学步园

开发工具：eclipse       运行环境：htc G9 android2.3.3

话不多说，先看效果图

其实左右边的A~Z是一个自定义的View，它直接覆盖在ListView上。

MyLetterListView：

public class MyLetterListView extends View {
	
	OnTouchingLetterChangedListener onTouchingLetterChangedListener;
	String[] b = {"#","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"};
	int choose = -1;
	Paint paint = new Paint();
	boolean showBkg = false;

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

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

	public MyLetterListView(Context context) {
		super(context);
	}
	
	@Override
	protected void onDraw(Canvas canvas) {
		super.onDraw(canvas);
		if(showBkg){
		    canvas.drawColor(Color.parseColor("#40000000"));
		}
		
	    int height = getHeight();
	    int width = getWidth();
	    int singleHeight = height / b.length;
	    for(int i=0;i<b.length;i++){
	       paint.setColor(Color.WHITE);
	       paint.setTypeface(Typeface.DEFAULT_BOLD);
	       paint.setAntiAlias(true);
	       if(i == choose){
	    	   paint.setColor(Color.parseColor("#3399ff"));
	    	   paint.setFakeBoldText(true);
	       }
	       float xPos = width/2  - paint.measureText(b[i])/2;
	       float yPos = singleHeight * i + singleHeight;
	       canvas.drawText(b[i], xPos, yPos, paint);
	       paint.reset();
	    }
	   
	}
	
	@Override
	public boolean dispatchTouchEvent(MotionEvent event) {
		final int action = event.getAction();
	    final float y = event.getY();
	    final int oldChoose = choose;
	    final OnTouchingLetterChangedListener listener = onTouchingLetterChangedListener;
	    final int c = (int) (y/getHeight()*b.length);
	    
		switch (action) {
			case MotionEvent.ACTION_DOWN:
				showBkg = true;
				if(oldChoose != c && listener != null){
					if(c > 0 && c< b.length){
						listener.onTouchingLetterChanged(b[c]);
						choose = c;
						invalidate();
					}
				}
				
				break;
			case MotionEvent.ACTION_MOVE:
				if(oldChoose != c && listener != null){
					if(c > 0 && c< b.length){
						listener.onTouchingLetterChanged(b[c]);
						choose = c;
						invalidate();
					}
				}
				break;
			case MotionEvent.ACTION_UP:
				showBkg = false;
				choose = -1;
				invalidate();
				break;
		}
		return true;
	}

	@Override
	public boolean onTouchEvent(MotionEvent event) {
		return super.onTouchEvent(event);
	}

	public void setOnTouchingLetterChangedListener(
			OnTouchingLetterChangedListener onTouchingLetterChangedListener) {
		this.onTouchingLetterChangedListener = onTouchingLetterChangedListener;
	}

	public interface OnTouchingLetterChangedListener{
		public void onTouchingLetterChanged(String s);
	}
	
}

然后我在Activity中OnTouchingLetterChangedListener中监听手指触摸到了哪个字母，然后让列表跳转到对应的位置，

弹出首字母提示框：

private class LetterListViewListener implements OnTouchingLetterChangedListener{

		@Override
		public void onTouchingLetterChanged(final String s) {
			if(alphaIndexer.get(s) != null) {
				int position = alphaIndexer.get(s);
				personList.setSelection(position);
				overlay.setText(sections[position]);
				overlay.setVisibility(View.VISIBLE);
				handler.removeCallbacks(overlayThread);
				//延迟一点五秒后执行，让overlay为不可见
				handler.postDelayed(overlayThread, 1500);
			} 
		}
    	
    }

延迟一秒让弹出的首字母提示框变为不可见，也就是那个首字母提示框只会显示一秒钟的时间：

//设置overlay不可见
    private class OverlayThread implements Runnable {

		@Override
		public void run() {
			overlay.setVisibility(View.GONE);
		}
    	
    }

还有关于解析汉子的首字母拼音的问题，我这里是查的系统数据库，里面正好有sort_key这一列，比如名字是张三，那么他对应的sort_key就是：ZHANG张SAN三，这样一来就容易多了：

//获得汉语拼音首字母
    private String getAlpha(String str) {  
        if (str == null) {  
            return "#";  
        }  
  
        if (str.trim().length() == 0) {  
            return "#";  
        }  
  
        char c = str.trim().substring(0, 1).charAt(0);  
        // 正则表达式，判断首字母是否是英文字母  
        Pattern pattern = Pattern.compile("^[A-Za-z]+{1}quot;);  
        if (pattern.matcher(c + "").matches()) {  
            return (c + "").toUpperCase();  
        } else {  
            return "#";  
        }  
    }  

如果你的数据不是从联系人表中查的，那可以使用第三方jar包，就是pinyin4j-2.5.0。
activity代码和布局文件比较长，我就不在这里贴了。

我上传了工程，有兴趣的朋友可以下载下来看下。写的还不够完善，希望大家见谅。

源码（0资源分）：http://download.csdn.net/detail/luck_apple/3629137