Question

我正在尝试创建一个ExpandableListView。组的初始视图显示正常。但是，当我单击列表项时，我的箭头不会更改。见下图。

enter image description here

如何更改箭头的方向？

我有布局XML：

  <ExpandableListView
        android:id="@+id/expandable_list"
        android:layout_width="fill_parent"
        android:layout_height="match_parent"            
        android:divider="@null"
        android:background="#ffffff"
        android:groupIndicator="@drawable/settings_selector"
        android:transcriptMode="alwaysScroll" />

settings_selector.xml ：

 <?xml version="1.0" encoding="utf-8"?>
<animation-list xmlns:android="http://schemas.android.com/apk/res/android" >

<selector xmlns:android="http://schemas.android.com/apk/res/android" >
    <item
        android:drawable="@drawable/arrow_down"
        android:state_empty="true"/>
    <item
        android:drawable="@drawable/arrow_right"
        android:state_expanded="true"/>
</selector>

</animation-list>

Answer 1

expandable listview

 <ExpandableListView
    android:id="@+id/expandable_list"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:groupIndicator="@drawable/group_indicator"
    android:transcriptMode="alwaysScroll" />

setindicator这里使用像这样的setindicator代码这很好用

 DisplayMetrics metrics = new DisplayMetrics();
    getWindowManager().getDefaultDisplay().getMetrics(metrics);
    int width = metrics.widthPixels; 

 mExpandableList = (ExpandableListView)findViewById(R.id.expandable_list);
 mExpandableList.setIndicatorBounds(width - GetPixelFromDips(50), width - GetPixelFromDips(10));  

   public int GetPixelFromDips(float pixels) {
    // Get the screen's density scale 
    final float scale = getResources().getDisplayMetrics().density;
    // Convert the dps to pixels, based on density scale
    return (int) (pixels * scale + 0.5f);
}

RES /抽拉/ group_indicator

  <?xml version="1.0" encoding="utf-8"?>

     <selector xmlns:android="http://schemas.android.com/apk/res/android">            
           <item android:drawable="@drawable/arrow_right" android:state_empty="true">  </item>            
           <item android:drawable="@drawable/arrow_down" android:state_expanded="true"></item>                
           <item android:drawable="@drawable/arrow_right"></item>
     </selector>

Answer 2

试试settings_selector.xml：

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android" >

    <item
        android:drawable="@drawable/arrow_right"
        android:state_expanded="true" />

    <item
        android:drawable="@drawable/arrow_down" />

</selector>

Answer 3

我已经走了以下路线：根据isExpanded标志确定groupView的左/右drawable。
通过这种方式，我们更容易自定义填充/背景和指标drawable的其他东西。

希望它有所帮助。

    public View getGroupView(int groupPosition, boolean isExpanded, View convertView,
            ViewGroup parent) {
        TextView textView = (TextView) mLayoutInflater.inflate(R.layout.menu_group, null);
        textView.setCompoundDrawablesWithIntrinsicBounds(0, 0, isExpanded ? 0 : android.R.drawable.ic_menu_more, 0);
        textView.setText(getGroup(groupPosition).toString());
        return textView;
    }

Answer 4

import java.util.ArrayList;

import android.app.Activity;
import android.content.Context;
import android.database.DataSetObserver;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.BaseExpandableListAdapter;
import android.widget.ExpandableListView;
import android.widget.TextView;

public class MyActivity extends Activity {

    private ExpandableListView mExpandableList;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_my);


        mExpandableList = (ExpandableListView)findViewById(R.id.expandable_list);
        mExpandableList.setGroupIndicator(null);
        ArrayList<Parent> arrayParents = new ArrayList<Parent>();
        ArrayList<String> arrayChildren = new ArrayList<String>();

        //here we set the parents and the children
        for (int i = 0; i < 10; i++){
            //for each "i" create a new Parent object to set the title and the children
            Parent parent = new Parent();
            parent.setTitle("Parent " + i);

            arrayChildren = new ArrayList<String>();
            for (int j = 0; j < 10; j++) {
                arrayChildren.add("Child " + j);
            }
            parent.setArrayChildren(arrayChildren);

