自定义一个字母Button

Posted 2020-08-15 点滴之水

  1 package com.example.administrator.yunstore.widget;
  2 
  3 import android.content.Context;
  4 import android.graphics.Canvas;
  5 import android.graphics.Color;
  6 import android.graphics.Paint;
  7 import android.graphics.Typeface;
  8 import android.util.AttributeSet;
  9 import android.view.MotionEvent;
 10 import android.widget.Button;
 11 
 12 /**
 13  * Created by Administrator on 2016/10/19.
 14  * 自定义的一个字母button
 15  */
 16 
 17 public class LetterButton extends Button {
 18 
 19     // 分类字母
 20     private String[] assort = { "A", "B", "C", "D", "E", "F", "G",
 21             "H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T",
 22             "U", "V", "W", "X", "Y", "Z" };
 23 
 24     private Paint paint = new Paint();
 25 
 26     private int selectIndex = -1;
 27 
 28     public LetterButton(Context context) {
 29         super(context);
 30     }
 31 
 32     public LetterButton(Context context, AttributeSet attrs) {
 33         super(context, attrs);
 34     }
 35 
 36     public LetterButton(Context context, AttributeSet attrs, int defStyleAttr) {
 37         super(context, attrs, defStyleAttr);
 38     }
 39 
 40     /**
 41      * @param canvas
 42      * 对按钮进行绘制
 43      */
 44     @Override
 45     protected void onDraw(Canvas canvas) {
 46         super.onDraw(canvas);
 47 
 48         int height=getHeight();
 49         int width=getWidth();
 50         int interval = height / assort.length;
 51 
 52         for (int i = 0, length = assort.length; i < length; i++) {
 53             // 抗锯齿
 54             paint.setAntiAlias(true);
 55             // 默认粗体
 56             paint.setTypeface(Typeface.DEFAULT_BOLD);
 57             // 白色
 58             paint.setColor(Color.BLUE);
 59             if (i == selectIndex) {
 60                 // 被选择的字母改变颜色和粗体
 61                 paint.setColor(Color.parseColor("#33bb99"));
 62                 paint.setFakeBoldText(true);
 63                 paint.setTextSize(30);
 64             }
 65             // 计算字母的X坐标
 66             float xPos = width / 2 - paint.measureText(assort[i]) / 2;
 67             // 计算字母的Y坐标
 68             float yPos = interval * i + interval;
 69             canvas.drawText(assort[i], xPos, yPos, paint);
 70             paint.reset();
 71         }
 72     }
 73 
 74     @Override
 75     public boolean dispatchTouchEvent(MotionEvent event) {
 76         float y = event.getY();
 77         int index = (int) (y / getHeight() * assort.length);
 78         if (index >= 0 && index < assort.length) {
 79 
 80             switch (event.getAction()) {
 81                 case MotionEvent.ACTION_MOVE:
 82                     // 如果滑动改变
 83                     if (selectIndex != index) {
 84                         selectIndex = index;
 85                         if (onTouch != null) {
 86                             onTouch.onTouchAssortListener(assort[selectIndex]);
 87                         }
 88 
 89                     }
 90                     break;
 91                 case MotionEvent.ACTION_DOWN:
 92                     selectIndex = index;
 93                     if (onTouch != null) {
 94                         onTouch.onTouchAssortListener(assort[selectIndex]);
 95                     }
 96 
 97                     break;
 98                 case MotionEvent.ACTION_UP:
 99                     if (onTouch != null) {
100                         onTouch.onTouchAssortUP();
101                     }
102                     selectIndex = -1;
103                     break;
104             }
105         } else {
106             selectIndex = -1;
107             if (onTouch != null) {
108                 onTouch.onTouchAssortUP();
109             }
110         }
111         invalidate();
112 
113         return true;
114     }
115 
116     @Override
117     public boolean onTouchEvent(MotionEvent event) {
118         return super.onTouchEvent(event);
119     }
120     //字母监听器
121     private OnTouchAssortListener onTouch;
122 
123     public interface OnTouchAssortListener {
124          void onTouchAssortListener(String s);
125           void onTouchAssortUP();
126     }
127 
128 
129     public void setOnTouchAssortListener(OnTouchAssortListener onTouch) {
130         this.onTouch = onTouch;
131     }
132 }