Android自定义View实现字母导航栏

<!--?xml version="1.0" encoding="utf-8"?--><linearlayout android:layout_height="match_parent" android:layout_width="match_parent" android:orientation="vertical" xmlns:android="http://schemas.android.com/apk/res/android">  <edittext android:background="@drawable/search_border" android:drawableleft="@android:drawable/ic_menu_search" android:layout_height="wrap_content" android:layout_width="match_parent" android:padding="8dp">  <relativelayout android:layout_height="match_parent" android:layout_width="match_parent">  <listview android:divider="@null" android:id="@+id/lv" android:layout_height="match_parent" android:layout_width="match_parent">  <textview android:background="#888888" android:gravity="center" android:id="@+id/tv" android:layout_centerinparent="true" android:layout_height="50dp" android:layout_width="50dp" android:textcolor="#000000" android:textsize="18dp" android:visibility="gone">  <com.handsome.tulin.view.navview android:id="@+id/nv" android:layout_alignparentright="true" android:layout_height="match_parent" android:layout_margin="16dp" android:layout_width="20dp"> </com.handsome.tulin.view.navview></textview></listview></relativelayout></edittext></linearlayout>

public class NavView extends View { private Paint textPaint = new Paint(); private String[] s = new String[]{   "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", "#"}; //鼠标点击、滑动时选择的字母 private int choose = -1; //中间的文本 private TextView tv; public NavView(Context context, AttributeSet attrs) {  super(context, attrs); } public NavView(Context context) {  super(context); }  public NavView(Context context, AttributeSet attrs, int defStyleAttr) {  super(context, attrs, defStyleAttr); }  private void initPaint() {  textPaint.setTextSize(20);  textPaint.setAntiAlias(true);  textPaint.setColor(Color.BLACK); }  @Override protected void onDraw(Canvas canvas) {  super.onDraw(canvas);  //画字母  drawText(canvas); } /**  * 画字母  *  * @param canvas  */ private void drawText(Canvas canvas) {  //获取View的宽高  int width = getWidth();  int height = getHeight();  //获取每个字母的高度  int singleHeight = height / s.length;  //画字母  for (int i = 0; i < s.length; i++) {   //画笔默认颜色   initPaint();   //高亮字母颜色   if (choose == i) {    textPaint.setColor(Color.RED);   }   //计算每个字母的坐标   float x = (width - textPaint.measureText(s[i])) / 2;   float y = (i + 1) * singleHeight;   canvas.drawText(s[i], x, y, textPaint);   //重置颜色   textPaint.reset();  } }}

public class MainActivity extends AppCompatActivity { private TextView tv; private ListView lv; private NavView nv; private List<user> list; private UserAdapter adapter; private String[] name = new String[]{   "潘粤明", "戴军", "薛之谦", "蓝雨", "任泉", "张杰", "秦俊杰",   "陈坤", "田亮", "夏雨", "保剑锋", "陆毅", "乔振宇", "吉杰", "郭敬明", "巫迪文", "欢子", "井柏然",   "左小祖咒", "段奕宏", "毛宁", "樊凡", "汤潮", "山野", "陈龙", "侯勇", "俞思远", "冯绍峰", "崔健",   "杜淳", "张翰", "彭坦", "柏栩栩", "蒲巴甲", "凌潇肃", "毛方圆", "武艺", "耿乐", "钱泳辰"}; @Override protected void onCreate(Bundle savedInstanceState) {  super.onCreate(savedInstanceState);  setContentView(R.layout.activity_main);  initView();  initData(); } private void initView() {  tv = (TextView) findViewById(R.id.tv);  lv = (ListView) findViewById(R.id.lv);  nv = (NavView) findViewById(R.id.nv);  nv.setTextView(tv); } private void initData() {  //初始化数据  list = new ArrayList<>();  for (int i = 0; i < name.length; i++) {   list.add(new User(name[i], CharacterUtils.getFirstSpell(name[i]).toUpperCase()));  }  //将拼音排序  Collections.sort(list, new Comparator<user>() {   @Override   public int compare(User lhs, User rhs) {    return lhs.getFirstCharacter().compareTo(rhs.getFirstCharacter());   }  });  //填充ListView  adapter = new UserAdapter(this, list);  lv.setAdapter(adapter); }}</user></user>

