Android控件之ListView

ListView是Android中最常用的控件之一. ListView中一个重要的概念就是适配器(Adapter),它是控件与数据源之间的桥梁.

常见的数据源有数组/集合(Array/List),游标(Cursor).

1, 从数组中获取数据:

运行结果:

        2, 从Cursor中获取数据:
[html]
// Get a cursor with all people
Cursor c = getContentResolver().query(People.CONTENT_URI, null, null, null, null);

startManagingCursor(c);//使用的cursor的生命周期随Activity生命周期变化而变化.

ListAdapter adapter = new SimpleCursorAdapter(this,
        // Use a template that displays a text view
        android.R.layout.simple_list_item_1,
        // Give the cursor to the list adatper
        c,
        // Map the NAME column in the people database to...
        new String[] {People.NAME} ,
        // The "text1" view defined in the XML template
        new int[] {android.R.id.text1});
setListAdapter(adapter);

运行结果:

3, 使用自定义Adapter

[java]
private class SpeechListAdapter extends BaseAdapter {
        public SpeechListAdapter(Context context) {
            mContext = context;
        }

        public int getCount() {
            return mTitles.length;
        }

        public Object getItem(int position) {//每个条目对应的对象
            return position;
        }

        public long getItemId(int position) {//每个条目的id
            return position;
        }

        public View getView(int position, View convertView, ViewGroup parent) {//ListView每个item对应的view
            SpeechView sv;
            if (convertView == null) {
                sv = new SpeechView(mContext, mTitles[position],
                        mDialogue[position]);
            } else {
                sv = (SpeechView) convertView;
                sv.setTitle(mTitles[position]);
                sv.setDialogue(mDialogue[position]);
            }

            return sv;
        }
}
       结果:

一些ListView效果

1, 带有分隔符的ListView.
效果所下图所示(红框表示的是分隔条):

[html]
private class MyListAdapter extends BaseAdapter {
    public MyListAdapter(Context context) {
        mContext = context;
    }

    public int getCount() {
        return mStrings.length;
    }

    @Override
    public boolean areAllItemsEnabled() {//是否所有的item都可点击和选中
        return false;
    }

    @Override
    public boolean isEnabled(int position) {//如果字符串是以"-"开头,那么对应的item为分隔item
        return !mStrings[position].startsWith("-");
    }



    public Object getItem(int position) {
        return position;
    }

    public long getItemId(int position) {
        return position;
    }

    public View getView(int position, View convertView, ViewGroup parent) {
        TextView tv;
        if (convertView == null) {
            tv = (TextView) LayoutInflater.from(mContext).inflate(
                    android.R.layout.simple_expandable_list_item_1, parent, false);
        } else {
            tv = (TextView) convertView;
        }
        tv.setText(mStrings[position]);
        return tv;
    }

    private Context mContext;
}

2, 带收缩和展开效果的ListView
效果如下图所示:

3 ,类似带悬浮字母效果的ListView(类似通讯录导航的效果 )
如下图所示