            //in this array we add the Parent object. We will use the arrayParents at the setAdapter
            arrayParents.add(parent);
        }

        //sets the adapter that provides data to the list.
        mExpandableList.setAdapter(new MyCustomAdapter(MyActivity.this,arrayParents));

    }

    public class Parent {
        private String mTitle;
        private ArrayList<String> mArrayChildren;

        public String getTitle() {
            return mTitle;
        }

        public void setTitle(String mTitle) {
            this.mTitle = mTitle;
        }

        public ArrayList<String> getArrayChildren() {
            return mArrayChildren;
        }

        public void setArrayChildren(ArrayList<String> mArrayChildren) {
            this.mArrayChildren = mArrayChildren;
        }
    }




    public class MyCustomAdapter extends BaseExpandableListAdapter implements OnClickListener{


        private LayoutInflater inflater;
        private ArrayList<Parent> mParent;

        public MyCustomAdapter(Context context, ArrayList<Parent> parent){
            mParent = parent;
            inflater = LayoutInflater.from(context);
        }


        @Override
        //counts the number of group/parent items so the list knows how many times calls getGroupView() method
        public int getGroupCount() {
            return mParent.size();
        }

        @Override
        //counts the number of children items so the list knows how many times calls getChildView() method
        public int getChildrenCount(int i) {
            return mParent.get(i).getArrayChildren().size();
        }

        @Override
        //gets the title of each parent/group
        public Object getGroup(int i) {
            return mParent.get(i).getTitle();
        }

        @Override
        //gets the name of each item
        public Object getChild(int i, int i1) {
            return mParent.get(i).getArrayChildren().get(i1);
        }

        @Override
        public long getGroupId(int i) {
            return i;
        }

        @Override
        public long getChildId(int i, int i1) {
            return i1;
        }

        @Override
        public boolean hasStableIds() {
            return true;
        }

        @Override
        //in this method you must set the text to see the parent/group on the list
        public View getGroupView(int i, boolean b, View view, ViewGroup viewGroup) {

            if (view == null) {
                view = inflater.inflate(R.layout.list_item_parent, viewGroup,false);
            }
            view.findViewById(R.id.button).setTag(i);
            view.findViewById(R.id.button).setOnClickListener(this);
            TextView textView = (TextView) view.findViewById(R.id.list_item_text_view);
            //"i" is the position of the parent/group in the list
            textView.setText(getGroup(i).toString());

            //return the entire view
            return view;
        }

        @Override
        //in this method you must set the text to see the children on the list
        public View getChildView(int i, int i1, boolean b, View view, ViewGroup viewGroup) {
            if (view == null) {
                view = inflater.inflate(R.layout.list_item_child, viewGroup,false);
            }

            TextView textView = (TextView) view.findViewById(R.id.list_item_text_child);
            //"i" is the position of the parent/group in the list and
            //"i1" is the position of the child
            textView.setText(mParent.get(i).getArrayChildren().get(i1));

            //return the entire view
            return view;
        }

        @Override
        public boolean isChildSelectable(int i, int i1) {
            return true;
        }

        @Override
        public void registerDataSetObserver(DataSetObserver observer) {
            /* used to make the notifyDataSetChanged() method work */
            super.registerDataSetObserver(observer);
        }


        /* (non-Javadoc)
         * @see android.view.View.OnClickListener#onClick(android.view.View)
         * @since Mar 20, 2013
         * @author rajeshcp 
         */
        @Override
        public void onClick(View v) {
            if(mExpandableList.isGroupExpanded((Integer)v.getTag()))
        {
            mExpandableList.collapseGroup((Integer)v.getTag());
        }else
        {
            mExpandableList.expandGroup((Integer)v.getTag());
        }
        }
    }


}

更改您的MyActivity，让我知道您还想要什么？

Answer 5

主题：

    int width = getResources().getDisplayMetrics().widthPixels;
    if (android.os.Build.VERSION.SDK_INT < android.os.Build.VERSION_CODES.JELLY_BEAN_MR2) {
        listView.setIndicatorBounds(width - getPixelValue(40), width - getPixelValue(10));
    } else {
        listView.setIndicatorBoundsRelative(width - getPixelValue(40), width - getPixelValue(10));
    }

