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Android 应用程序 - 搜索 SQLite 数据库并在 ListView 中显示

[英]Android app - search SQLite database and display in ListView

 原文  2021-07-29 05:24:03  8   0    java/ android/ sqlite/ listview

问题描述

我在 Android 中有一个日记应用程序，我希望能够根据用户在 EditText 字段中键入的内容在 SQLite 数据库中搜索条目。 问题是我必须使用旧版本，这使得使用 RecyclerView 变得困难（我认为）。 我的设置如下：

用户可以在 ./NoteDetailActivity 输入新笔记：

import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.ListView;

public class NoteDetailActivity extends AppCompatActivity {

    private EditText editID, editSubject, editContent, editDate, editLatitude, editLongitude;
    private Diary selectedDiary;
    SecondDataBaseHelper secondDataBaseHelper;

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

        editID = findViewById(R.id.IDEditText);
        editSubject = findViewById(R.id.SubjectEditText);
        editContent = findViewById(R.id.contentEditText);
        editDate = findViewById(R.id.dateEditText);
        editLatitude = findViewById(R.id.latitudeEditText);
        editLongitude = findViewById(R.id.longitudeEditText);

        checkForEdit();
    }

    private void checkForEdit() {
        Intent previousIntent = getIntent();

        int passedDiaryID = previousIntent.getIntExtra(Diary.DIARY_EDIT_EXTRA, -1);

        selectedDiary = Diary.getDiaryForID(passedDiaryID);

        if (selectedDiary != null) {
            editID.setText(selectedDiary.getId());
            editSubject.setText(selectedDiary.getSubject());
            editContent.setText(selectedDiary.getContent());
            editDate.setText(selectedDiary.getDate());
            editLatitude.setText(selectedDiary.getLatitude());
            editLongitude.setText(selectedDiary.getLongitude());
         }
    }

    public void saveEntry(View view) {
        SecondDataBaseHelper secondDataBaseHelper = SecondDataBaseHelper.databaseInstance(this);
        String id = String.valueOf(editID.getText());
        String subject = String.valueOf(editSubject.getText());
        String content = String.valueOf(editContent.getText());
        String date = String.valueOf(editDate.getText());
        String latitude = String.valueOf(editLatitude.getText());
        String longitude = String.valueOf(editLongitude.getText());

        if (selectedDiary == null) {
            Diary newDiary = new Diary(id, subject, content, date, latitude, longitude);
            Diary.diaryArrayList.add(newDiary);
            secondDataBaseHelper.addEntryToDatabase(newDiary);
        } else {
            selectedDiary.setId(id);
            selectedDiary.setSubject(subject);
            selectedDiary.setContent(content);
            selectedDiary.setDate(date);

            secondDataBaseHelper.addEntryToDatabase(selectedDiary);
        }
        finish();
    }
}

数据库 ./SecondDataBaseHelper 设置如下：

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

public class SecondDataBaseHelper extends SQLiteOpenHelper {

    private static SecondDataBaseHelper secondDataBaseHelper;

    SQLiteDatabase db = this.getWritableDatabase();

    public final static String DATABASE_NM ="RECORD_OF_USER";
    public final static String TABLE_NM ="DATA_OF_USER";
    public final static String COL_1 = "ID";
    public final static String COL_2 = "SUBJECT";
    public final static String COL_3 = "ENTRY";
    public final static String COL_4 = "DATE";
    public final static String COL_5 = "LATITUDE";
    public final static String COL_6 = "LONGITUDE";


    public SecondDataBaseHelper(Context context) {
        super(context, DATABASE_NM, null, 1);
    }

    public static SecondDataBaseHelper databaseInstance(Context context) {
        if (secondDataBaseHelper == null) {
            secondDataBaseHelper = new SecondDataBaseHelper(context);
        }

        return secondDataBaseHelper;
    }

    @Override
    public void onCreate(SQLiteDatabase db) {

        db.execSQL("CREATE TABLE IF NOT EXISTS " + TABLE_NM +" (ID TEXT, SUBJECT TEXT, ENTRY TEXT, DATE TEXT, LATITUDE TEXT, LONGITUDE TEXT)");

