compile 'com.android.support:recyclerview-v7:26.0.0-alpha1'
compile files('libs/pinyin4j-2.5.0.jar')

public class MainActivity extends AppCompatActivity {
  //參考網(wǎng)址：https://github.com/JanecineJohn/WeChatList
  private RecyclerView contactList;
  private String[] contactNames;
  private LinearLayoutManager layoutManager;
  private LetterView letterView;
  private ContactAdapter adapter;
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    contactNames = new String[] {"安然","奧茲","德瑪","張三豐", "郭靖", "黃蓉", "黃老邪", "趙敏", "123", "天山童姥", "任我行", "于萬亭", "陳家洛", "韋小寶", "$6", "穆人清", "陳圓圓", "郭芙", "郭襄", "穆念慈", "東方不敗", "梅超風(fēng)", "林平之", "林遠圖", "滅絕師太", "段譽", "鳩摩智"};
    contactList = (RecyclerView) findViewById(R.id.contact_list);
    letterView = (LetterView) findViewById(R.id.letter_view);
    layoutManager = new LinearLayoutManager(this);
    adapter = new ContactAdapter(this, contactNames);
    contactList.setLayoutManager(layoutManager);
    contactList.addItemDecoration(new DividerItemDecoration(this, DividerItemDecoration.VERTICAL_LIST));
    contactList.setAdapter(adapter);
    letterView.setCharacterListener(new LetterView.CharacterClickListener() {
      @Override
      public void clickCharacter(String character) {
        layoutManager.scrollToPositionWithOffset(adapter.getScrollPosition(character),0);
      }
      @Override
      public void clickArrow() {
        layoutManager.scrollToPositionWithOffset(0,0);
      }
    });
  }
}
（3）Contact類
public class Contact implements Serializable {
  private String mName;
  private int mType;
  public Contact(String name, int type) {
    mName = name;
    mType = type;
  }
  public String getmName() {
    return mName;
  }
  public int getmType() {
    return mType;
  }
}

public class ContactAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder>{
  private LayoutInflater mLayoutInflater;
  private Context mContext;
  private String[] mContactNames; // 聯(lián)系人名稱字符串?dāng)?shù)組
  private List<String> mContactList; // 聯(lián)系人名稱List（轉(zhuǎn)換成拼音）
  private List<Contact> resultList; // 最終結(jié)果（包含分組的字母）
  private List<String> characterList; // 字母List
  public enum ITEM_TYPE {
    ITEM_TYPE_CHARACTER,
    ITEM_TYPE_CONTACT
  }
  public ContactAdapter(Context context, String[] contactNames) {
    mContext = context;
    mLayoutInflater = LayoutInflater.from(context);
    mContactNames = contactNames;
    handleContact();
  }
  private void handleContact() {
    mContactList = new ArrayList<>();
    Map<String, String> map = new HashMap<>();
    for (int i = 0; i < mContactNames.length; i++) {
      String pinyin = Utils.getPingYin(mContactNames[i]);
      map.put(pinyin, mContactNames[i]);
      mContactList.add(pinyin);
    }
    Collections.sort(mContactList, new ContactComparator());
    resultList = new ArrayList<>();
    characterList = new ArrayList<>();
    for (int i = 0; i < mContactList.size(); i++) {
      String name = mContactList.get(i);
      String character = (name.charAt(0) + "").toUpperCase(Locale.ENGLISH);
      if (!characterList.contains(character)) {
        if (character.hashCode() >= "A".hashCode() && character.hashCode() <= "Z".hashCode()) { // 是字母
          characterList.add(character);
          resultList.add(new Contact(character, ITEM_TYPE.ITEM_TYPE_CHARACTER.ordinal()));
        } else {
          if (!characterList.contains("#")) {
            characterList.add("#");
            resultList.add(new Contact("#", ITEM_TYPE.ITEM_TYPE_CHARACTER.ordinal()));
          }
        }
      }
      resultList.add(new Contact(map.get(name), ITEM_TYPE.ITEM_TYPE_CONTACT.ordinal()));
    }
  }
  @Override
  public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    if (viewType == ITEM_TYPE.ITEM_TYPE_CHARACTER.ordinal()) {
      return new CharacterHolder(mLayoutInflater.inflate(R.layout.item_character, parent, false));
    } else {
      return new ContactHolder(mLayoutInflater.inflate(R.layout.item_contact, parent, false));
    }
  }
  @Override
  public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
    if (holder instanceof CharacterHolder) {
      ((CharacterHolder) holder).mTextView.setText(resultList.get(position).getmName());
    } else if (holder instanceof ContactHolder) {
      ((ContactHolder) holder).mTextView.setText(resultList.get(position).getmName());
    }
  }
  @Override
  public int getItemViewType(int position) {
    return resultList.get(position).getmType();
  }
  @Override
  public int getItemCount() {
    return resultList == null ? 0 : resultList.size();
  }
  public class CharacterHolder extends RecyclerView.ViewHolder {
    TextView mTextView;
    CharacterHolder(View view) {
      super(view);
      mTextView = (TextView) view.findViewById(R.id.character);
    }
  }
  public class ContactHolder extends RecyclerView.ViewHolder {
    TextView mTextView;
    ContactHolder(View view) {
      super(view);
      mTextView = (TextView) view.findViewById(R.id.contact_name);
    }
  }
  public int getScrollPosition(String character) {
    if (characterList.contains(character)) {
      for (int i = 0; i < resultList.size(); i++) {
        if (resultList.get(i).getmName().equals(character)) {
          return i;
        }
      }
    }
    return -1; // -1不會滑動
  }
}

public class ContactComparator implements Comparator<String> {
  @Override
  public int compare(String o1, String o2) {
    int c1 = (o1.charAt(0) + "").toUpperCase().hashCode();
    int c2 = (o2.charAt(0) + "").toUpperCase().hashCode();
    boolean c1Flag = (c1 < "A".hashCode() || c1 > "Z".hashCode()); // 不是字母
    boolean c2Flag = (c2 < "A".hashCode() || c2 > "Z".hashCode()); // 不是字母
    if (c1Flag && !c2Flag) {
      return 1;
    } else if (!c1Flag && c2Flag) {
      return -1;
    }
    return c1 - c2;
  }
}

public class DividerItemDecoration extends RecyclerView.ItemDecoration {
  private static final int[] ATTRS = new int[]{
      android.R.attr.listDivider
  };
  public static final int HORIZONTAL_LIST = LinearLayoutManager.HORIZONTAL;
  public static final int VERTICAL_LIST = LinearLayoutManager.VERTICAL;
  private Drawable mDivider;
  private int mOrientation;
  public DividerItemDecoration(Context context, int orientation) {
    final TypedArray a = context.obtainStyledAttributes(ATTRS);
    mDivider = a.getDrawable(0);
    a.recycle();
    setOrientation(orientation);
  }
  private void setOrientation(int orientation) {
    if (orientation != HORIZONTAL_LIST && orientation != VERTICAL_LIST) {
      throw new IllegalArgumentException("invalid orientation");
    }
    mOrientation = orientation;
  }
  @Override
  public void onDraw(Canvas c, RecyclerView parent) {
    if (mOrientation == VERTICAL_LIST) {
      drawVertical(c, parent);
    } else {
      drawHorizontal(c, parent);
    }
  }
//  @Override
//  public void onDraw(Canvas c, RecyclerView parent, RecyclerView.State state) {
//    //super.onDraw(c, parent, state);
//    if (mOrientation == VERTICAL_LIST) {
//      drawVertical(c, parent);
//    } else {
//      drawHorizontal(c, parent);
//    }
//  }
  public void drawVertical(Canvas c, RecyclerView parent) {
    final int left = parent.getPaddingLeft();
    final int right = parent.getWidth() - parent.getPaddingRight();
    final int childCount = parent.getChildCount();
    for (int i = 0; i < childCount; i++) {
      final View child = parent.getChildAt(i);
      final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child
          .getLayoutParams();
      final int top = child.getBottom() + params.bottomMargin +
          Math.round(ViewCompat.getTranslationY(child));
      final int bottom = top + mDivider.getIntrinsicHeight();
      mDivider.setBounds(left, top, right, bottom);
      mDivider.draw(c);
    }
  }
  public void drawHorizontal(Canvas c, RecyclerView parent) {
    final int top = parent.getPaddingTop();
    final int bottom = parent.getHeight() - parent.getPaddingBottom();
    final int childCount = parent.getChildCount();
    for (int i = 0; i < childCount; i++) {
      final View child = parent.getChildAt(i);
      final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child
          .getLayoutParams();
      final int left = child.getRight() + params.rightMargin +
          Math.round(ViewCompat.getTranslationX(child));
      final int right = left + mDivider.getIntrinsicHeight();
      mDivider.setBounds(left, top, right, bottom);
      mDivider.draw(c);
    }
  }
  @Override
  public void getItemOffsets(Rect outRect, int itemPosition, RecyclerView parent) {
    if (mOrientation == VERTICAL_LIST) {
      outRect.set(0, 0, 0, mDivider.getIntrinsicHeight());
    } else {
      outRect.set(0, 0, mDivider.getIntrinsicWidth(), 0);
    }
  }
//  @Override
//  public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
//    if (mOrientation == VERTICAL_LIST){
//      outRect.set(0,0,0,mDivider.getIntrinsicHeight());
//    }else {
//      outRect.set(0,0,mDivider.getIntrinsicWidth(),0);
//    }
//  }
}

public class LetterView extends LinearLayout{
  private Context mContext;
  private CharacterClickListener mListener;
  public LetterView(Context context,AttributeSet attrs) {
    super(context, attrs);
    mContext = context;//接收傳進來的上下文
    setOrientation(VERTICAL);
    initView();
  }
  private void initView(){
    addView(buildImageLayout());
    for (char i = 'A';i<='Z';i++){
      final String character = i + "";
      TextView tv = buildTextLayout(character);
      addView(tv);
    }
    addView(buildTextLayout("#"));
  }
  private TextView buildTextLayout(final String character){
    LinearLayout.LayoutParams layoutParams =
        new LinearLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT,1);
    TextView tv = new TextView(mContext);
    tv.setLayoutParams(layoutParams);
    tv.setGravity(Gravity.CENTER);
    tv.setClickable(true);
    tv.setText(character);
    tv.setOnClickListener(new OnClickListener() {
      @Override
      public void onClick(View view) {
        if (mListener != null){
          mListener.clickCharacter(character);
        }
      }
    });
    return tv;
  }
  private ImageView buildImageLayout() {
    LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT, 1);
    ImageView iv = new ImageView(mContext);
    iv.setLayoutParams(layoutParams);
    iv.setBackgroundResource(R.mipmap.ic_launcher);
    iv.setOnClickListener(new OnClickListener() {
      @Override
      public void onClick(View v) {
        if (mListener != null) {
          mListener.clickArrow();
        }
      }
    });
    return iv;
  }
  public void setCharacterListener(CharacterClickListener listener) {
    mListener = listener;
  }
  public interface CharacterClickListener {
    void clickCharacter(String character);
    void clickArrow();
  }
}

public class Utils {
  public static String getPingYin(String inputString) {
    HanyuPinyinOutputFormat format = new HanyuPinyinOutputFormat();
    format.setCaseType(HanyuPinyinCaseType.LOWERCASE);
    format.setToneType(HanyuPinyinToneType.WITHOUT_TONE);
    format.setVCharType(HanyuPinyinVCharType.WITH_V);
    char[] input = inputString.trim().toCharArray();
    String output = "";
    try {
      for (char curchar : input) {
        if (java.lang.Character.toString(curchar).matches("[\\u4E00-\\u9FA5]+")) {
          String[] temp = PinyinHelper.toHanyuPinyinStringArray(curchar, format);
          output += temp[0];
        } else {
          output += java.lang.Character.toString(curchar);
        }
      }
    } catch (BadHanyuPinyinOutputFormatCombination e) {
      e.printStackTrace();
    }
    return output;
  }
}