更改 ExpandableListView 中的可扩展指示器

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【中文标题】更改 ExpandableListView 中的可扩展指示器【英文标题】:Change expandable indicator in ExpandableListView 【发布时间】:2013-03-08 05:46:54 【问题描述】:

尝试创建 ExpandableListView。组的初始视图显示良好。但是,当我单击列表项时,我的箭头不会改变。请参阅下面的图片。

如何改变箭头的方向?

布局 XML:

  <ExpandableListView
        android:id="@+id/expandable_list"
        android:layout_
        android:layout_            
        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>

【问题讨论】:

发布listView行xml @RajeshCP 查看更新一 onItemClick 函数的 Onclick 您可以更改 group_indicator 的来源,因为您需要一个向上箭头按钮,或者您可以将位图旋转一些粗略并将其设置为该 ImageView 的来源 @RajeshCP 在左侧箭头工作得很好用这个hrupin.com/2012/08/… 一个但是如何解决右侧箭头 相应地编辑您的布局 【参考方案1】:

可扩展的列表视图

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

setindicator 这里我正在使用这样的 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/drawable/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>

【讨论】:

mExpandableList.setIndicatorBounds(width - 50, width - 10); 给出相同的输出.. 为什么????? 在 android 4.3 中使用 expListView.setIndicatorBoundsRelative 您可以在dimens.xml中保存指标大小:-50dp 然后使用内置方法计算dp到像素:getResources().getDimensionPixelSize( R.dimen.indicator_bounds) 图标被拉伸到布局的高度【参考方案2】:

试试你的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>

【讨论】:

当我发布我的答案时你没有发布你的答案:) 因为它对任何新开发人员都很有用。【参考方案3】:

我采取了以下方式:根据 isExpanded 标志为您的 groupView 决定左/右可绘制对象。 这样,我们就更容易自定义指标drawable的padding/background等东西了。

希望对你有帮助。

    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;
    

【讨论】:

【参考方案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());
        
        
    



像这样更改您的MyActivity,让我知道您还想要什么?

【讨论】:

在此没有 onitemclick 在可扩展列表视图中使用 onitemclick 所必需的。 我真的不明白你想要什么? 见hrupin.com/2012/08/…这个例子代替左侧图像如何将该图像更改为右侧。 我正在使用该示例,只是该图像如何像从左到右一样改变,就像我的图像有问题一样有一个这样的图像.. 嘿,运行应用程序后看到编辑后的答案,只需单击行中的每个按钮【参考方案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);

【讨论】:

【参考方案6】:

只需在组项示例的 xml 中创建您想要的视图/图像视图:

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

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

<TextView
    android:id="@+id/group_name"
    android:layout_
    android:layout_
    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    ;
        
    );

【讨论】:

【参考方案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:

    如果一个组有孩子,则显示 down_arrow (V) 如果一个组没有孩子,则没有箭头/图像 如果扩展了包含子项的组,则显示向上箭头 (^)

要达到类似的效果:

    您的ExpandableListView 看起来与android:groupIndicator null 类似

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

    您的组/标题布局将如下所示,最后带有文本和图像:

<androidx.appcompat.widget.AppCompatImageView
    android:id="@+id/ivDrawerHeaderItemIcon"
    android:layout_
    android:layout_
    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_
    android:layout_
    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_
    android:layout_
    android:layout_gravity="center_vertical"
    android:layout_marginStart="@dimen/dp_10"
    android:layout_marginEnd="@dimen/dp_10" />

    在您的BaseExpandableListAdaptergetGroupView() 方法中,使用

         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);
         
     
    

其中,expandableListTitle 是组,expandableListDetail 是其子项

【讨论】:

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