    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

    }

    public void addEntryToDatabase(Diary entry) {
        ContentValues contentValues = new ContentValues();

        contentValues.put(COL_1, entry.getId());
        contentValues.put(COL_2, entry.getSubject());
        contentValues.put(COL_3, entry.getContent());
        contentValues.put(COL_4, entry.getDate());
        contentValues.put(COL_5, entry.getLatitude());
        contentValues.put(COL_6, entry.getLongitude());

        db.insert(TABLE_NM, null, contentValues);
    }

    public void populateDiaryListArray() {
        SQLiteDatabase sqLiteDatabase = this.getReadableDatabase();

        try (Cursor result = sqLiteDatabase.rawQuery("SELECT * FROM " + TABLE_NM, null)) {
            if (result.getCount() != 0) {
                while (result.moveToNext()) {
                    String id = result.getString(1);
                    String subject = result.getString(2);
                    String content = result.getString(3);
                    String date = result.getString(4);
                    String latitude = result.getString(5);
                    String longitude = result.getString(6);

                    Diary diary = new Diary(id, subject, content, date, latitude, longitude);
                    Diary.diaryArrayList.add(diary);
                }
            }
        }
    }


    public void updateDiaryInDB(Diary entry) {
        SQLiteDatabase sqLiteDatabase = this.getWritableDatabase();
        ContentValues contentValues = new ContentValues();

        contentValues.put(COL_1, entry.getId());
        contentValues.put(COL_2, entry.getSubject());
        contentValues.put(COL_3, entry.getContent());
        contentValues.put(COL_4, entry.getDate());
        contentValues.put(COL_5, entry.getLatitude());
        contentValues.put(COL_6, entry.getLongitude());

        sqLiteDatabase.update(TABLE_NM, contentValues, COL_1 + " ?= ", new String[]{String.valueOf(entry.getId())});
    }

    public Cursor viewEntries() {
        SQLiteDatabase sqLiteDatabase = this.getReadableDatabase();

        String query = "SELECT * FROM " +TABLE_NM;

        Cursor cursor = sqLiteDatabase.rawQuery(query, null);

        return cursor;
    }

}

./Diary 日记条目，包含所有 getter/setter：

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

public class SecondDataBaseHelper extends SQLiteOpenHelper {

    private static SecondDataBaseHelper secondDataBaseHelper;

    SQLiteDatabase db = this.getWritableDatabase();

    public final static String DATABASE_NM ="RECORD_OF_USER";
    public final static String TABLE_NM ="DATA_OF_USER";
    public final static String COL_1 = "ID";
    public final static String COL_2 = "SUBJECT";
    public final static String COL_3 = "ENTRY";
    public final static String COL_4 = "DATE";
    public final static String COL_5 = "LATITUDE";
    public final static String COL_6 = "LONGITUDE";


    public SecondDataBaseHelper(Context context) {
        super(context, DATABASE_NM, null, 1);
    }

    public static SecondDataBaseHelper databaseInstance(Context context) {
        if (secondDataBaseHelper == null) {
            secondDataBaseHelper = new SecondDataBaseHelper(context);
        }

        return secondDataBaseHelper;
    }

    @Override
    public void onCreate(SQLiteDatabase db) {

        db.execSQL("CREATE TABLE IF NOT EXISTS " + TABLE_NM +" (ID TEXT, SUBJECT TEXT, ENTRY TEXT, DATE TEXT, LATITUDE TEXT, LONGITUDE TEXT)");

    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

    }

    public void addEntryToDatabase(Diary entry) {
        ContentValues contentValues = new ContentValues();

        contentValues.put(COL_1, entry.getId());
        contentValues.put(COL_2, entry.getSubject());
        contentValues.put(COL_3, entry.getContent());
        contentValues.put(COL_4, entry.getDate());
        contentValues.put(COL_5, entry.getLatitude());
        contentValues.put(COL_6, entry.getLongitude());

        db.insert(TABLE_NM, null, contentValues);
    }

    public void populateDiaryListArray() {
        SQLiteDatabase sqLiteDatabase = this.getReadableDatabase();

        try (Cursor result = sqLiteDatabase.rawQuery("SELECT * FROM " + TABLE_NM, null)) {
            if (result.getCount() != 0) {
                while (result.moveToNext()) {
                    String id = result.getString(1);
                    String subject = result.getString(2);
                    String content = result.getString(3);
                    String date = result.getString(4);
                    String latitude = result.getString(5);
                    String longitude = result.getString(6);

