Question

所以这是我的代码.. 我有很多活动需要切换，这段代码似乎完美无缺。但我想知道是否有另一种方法不那么复杂且易于实现，而不是“SWITCH CASE”方法。

在这里输入代码

package com.prashant.dfs;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.view.Menu;
import android.view.View;
import android.widget.ExpandableListView;
import android.widget.ExpandableListView.OnChildClickListener;

public class Chapter_1_full extends Activity {


ExpandableListAdapter listAdapter;
ExpandableListView expListView;
List<String> ListDataHeader;
HashMap<String,List<String>> listDataChild;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_chapter_1_full);

    //get the listView(expand)
    expListView = (ExpandableListView) findViewById(R.id.ch1_expand);
    //prepareDataList
    prepareListData();

    listAdapter=new ExpandableListAdapter(this, ListDataHeader, listDataChild);

    expListView.setAdapter(listAdapter);
}

private void prepareListData() {
    ListDataHeader = new ArrayList<String>();
    listDataChild=new HashMap<String, List<String>>();
    //Adding child Data

    ListDataHeader.add("1.1 Introductin to Algorithms");
    ListDataHeader.add("1.2 Data Structures");
    ListDataHeader.add("1.3 ADT");



    List<String> Intro = new ArrayList<String>();
    Intro.add("Algoithem Design ");
    Intro.add("Flowcharting");
    Intro.add("Pseudo-Language");


    List<String> dataStructure = new ArrayList<String>();
    dataStructure.add("Type of Data Structure");
    dataStructure.add("Primitive and Non-Primitive");
    dataStructure.add("Linear and Non-Linear");
    dataStructure.add("Static and Dynamic");


    List<String> ADT = new ArrayList<String>();
    ADT.add("Datat Object");    

    listDataChild.put(ListDataHeader.get(0),Intro);
    listDataChild.put(ListDataHeader.get(1),dataStructure);
    listDataChild.put(ListDataHeader.get(2),ADT);

    expListView.setOnChildClickListener(new OnChildClickListener() {

        @Override
        public boolean onChildClick(ExpandableListView parent, View v,
                int groupPosition, int childPosition, long id) {

            final Object childObj=parent.getExpandableListAdapter().getChild(groupPosition, childPosition);

            if(childObj!=null)
            {
                switch (groupPosition)
                {
                case 0:
                {
                    switch (childPosition)
                    {
                        case 0:
                        {
                            startActivity(new Intent(Chapter_1_full.this,TestActivity.class));
                            break;
                        }
                        case 1:
                        {
                            startActivity(new Intent(Chapter_1_full.this,TestActivity2.class));
                            break;
                        }
                        case 2:
                        {
                            startActivity(new Intent(Chapter_1_full.this,TestActivity3.class));
                            break;
                        }
                    }
                    break;
                }   
                case 1:
                    startActivity(new Intent(Chapter_1_full.this,TestActivity4.class));
                }

            }


            return true;
        }
    });
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.chapter_1_full, menu);
    return true;
}

}

Answer 1

您可以创建一个自定义类来存储项目标签和负责管理该选择的活动，例如toString允许您使用字符串处理时所遵循的相同行为。

    public class EntryList{
    public String label;        
    public Class<?> activity;

    public EntryList( String label,Class<?> activity ){
        this.label  =label;
        this.activity = activity;
    }       
    @Override
    public String toString() {      
        return label;
    }
}

然后，您可以使用此listDataChild=new HashMap<String, List<EntryList>>();替换您的地图，并将子项添加为

       List< EntryList > Intro = new ArrayList< EntryList >();
       Intro.add( new EntryList("Algoithem Design ", youractivity.class) );
       Intro.add( new EntryList("Flowcharting", youractivity.class);
       Intro.add( new EntryList("Pseudo-Language", youractivity.class));

最后在你需要的setOnChildClickListener方法内部

       EntryList entry = listDataChild.get( groupPosition ).get( childPosition );
       startActivity( new Intent( context, entry.activity ) );

Answer 2

您可以在数组中存储Activity类，并使用childPosition作为索引访问它们。

Class[] activityClasses = new Class[]{TestActivity1.class, TestActivity2.class, TestActivity3.class};
startActivity(new Intent(Chapter_1_full.this, activityClasses[childPosition]));

你的代码看起来像这样.-

switch (groupPosition) {
    case 0:
        startActivity(new Intent(Chapter_1_full.this, activityClasses[childPosition]));
    break;
    case 1:
        startActivity(new Intent(Chapter_1_full.this,TestActivity4.class));
    break;
}

为了替换两个switch个句子，数组会更加混乱.-

Class[][] activityClasses = new Class[][]{{TestActivity1.class, TestActivity2.class, TestActivity3.class}, {TestActivity4.class}};

然后你的整个切换句子可以只用一行代替.-

startActivity(new Intent(Chapter_1_full.this, activityClasses[groupPosition][childPosition]));

Answer 3

这应该就是您所需要的一切！

Intent YourIntent = new Intent(this, YourActivity.class);
startActivity(YourIntent);

另一种调用活动的方法。

3 个答案: