Android Studio:使用ListView显示SQLite数据库行的ArrayList
创始人
2024-08-18 20:30:13
0

以下是一个使用ListView显示SQLite数据库行的ArrayList的示例代码:

  1. 创建一个包含ListView的布局文件(例如,activity_main.xml):



    


  1. 创建一个自定义的Adapter类(例如,CustomAdapter.java):
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.TextView;

import java.util.ArrayList;

public class CustomAdapter extends ArrayAdapter {
    private ArrayList dataSet;
    Context mContext;

    // View lookup cache
    private static class ViewHolder {
        TextView txtName;
        TextView txtEmail;
    }

    public CustomAdapter(ArrayList data, Context context) {
        super(context, R.layout.row_item, data);
        this.dataSet = data;
        this.mContext = context;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        // Get the data item for this position
        ModelClass dataModel = getItem(position);

        // Check if an existing view is being reused, otherwise inflate the view
        ViewHolder viewHolder; // view lookup cache stored in tag

        if (convertView == null) {
            viewHolder = new ViewHolder();
            LayoutInflater inflater = LayoutInflater.from(getContext());
            convertView = inflater.inflate(R.layout.row_item, parent, false);
            viewHolder.txtName = convertView.findViewById(R.id.textViewName);
            viewHolder.txtEmail = convertView.findViewById(R.id.textViewEmail);
            convertView.setTag(viewHolder);
        } else {
            viewHolder = (ViewHolder) convertView.getTag();
        }

        // Set the TextViews with the data from the ModelClass
        viewHolder.txtName.setText(dataModel.getName());
        viewHolder.txtEmail.setText(dataModel.getEmail());

        // Return the completed view to render on screen
        return convertView;
    }
}
  1. 创建一个ModelClass类(例如,ModelClass.java)以存储SQLite数据库中的行数据:
public class ModelClass {
    private String name;
    private String email;

    public ModelClass(String name, String email) {
        this.name = name;
        this.email = email;
    }

    public String getName() {
        return name;
    }

    public String getEmail() {
        return email;
    }
}
  1. 创建一个数据库帮助类(例如,DatabaseHelper.java)以处理SQLite数据库操作:
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

import java.util.ArrayList;

public class DatabaseHelper extends SQLiteOpenHelper {
    private static final String DATABASE_NAME = "mydatabase.db";
    private static final String TABLE_NAME = "mytable";
    private static final String COL_NAME = "name";
    private static final String COL_EMAIL = "email";

    public DatabaseHelper(Context context) {
        super(context, DATABASE_NAME, null, 1);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL("CREATE TABLE " + TABLE_NAME + " (" +
                COL_NAME + " TEXT, " +
                COL_EMAIL + " TEXT)");
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        db.execSQL("DROP TABLE IF EXISTS " + TABLE_NAME);
        onCreate(db);
    }

    public boolean insertData(String name, String email) {
        SQLiteDatabase db = this.getWritableDatabase();
        ContentValues contentValues = new ContentValues();
        contentValues.put(COL_NAME, name);
        contentValues.put(COL_EMAIL, email);
        long result = db.insert(TABLE_NAME, null, contentValues);
        return result != -1;
    }

    public ArrayList getAllData() {
        ArrayList arrayList = new ArrayList<>();
        SQLiteDatabase db = this.getReadableDatabase();
        Cursor cursor = db.rawQuery("SELECT * FROM " + TABLE_NAME, null);
        while (cursor.moveToNext()) {
            String name = cursor.getString(cursor.getColumnIndex(COL_NAME));
            String email = cursor.getString(cursor.getColumnIndex(COL_EMAIL));
            ModelClass model = new ModelClass(name, email);
            arrayList.add(model);
        }
        cursor

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