本文介绍Android实现首字母导航条，先看张效果图，具体怎么实现看代码吧

具体的步骤

1.整体布局的显示

2. 实现A-Z的分组

3. 自定义A-Z的导航条

4. 中间显示/隐藏触摸到导航条具体的字母

activity_main.xml

<"1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:background="#fff" android:orientation="vertical" tools:context="com.example.firstnavigation.MainActivity"> <FrameLayout android:layout_width="match_parent" android:layout_height="wrap_content"> <> <ListView android:id="@+id/friend_listview" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_gravity="center" /> <> <TextView android:id="@+id/tv_first" android:layout_width="80dp" android:layout_height="80dp" android:layout_gravity="center" android:text="A" android:textColor="#ff0000" android:textSize="30sp" android:visibility="gone" /> <> <com.example.firstnavigation.SlidView android:id="@+id/slidView" android:layout_width="30dp" android:layout_height="match_parent" android:layout_gravity="right|center" /> </FrameLayout> </LinearLayout>

item.xml —-》ListView对应item

<"1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:background="#fff" android:orientation="vertical"> <> <TextView android:id="@+id/tv" android:layout_width="match_parent" android:layout_height="wrap_content" android:background="#9e9d9d" android:textColor="#fff" android:textSize="16sp" /> <> <TextView android:id="@+id/name" android:layout_width="wrap_content" android:layout_height="wrap_content" android:textColor="#262626" android:textSize="16sp" /> </LinearLayout>

联系人Bean

public class Contact { //姓名 private String name; //姓名的首字母 private String firstWord; public String getName() { return name; } public void setName(String name) { this.name = name; } public String getFirstWord() { return firstWord; } public void setFirstWord(String ch) { this.firstWord = ch; } }

ContactAdapter.java

public class ContactAdapter extends BaseAdapter { private ArrayList<Contact> arrayList; private Context context; private String pre = "A"; public ContactAdapter(ArrayList<Contact> arrayList, Context context) { this.arrayList = arrayList; this.context = context; } @Override public int getCount() { return arrayList.size(); } @Override public Object getItem(int position) { return arrayList.get(position); } @Override public long getItemId(int position) { return position; } @Override public View getView(int position, View convertView, ViewGroup parent) { ViewHolder viewHolder; if (convertView == null) { viewHolder = new ViewHolder(); convertView = LayoutInflater.from(context).inflate(R.layout.item, parent, false); viewHolder.tv_firstWord = (TextView) convertView.findViewById(R.id.tv); viewHolder.name = (TextView) convertView.findViewById(R.id.name); convertView.setTag(viewHolder); } else { viewHolder = (ViewHolder) convertView.getTag(); } viewHolder.tv_firstWord.setText(String.valueOf(arrayList.get(position).getFirstWord())); viewHolder.name.setText(arrayList.get(position).getName()); /** * 分组:根据汉字的首字母 */ viewHolder.tv_firstWord.setVisibility(!arrayList.get(position).getFirstWord().equals(pre) ? View.VISIBLE : View.GONE); pre = arrayList.get(position).getFirstWord(); return convertView; } class ViewHolder { TextView tv_firstWord; TextView name; }

