切换案例最大化实施？ [英] Switch cases maximum implementation?

问题描述

我正在使用单个开关案例，其中将使用超过100个案例语句。是否有任何限制？

I am using a single switch cases which will have more than 100 cases statement to be used. Are there any limit ?

案例的使用是针对我的AutoCompleteTextView，android教程的建议。

The usage of cases are for the suggestions of my AutoCompleteTextView, android tutorial.

以下是我的代码的一部分，忽略Badrul.class，稍后将更改它们。

Here are part of my codes, ignore the Badrul.class they will be changed later.

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"};
}

推荐答案

以前代码将无法管理你达到了Java所施加的任何限制。

The code will become unmanageable before you hit any limit that Java imposes.

您是否考虑过重构代码？根据switch语句的设计目标，您可以：

Have you considered refactoring the code? Depending on what the switch statement is designed to achieve you could either:

• 使用地图提供不同的结果


• 创建一个简单对象的层次结构，为每个案例提供所需的行为

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

所以在你的情况下，你最好定义一个静态 Map 的索引值为类：

So in your case, you would be better off defining a static Map of index values to 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，定义一个私有的 startActivity（）方法，该方法使用索引并包含所有switch语句替换代码。

This makes the code in onItemClick() easier to read. You could go one step further and define a private startActivity() method that takes the index to be used and contains all the switch statement replacement code.

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