联系人字母索引实现

public class HeaderAdapter extends ArrayAdapter<String> implements SectionIndexer {

private List<String> items=new ArrayList<String>();
private LayoutInflater mInflater;
private int resource;
private int textViewResourceId;
private String[] sections;
private HashMap<String,Integer> maps=new HashMap<String, Integer>();

public HeaderAdapter(Context context, int resource, int textViewResourceId,
List<String> items) {

super(context, resource, textViewResourceId, items);
this.items=items;
mInflater=LayoutInflater.from(context);
this.resource=resource;
this.textViewResourceId=textViewResourceId;
//A-Z字母列表
sections=context.getResources().getStringArray(R.array.sections);
initMaps();
// TODO Auto-generated constructor stub
}
private void initMaps(){

//遍历数据源，用来保存相应字母的position位置

for (int i=0;i<items.size();i++) {
String start=items.get(i).substring(0,1).toUpperCase();
if(!maps.containsKey(start)){
maps.put(start, i);
}
}
}

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

@Override
public String getItem(int position) {
// TODO Auto-generated method stub
return items.get(position);
}

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

@Override
public int getPosition(String item) {
// TODO Auto-generated method stub
return super.getPosition(item);
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
// TODO Auto-generated method stub
convertView =mInflater.inflate(resource, null);
TextView textView=(TextView)convertView.findViewById(textViewResourceId);
TextView header=(TextView)convertView.findViewById(R.id.header);
String text=items.get(position);
String start=text.substring(0, 1).toUpperCase();
if(maps.containsKey(start)&&maps.containsValue(position)){
header.setVisibility(View.VISIBLE);
header.setText(start);
}

textView.setText(text);

return convertView;
}

public int getPositionForSection(int sectionIndex) {
// TODO Auto-generated method stub

//主要方法根据字母索引位置，获取需要滚动的position位置

if(maps.get(sections[position])==null){
return -1;
}
return maps.get(sections[sectionIndex]);
}

public int getSectionForPosition(int position) {
// TODO Auto-generated method stub

return 0;
}

public String[] getSections() {
// TODO Auto-generated method stub

return sections;
}

}

public class SearchBar extends View {
private String[] section;
private int height;

private int indexHeight;//
private Paint textPaint;
private int width;
private int sectionLength;
private int curSetion;
private Rect mIndicatorRect = new Rect();
private Drawable mIndicatorDrawable;
private SectionIndexer mIndexer;
private ListView mList;
private PopupWindow mPopupWindow;
private TextView mPromptText;
public SearchBar(Context context) {
this(context,null);
// TODO Auto-generated constructor stub
}
public SearchBar(Context context,AttributeSet attr) {
this(context,attr,0);
// TODO Auto-generated constructor stub
}
public SearchBar(Context context,AttributeSet attr,int def) {
super(context,attr,0);
// TODO Auto-generated constructor stub

//A-Z

section=getResources().getStringArray(R.array.sections);
sectionLength=section.length;
textPaint=new Paint();
textPaint.setColor(Color.BLACK);
textPaint.setTextSize(14);
mIndicatorDrawable = getResources().getDrawable(R.drawable.bladeview_indicator_normal);
mPromptText=(TextView)LayoutInflater.from(context).inflate(R.layout.popup_text, null);
}

@Override
protected void onDraw(Canvas canvas) {
// TODO Auto-generated method stub
super.onDraw(canvas);
int offsetX=0;

mIndicatorRect.set(offsetX, indexHeight*curSetion, width,
indexHeight*(curSetion+1));
mIndicatorDrawable.setBounds(mIndicatorRect);
mIndicatorDrawable.draw(canvas);

for (int i=0;i<section.length;i++) {
canvas.drawText(section[i], width/2, (i+1)*indexHeight, textPaint);
}
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
// TODO Auto-generated method stub
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
height=getHeight();
width=getWidth();
indexHeight=height/section.length;
}
@Override
public boolean onTouchEvent(MotionEvent event) {
// TODO Auto-generated method stub
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:

float y=event.getY();
curSetion=getIndex(y);
setPromptText(curSetion);
showPopupWindows();
int position=0;
if(mIndexer!=null){
position=mIndexer.getPositionForSection(curSetion);

mList.setSelectionFromTop(position, 0);
}

break;
case MotionEvent.ACTION_MOVE:

y=event.getY();
curSetion=getIndex(y);
setPromptText(curSetion);
showPopupWindows();
position=0;
if(mIndexer!=null){
position=mIndexer.getPositionForSection(curSetion);

mList.setSelectionFromTop(position, 0);
}

invalidate();

break;
case MotionEvent.ACTION_UP:
case MotionEvent.ACTION_CANCEL:
disMissPopupWindows();
break;

default:
break;
}

return true;
}

//根据触摸Y值获取字母Index

private int getIndex(float y){
for (int i = 1; i <sectionLength; i++) {
if(y>i*indexHeight&&y<(i+1)*indexHeight){
return i;
}
}

return 0;

}
public void setListView(ListView list){
Adapter adapter=list.getAdapter();
if(adapter instanceof SectionIndexer){
mIndexer=(SectionIndexer)adapter;
mList=list;
}

}
private void setPromptText(int sec){
mPromptText.setText(section[sec]);

}
private void createPopupWindows(){
if(mPopupWindow==null){
mPopupWindow=new PopupWindow();
mPopupWindow.setContentView(mPromptText);
mPopupWindow.setHeight(LayoutParams.WRAP_CONTENT);
mPopupWindow.setWidth(LayoutParams.WRAP_CONTENT);
ColorDrawable d=new ColorDrawable(Color.TRANSPARENT);
mPopupWindow.setBackgroundDrawable(d);

}

}
private  void showPopupWindows(){
createPopupWindows();
mPopupWindow.showAtLocation(this, Gravity.CENTER, -1, -1);

}
private void disMissPopupWindows(){
mPopupWindow.dismiss();
}
}

public class MainActivity extends Activity {
private List<String> items=new ArrayList<String>();

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ListView list=(ListView)findViewById(R.id.listView1);
SearchBar bar=(SearchBar)findViewById(R.id.searchbar);

items.add("Action");
items.add("Adventure");
items.add("asg");
items.add("agf");
items.add("bdd");
items.add("ball");
items.add("call");
items.add("Documentary");
items.add("Foreign");
items.add("full");
items.add("History");
items.add("Independent");
items.add("Romance");
list.setAdapter(new HeaderAdapter(this, R.layout.listitem, R.id.items, items));
bar.setListView(list);

}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
//  getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
}