Android学习笔记之树形菜单的应用...

            <
            LinearLayout 
            xmlns:android
            ="http://schemas.android.com/apk/res/android"
            
    xmlns:tools
            ="http://schemas.android.com/tools"
            
    android:layout_width
            ="match_parent"
            
    android:layout_height
            ="match_parent"
            
    android:orientation
            ="vertical"
            
    tools:context
            =".MainActivity"
            >
            <
            TextView 
        
            android:layout_width
            ="fill_parent"
            
        android:layout_height
            ="wrap_content"
            
        android:text
            ="树形菜单..."
            
        android:textSize
            ="18dp"
            
        android:gravity
            ="center"
            />
            <
            ExpandableListView 
        
            android:id
            ="@+id/expandablelistview"
            
        android:layout_width
            ="fill_parent"
            
        android:layout_height
            ="fill_parent"
            
        android:background
            ="#ffffff"
            >
            </
            ExpandableListView
            >
            </
            LinearLayout
            >
        

            package
             com.example.expandablelistview;


            import
             android.os.Bundle;

            import
             android.app.Activity;

            import
             android.database.DataSetObserver;

            import
             android.graphics.Color;

            import
             android.view.Gravity;

            import
             android.view.Menu;

            import
             android.view.View;

            import
             android.view.ViewGroup;


            import
             android.widget.AbsListView;



            import
             android.widget.ExpandableListAdapter;

            import
             android.widget.ExpandableListView;

            import
             android.widget.ExpandableListView.OnChildClickListener;

            import
             android.widget.LinearLayout;

            import
             android.widget.TextView;

            import
             android.widget.Toast;

            public
            class MainActivity extends Activity {
    
    @Override
    protectedvoid onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        //设置一个ExpandableListView设置一个适配器...然后在总画布上进行显示...final ExpandableListAdapter adapter=new ExpandableListAdapter() {
            private String[] MainView=new String[]{"一班","二班","三班"};//一级列表所要显示的内容...
            //列表组件需要使用到适配器...这个适配器的使用，目的是列表下的子选项以什么样的格式进行展示...private String[][] SubView=new String[][]{{"aa","bb","cc","dd","ee"},{"aaa","bbb","ccc","ddd","eee"},{"a","b","c","d","e"}};//树形菜单子列表的内容...            TextView getTextView(){
            
                @SuppressWarnings("deprecation")
                AbsListView.LayoutParams lp=new AbsListView.LayoutParams(ViewGroup.LayoutParams.FILL_PARENT,64);//定义了一个布局,设置其长度和宽度...
                TextView textview=new TextView(MainActivity.this);
                textview.setLayoutParams(lp);//目的是把自身放在lp这个布局中进行显示...
                textview.setGravity(Gravity.CENTER_VERTICAL);//设置居中显示...
                textview.setPadding(36, 0, 0, 0);//设置相对位置...
                textview.setTextSize(16);//设置字体的大小...
                textview.setTextColor(Color.BLACK);//设置字体的颜色...return textview;
            }
            @Override
            publicvoid unregisterDataSetObserver(DataSetObserver observer) {
                // TODO Auto-generated method stub                
            }
            
            @Override
            publicvoid registerDataSetObserver(DataSetObserver observer) {
                // TODO Auto-generated method stub                
            }
            
            @Override
            publicvoid onGroupExpanded(int groupPosition) {
                // TODO Auto-generated method stub                
            }
            
            @Override
            publicvoid onGroupCollapsed(int groupPosition) {
                // TODO Auto-generated method stub                
            }
            
            @Override
            publicboolean isEmpty() {
                // TODO Auto-generated method stubreturnfalse;
            }
            
            @Override
            publicboolean isChildSelectable(int groupPosition, int childPosition) {
                // TODO Auto-generated method stubreturntrue;
            }
            
            @Override
            publicboolean hasStableIds() {
                // TODO Auto-generated method stubreturntrue;
            }
            
            //必须需要重写的方法...获取组视图...其实就是主视图...为主视图设置一个显示的方式...            
            @Override
            public View getGroupView(int groupPosition, boolean isExpanded,
                    View convertView, ViewGroup parent) {
                // TODO Auto-generated method stub
                LinearLayout ll=new LinearLayout(MainActivity.this);
                ll.setOrientation(0);
                TextView textview=getTextView();
                textview.setTextColor(Color.BLACK);
                textview.setText(getGroup(groupPosition).toString());//设置主视图的数据信息...                ll.addView(textview);
                return ll;
            }
            
            @Override
            publiclong getGroupId(int groupPosition) {
                // TODO Auto-generated method stub
                //获取被触发列表项的定位...return groupPosition;
            }
            
            @Override
            publicint getGroupCount() {
                // TODO Auto-generated method stub
                //返回父菜单项的字符数组长度...return MainView.length;
            }
            
            @Override
            public Object getGroup(int groupPosition) {
                // TODO Auto-generated method stub
                //返回一个字符串对象...这个字符串我们自己可以定义其值...return MainView[groupPosition];
            }
            
            @Override
            publiclong getCombinedGroupId(long groupId) {
                // TODO Auto-generated method stubreturn 0;
            }
            
            @Override
            publiclong getCombinedChildId(long groupId, long childId) {
                // TODO Auto-generated method stubreturn 0;
            }
            
            @Override
            publicint getChildrenCount(int groupPosition) {
                // TODO Auto-generated method stub
                //返回子菜单项的数组长度...return SubView[groupPosition].length;
            }
            //设置子视图的布局...显示的信息，以及如何显示...            @Override
            public View getChildView(int groupPosition, int childPosition,
                    boolean isLastChild, View convertView, ViewGroup parent) {
                // TODO Auto-generated method stub
                LinearLayout ll=new LinearLayout(MainActivity.this);//设置一个布局...
                ll.setOrientation(0);
                TextView textview=new TextView(MainActivity.this);
                textview.setText(getChild(groupPosition, childPosition).toString());//textView所要显示的内容...
                ll.addView(textview);//将这个布局中添加textView控件...return ll;
            }
            
            @Override
            publiclong getChildId(int groupPosition, int childPosition) {
                // TODO Auto-generated method stubreturn childPosition;
            }
            
            @Override
            public Object getChild(int groupPosition, int childPosition) {
                // TODO Auto-generated method stub
                //这里返回父菜单下的子菜单项的字符数组对象...return SubView[groupPosition][childPosition];
            }
            
            @Override
            publicboolean areAllItemsEnabled() {
                // TODO Auto-generated method stubreturnfalse;
            }
        }; 
        ExpandableListView expandableListView=(ExpandableListView) findViewById(R.id.expandablelistview);//获取组件...
        expandableListView.setAdapter(adapter);//绑定适配器...
        expandableListView.setOnChildClickListener(new OnChildClickListener() {
            //这里设置了一个监听，就是当每一个子菜单被点击的时候，我们也可以触发一些操作...            @Override
            publicboolean onChildClick(ExpandableListView parent, View v,
                    int groupPosition, int childPosition, long id) {
                // TODO Auto-generated method stub
                Toast.makeText(MainActivity.this, "您刚才点击了"+adapter.getChild(groupPosition, childPosition), Toast.LENGTH_LONG).show();
                returnfalse;
            }
        });   

    
    }

    @Override
    publicboolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.        getMenuInflater().inflate(R.menu.main, menu);
        returntrue;
    }
   
}