ListView 支持展开显示

 转自http://griffinshi.javaeye.com/blog/583783

 

默认的ListView显示的item 是静态的 即不能改变的

 

 

[功能]

但是我们有有这样的需求 比如：当不选中某个item的时候 就显示一下大致信息 而当点开该item 会显示更多信息

 

有2个办法实现之：

1. ExpandableListActivity

2. BaseAdapter + notifyDataSetChanged()

 

[前提]

本例显示的大致信息是：星期一到星期天 当单击某个item 会显示更多信息 比如：ImageView TextView ...

 

 

写道

因为要显示的内容不是固定的 所以系统默认的Adapter肯定是不行的 只能 extends BaseAdapter

 

 

 

 

[代码 步骤]

1. 准备一些始终显示的内容 本例为：

 

String[] week = new String[] {
            "January ","February ","March ","April ",
            "May","June","July","August","September","October","November","December "
    };

 

 

 

2. 定义 CustomItemAdapter extends BaseAdapter

public class CustomItemAdapter extends BaseAdapter {
        Activity activity;

        public CustomItemAdapter(Activity a){
            activity = a;
        }

        @Override
        public int getCount() {
            // TODO Auto-generated method stub
            return 0;
        }

        @Override
        public Object getItem(int arg0) {
            // TODO Auto-generated method stub
            return null;
        }

        @Override
        public long getItemId(int position) {
            // TODO Auto-generated method stub
            return 0;
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            // TODO Auto-generated method stub
            return null;
        }

    }

 

 

 

3. 填充CustomItemAdapter的各个method

写道

其中 关键是 getView() 实现 要求： 

1. 星期TextView 是始终要显示的 

2. 当某项item 被单击 要显示更多细节 


所以 我打算如下做： 

1. 定义 View addDefaultViewByPosition(int i) 用于星期的显示 

2. 定义 View addCustomViewByPosition(int i) 用于更多细节的显示

 

public View addDefaultViewByPosition(int i){
            TextView tv = new TextView(activity);
            tv.setText(week[i]);

            tv.setTextColor(Color.RED);
            tv.setGravity(Gravity.CENTER_HORIZONTAL);
            return tv;
        }

        public View addCustomViewByPosition(int i){
            View view = new View(activity);

            switch(i){
            case 0:
                ImageView iv0 = new ImageView(activity);
                iv0.setImageResource(R.drawable.icon);

                view = iv0;
                break;

            case 1 :
                RadioGroup group1 = new RadioGroup(activity);
                group1.setOrientation(LinearLayout.HORIZONTAL);
                RadioButton radio1 = new RadioButton(activity);
                radio1.setText("Radio 1");
                group1.addView(radio1);
                RadioButton radio2 = new RadioButton(activity);
                radio2.setText("Radio 2");
                group1.addView(radio2);

                view = group1;
                break;

            case 2:
                TextView tv = new TextView(activity);
                tv.setText("Hello to Gryphone!");
                tv.setTextSize(20);

                view = tv;
                break;
            }

            return view;
        }

  

 

 

4. 通过 LinearLayout 把 addDefaultViewByPosition() 与 addCustomViewByPosition() 把二者以 LinearLayout.VERTICAL 方式组织起来

public View getView(int arg0, View arg1, ViewGroup arg2) {
            // TODO Auto-generated method stub
            LinearLayout layout = new LinearLayout(activity);
            layout.setOrientation(LinearLayout.VERTICAL);

            layout.addView(addDefaultViewByPosition(arg0));

            if(ID == arg0){
                layout.addView(addCustomViewByPosition(arg0));
            }

            return layout;
        }

 

 

 

5. 上面用到的变量 ID  用来代表你单击的item的id

list.setOnItemClickListener(new OnItemClickListener(){

            @Override
            public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
                    long arg3) {
                // TODO Auto-generated method stub
                ID = arg2;

                adapter.notifyDataSetChanged();
            }

        });

 

 

 

6. emulator 运行截图：

* 无任何单击的截图：

 

 

* 单击item 1 的截图 并与 addCustomViewByPosition() 里的界面代码比较一下

 

 

 

* 单击item 2 的截图 并与 addCustomViewByPosition() 里的界面代码比较一下