删除列表视图和sqllite数据库中的所选项目并修改所选项目

问题描述 投票:0回答:1

我的应用获取餐厅的名称和地址以及类型(坐下,外卖,电话订购)并将其添加到sqlite,然后添加到列表视图。

当长按列表视图中的一项时,我试图拥有一个删除选项,但是我不知道该怎么办,并且希望在生成行项之后拥有编辑选项,因此我创建了一个长按上下文菜单以及一个删除和编辑选项,如果用户选择了编辑选项,则会弹出一个对话框,并显示编辑文本和广播组,以便用户可以修改所选的项目

我是android新手。

MainActivity:

package com.test.fastfoodfinder;

import androidx.appcompat.app.AppCompatActivity;

import android.app.AlertDialog;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.graphics.Color;
import android.os.Bundle;
import android.os.Handler;
import android.view.ContextMenu;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.CursorAdapter;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.RadioGroup;
import android.widget.TabHost;
import android.widget.TextView;
import android.widget.Toast;

import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {

    private ListView listview;
    private Button btn;
    Cursor model = null;
    RestaurantAdapter adapter = null;
    EditText ffname = null;
    EditText ffaddress = null;
    RadioGroup types = null;
    RestaurantHelper helper = null;

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

        btn = findViewById(R.id.btn);
        helper = new RestaurantHelper(this);
        ffname = findViewById(R.id.edittext_name);
        ffaddress = findViewById(R.id.edittext_name);
        types = findViewById(R.id.radiogroup_type);
        listview = findViewById(R.id.list_view);

        model = helper.getAll();
        startManagingCursor(model);
        adapter = new RestaurantAdapter(model);
        listview.setAdapter(adapter);
        btn.setOnClickListener(onSave);


        registerForContextMenu(listview);
    }

    public void onDestroy() {
        super.onDestroy();
        helper.close();
    }


    boolean doubleBackToExitPressedOnce = false;

    public void onBackPressed() {
        if (doubleBackToExitPressedOnce) {
            super.onBackPressed();
            return;
        }
        this.doubleBackToExitPressedOnce = true;
        Toast.makeText(this, "Please click BACK again to exit", Toast.LENGTH_SHORT).show();
        new Handler().postDelayed(new Runnable() {
            @Override
            public void run() {
                doubleBackToExitPressedOnce = false;
            }
        }, 2000);
    }

    public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {
        super.onCreateContextMenu(menu, v, (ContextMenu.ContextMenuInfo) menuInfo);
        AdapterView.AdapterContextMenuInfo info = (AdapterView.AdapterContextMenuInfo) menuInfo;
        menu.add(0, 1, 0, "Edit");
        menu.add(0, 2, 1, "Remove");
        menu.add(0, 3, 2, "Add Note");
        menu.add(0, 4, 3, "All Notes");
    }

    public boolean onContextItemSelected(MenuItem item) {

        if (item.getTitle().equals("Edit")) {
            TextView title = new TextView(this);
            title.setText("Edit Your Inputs");
            title.setBackgroundColor(Color.DKGRAY);
            title.setPadding(10, 16, 10, 10);
            title.setGravity(Gravity.CENTER);
            title.setTextColor(Color.WHITE);
            title.setTextSize(20);

            AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);
            LayoutInflater inflater = (LayoutInflater) getSystemService(LAYOUT_INFLATER_SERVICE);
            View loginForm = inflater.inflate(R.layout.set_dialog, null, false);
            builder.setView(loginForm);
            builder.setCustomTitle(title);
            AlertDialog dialog = builder.create();
            dialog.getWindow().getAttributes().windowAnimations = R.style.customdialog;
            dialog.show();


        } else if (item.getTitle().equals("Remove")) {

        } else if (item.getTitle().equals("Add Note")) {

        } else if (item.getTitle().equals("All Notes")) {

        }
        return super.onContextItemSelected(item);
    }

    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.main_menu, menu);
        return super.onCreateOptionsMenu(menu);
    }

    public boolean onOptionsItemSelected(MenuItem item) {
        ListView listView = findViewById(R.id.list_view);
        EditText nameInput = findViewById(R.id.edittext_name);
        EditText addressInput = findViewById(R.id.editText_address);
        RadioGroup types = findViewById(R.id.radiogroup_type);
        int id = item.getItemId();

        switch (id) {
            case R.id.clearlist:
                helper.deleteDatabase(this);
                listView.setAdapter(null);
                break;

            case R.id.clearforum:
                nameInput.setText("");
                addressInput.setText("");
                types.check(0);
                break;

            case R.id.settings:
                break;

            case R.id.exit:
                finish();
                System.exit(0);
                break;

