Android 字母导航条实现

在Activity中进行功能的实现，需要用到第三方jar包:pinyin4j.jar，此jar包用于将汉字转换为汉语拼音。

首先，设置右侧边栏索引列表(A-Z)，并且设置列表点击，Touch事件，点击索引，如果在内容列表中存在对应的数据，则自动跳转显示到那一条数据，如果没有则不处理，长按的时候在内容列表中显示当前选择了哪一项；
获取内容列表list，并且获取此列表中联系人对象的名字所对应的第一个字母，将所有的联系人名字第一个字母取出(无重复)，然后将两个列表合并，最后根据联系人或者是联系人组目录拼音进行排序比较；

public class ContactsActivity extends Activity {
    private TextView tv_center = null;
    private ListView content; // 左边的联系人列表
    private ListView lvseek; // 右边的索引列表
    private HanyuPinyinOutputFormat spellFormat; // 转换汉字得到其汉语拼音
    private List<String> index_list = new ArrayList<String>(); // 联系人列表的组索引列表
    private ContactsAdapter adapter; // 联系人列表的适配器

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

    /**
     * 初始化变量
     */
    private void init() {
        lvseek = (ListView) findViewById(R.id.layout);
        tv_center = (TextView) findViewById(R.id.tv);

        spellFormat = new HanyuPinyinOutputFormat();
        spellFormat.setCaseType(HanyuPinyinCaseType.LOWERCASE);
        spellFormat.setToneType(HanyuPinyinToneType.WITHOUT_TONE);
        spellFormat.setVCharType(HanyuPinyinVCharType.WITH_V);

        content = (ListView) findViewById(R.id.listView1);
        setContent(content);
        setLvSeekAdapter(lvseek);
        setLvSeekListener(lvseek);
    }

    /**
     * 设置索引列表的数据源适配器
     * 
     * @param lvseek2
     */
    private void setLvSeekAdapter(ListView lvseek2) {
        AZAdapter adapter = new AZAdapter(this, getList());
        int per_height = getResources().getDisplayMetrics().heightPixels / 26;
        adapter.setHeight(per_height);
        lvseek2.setAdapter(adapter);
    }

    /**
     * 设置seekLv事件响应
     * 
     * @param lvseek2
     */
    private void setLvSeekListener(final ListView lvseek2) {
        // Touch事件，按下和放开两个事件处理
        lvseek2.setOnTouchListener(new OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                if (event.getAction() == MotionEvent.ACTION_UP) {
                    tv_center.setVisibility(View.INVISIBLE);
                    lvseek2.setBackgroundColor(Color.parseColor("#FDFDFD"));
                } else if (event.getAction() == MotionEvent.ACTION_DOWN) {
                    lvseek2.setBackgroundColor(Color.parseColor("#F2F1F0"));
                }
                return false;
            }
        });
        // 长按的时候在屏幕中间显示当前选择的是哪一个索引项
        lvseek2.setOnItemLongClickListener(new OnItemLongClickListener() {
            @Override
            public boolean onItemLongClick(AdapterView<?> parent, View view,
                    int position, long id) {
                String str = (String) parent.getAdapter().getItem(position);
                tv_center.setVisibility(View.VISIBLE);
                tv_center.setText(str);
                int index = adapter.getItemIndex(str);
                if (index != -1)
                    content.setSelection(index);
                return false;
            }
        });

        lvseek2.setOnItemClickListener(new OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view,
                    int position, long id) {
                String str = (String) parent.getAdapter().getItem(position);
                int index = adapter.getItemIndex(str);
                if (index != -1)
                    content.setSelection(index);
            }
        });
    }

    /**
     * 将内容添加到列表
     * 
     * @param content2
     */
    private void setContent(ListView content2) {
        adapter = new ContactsAdapter(this, getList_content());
        content2.setAdapter(adapter);
    }

    // 李四, 王五, 张三, 赵六
    private List<Object> getList_content() {
        List<Object> list = new ArrayList<Object>();
        List<Contact> contact_list = new ArrayList<Contact>();
        contact_list.add(new Contact("张三", null, ""));
        contact_list.add(new Contact("李四", null, ""));
        。。。// 将联系人添加进列表
        list.addAll(contact_list);
        // 获取联系人索引列表
        getIndex_List(contact_list);
        // 将索引列表添加进list;
        list.addAll(index_list);
        Collections.sort(list, new PinyinComparator());
        return list;
    }

    /**
     * 根据联系人列表获取索引
     * 
     * @param list
     */
    private void getIndex_List(List<Contact> list) {
        for (Contact con : list) {
            String pinying = PinyinHelper.toHanyuPinyinString(con.getName(),
                    spellFormat, "");
            String first_s = pinying.substring(0, 1);
            String str = first_s.toUpperCase();
            if (isA_Z(str)) {// 首字母是a-z
                if (!index_list.contains(str)) {
                    index_list.add(str);
                }
            }
        }
    }

    class PinyinComparator implements Comparator<Object> { // 比较器，在内容列表中有两种类型的数据，所以定义为Object；
        public int compare(Object o1, Object o2) {
            String str1;
            String str2;
            if (o1.getClass() == Contact.class) {
                str1 = ((Contact) o1).getName();
            } else {
                str1 = o1.toString();
            }
            if (o2.getClass() == Contact.class) {
                str2 = ((Contact) o2).getName();
            } else {
                str2 = o2.toString();
            }
            return chineneToSpell(str1).compareTo(chineneToSpell(str2));
        }

