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 == -) {
                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 ;
    }
    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();
        if (position == ) {
            setSection(header, label);
        } else {
            String preLabel = stringArray.get(position - );
            char preFirstChar = preLabel.toUpperCase().charAt();
            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(, ).toUpperCase());
        text.setTextSize();
        text.setPadding(, , , );
        text.setGravity(Gravity.CENTER_VERTICAL);
        header.addView(text);
    }
    public int getPositionForSection(int section) {
        if (section == ) {
            return ;
        }
        for (int i = ; i < stringArray.size(); i++) {
            String l = stringArray.get(i);
            char firstChar = l.toUpperCase().charAt();
            if (firstChar == section) {
                return i;
            }
        }
        return -;
    }
    public int getSectionForPosition(int arg0) {
        return ;
    }
    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 = ;
    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 - ;
        } else if (idx < ) {
            idx = ;
        }
        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 == -) {
                return true;
            }
            list.setSelection(position);
        }
        return true;
    }
    protected void onDraw(Canvas canvas) {
        Paint paint = new Paint();
        paint.setColor(0xFFA6A9AA);
        paint.setTextSize(getMeasuredHeight()/);
        paint.setTextAlign(Paint.Align.CENTER);
        float widthCenter = getMeasuredWidth() / ;
        for (int i = ; 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;
    }
}