        }
        return super.onOptionsItemSelected(item);
    }


    private View.OnClickListener onSave = new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            String type = null;
            switch (types.getCheckedRadioButtonId()) {
                case R.id.sitdown:
                    type = ("sitdown");
                    break;
                case R.id.take_away:
                    type = ("take_away");
                    break;
                case R.id.phone_order:
                    type = ("phone_order");
                    break;
            }
            if (ffname.getText().toString().isEmpty()) {
                Toast.makeText(MainActivity.this, "Please enter a name to continue", Toast.LENGTH_SHORT).show();
                Animation right = AnimationUtils.loadAnimation(MainActivity.this, R.anim.alert);
                ffname.startAnimation(right);
                btn.startAnimation(right);

            } else if (ffaddress.getText().toString().isEmpty()) {
                Toast.makeText(MainActivity.this, "Please enter an address to continue", Toast.LENGTH_SHORT).show();
                Animation shake = AnimationUtils.loadAnimation(MainActivity.this, R.anim.alert);
                ffaddress.startAnimation(shake);
                btn.startAnimation(shake);
            } else if (type.equals("")) {
                Toast.makeText(MainActivity.this, "Please select a type", Toast.LENGTH_SHORT).show();
                Animation shake = AnimationUtils.loadAnimation(MainActivity.this, R.anim.alert);
                types.startAnimation(shake);
            } else {
                helper.insert(ffname.getText().toString(), ffaddress.getText().toString(), type, null);
                model.requery();
                Toast.makeText(MainActivity.this, "Total number of FastFoods in the list:" + listview.getAdapter().getCount(), Toast.LENGTH_SHORT).show();

            }
        }
    };

    class RestaurantAdapter extends CursorAdapter {
        RestaurantAdapter(Cursor cursor) {
            super(MainActivity.this, cursor);
        }

        public void bindView(View row, Context context, Cursor cursor) {
            RestaurantHolder holder = (RestaurantHolder) row.getTag();
            holder.populateFrom(cursor, helper);
        }

        public View newView(Context context, Cursor cursor, ViewGroup parent) {
            LayoutInflater inflater = getLayoutInflater();
            View row = inflater.inflate(R.layout.row_layout, parent, false);
            Animation animation = AnimationUtils.loadAnimation(MainActivity.this, R.anim.fadein);
            row.startAnimation(animation);
            RestaurantHolder holder = new RestaurantHolder(row);

            row.setTag(holder);
            return (row);
        }
    }

    static class RestaurantHolder {
        private TextView nameV = null;
        private TextView addressV = null;
        private ImageView icon = null;

        RestaurantHolder(View row) {
            nameV = row.findViewById(R.id.listview_name);
            addressV = row.findViewById(R.id.listview_address);
            icon = row.findViewById(R.id.type_ic);

        }

        void populateFrom(Cursor cursor, RestaurantHelper helper) {
            nameV.setText(helper.getName(cursor));
            addressV.setText(helper.getName(cursor));

            if (helper.getType(cursor).equals("sitdown")) {
                icon.setImageResource(R.drawable.sitdownn);
            } else if (helper.getType(cursor).equals("take_away")) {
                icon.setImageResource(R.drawable.takeaway);
            } else if (helper.getType(cursor).equals("phone_order")) {
                icon.setImageResource(R.drawable.phoneorderr);
            }

        }

    }
}



sqlopenhelper

package com.test.fastfoodfinder;

