseInt(edtGeselecteerdeID.getText().toString())+1;
        String strVolgendeID=Integer.toString(intVolgendeID);

        String[] selectionArgs = {strVolgendeID};

        // How you want the results sorted in the resulting Cursor
        String sortOrder = MainActivity.FeedReaderContract.FeedEntry.COLUMN_NAME_SUBTITLE + " DESC";

        Cursor c = db.query(
                MainActivity.FeedReaderContract.FeedEntry.TABLE_NAME,  // The table to query
                projection,                               // The columns to return
                selection,                                // The columns for the WHERE clause
                selectionArgs,                            // The values for the WHERE clause
                null,                                     // don't group the rows
                null,                                     // don't filter by row groups
                sortOrder                                 // The sort order
        );


        if (c.getCount()>0) {
            c.moveToFirst();
            int itemId = c.getInt(c.getColumnIndexOrThrow(MainActivity.FeedReaderContract.FeedEntry._ID));
            String strTitel = c.getString(c.getColumnIndexOrThrow(MainActivity.FeedReaderContract.FeedEntry.COLUMN_NAME_TITLE));
            String strSubtitel = c.getString(c.getColumnIndexOrThrow(MainActivity.FeedReaderContract.FeedEntry.COLUMN_NAME_SUBTITLE));

            EditText edtID = (EditText) findViewById(R.id.txtInvoer);
            edtID.setText(Integer.toString(itemId));

            EditText edtTitle = (EditText) findViewById(R.id.txtTitel2);
            edtTitle.setText(strTitel);

            EditText edtSubtitle = (EditText) findViewById(R.id.txtSubtitel2);
            edtSubtitle.setText(strSubtitel);
        } else {
            Toast.makeText(getApplicationContext(), "Geen data in db", Toast.LENGTH_LONG).show();

        }

    }




}

因此，在MainActivity中，我已经获得了将数据添加到数据库中的代码。＆＃39; DisplayMessageActivity＆＃39;用于测试新的东西。我的数据库由3列组成：ID，标题和副标题。我使用方法＆＃39;测试＆＃39;在Edittext对象中显示数据，以及方法＆＃39; Vorige＆＃39;和＆＃39; Volgende＆＃39;浏览数据。现在我试图在gridview或listview中显示数据（id，title＆amp; subtitle）（我真的不知道该使用什么）。您可以在第一个onCreate类中找到我的问题的所有代码。

我想要达到这样的目标：

因此第一行显示不同的列标题，所有其他行显示数据。 显示标题的第一行甚至不需要，我可以使用EditText字段轻松添加它们。

任何人都可以帮助我吗？我们也欢迎其他改进我的代码的建议;）

使用SQL数据库填充Gridview

0 个答案: