欢迎您访问程序员文章站本站旨在为大家提供分享程序员计算机编程知识!
您现在的位置是: 首页  >  移动技术

Android画个时钟玩玩

程序员文章站 2023-12-22 10:07:40
先看下最终的效果   开始实现 新建一个clockview集成view public class clockview extends vi...

先看下最终的效果

Android画个时钟玩玩 

开始实现
新建一个clockview集成view

  public class clockview extends view {

  }

先重写onmeasure方法,这里要先说一下view的测量模式,一共有三种:
1、exactly

即精确值模式,当我们将控件的layout_width属性或layout_height属性指定为具体数值时,比如android:layout_width="100dp",或者指定为math_parent属性时(占据父view的大小),系统使用的是exactly模式。

2、at_most

即最大值模式,当控件的layout_width属性或layout_height属性指定为wrap_content时,控件大小一般随着控件的子控件或内容的变化而变化,此时控件的尺寸只要不超过父控件允许的最大尺寸即可。

3、unspecified

这个属性比较奇怪——它不指定其大小测量模式,view想多大就多大,通常情况下在绘制自定义view时才会使用。

因为view的onmeasure方法只支持exactly模式,当layout_width和layout_height为wrap_content时,view的大小就显得很奇怪了,如下图。

Android画个时钟玩玩

所以我们重写一下onmeasure方法可以指定view width、height的最小值

  /**
   * 当布局为wrap_content时设置默认长宽
   * @param widthmeasurespec
   * @param heightmeasurespec
   */
  @override
  protected void onmeasure(int widthmeasurespec, int heightmeasurespec) {
    setmeasureddimension(measure(widthmeasurespec), measure(heightmeasurespec));
  }

  private int measure(int origin){
    int result = default_min_width;
    int specmode = measurespec.getmode(origin);
    int specsize = measurespec.getsize(origin);
    if(specmode == measurespec.exactly){
      result = specsize;
    }else{
      if(specmode == measurespec.at_most){
        result = math.min(result, specsize);
      }
    }
    return result;
  }

下面就是最重要的重写ondraw方法来绘制表盘、刻度、指针……,大致流程如下
1、画表盘,用drawcircle绘制一个圆作为表盘, 圆心坐标为(getwidth()/2, getheight()/2),半径为math.min(getheight()/2, getwidth()/2)。

//画外圆
float borderwidth = default_border_width;
paint paintcircle = new paint();
paintcircle.setstyle(paint.style.stroke);
paintcircle.setantialias(true);
paintcircle.setstrokewidth(borderwidth);
canvas.drawcircle(getwidth() / 2, getheight() / 2, math.min(getheight() / 2, getwidth() / 2) - borderwidth / 2, paintcircle);

2、画刻度线在这里我们可以利用一个`canvas.rotate'方法就可以不用计算角度了

//画刻度线
float degreelength = 0f;
paint paintdegree = new paint();
paintdegree.setantialias(true);
for(int i=0;i<60;i++){
  if(i % 5 == 0){
    paintdegree.setstrokewidth(6);
    degreelength = default_long_degree_length;
  }else{
    paintdegree.setstrokewidth(3);
    degreelength = default_short_degree_length;
  }
  canvas.drawline(getwidth()/2, math.abs(getwidth()/2 - getheight()/2), getwidth()/2, math.abs(getwidth()/2 - getheight()/2) + degreelength, paintdegree);
  canvas.rotate(360/60, getwidth()/2, getheight()/2);
}

3、画刻度上的数字

//刻度数字
int degressnumbersize = 30;
canvas.translate(getwidth() / 2, getheight() / 2);
paint paintdegreenumber = new paint();
paintdegreenumber.settextalign(paint.align.center);
paintdegreenumber.settextsize(degressnumbersize);
paintdegreenumber.setfakeboldtext(true);
for(int i=0;i<12;i++){
  float[] temp = calculatepoint((i+1)*30, r - default_long_degree_length - degressnumbersize/2 - 15);
  canvas.drawtext((i+1)+"", temp[2], temp[3] + degressnumbersize/2-6, paintdegreenumber);
}

/**
 * 根据角度和长度计算线段的起点和终点的坐标
 * @param angle
 * @param length
 * @return
 */
private float[] calculatepoint(float angle, float length){
  float[] points = new float[4];
  if(angle <= 90f){
    points[0] = -(float) math.sin(angle*math.pi/180) * default_point_back_length;
    points[1] = (float) math.cos(angle*math.pi/180) * default_point_back_length;
    points[2] = (float) math.sin(angle*math.pi/180) * length;
    points[3] = -(float) math.cos(angle*math.pi/180) * length;
  }else if(angle <= 180f){
    points[0] = -(float) math.cos((angle-90)*math.pi/180) * default_point_back_length;
    points[1] = -(float) math.sin((angle-90)*math.pi/180) * default_point_back_length;
    points[2] = (float) math.cos((angle-90)*math.pi/180) * length;
    points[3] = (float) math.sin((angle-90)*math.pi/180) * length;
  }else if(angle <= 270f){
    points[0] = (float) math.sin((angle-180)*math.pi/180) * default_point_back_length;
    points[1] = -(float) math.cos((angle-180)*math.pi/180) * default_point_back_length;
    points[2] = -(float) math.sin((angle-180)*math.pi/180) * length;
    points[3] = (float) math.cos((angle-180)*math.pi/180) * length;
  }else if(angle <= 360f){
    points[0] = (float) math.cos((angle-270)*math.pi/180) * default_point_back_length;
    points[1] = (float) math.sin((angle-270)*math.pi/180) * default_point_back_length;
    points[2] = -(float) math.cos((angle-270)*math.pi/180) * length;
    points[3] = -(float) math.sin((angle-270)*math.pi/180) * length;
  }
  return points;
}

4、画指针

//画指针
paint painthour = new paint();
painthour.setantialias(true);
painthour.setstrokewidth(15);
paint paintminute = new paint();
paintminute.setantialias(true);
paintminute.setstrokewidth(10);
paint paintsecond = new paint();
paintsecond.setantialias(true);
paintsecond.setstrokewidth(5);
calendar now = calendar.getinstance();
float[] hourpoints = calculatepoint(now.get(calendar.hour_of_day)%12/12f*360, hourpointerlength);
canvas.drawline(hourpoints[0], hourpoints[1], hourpoints[2], hourpoints[3], painthour);
float[] minutepoints = calculatepoint(now.get(calendar.minute)/60f*360, minutepointerlength);
canvas.drawline(minutepoints[0], minutepoints[1], minutepoints[2], minutepoints[3], paintminute);
float[] secondpoints = calculatepoint(now.get(calendar.second)/60f*360, secondpointerlength);
canvas.drawline(secondpoints[0], secondpoints[1], secondpoints[2], secondpoints[3], paintsecond);

5、画圆心

//画圆心
paint paintcenter = new paint();
paintcenter.setcolor(color.white);
canvas.drawcircle(0, 0, 2, paintcenter);
最后只要启动一个无限循环的线程,每隔1秒针重绘一下view就能让指针动起来了
private thread timethread = new thread() {
  @override
  public void run() {
    try {
      while(true){
        updatehandler.sendemptymessage(0);
        thread.sleep(1000);
      }
    } catch (interruptedexception e) {
      e.printstacktrace();
    }
  }
};

private handler updatehandler = new handler() {
  @override
  public void handlemessage(message msg) {
    invalidate();
  }
};

以上就是教大家如何利用android画个时钟的详细步骤代码,希望对大家的学习android软件编程有所帮助。

上一篇:

下一篇: