Android SectionIndexer 的使用（联系人分类索引）

// 获取标题栏索引
int position = sectionIndexter.getPositionForSection(l[idx]);  
            if (position == -1) {  
                return true;  
            }  
// 设置调整到指定区域
            list.setSelection(position); 

1. Main.xml 

<?xml version="1.0" encoding="utf-8"?>  
<RelativeLayout  
    xmlns:android="http://schemas.android.com/apk/res/android"  
    android:layout_width="fill_parent"  
    android:layout_height="fill_parent">  
<ListView android:id="@+id/myListView"  
    android:layout_width="fill_parent"  
    android:layout_height="fill_parent"  
/>  
<android.test.SideBar  
    android:id = "@+id/sideBar"  
    android:layout_height="fill_parent"  
    android:layout_width="22px"  
    android:layout_alignParentRight="true"  
/>  
</RelativeLayout>  

2. listview_row.xml 

<?xml version="1.0" encoding="utf-8"?>  
<LinearLayout  
    xmlns:android="http://schemas.android.com/apk/res/android"  
    android:orientation="vertical"  
    android:layout_width="fill_parent"  
    android:layout_height="wrap_content">  
<LinearLayout  
    android:id="@+id/section"  
    android:layout_width="fill_parent"  
    android:layout_height="wrap_content"  
/>  
<TextView android:id="@+id/textView"  
    android:layout_width="wrap_content"  
    android:layout_height="80sp"  
    android:textSize="45sp"  
/>  
</LinearLayout>  

3. MyAdapter.Java 

package android.test;  
import java.util.ArrayList;  
import android.app.Activity;  
import android.content.Context;  
import android.graphics.Color;  
import android.view.Gravity;  
import android.view.LayoutInflater;  
import android.view.View;  
import android.view.ViewGroup;  
import android.widget.BaseAdapter;  
import android.widget.LinearLayout;  
import android.widget.SectionIndexer;  
import android.widget.TextView;  
public class MyAdapter extends BaseAdapter implements SectionIndexer {  
    private ArrayList<String> stringArray;  
    private Context context;  
    public MyAdapter(Context _context, ArrayList<String> arr) {  
        stringArray = arr;  
        context = _context;  
    }  
    public int getCount() {  
        return stringArray.size();  
    }  
    public Object getItem(int arg0) {  
        return stringArray.get(arg0);  
    }  
    public long getItemId(int arg0) {  
        return 0;  
    }  
    public View getView(int position, View v, ViewGroup parent) {  
        LayoutInflater inflate = ((Activity) context).getLayoutInflater();  
        View view = (View) inflate.inflate(R.layout.listview_row, null);  
        LinearLayout header = (LinearLayout) view.findViewById(R.id.section);  
        String label = stringArray.get(position);  
        char firstChar = label.toUpperCase().charAt(0);  
        if (position == 0) {  
            setSection(header, label);  
        } else {  
            String preLabel = stringArray.get(position - 1);  
            char preFirstChar = preLabel.toUpperCase().charAt(0);  
            if (firstChar != preFirstChar) {  
                setSection(header, label);  
            } else {  
                header.setVisibility(View.GONE);  
            }  
        }  
        TextView textView = (TextView) view.findViewById(R.id.textView);  
        textView.setText(label);  
        return view;  
    }  
    private void setSection(LinearLayout header, String label) {  
        TextView text = new TextView(context);  
        header.setBackgroundColor(0xffaabbcc);  
        text.setTextColor(Color.WHITE);  
        text.setText(label.substring(0, 1).toUpperCase());  
        text.setTextSize(20);  
        text.setPadding(5, 0, 0, 0);  
        text.setGravity(Gravity.CENTER_VERTICAL);  
        header.addView(text);  
    }  
    public int getPositionForSection(int section) {  
        if (section == 35) {  
            return 0;  
        }  
        for (int i = 0; i < stringArray.size(); i++) {  
            String l = stringArray.get(i);  
            char firstChar = l.toUpperCase().charAt(0);  
            if (firstChar == section) {  
                return i;  
            }  
        }  
        return -1;  
    }  
    public int getSectionForPosition(int arg0) {  
        return 0;  
    }  
    public Object[] getSections() {  
        return null;  
    }  
}  

4.  SideBar.java 

package android.test;  
import android.content.Context;  
import android.graphics.Canvas;  
import android.graphics.Paint;  
import android.util.AttributeSet;  
import android.view.MotionEvent;  
import android.view.View;  
import android.widget.ListView;  
import android.widget.SectionIndexer;  
public class SideBar extends View {  
    private char[] l;  
    private SectionIndexer sectionIndexter = null;  
    private ListView list;  
    private final int m_nItemHeight = 60;  
    public SideBar(Context context) {  
        super(context);  
        init();  
    }  
    public SideBar(Context context, AttributeSet attrs) {  
        super(context, attrs);  
        init();  
    }  
    private void init() {  
        l = new char[] { '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' };  
        setBackgroundColor(0x44FFFFFF);  
    }  
    public SideBar(Context context, AttributeSet attrs, int defStyle) {  
        super(context, attrs, defStyle);  
        init();  
    }  
    public void setListView(ListView _list) {  
        list = _list;  
        sectionIndexter = (SectionIndexer) _list.getAdapter();  
    }  
    public boolean onTouchEvent(MotionEvent event) {  
        super.onTouchEvent(event);  
        int i = (int) event.getY();  
        int idx = i / m_nItemHeight;  
        if (idx >= l.length) {  
            idx = l.length - 1;  
        } else if (idx < 0) {  
            idx = 0;  
        }  
        if (event.getAction() == MotionEvent.ACTION_DOWN || event.getAction() == MotionEvent.ACTION_MOVE) {  
            if (sectionIndexter == null) {  
                sectionIndexter = (SectionIndexer) list.getAdapter();  
            }  
            int position = sectionIndexter.getPositionForSection(l[idx]);  
            if (position == -1) {  
                return true;  
            }  
            list.setSelection(position);  
        }  
        return true;  
    }  
    protected void onDraw(Canvas canvas) {  
        Paint paint = new Paint();  
        paint.setColor(0xFFA6A9AA);  
        paint.setTextSize(getMeasuredHeight()/26);  
        paint.setTextAlign(Paint.Align.CENTER);  
        float widthCenter = getMeasuredWidth() / 2;  
        for (int i = 0; i < l.length; i++) {  
            canvas.drawText(String.valueOf(l[i]), widthCenter, m_nItemHeight + (i * m_nItemHeight), paint);  
        }  
        super.onDraw(canvas);  
    }  
}  

5. Main.java 

package android.test;  
import java.util.ArrayList;  
import android.app.Activity;  
import android.os.Bundle;  
import android.widget.ListView;  
public class Main extends Activity {  
    /** Called when the activity is first created. */  
    @Override  
    public void onCreate(Bundle savedInstanceState) {  
        super.onCreate(savedInstanceState);  
        setContentView(R.layout.main);  
        ListView list = (ListView) findViewById(R.id.myListView);  
        ArrayList<String> stringList = InitListViewData();  
        MyAdapter adapter = new MyAdapter(this, stringList);  
        list.setAdapter(adapter);  
        SideBar indexBar = (SideBar) findViewById(R.id.sideBar);  
        indexBar.setListView(list);  
    }  
    private ArrayList<String> InitListViewData() {  
        ArrayList<String> stringList = new ArrayList<String>();  
        stringList.add("aback");  
        stringList.add("abash");  
        stringList.add("abbey");  
        stringList.add("abhor");  
        stringList.add("abide");  
        stringList.add("abuse");  
        stringList.add("candidate");  
        stringList.add("capture");  
        stringList.add("careful");  
        stringList.add("catch");  
        stringList.add("cause");  
        stringList.add("celebrate");  
        stringList.add("forever");  
        stringList.add("fable");  
        stringList.add("fidelity");  
        stringList.add("fox");  
        stringList.add("funny");  
        stringList.add("fail");  
        stringList.add("jail");  
        stringList.add("jade");  
        stringList.add("jailor");  
        stringList.add("january");  
        stringList.add("jasmine");  
        stringList.add("jazz");  
        stringList.add("zero");  
        stringList.add("zoo");  
        stringList.add("zeus");  
        stringList.add("zebra");  
        stringList.add("zest");  
        stringList.add("zing");  
        return stringList;  
    }  
}