Question

我在this教程之后开发了一个购物清单应用。现在，在完成整个教程后，我想为每个项目列表添加单选按钮，以便了解哪些项目已从购物清单中购买。但我不知道如何做到这一点。如果你可以指导我这将有所帮助。

这是我的源代码

package com.dopenets.myapplication;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.ArrayAdapter;
import android.widget.ListView;

import java.util.ArrayList;
import java.util.Collections;

import java.util.HashSet;
import java.util.Set;
import android.app.AlertDialog;
import android.widget.EditText;
import android.content.DialogInterface;
import android.content.Context;
import android.content.SharedPreferences;
import android.app.Activity;

import android.widget.Toast;
import android.widget.AdapterView;
import android.widget.TextView;
import android.view.View;

public class MainActivity extends AppCompatActivity {
    ArrayList<String> shoppingList = null;
    ArrayAdapter<String> adapter = null;
    ListView lv = null;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);


        shoppingList = getArrayVal(getApplicationContext());
        Collections.sort(shoppingList);
        adapter = new ArrayAdapter(this, android.R.layout.simple_list_item_1, shoppingList);
        lv = (ListView) findViewById(R.id.listView);
        lv.setAdapter(adapter);

        lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            public void onItemClick(AdapterView parent, View view, final int position, long id) {
                String selectedItem = ((TextView) view).getText().toString();
                if (selectedItem.trim().equals(shoppingList.get(position).trim())) {
                    removeElement(selectedItem, position);
                } else {
                    Toast.makeText(getApplicationContext(),"Error Removing Element", Toast.LENGTH_LONG).show();
                }
            }
        });


    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        if (id == R.id.action_add){
            AlertDialog.Builder builder = new AlertDialog.Builder(this);
            builder.setTitle("Add Item");
            final EditText input = new EditText(this);
            builder.setView(input);
            builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {
                    shoppingList.add(preferredCase(input.getText().toString()));
                    Collections.sort(shoppingList);
                    storeArrayVal(shoppingList, getApplicationContext());
                    lv.setAdapter(adapter);
                }
            });
            builder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {
                    dialog.cancel();
                }
            });
            builder.show();
            return true;
        }


        return super.onOptionsItemSelected(item);
    }

    public static String preferredCase (String original)
    {
        if (original.isEmpty())
            return original;
        return original.substring(0,1).toUpperCase() + original.substring(1).toLowerCase();
    }

    public static void storeArrayVal( ArrayList<String> inArrayList, Context context)
    {
        Set<String> WhatToWrite = new HashSet<String>(inArrayList);
        SharedPreferences WordSearchPutPrefs = context.getSharedPreferences("dbArrayValues", Activity.MODE_PRIVATE);
        SharedPreferences.Editor prefEditor = WordSearchPutPrefs.edit();
        prefEditor.putStringSet("myArray", WhatToWrite);
        prefEditor.commit();
    }

    public static ArrayList getArrayVal( Context dan)
    {
        SharedPreferences WordSearchGetPrefs = dan.getSharedPreferences("dbArrayValues",Activity.MODE_PRIVATE);
        Set<String> tempSet = new HashSet<String>();
        tempSet = WordSearchGetPrefs.getStringSet("myArray", tempSet);
        return new ArrayList<String>(tempSet);
    }

    public void removeElement(String selectedItem, final int position){
        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setTitle("Remove " + selectedItem + "?");
        builder.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                shoppingList.remove(position);
                Collections.sort(shoppingList);
                storeArrayVal(shoppingList, getApplicationContext());
                lv.setAdapter(adapter);
            }
        });
        builder.setNegativeButton("No", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                dialog.cancel();
            }
        });
        builder.show();
    }
}

Answer 1

查看Android Developer，它解释了如何实现Radio Buttons。 https://developer.android.com/guide/topics/ui/controls/radiobutton.html

使用单选按钮选项在布局中添加无线电组，如示例所示。因为听起来你在点击它们时没有做任何动作，你只需将Radio Group（带单选按钮）添加到simple_list_item_1然后当调用onRadioButtonClicked时它只更改收音机以显示它为已选中（此代码为添加到您的MainActivity）：

public void onRadioButtonClicked(View view) {
// Is the button now checked?
boolean checked = ((RadioButton) view).isChecked();

希望这有帮助！

Answer 2

1.create custom layout with radiobutton or checkbox and textview (xml)
2.create custom adapter with custom class
3. custom class which contains string productname,boolean checked;

Your Custom Layout

    <RelativeLayout>

    <RadioButton></RadioButton>
    <TextView></TextView>

    </RelativeLayout>

Your Custom Class

    public class mycustomclass
    {
    public String ProductName;
    public boolean productChecked;
    }

Your Custom Adapter

public class MyAdapter extends ArrayAdapter<mycustomclass>
{
 //your code
}

update mycustom class boolean field when radio checked and unchecked

如何在列表中添加单选按钮

2 个答案: