EditText限制小数点前后位数的实例

public class MyWatcher implements TextWatcher {
  private int beforeDot;
  private int afterDot;
  /**
   * 构造器
   *
   * @param beforeDot 小数点前位数  不限制输入-1
   * @param afterDot 小数点后位数  不限制输入-1
   */
  public MyWatcher(int beforeDot, int afterDot) {
    this.beforeDot = beforeDot;
    this.afterDot = afterDot;
  }


  @Override
  public void beforeTextChanged(CharSequence s, int start, int count, int after) {

  }

  @Override
  public void onTextChanged(CharSequence s, int start, int before, int count) {

  }

  @Override
  public void afterTextChanged(Editable s) {
    judge(s);
  }

  private void judge(Editable editable) {
    String temp = editable.toString();
    int posDot = temp.indexOf(".");
    //直接输入小数点的情况
    if (posDot == 0) {
      editable.insert(0, "0");
      return;
    }
    //连续输入0
    if (temp.equals("00")) {
      editable.delete(1, 2);
      return;
    }
    //输入"08" 等类似情况
    if (temp.startsWith("0") && temp.length() > 1 && (posDot == -1 || posDot > 1)) {
      editable.delete(0, 1);
      return;
    }

    //不包含小数点 不限制小数点前位数
    if (posDot < 0 && beforeDot == -1) {
      //do nothing 仅仅为了理解逻辑而已
      return;
    } else if (posDot < 0 && beforeDot != -1) {
      //不包含小数点 限制小数点前位数
      if (temp.length() <= beforeDot) {
        //do nothing 仅仅为了理解逻辑而已
      } else {
        editable.delete(beforeDot, beforeDot + 1);
      }
      return;
    }

    //如果包含小数点 限制小数点后位数
    if (temp.length() - posDot - 1 > afterDot && afterDot != -1) {
      editable.delete(posDot + afterDot + 1, posDot + afterDot + 2);//删除小数点后多余位数
    }
  }
}

<EditText
          android:id="@+id/et_i_want"
          android:layout_width="wrap_content"
          android:layout_height="25dp"
          android:hint="0.00"
          android:inputType="numberDecimal"/>etIWant.addTextChangedListener(new MyWatcher(-1, 2));//限制小数点后最多2位