本文实例讲述了Android开发之自定义view实现通讯录列表A~Z字母提示效果。分享给大家供大家参考，具体如下：
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：
代码语言：javascript复制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：
代码语言：javascript复制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：
代码语言：javascript复制//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：
代码语言：javascript复制//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。
希望本文所述对大家Android程序设计有所帮助。