MainActivity

public class MainActivity extends AppCompatActivity { private ListView listView; private TextView tv_first; private ArrayList<Contact> contacts; private SlidView slidView; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); initView(); initData(); } private void initView() { listView = (ListView) findViewById(R.id.friend_listview); tv_first = (TextView) findViewById(R.id.tv_first); slidView = (SlidView) findViewById(R.id.slidView); slidView.setFirstListener(new OnTouchFirstListener() { @Override public void onTouch(String str) { tv_first.setVisibility(View.VISIBLE); tv_first.setText(str); for (int i = 0; i < contacts.size(); i++) { if (str.equals(contacts.get(i).getFirstWord())) { listView.setSelection(i); } } } @Override public void onRelease() { new Handler().postDelayed(new Runnable() { @Override public void run() { tv_first.setVisibility(View.GONE); } }, 300); } }); } private void initData() { contacts = new ArrayList<>(); //获取字符数组资源 String[] attrs = getResources().getStringArray(R.array.myFriend); Contact contact; for (int i = 0; i < attrs.length; i++) { contact = new Contact(); contact.setName(attrs[i]); contact.setFirstWord(getPinYinHeadChar(attrs[i], 2)); contacts.add(contact); } //排序A-Z Collections.sort(contacts, new Comparator<Contact>() { @Override public int compare(Contact lhs, Contact rhs) { return lhs.getFirstWord().compareTo(rhs.getFirstWord()); } }); ContactAdapter contactAdapter = new ContactAdapter(contacts, this); listView.setAdapter(contactAdapter); } /** * 提取汉字的首字母，如果里面含有费中文字符则忽略之；如果全为非中文则返回""。 * * @param caseType 当为1时获取的首字母为小写，否则为大写。 */ public static String getPinYinHeadChar(String zn_str, int caseType) { if (zn_str != null && !zn_str.trim().equalsIgnoreCase("")) { char[] strChar = zn_str.toCharArray(); // 汉语拼音格式输出类 HanyuPinyinOutputFormat hanYuPinOutputFormat = new HanyuPinyinOutputFormat(); // 输出设置，大小写，音标方式等 if (1 == caseType) { hanYuPinOutputFormat.setCaseType(HanyuPinyinCaseType.LOWERCASE); } else { hanYuPinOutputFormat.setCaseType(HanyuPinyinCaseType.UPPERCASE); } hanYuPinOutputFormat.setToneType(HanyuPinyinToneType.WITHOUT_TONE); hanYuPinOutputFormat.setVCharType(HanyuPinyinVCharType.WITH_V); StringBuffer pyStringBuffer = new StringBuffer(); char c = strChar[0]; char pyc; if (String.valueOf(c).matches("[u4E00-u9FA5]+")) {//是中文或者a-z或者A-Z转换拼音 try { String[] pyStirngArray = PinyinHelper.toHanyuPinyinStringArray(strChar[0], hanYuPinOutputFormat); if (null != pyStirngArray && pyStirngArray[0] != null) { pyc = pyStirngArray[0].charAt(0); pyStringBuffer.append(pyc); } } catch (BadHanyuPinyinOutputFormatCombination e) { e.printStackTrace(); } } return pyStringBuffer.toString(); } return null; }

提取首字母需要用到pingyin4j.jar，小编在这不提供，大家可以在网上下载

//自定义字母导航控件 public class SlidView extends View { private String[] strs = {"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"}; private Paint paint; private OnTouchFirstListener listener; public SlidView(Context context) { this(context, null); } public SlidView(Context context, AttributeSet attrs) { this(context, attrs, 0); } public SlidView(Context context, AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); paint = new Paint(); paint.setAntiAlias(true); paint.setColor(Color.GRAY); paint.setTypeface(Typeface.DEFAULT_BOLD); } // px---->sp protected int sp2px(int spVal) { return (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_SP, spVal, getResources().getDisplayMetrics()); } @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); for (int i = 0; i < strs.length; i++) { paint.setColor(i == index ? Color.RED : Color.BLACK); paint.setTextSize(i == index ? sp2px(18) : sp2px(16)); int x = (int) (getWidth() - paint.measureText(strs[i])) / 2; int y = getHeight() / strs.length * (i + 1); canvas.drawText(strs[i], x, y, paint); } } int index = -1; //获取触摸到字母索引的位置 //触碰事件 //按下，松开，拖动 @Override public boolean onTouchEvent(MotionEvent event) { switch (event.getAction()) { case MotionEvent.ACTION_DOWN: case MotionEvent.ACTION_MOVE: float y = event.getY(); this.setBackgroundColor(Color.GRAY); //获取触摸到字母的位置 index = (int) y * strs.length / getHeight(); listener.onTouch(strs[index]); break; case MotionEvent.ACTION_UP: this.setBackgroundColor(android.R.color.transparent); index = -1; listener.onRelease(); break; } //重绘 invalidate(); return true; } public void setFirstListener(OnTouchFirstListener listener) { this.listener = listener; } } /** * OnTouchFirstListener 接口 * onTouch：触摸到了那个字母 * onRelease:up释放时中间显示的字母需要设置为GONE */ public interface OnTouchFirstListener { void onTouch(String ch); void onRelease(); }

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持查字典教程网。