android开发 自定义View实现TextView文本间距

一、应用背景：

在工作中遇到凭证界面展示金额的时候，用原生TextView数字之间间距太小，于是想到自定控件来实现。

二、具体实现：

public class MoneyTextView extends View {
   private float letterSpacing;//字符间距
   private Paint letterPaint;//画笔
   private CharSequence content = "13200000081";//金额，最多11位数
   private Context context;
   
   public MoneyTextView(Context context) {
      super(context);
      this.context = context;
      init();
   }
   
   public MoneyTextView(Context context, @Nullable AttributeSet attrs) {
      super(context, attrs);
      this.context = context;
      init();
   }
   
   public void setText(CharSequence text) {
      content = text;
      invalidate();
   }
   
   private void init() {
      Paint mPaint = new Paint();
      mPaint.setStrokeWidth(3);
      mPaint.setTextSize(dip2px(14));
      mPaint.setAntiAlias(true);
      mPaint.setColor(Color.RED);
      mPaint.setTextAlign(Paint.Align.LEFT);
      
      letterPaint = mPaint;
   }
   
   public MoneyTextView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
      super(context, attrs, defStyleAttr);
      this.context = context;
      init();
   }
   
   /**
    * 根据手机的分辨率从 dp 的单位 转成为 px(像素)
    */
   public int dip2px(float dpValue) {
      final float scale = context.getResources().getDisplayMetrics().density;
      return (int) (dpValue * scale + 0.5f);
   }
   
   /**
    * 根据手机的分辨率从 px(像素) 的单位 转成为 dp
    */
   public int px2dip(float pxValue) {
      final float scale = context.getResources().getDisplayMetrics().density;
      return (int) (pxValue / scale + 0.5f);
   }
   
   
   @Override
   protected void onDraw(Canvas canvas) {
      super.onDraw(canvas);
      
      if(content != null ) {
         letterSpacing = (float) (getMeasuredWidth()/11.0);//项目需要固定十一份大小，可根据需要调整
         Log.e("onDraw",letterSpacing+","+getMeasuredWidth());
         for (int i = content.length() - 1, j = 0; i >= 0; i--) {
            
            Rect bounds = new Rect();
            String str = String.valueOf(content.charAt(i));
            Log.e("onDraw", str + "");
            letterPaint.getTextBounds(str, 0, str.length(), bounds);
            Paint.FontMetricsInt fontMetrics = letterPaint.getFontMetricsInt();
            int baseline = (getMeasuredHeight() - fontMetrics.bottom + fontMetrics.top) / 2 - fontMetrics.top;
            canvas.drawText(str, getMeasuredWidth() - bounds.width() - (letterSpacing/2 - bounds.width()/2 )- j++ * letterSpacing, baseline, letterPaint);
         }
         
      }
   }
}

三、效果如下：

MoneyTextView tv = (MoneyTextView) findViewById(R.id.moneyTv);
tv.setText("15000320");

参考文章：http://blog.****.net/lovexieyuan520/article/details/43153275