和辅助方法：

public static int getPixelValue(int dp) {

    final float scale = getResources().getDisplayMetrics().density;
    return (int) (dp * scale + 0.5f);
}

Answer 6

只需在组项目示例的xml中的任意位置创建一个视图/ Imageview：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/parent_group"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:padding="10dp">

<ImageView
    android:id="@+id/expandable_icon"
    android:layout_width="25dp"
    android:layout_height="25dp"
    android:layout_marginTop="6dp"
    android:src="@drawable/group_icon_not_expanded" />

<TextView
    android:id="@+id/group_name"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_gravity="center"
    android:layout_marginLeft="10dp"
    android:fontFamily="@font/roboto_thin"
    android:textColor="@android:color/black"
    android:textSize="17sp" />

然后为您的ExpandableListView使用GroupClickListener以编程方式更改ImageView的图像，例如：

listView.setOnGroupClickListener(new ExpandableListView.OnGroupClickListener() {
        @Override
        public boolean onGroupClick(ExpandableListView parent, View v, int groupPosition, long id) {
            parent.smoothScrollToPosition(groupPosition);

            if (parent.isGroupExpanded(groupPosition)) {
                ImageView imageView = v.findViewById(R.id.expandable_icon);
                imageView.setImageDrawable(getResources().getDrawable(R.drawable.group_icon_not_expanded));
            } else {
                ImageView imageView = v.findViewById(R.id.expandable_icon);
                imageView.setImageDrawable(getResources().getDrawable(R.drawable.group_icon_expanded));
            }
            return false    ;
        }
    });

Answer 7

我参加聚会有点晚了，但我的要求与此类似但有所不同。

我有3个要求：

如果一个小组有孩子，则显示down_arrow（V）
如果一个小组没有孩子，那么就没有箭头/图像
如果有孩子的小组扩大了，则显示up_arrow（^）

要达到以下目的：

您的ExpandableListView看起来类似于android:groupIndicator为空

 <ExpandableListView
 android:id="@+id/expandableListView"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 android:divider="@android:color/darker_gray"
 android:dividerHeight="0.5dp"
 android:groupIndicator="@null" />

您的组/标题布局看起来像这样，结尾处是文本和图像：

<androidx.appcompat.widget.AppCompatImageView
    android:id="@+id/ivDrawerHeaderItemIcon"
    android:layout_width="@dimen/dp_30"
    android:layout_height="@dimen/dp_30"
    android:layout_gravity="center_vertical"
    android:layout_marginStart="@dimen/dp_10"
    android:layout_marginEnd="@dimen/dp_10"
    android:src="@drawable/switch" />

<androidx.appcompat.widget.AppCompatTextView
    android:id="@+id/lblListHeader"
    android:layout_width="0dp"
    android:layout_height="wrap_content"
    android:layout_margin="@dimen/dp_5"
    android:layout_weight="1"
    android:fontFamily="@font/roboto_condensed_regular"
    android:gravity="center_vertical"
    android:padding="@dimen/dp_10"
    android:textAllCaps="true"
    android:textColor="@android:color/white"
    android:textSize="@dimen/sp_16" />

<androidx.appcompat.widget.AppCompatImageView
    android:id="@+id/ivIcon"
    android:layout_width="@dimen/dp_15"
    android:layout_height="@dimen/dp_15"
    android:layout_gravity="center_vertical"
    android:layout_marginStart="@dimen/dp_10"
    android:layout_marginEnd="@dimen/dp_10" />

在您的BaseExpandableListAdapter的{{1}}方法中，使用
```
getGroupView()
```

if (Objects.requireNonNull(expandableListDetail.get(expandableListTitle.get(listPosition))).size() > 0) { if (isExpanded) { ivIcon.setImageResource(R.drawable.arrow_up); } else { ivIcon.setImageResource(R.drawable.arrow_down); } }是组，expandableListTitle是其子级

在ExpandableListView中更改可扩展指示器

7 个答案: