如何将可扩展列表视图中的子行连接到SQL数据库表中的特定行

时间：2018-02-07 05:08:57

标签： java android sqlite expandablelistview assets

我正在尝试制作一种目录类型的android应用程序。目录是关于一些材料。我的想法是使用包含子行的可扩展列表视图。子行充满了可点击的文本，这些文本是材料名称，并将在警报对话框中显示材料的数据（标记，数量，轮廓，长度，重量，总重量）。材料的数据库是在数据库浏览器中创建的，并保存在Android Studio的资源文件夹中。

这是数据库表（示例）：

Database Table Sample

以下是可扩展列表视图活动：

Expandable List View Activity

以下是代码：

DatabaseHelper.java 

package com.example.sutetpedia;

import android.content.Context;
import android.content.Intent;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;
import android.database.sqlite.SQLiteOpenHelper;
import android.os.Bundle;
import android.util.Log;

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

public class DatabaseHelper extends SQLiteOpenHelper {

    String DB_PATH = null;
    private static String DB_NAME = "marking";
    public static final String TABLE_NAME = "MARKING_DATA";
    private SQLiteDatabase myDataBase;
    private final Context myContext;

    public DatabaseHelper(Context context) {
        super(context, DB_NAME, null, 10);
        this.myContext = context;
        this.DB_PATH = "/data/data/" + context.getPackageName() + "/" + "databases/";
        Log.e("Path 1", DB_PATH);
    }




    private boolean checkDataBase() {
        SQLiteDatabase checkDB = null;
        try {
            String myPath = DB_PATH + DB_NAME;
            checkDB = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
        } catch (SQLiteException e) {
        }
        if (checkDB != null) {
            checkDB.close();
        }
        return checkDB != null ? true : false;
    }



    public void openDataBase() throws SQLException {
        String myPath = DB_PATH + DB_NAME;
        myDataBase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);

    }

    @Override
    public synchronized void close() {
        if (myDataBase != null)
            myDataBase.close();
        super.close();
    }


    @Override
    public void onCreate(SQLiteDatabase db) {
    }

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

    public Cursor getRow(String key){
        SQLiteDatabase db = this.getWritableDatabase();
        Cursor res = db.rawQuery("select * from " + TABLE_NAME + "where marking = "+key,null);

        return res;
    }




}

MyExpandableListAdapter.java 

package com.example.sutetpedia;

import android.app.AlertDialog;
import android.content.Context;
import android.content.Intent;
import android.database.Cursor;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseExpandableListAdapter;
import android.widget.TextView;
import com.example.sutetpedia.DatabaseHelper;
import android.widget.Toast;

import com.example.sutetpedia.ChildRow;
import com.example.sutetpedia.ParentRow;
import com.example.sutetpedia.R;

import java.util.ArrayList;

public class MyExpandableListAdapter extends BaseExpandableListAdapter {



    DatabaseHelper myDb;
    String key;

    private Context context;
    private ArrayList<ParentRow> parentRowList;

    private ArrayList<ParentRow> originalList;

    public MyExpandableListAdapter(Context context
            , ArrayList<ParentRow> originalList) {
        this.context = context;
        this.parentRowList = new ArrayList<>();
        this.parentRowList.addAll(originalList);

        this.originalList = new ArrayList<>();
        this.originalList.addAll(originalList);
    }

    @Override
    public int getGroupCount() {
        return parentRowList.size();
    }

    @Override
    public int getChildrenCount(int groupPosition) {
        return parentRowList.get(groupPosition).getChildList().size();
    }

    @Override
    public Object getGroup(int groupPosition) {
        return parentRowList.get(groupPosition);
    }

    @Override
    public Object getChild(int groupPosition, int childPosition) {
        return parentRowList.get(groupPosition).getChildList().get(childPosition);
    }

    @Override
    public long getGroupId(int groupPosition) {
        return groupPosition;
    }

    @Override
    public long getChildId(int groupPosition, int childPosition) {
        return childPosition;
    }

    @Override
    public boolean hasStableIds() {
        return true;
    }

    @Override
    public View getGroupView(int groupPosition, boolean isExpanded, View convertView, ViewGroup parent) {
        ParentRow parentRow = (ParentRow) getGroup(groupPosition);

        if (convertView == null) {
            LayoutInflater layoutInflater = (LayoutInflater)
                    context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            convertView = layoutInflater.inflate(R.layout.parent_row, null);

        }


        TextView heading = (TextView) convertView.findViewById(R.id.parent_text);

        heading.setText(parentRow.getName().trim());
        return convertView;
    }

    @Override
    public View getChildView(int groupPosition, int childPosition, boolean isLastChild, View convertView, ViewGroup parent) {
        ChildRow childRow = (ChildRow) getChild(groupPosition, childPosition);
        if (convertView == null) {
            LayoutInflater layoutInflater = (LayoutInflater)
                    context.getSystemService(context.LAYOUT_INFLATER_SERVICE);
            convertView = layoutInflater.inflate(R.layout.child_row, null);
        }



        final TextView childText = (TextView) convertView.findViewById(R.id.child_text);
        childText.setText(childRow.getText().trim());
        final View finalConvertView = convertView;
        childText.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Cursor res = myDb.getRow(key);
                if(res.getCount() == 0) {
                    // show message
                    showMessage("Error","Nothing found");
                    return;
                }
                StringBuffer buffer = new StringBuffer();
                while (res.moveToNext()) {
                    buffer.append("Marking :"+ res.getString(0)+"\n");
                    buffer.append("Quantity :"+ res.getString(1)+"\n");
                    buffer.append("Profile :"+ res.getString(2)+"\n");
                    buffer.append("Length :"+ res.getString(3)+"\n\n");
                    buffer.append("Weight :"+ res.getString(4)+"\n\n");
                    buffer.append("Total Weight :"+ res.getString(5)+"\n\n");
                }

                // Show all data
                showMessage("Data",buffer.toString());


            }
        });


        return convertView;
    }

    public void showMessage(String title,String Message){
        AlertDialog.Builder builder = new AlertDialog.Builder(context);
        builder.setCancelable(true);
        builder.setTitle(title);
        builder.setMessage(Message);
        builder.show();
    }



    @Override
    public boolean isChildSelectable(int groupPosition, int childPosition) {
        return true;
    }

    public void filterData(String query) {
        query = query.toLowerCase();
        parentRowList.clear();

        if (query.isEmpty()) {
            parentRowList.addAll(originalList);
        }
        else {
            for (ParentRow parentRow : originalList) {
                ArrayList<ChildRow> childList = parentRow.getChildList();
                ArrayList<ChildRow> newList = new ArrayList<ChildRow>();

                for (ChildRow childRow: childList) {
                    if (childRow.getText().toLowerCase().contains(query)) {
                        newList.add(childRow);
                    }
                } // end for (com.example.user.searchviewexpandablelistview.ChildRow childRow: childList)
                if (newList.size() > 0) {
                    ParentRow nParentRow = new ParentRow(parentRow.getName(), newList);
                    parentRowList.add(nParentRow);
                }
            } // end or (com.example.user.searchviewexpandablelistview.ParentRow parentRow : originalList)
        } // end else

        notifyDataSetChanged();
    }
}

我将代码运行到我的设备中并成功编译。但是当我点击其中一个Child Rows时，应用程序会在几秒钟后停止。

请告诉我，我的代码中是否有任何更改。先谢谢！

0 个答案:

没有答案
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