        /**
         * 使用PinYin4j.jar将汉字转换为拼音
         * 
         * @param chineseStr
         * @return
         */
        private String chineneToSpell(String chineseStr) {
            if (isChinese(chineseStr)) {
                String pinying = PinyinHelper.toHanyuPinyinString(chineseStr, spellFormat, "");
                return pinying.toUpperCase();
            } else
                return chineseStr;
        }
    }

    /**
     * 加载右边显示栏
     * 
     * @return
     */
    private List<String> getList() {
        return Arrays.asList(Utils.RIGHT_INDEX);
    }
}

至此基本功能已经实现；
补充:最近在学习的过程中，发现了另一种方式，相比前一种方式，更加合理，记录如下:

public class MyTrackView extends View {
    private OnTrackListener listener;
    private String bg = "#40000000";
    private boolean showbg = false;
    private Paint paint = new Paint();
    private String[] b = new String[] { "#", "A", "B", "C", "D", "E", "F", "G",
            "H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T",
            "U", "V", "W", "X", "Y", "Z", "$" };
    private int choose = -1;

    public MyTrackView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }

    public MyTrackView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public MyTrackView(Context context) {
        super(context);
    }

    @Override
    public boolean dispatchTouchEvent(MotionEvent event) {
        int item = (int) (event.getY() / getHeight() * b.length);
        switch (event.getAction()) {
        case MotionEvent.ACTION_DOWN:
            if (item >= 0 && item < b.length) {
                showbg = true;
                choose = item;
                invalidate();
                if (listener != null) {
                    listener.getStr(b[item]);
                }
            }
            break;
        case MotionEvent.ACTION_MOVE:
            if (item >= 0 && item < b.length) {
                showbg = true;
                choose = item;
                invalidate();
                if (listener != null) {
                    listener.getStr(b[item]);
                }
            }
            break;
        case MotionEvent.ACTION_UP:
            showbg = false;
            choose = -1;
            invalidate();
            if (listener != null) {
                listener.getStr(-1 + "");
            }
            break;
        }
        return true;
    }

    @Override
    protected void onDraw(Canvas canvas) {
        int singleHeight = getHeight() / b.length;
        if (showbg) {
            canvas.drawColor(Color.parseColor(bg));
        }
        for (int i = 0; i < b.length; i++) {
            paint.setColor(Color.WHITE);
            paint.setAntiAlias(true);
            float textWidth = paint.measureText(b[i]);
            if (i == choose) {
                paint.setColor(Color.RED);
                paint.setFakeBoldText(true);
            }
            canvas.drawText(b[i], (getWidth() - textWidth) / 2, (i + 1)
                    * singleHeight, paint);
            paint.reset();
        }
        super.onDraw(canvas);
    }

    public void setTrackListener(OnTrackListener listener) {
        this.listener = listener;
    }

    interface OnTrackListener {
        public void getStr(String str);
    }
}

利用pinyin.jar轻松将汉字转换为拼音

public class Main{private HanyuPinyinOutputFormat spellFormat; // 转换汉字得到其汉语拼音
public Main() {
        spellFormat = new HanyuPinyinOutputFormat();
        spellFormat.setCaseType(HanyuPinyinCaseType.LOWERCASE);
        spellFormat.setToneType(HanyuPinyinToneType.WITHOUT_TONE);
        spellFormat.setVCharType(HanyuPinyinVCharType.WITH_V);
        Log.e(chineneToSpell("大家好"), "fuck");
    }

    /**
     * 使用PinYin4j.jar将汉字转换为拼音
     * 
     * @param chineseStr
     * @return
     */
    private String chineneToSpell(String chineseStr) {
        if (isChinese(chineseStr)) {
            String pinying = PinyinHelper.toHanyuPinyinString(chineseStr,
                    spellFormat, "");
            return pinying.toUpperCase();
        }
        return chineseStr;
    }

    /**
     * 判断字符串中是否包含有中文
     * 
     * @param str
     * @return
     */
    protected static boolean isChinese(String str) {
        String regex = "[\\u4e00-\\u9fa5]";
        Pattern pattern = Pattern.compile(regex);
        Matcher matcher = pattern.matcher(str);
        return matcher.find();
    }

    /**
     * 判断是否是a-z
     * 
     * @param str
     * @return
     */
    protected static boolean isA2Z(String str) {
        String regex = "[A-Za-z]";
        Pattern pattern = Pattern.compile(regex);
        Matcher matcher = pattern.matcher(str);
        return matcher.find();
    }
}