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

class RestaurantHelper extends SQLiteOpenHelper {
    private static final String DATABASE_NAME="lunchlist.db";
    private static final int SCHEMA_VERSION=1;

    public RestaurantHelper(Context context) {
        super(context, DATABASE_NAME, null, SCHEMA_VERSION);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL("CREATE TABLE IF NOT EXISTS restaurants (_id INTEGER PRIMARY KEY AUTOINCREMENT, name TEXT, address TEXT, type TEXT, notes TEXT);");
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        // no-op, since will not be called until 2nd schema
        // version exists
    }

    public Cursor getAll() {
        return(getReadableDatabase()
                .rawQuery("SELECT _id, name, address, type, notes FROM restaurants ORDER BY name",
                        null));
    }

    public void deleteDatabase(Context mContext) {
        mContext.deleteDatabase(DATABASE_NAME);

    }



    public void insert(String name, String address,
                       String type, String notes) {
        ContentValues cv=new ContentValues();

        cv.put("name", name);
        cv.put("address", address);
        cv.put("type", type);
        cv.put("notes", notes);

        getWritableDatabase().insert("restaurants", "name", cv);
    }


    public String getName(Cursor c) {
        return(c.getString(1));
    }

    public String getAddress(Cursor c) {
        return(c.getString(2));
    }

    public String getType(Cursor c) {
        return(c.getString(3));
    }

    public String getNotes(Cursor c) {
        return(c.getString(4));
    }
}

对话

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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"
    android:padding="16dp"><![CDATA[>
        ]]>

    <TextView
        android:id="@+id/address"
        style="@style/texts"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="48dp"
        android:text="Address"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/name" />

    <TextView
        android:id="@+id/type"
        style="@style/texts"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="52dp"
        android:text="Type"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/address" />

    <TextView
        android:id="@+id/name"
        style="@style/texts"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="16dp"
        android:text="Name"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"></TextView>

    <EditText
        android:id="@+id/edittext_name"
        style="@style/texts"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="60dp"
        android:layout_marginLeft="60dp"
        android:hint="Please enter fast food name"
        app:layout_constraintStart_toEndOf="@+id/name"
        app:layout_constraintTop_toTopOf="parent" />

    <EditText
        android:id="@+id/editText_address"
        style="@style/texts"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="46dp"
        android:layout_marginLeft="46dp"
        android:layout_marginTop="16dp"
        android:hint="Please enter fast food address"
        app:layout_constraintStart_toEndOf="@+id/address"
        app:layout_constraintTop_toBottomOf="@+id/edittext_name" />

    <RadioGroup
        android:id="@+id/radiogroup_type"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="14dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toEndOf="@+id/type"
        app:layout_constraintTop_toBottomOf="@+id/editText_address">

        <RadioButton
            android:id="@+id/sitdown"
            style="@style/texts"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="Sit Down" />

        <RadioButton
            android:id="@+id/take_away"
            style="@style/texts"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="Take away" />

        <RadioButton
            android:id="@+id/phone_order"
            style="@style/texts"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="Phone Order" />
    </RadioGroup>

    <Button
        android:id="@+id/btn"
        style="@style/texts"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="16dp"
        android:paddingTop="16dp"
        android:text="Add"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/radiogroup_type" />

    <androidx.constraintlayout.widget.Guideline
        android:id="@+id/guideline"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        app:layout_constraintGuide_begin="0dp" />

    <androidx.constraintlayout.widget.Barrier
        android:id="@+id/barrier"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:barrierDirection="left" />


</androidx.constraintlayout.widget.ConstraintLayout>

任何帮助将不胜感激

android sqlite
1个回答
0
投票

首先,您应该在RestaurantHelper.java中创建用于更新和删除的方法。

此示例更新项目。

public boolean UpdateData(String name, String address, String type, String note) {

        SQLiteDatabase db = this.getWritableDatabase();

        ContentValues contentValues = new ContentValues();
        contentValues.put(YOUR_COLUMN_NAME, name);
        contentValues.put(YOUR_COLUMN_ADDRESS, address);
        contentValues.put(YOUR_COLUMN_TYPE, type);
        contentValues.put(YOUR_COLUMN_NOTE, note);
        db.update(YOUR_TABLE, contentValues, "name= ? AND address = ?", new String[] { name, address } ); // update the item WHERE name = 'name' and address = 'address'

        return true;

    }

然后还要创建删除方法。

public Cursor deleteData(String your_uniqure_id) {
    SQLiteDatabase db = this.getReadableDatabase();
    db.execSQL("DELETE FROM your_table WHERE _id = " + your_uniqure_id);
    return null;
}

随时调用此方法。

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