Android Dev：通过Onclick展开ExpandableList子项的方法方法

Question

我对ExpandableListView的childPosition实施onclick意向问题。基本上，我正在创建一个简单的食谱应用程序。该应用程序有4个父母职位（早餐，沙拉，主菜和小吃）。每个父母职位下面有2个项目。我希望能够点击子项目并加载新的意图（或页面）。

例如，点击儿童香蕉煎饼时，我希望它加载breakfast_banana_pancakes.xml文件。该文件将包含图片和配方说明。

我知道这可能不是最佳的方式来做到这一点，但我正在做一个课程，并且不允许使用任何数据库或让应用程序使用任何权限。

这是我的mainScreen xml文件中的代码。

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
xmlns:tools="http://schemas.android.com/tools" 
xmlns:android1="http://schemas.android.com/apk/res/android" 
android:layout_width="match_parent" 
android:layout_height="match_parent" 
android:background="@drawable/paleoportraitxhdpi" 
android:paddingBottom="@dimen/activity_vertical_margin" 
android:paddingLeft="@dimen/activity_horizontal_margin" 
android:paddingRight="@dimen/activity_horizontal_margin" 
android:paddingTop="@dimen/activity_vertical_margin" 
tools:context=".MainScreen" > 

<TextView 
    android:id="@+id/textView1" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:layout_alignBottom="@+id/textViewPaleoFact" 
    android:layout_alignParentLeft="true" 
    android:paddingRight="4dp" 
    android:text="@string/paleoFactText" /> 

<TextView 
    android:id="@+id/textViewPaleoFact" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:layout_alignParentBottom="true" 
    android:layout_toRightOf="@+id/textView1" 
    android:text="@string/paleoFactText" 
    android:textSize="12sp" /> 

<ExpandableListView 
    android1:id="@+id/expandableListView1" 
    android1:layout_width="match_parent" 
    android1:layout_height="250dp" 
    android1:layout_alignLeft="@+id/textView1" 
    android1:layout_alignParentTop="true" 
    android1:layout_marginTop="14dp" 
    android1:padding="10dp" > 
</ExpandableListView> 

这是我为我的mainScreenJava文件的代码。

public class MainScreen extends Activity { 
    ExpandableListView exv; 
    // Random Paleo Fact Via Strings.xml  
    String[] myString; 
    final Random rgenerator = new Random(); 


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


      exv=(ExpandableListView)findViewById(R.id.expandableListView1); 
      exv.setAdapter(new MyAdapter(this)); 

     //Paleo Fact 
     Resources res = getResources(); 

     myString = res.getStringArray(R.array.paleoFacts); 

     String q = myString[rgenerator.nextInt(myString.length)]; 

     TextView tv2 = (TextView)findViewById(R.id.textViewPaleoFact); 
     tv2.setText(q); 


    } 

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

} 

这里是我的myAdapter文件中的代码，它控制我的扩展列表

@SuppressWarnings("unused") 
public class MyAdapter extends BaseExpandableListAdapter { 
private Context context; 

String []parentList={"Breakfast", "Salads", "Main Dishes", "Snacks"}; 
String [][]childList={ 
     { 
     "Banana Pancakes", "Breakfast Casserole" 
     }, 
     { 
     "Bacon Chickn Avacado Salad", "Curried Salmon Salad" 
     }, 
     { 
     "Watercress Bacon Soup", "Spicy Chicken and Bacon Poppers" 
     }, 
     { 
     "Primal Trail Mix", "Fat Guacamole Devils" 
     }, 
}; 


    public MyAdapter(Context context) { 
     // TODO Auto-generated constructor stub 
     this.context=context; 
    } 


    public Object getChild(int groupPosition, int childPosition) { 
     // TODO Auto-generated method stub 
     return null; 
    } 


    public long getChildId(int groupPosition, int childPosition) { 
     // TODO Auto-generated method stub 
     return 0; 
    } 


    public View getChildView(int groupPosition, int childPosition, 
      boolean isLastChild, View convertView, ViewGroup parent) { 
     // TODO Auto-generated method stub 
     TextView tv=new TextView(context); 
     tv.setText(childList[groupPosition][childPosition]); 
     tv.setPadding(100, 15, 0, 15); 

     return tv; 
    } 


    public int getChildrenCount(int groupPosition) { 
     // TODO Auto-generated method stub 
     return childList[groupPosition].length; 
    } 


    public Object getGroup(int groupPosition) { 
     // TODO Auto-generated method stub 
     return groupPosition; 
    } 


    public int getGroupCount() { 
     // TODO Auto-generated method stub 
     return parentList.length; 
    } 


    public long getGroupId(int groupPosition) { 
     // TODO Auto-generated method stub 
     return groupPosition; 
    } 


    public View getGroupView(int groupPosition, boolean isExpanded, View convertView, ViewGroup parent) { 
     // TODO Auto-generated method stub 
     TextView tv=new TextView(context); 
     tv.setText(parentList[groupPosition]); 
     tv.setPadding(60, 15, 0, 15); 
     return tv; 
    } 


    public boolean hasStableIds() { 
     // TODO Auto-generated method stub 
     return false; 
    } 


    public boolean isChildSelectable(int groupPosition, int childPosition) { 
     // TODO Auto-generated method stub 

     return true; 

    } 
} 

这里是我试过MyAdapter.java文件

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

if(groupPosition == 0 && childPosition == 0){ 
    Intent i = new Intent(v.getContext(), breakfast_banana_pancakes.class); 
    v.getContext().startActivity(i); 
    Log.e ("Banana", "Banana pancakes was clicked"); 
} 


//Intent i = new Intent(mActivity, TargetActivity.class); 
//i.putExtra(TargetActivity.EXTRA_WHATEVER, MyAdapter.getChild(groupPosition, childPosition)); 
//startActivity(i); 
return true; 
} 

Answer 1

如果我执行代码你正确地认识你，你会想听onChildClick：

@Override 
public boolean onChildClick(ExpandableListView parent, View v, int groupPosition, int childPosition, long id) { 
    Intent i = new Intent(mActivity, TargetActivity.class); 
    i.putExtra(TargetActivity.EXTRA_WHATEVER, mListAdapter.getChild(groupPosition, childPosition)); 
    startActivity(i); 
    return false; 
} 

这会启动你进入下一个活动。您可以发送任何你需要在Intent

通过extras加载适当的布局此外，还要确保列表视图知道调用这个方法： getExpandableListview().setOnChildClickListener(this);（如果该活动实现OnChildClickListener）

编辑格式化

onChildClick应存在于MainScreen。

你的定义应该是：

public class MainScreen extends Activity implements ExpandableListView.OnChildClickListener {...} 

然后你需要告诉ListView控件调用onChildClick：

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

    exv=(ExpandableListView)findViewById(R.id.expandableListView1); 
    exv.setAdapter(new MyAdapter(this)); 
    exv.setOnChildClickListener(this); // Add this--make sure the list knows to use this as a listener, since we implemented the interface.