Question

我在为onclick的childPosition实施意图ExpandableListView时遇到问题。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）。每个父母职位下面都有2个项目。我希望能够点击子项并加载新的意图（或页面）。

例如，当点击子香蕉煎饼时，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好的方法，但是我正在为一门课程做这件事，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;
    }

}

以下是myAdapter文件的代码，它控制我的可扩展列表

@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; 

    }
}

以下是我尝试在MyAdapter.java文件上实现的代码

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

如果我正确地为你服务，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;
}

这会让您进入下一个活动。您可以通过extras

中的Intent发送所需的任何内容来加载正确的布局

另外，请确保listview知道调用此方法： getExpandableListview().setOnChildClickListener(this);（如果活动实施OnChildClickListener）

修改格式

onChildClick应存在于MainScreen。

中

您的定义应该是：

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

然后，您需要告诉ListView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.

Android Dev：通过Onclick方法实现ExpandableList子项的意图

1 个答案: