java - 开关盒最大实现？

Question

我正在使用一个 switch case，它将使用 100 多个 case 语句。有没有限制？

case的使用是我的AutoCompleteTextView，android教程的建议。

这是我的部分代码，忽略Badrul.class，稍后会更改。

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ArrayAdapter;
import android.widget.AutoCompleteTextView;
import android.widget.Toast;

public class Search extends Activity
{
    public void onCreate(Bundle savedInstanceSate)
    {
        final AutoCompleteTextView autoComplete;
        super.onCreate(savedInstanceSate);
        setContentView(R.layout.searchshop);

        autoComplete = (AutoCompleteTextView) findViewById(R.id.autoCompleteTextView1);
        ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, R.layout.list_item, shops);
        autoComplete.setAdapter(adapter); 
        autoComplete.setThreshold(1);
        autoComplete.setOnItemClickListener(new OnItemClickListener()
        {
        @Override
        public void onItemClick(AdapterView<?> arg0, View arg1, int position, long arg3) 
        {
            int index=999;
            for(int i=0;i<shops.length;i++)
            {
                if(autoComplete.getText().toString().trim().equals(shops[i]))
                {
                    index=i;
                    break;
                }
            }

                switch(index)
                {
                case 0:
                    startActivity(new Intent(Search.this, Adidas.class));
                    break;

                case 1:
                    startActivity(new Intent(Search.this, Affin.class));
                    break;
                case 2:
                    startActivity(new Intent(Search.this, AlamArt.class));
                    break;
                case 3:
                    startActivity(new Intent(Search.this, AlAmin.class));
                    break;
                case 4:
                    startActivity(new Intent(Search.this, Anakku.class));
                    break;
                case 5:
                    startActivity(new Intent(Search.this, Anggerik.class));
                    break;
                case 6:
                    startActivity(new Intent(Search.this, Asiari.class));
                    break;
                case 7:
                    startActivity(new Intent(Search.this, AsterSpring.class));
                    break;
                case 8:
                    startActivity(new Intent(Search.this, Audrey.class));
                    break;
                case 9:
                    startActivity(new Intent(Search.this, Badrul.class));
                    break;
                case 10:
                    startActivity(new Intent(Search.this, Badrul.class));
                    break;
                case 11:
                    startActivity(new Intent(Search.this, Badrul.class));
                    break;
                default:
                    Toast.makeText(Search.this, "Invalid Selection", Toast.LENGTH_SHORT).show();
                }
            }
            });

        }
static final String[] shops = new String[]
            {
                "Adidas", "Affin Bank ATM", "Alam Art Gallery", "Al Amin Kids", "Anakku", "Anggerik", "Asiari", 
                "Aster Spring", "Audrey", "Badrul Songket", "Bata"};
}

Answer 1

在达到 Java 强加的任何限制之前，代码将变得难以管理。

您是否考虑过重构代码？根据 switch 语句旨在实现的目的，您可以:

• Use a map to provide different results
• Create a hierarchy of simple objects that give the behaviour you require for each case

因此，在您的情况下，您最好将索引值的静态 Map 定义为 Classes:

public class MyClass
{
    private static final Map<Integer, Class> LOOKUP = 
      new HashMap<Integer, Class>(...);
    static
    {
      LOOKUP.put(0, Adidas.class);
      LOOKUP.put(1, Affin.class);
      ...
    }

    public void onItemClick(...)
    {
      ...
      // Replace switch statement with:
      if (LOOKUP.containsKey(index))
      {
        startActivity(new Intent(Search.this, LOOKUP.get(index)));
      }
      else
      { 
        Toast.makeText(Search.this, 
                       "Invalid Selection", 
                       Toast.LENGTH_SHORT).show();
      }
    }
    ...
  }

这使得 onItemClick() 中的代码更易于阅读。您可以更进一步，定义一个私有(private) startActivity() 方法，该方法采用要使用的索引并包含所有 switch 语句替换代码。