从微调器创建计算器

Posted 2023-04-18

【中文标题】从微调器创建计算器

【英文标题】：Create a calculator from a spinner

【发布时间】：2015-04-07 15:41:33

【问题描述】：

我创建了两个微调器，用户可以在其中选择膳食类型，然后选择食物（例如“早餐”和“粥”）。然后，我需要将食物卡路里乘以用户在编辑文本中输入的重量，但我不确定我是如何做到这一点的。

如何将我的微调器选项与数字相关联？

public class MainActivity3 extends ActionBarActivity 

    EditText num1;
    EditText num2;
    EditText num3;
    EditText num4;
    EditText num5;
    Button btnSave;
    EditText calorieResult;


    public Spinner catspinner, planspinner3, planspinner1, planspinner2;

    protected void onCreate(Bundle mbfSplash) 
        super.onCreate(mbfSplash);
        setContentView(R.layout.addmeal);

        chooseCategory();
        chooseBreakfast();
        chooseLunch();
        chooseDinner();
        chooseSnack();
    

    public void chooseCategory() 

        catspinner = (Spinner) findViewById(R.id.catspinner);
        ArrayAdapter<CharSequence> catAdapter = ArrayAdapter.createFromResource(this, R.array.ducategory, android.R.layout.simple_spinner_item);
        catAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        catspinner.setAdapter(catAdapter);
        catspinner.setOnItemSelectedListener(new planOnClickListener());
    

    private void chooseBreakfast() 
        planspinner1 = (Spinner) findViewById(R.id.planspinner);
        List<String> planlist = new ArrayList<String>();
        planlist.add("Porridge-40g/140cal");
        planlist.add("Coffee-10g/10cal");
        planlist.add("Toast-30g/87cal");
        ArrayAdapter<String> planAdapter1 = new ArrayAdapter<String>(this,
                android.R.layout.simple_spinner_item, planlist);
        planAdapter1.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        planspinner1.setAdapter(planAdapter1);
    

    private void chooseLunch() 

        planspinner2 = (Spinner) findViewById(R.id.planspinner);
        List<String> planlist1 = new ArrayList<String>();
        planlist1.add("Salad-50g/40cal");
        planlist1.add("Sandwich-50g/200cal");
        ArrayAdapter<String> planAdapter2 = new ArrayAdapter<String>(this,
                android.R.layout.simple_spinner_item, planlist1);
        planAdapter2.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        planspinner2.setAdapter(planAdapter2);
    

    private void chooseDinner() 

        planspinner2 = (Spinner) findViewById(R.id.planspinner);
        List<String> planlist2 = new ArrayList<String>();
        planlist2.add("Curry-100g/400cal");
        planlist2.add("Pasta-40g/160cal");
        planlist2.add("Pizza100g/220cal");
        ArrayAdapter<String> planAdapter3 = new ArrayAdapter<String>(this,
                android.R.layout.simple_spinner_item, planlist2);
        planAdapter3.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        planspinner2.setAdapter(planAdapter3);
    

    private void chooseSnack() 
        planspinner1 = (Spinner) findViewById(R.id.planspinner);
        List<String> planlist = new ArrayList<String>();
        planlist.add("Crisps-30g/70cal");
        planlist.add("Chocolate-100g/210cal");
        ArrayAdapter<String> planAdapter1 = new ArrayAdapter<String>(this,
                android.R.layout.simple_spinner_item, planlist);
        planAdapter1.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        planspinner1.setAdapter(planAdapter1);
    

    public class planOnClickListener implements OnItemSelectedListener 

        @Override
        public void onItemSelected(AdapterView<?> parent, View v, int pos,
                                   long id) 

            parent.getItemAtPosition(pos);

            if (pos == 0) 
                chooseBreakfast();
             else if (pos == 1) 
                chooseLunch();
             else if (pos == 2) 
                chooseDinner();
             else if (pos == 3) 
                chooseSnack();
            
        

        @Override
        public void onNothingSelected(AdapterView<?> arg0) 
            // TODO Auto-generated method stub
        
    

【问题讨论】：

阅读面向对象编程

让我正确理解这一点。有两个Spinners。一个显示早餐类型，另一个显示食物。然后有一个EditText，用户在其中输入重量。你必须将与食物相关的卡路里乘以重量。这是正确的吗？

是的，没错。

【参考方案1】：

我在没有代码编辑器的情况下执行此操作，因此请原谅语法错误，但通常您应该使用一个对象来存储相关数据。为您的微调器使用自定义适配器。这是一些帮助您入门的代码。

您应该创建一个名为 Food 的对象。

public class Food 
int mCalories;
String mName;

public Food(String name, int calories) 
    mName= name;
    mCalories = calories;
    

现在您可以为您的微调器使用自定义数组适配器。

public class FoodArrayAdapter extends ArrayAdapter<Food> 

private List<Food> mItems;
private Context mContext;
private int mResource;

public FoodArrayAdapter(Context ctx, int resource, List<Food> items) 
    super(activity, resource);
    mItems = items;
    mContext = ctx;
    mResource = resource;


@Override
public View getDropDownView(int position, View convertView, ViewGroup parent) 
    //You could use a view holder pattern here, won't really matter for a simple text spinner.
    Food item = mItems.get(position);
    LayoutInflater inflater = (LayoutInflater) mContext
    .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    View v = inflater.inflate(mResource, parent);
    TextView textView = (TextView) v.findViewById(android.R.id.text1);

    if (item != null) 
        textView.setText(food.getName());
    

    return v;


@Override
public Food getItem(int position) 
    return items.get(position);


@Override
public View getView(int position, View convertView, ViewGroup parent) 
    return getDropDownView(int position, View convertView, ViewGroup parent);
    //or make another view for when the spinner is expanded


@Override
public int getCount() 
    return mItems.getSize();

现在只需将您的自定义适配器与您的主要活动中的微调器相关联。

Spinner spinner = (Spinner) layout.findViewById(R.id.myspinner1);
spinner.setAdapter(new FoodAdapter(this, android.R.layout.simple_spinner_item, list);
spinner.setOnItemSelectedListener(new OnItemSelectedListener()
    public void onItemSelected(AdapterView<?> parent, View view, int pos, long id)
      Food food = (Food) parent.getItemAtPosition(pos);
      //Do whatever you need to do with selected value.  You have reference to both the food and the calories.
    
    public void onNothingSelected(    AdapterView<?> parent)

    
  

);

【讨论】：

你给了我一个很好的开始。谢谢！ :)