废话不多说了，具体代码如下所示：

public class LetterView extends View { private String TAG = LetterView.class.getSimpleName(); //A,B,C....Z,# public List<String> letters; private Paint mPaint; private int selectPosition = -1; private TextView mLetter; public void setmLetter(TextView mLetter) { this.mLetter = mLetter; } public LetterView(Context context) { this(context,null); } public LetterView(Context context, AttributeSet attrs) { this(context, attrs,0); } public LetterView(Context context, AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); //生产字母 letters = new ArrayList<>(); for (int i = 65; i < 91; i++) { letters.add(String.format(Locale.CHINA,"%c",i)); Log.e(TAG, "LetterView: "+ String.format(Locale.CHINA,"%c",i)); } letters.add("#");//追加一个# //初始化画笔 mPaint = new Paint(); mPaint.setAntiAlias(true); mPaint.setColor(Color.BLUE); mPaint.setTextSize(30); } @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); /** * 获取View的宽度 * 获取View的高度 */ int width = getMeasuredWidth(); int height = getMeasuredHeight(); //测量字的宽度 int size = letters.size(); for (int i = 0; i < size; i++) { float textWidth = mPaint.measureText(letters.get(i)); int singleHeight = height / size; if (selectPosition == i){//被选中的 mPaint.setColor(Color.RED); }else{ mPaint.setColor(Color.BLUE); } canvas.drawText(letters.get(i),(width - textWidth)/2, singleHeight * (i + 1),mPaint); /** * drawText() x y \_ 为基准线 */ invalidate(); } } /** * Android将触摸事件封装,包装了动作,位置信息;onClick也是一种motionEvent * onClick 事件 实际上是 onTouchEvent事件 * @param event * @return */ @Override public boolean onTouchEvent(MotionEvent event) { //包装了动作,位置信息// event.getY();//相对于View本身的坐标值// event.getRawY();//返回的是相对于屏幕的坐标值 float y = event.getY(); Log.e(TAG, "onTouchEvent: Y:"+ y);// Log.e(TAG, "onTouchEvent: RawY:"+event.getRawY() ); int measuredHeight = getMeasuredHeight(); int singleHeight = measuredHeight / letters.size(); int position = (int) (y / singleHeight); Log.e(TAG, "onTouchEvent: " + position ); switch (event.getAction()) { case MotionEvent.ACTION_MOVE: Log.e(TAG, "onTouchEvent: ACTION_MOVE" ); case MotionEvent.ACTION_DOWN: Log.e(TAG, "onTouchEvent: ACTION_DOWN" ); selectPosition = position; if (mLetter != null) { mLetter.setVisibility(View.VISIBLE); //极限情况有可能下标越界,需要判断一下 if (position < letters.size() && position >= 0){ mLetter.setText(letters.get(position)); } } break; case MotionEvent.ACTION_UP: Log.e(TAG, "onTouchEvent: ACTION_UP" ); selectPosition = -1; if (mLetter != null) { mLetter.setVisibility(View.GONE); } break; } //返回true代表事件被处理了 return true; }}