                    Diary diary = new Diary(id, subject, content, date, latitude, longitude);
                    Diary.diaryArrayList.add(diary);
                }
            }
        }
    }


    public void updateDiaryInDB(Diary entry) {
        SQLiteDatabase sqLiteDatabase = this.getWritableDatabase();
        ContentValues contentValues = new ContentValues();

        contentValues.put(COL_1, entry.getId());
        contentValues.put(COL_2, entry.getSubject());
        contentValues.put(COL_3, entry.getContent());
        contentValues.put(COL_4, entry.getDate());
        contentValues.put(COL_5, entry.getLatitude());
        contentValues.put(COL_6, entry.getLongitude());

        sqLiteDatabase.update(TABLE_NM, contentValues, COL_1 + " ?= ", new String[]{String.valueOf(entry.getId())});
    }

    public Cursor viewEntries() {
        SQLiteDatabase sqLiteDatabase = this.getReadableDatabase();

        String query = "SELECT * FROM " +TABLE_NM;

        Cursor cursor = sqLiteDatabase.rawQuery(query, null);

        return cursor;
    }

}

适配器类 ./DiaryAdapter 显示单元格中的 ID/主题组合：

import java.util.List;

public class DiaryAdapter extends ArrayAdapter<Diary>{
    public DiaryAdapter(Context context, List<Diary> entries) {
        super(context, 0, entries);
    }

    @NonNull
    @Override
    public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {
        Diary diary = getItem(position);

        if (convertView == null) {
            convertView = LayoutInflater.from(getContext()).inflate(R.layout.note_cell, parent, false);
        }

        TextView entryID = convertView.findViewById(R.id.entryID);
        TextView entrySubject = convertView.findViewById(R.id.entrySubject);

        entryID.setText(diary.getId());
        entrySubject.setText(diary.getSubject());

        return convertView;
    }
}

进行搜索的实际类是 ./SearchEntries：

import androidx.appcompat.app.AppCompatActivity;

import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

import java.util.ArrayList;

public class SearchEntries extends AppCompatActivity {

    ArrayList<String> listItem;
    ArrayAdapter adapter;

    SecondDataBaseHelper secondDataBaseHelper = new SecondDataBaseHelper(this);

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


    }
    
}

布局文件是./activity_search_entries.xml：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".SearchEntries">

    <androidx.appcompat.widget.Toolbar
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:minHeight="?actionBarSize"
        android:theme="?actionBarTheme"
        android:background="@color/darkGray">

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Search"
            android:textSize="35sp"
            android:paddingRight="25dp"
            android:textColor="@color/white"
            android:textStyle="bold"
            android:layout_gravity="center"/>

    </androidx.appcompat.widget.Toolbar>

    <EditText
        android:hint="Enter text here"
        android:id="@+id/searchTextField"
        android:layout_width="300dp"
        android:layout_height="wrap_content"
        android:textSize="25sp"
        android:layout_marginTop="30dp"
        android:layout_gravity="center"
        android:maxLines="1"/>

    <ListView
        android:id="@+id/diarySearchResults"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_marginTop="8dp"
        android:dividerHeight="3dp"
        android:divider="@color/darkGray"/>
    
</LinearLayout>

所以基本上，我想在 .xml 文件的 /searchTextField 中输入文本，并将其显示在 ./diarySearchResults ListView 字段中，其中每个条目仅由来自适配器的 ID/主题组合组成。 就像我说的，我能找到的大部分内容都适用于 RecyclerView，所以我不太确定如何到达我需要的地方，因此非常感谢任何帮助。 谢谢！

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