<!--?xml version="1.0" encoding="utf-8"?--><linearlayout android:background="#ffffff" android:layout_height="match_parent" android:layout_width="match_parent" android:orientation="vertical" xmlns:android="http://schemas.android.com/apk/res/android">  <textview android:background="#DBDBDA" android:id="@+id/tv_firstCharacter" android:layout_height="wrap_content" android:layout_width="match_parent" android:padding="8dp" android:text="A" android:textcolor="#000000" android:textsize="14dp">  <textview android:background="#ffffff" android:id="@+id/tv_name" android:layout_height="wrap_content" android:layout_width="match_parent" android:padding="8dp" android:text="张栋梁" android:textcolor="#2196F3" android:textsize="14dp"> </textview></textview></linearlayout>

public class UserAdapter extends BaseAdapter { private List<user> list; private User user; private LayoutInflater mInflater; private Context context; public UserAdapter(Context context, List<user> list) {  this.list = list;  mInflater = LayoutInflater.from(context);  this.context = context; } @Override public int getCount() {  return list.size(); } @Override public Object getItem(int position) {  return list.get(position); } @Override public long getItemId(int position) {  return position; } @Override public View getView(int position, View convertView, ViewGroup parent) {  if (convertView == null) {   convertView = mInflater.inflate(R.layout.adapter_user, null);  }  ViewHolder holder = getViewHolder(convertView);  user = list.get(position);  if (position == 0) {   //第一个数据要显示字母和姓名   holder.tv_firstCharacter.setVisibility(View.VISIBLE);   holder.tv_firstCharacter.setText(user.getFirstCharacter());   holder.tv_name.setText(user.getUsername());  } else {   //其他数据判断是否为同个字母，这里使用Ascii码比较大小   if (CharacterUtils.getCnAscii(list.get(position - 1).getFirstCharacter().charAt(0)) <     CharacterUtils.getCnAscii(user.getFirstCharacter().charAt(0))) {    //后面字母的值大于前面字母的值，需要显示字母    holder.tv_firstCharacter.setVisibility(View.VISIBLE);    holder.tv_firstCharacter.setText(user.getFirstCharacter());    holder.tv_name.setText(user.getUsername());   } else {    //后面字母的值等于前面字母的值，不显示字母    holder.tv_firstCharacter.setVisibility(View.GONE);    holder.tv_name.setText(user.getUsername());   }  }  return convertView; } /**  * 获得控件管理对象  *  * @param view  * @return  */ private ViewHolder getViewHolder(View view) {  ViewHolder holder = (ViewHolder) view.getTag();  if (holder == null) {   holder = new ViewHolder(view);   view.setTag(holder);  }  return holder; } /**  * 控件管理类  */ private class ViewHolder {   private TextView tv_firstCharacter, tv_name;   ViewHolder(View view) {   tv_firstCharacter = (TextView) view.findViewById(R.id.tv_firstCharacter);   tv_name = (TextView) view.findViewById(R.id.tv_name);  } }  /**  * 通过字符查找位置  *  * @param s  * @return  */ public int getSelectPosition(String s) {  for (int i = 0; i < getCount(); i++) {   String firChar = list.get(i).getFirstCharacter();   if (firChar.equals(s)) {    return i;   }  }  return -1; }}</user></user>

@Overridepublic boolean dispatchTouchEvent(MotionEvent event) { //计算选中字母 int index = (int) (event.getY() / getHeight() * s.length); //防止脚标越界 if (index >= s.length) {  index = s.length - 1; } else if (index < 0) {  index = 0; } switch (event.getAction()) {  case MotionEvent.ACTION_DOWN:  case MotionEvent.ACTION_MOVE:   setBackgroundColor(Color.GRAY);   //选中字母高亮   choose = index;   //出现中间文字   tv.setVisibility(VISIBLE);   tv.setText(s[choose]);   //调用ListView连动接口   if (listener != null) {    listener.touchCharacterListener(s[choose]);   }   //重绘   invalidate();   break;  default:   setBackgroundColor(Color.TRANSPARENT);   //取消选中字母高亮   choose = -1;   //隐藏中间文字   tv.setVisibility(GONE);   //重绘   invalidate();   break; } return true;}public onTouchCharacterListener listener;public interface onTouchCharacterListener { void touchCharacterListener(String s);} public void setListener(onTouchCharacterListener listener) { this.listener = listener;} /** * 传进来一个TextView * * @param tv */public void setTextView(TextView tv) { this.tv = tv;}

//ListView连动接口nv.setListener(new NavView.onTouchCharacterListener() { @Override public void touchCharacterListener(String s) {  int position = adapter.getSelectPosition(s);  if (position != -1) {   lv.setSelection(position);  } }});