Android自定义View实现箭头沿圆转动实例代码

具体代码如下所示：

//mycircleview类
public class mycircleview extends view{
 //当前画笔画圆的颜色
 private int currencircleboundcolor;
 private paint paint;
 ////从xml中获取的颜色
 private int circlebundcolor;
 private float circleboundwidth;
 private float pivotx;
 private float pivoty;
 private float radius=130;
 private float currentdegree=0;
 private int currentspeed=1;
 private boolean ispause=false;
 public mycircleview(context context) {
  super(context);
  initview(context);
 }
 public mycircleview(context context, @nullable attributeset attrs) {
  super(context, attrs);
  initview(context);
  typedarray typedarray = context.obtainstyledattributes(attrs, r.styleable.mycircleview);
  for (int i = 0; i < typedarray.getindexcount(); i++) {
   //就是我们自定义的属性的资源id
   int attr = typedarray.getindex(i);
   switch (attr){
    case r.styleable.mycircleview_circlr_bound_color:
     circlebundcolor = typedarray.getcolor(attr, color.red);
     currencircleboundcolor=circlebundcolor;
     break;
    case r.styleable.mycircleview_circlr_bound_width:
     circleboundwidth = typedarray.getdimension(attr, 3);
     break;
   }
  }
 }
 public mycircleview(context context, @nullable attributeset attrs, int defstyleattr) {
  super(context, attrs, defstyleattr);
  initview(context);
 }
 private void initview(context context){
  paint = new paint();
 }
 public void setcolor(int color){
  if (currencircleboundcolor!=color){
   currencircleboundcolor=color;
  }else {
   currencircleboundcolor=circlebundcolor;
  }
 }
 @override
 protected void ondraw(canvas canvas) {
  super.ondraw(canvas);
  paint.setantialias(true);
  paint.setcolor(currencircleboundcolor);
  paint.setstrokewidth(circleboundwidth);
  paint.setstyle(paint.style.stroke);
  pivotx = getwidth() / 2;
  pivoty = getheight() / 2;
  canvas.drawcircle(pivotx,pivoty,radius,paint);
  canvas.save();
  //旋转画布 , 如果旋转的的度数大的话,视觉上看着是旋转快的
  canvas.rotate(currentdegree,pivotx,pivoty);
  //提供了一些api可以用来画线(画路径)
  path path = new path();
  //从哪开始画 从a开始画
  path.moveto(pivotx+radius,pivoty);
  //从a点画一个直线到d点
  path.lineto(pivotx+radius-20,pivoty-20);
  //从d点画一个直线到b点
  path.lineto(pivotx+radius,pivoty+20);
  //从b点画一个直线到c点
  path.lineto(pivotx+radius+20,pivoty-20);
  //闭合 -- 从c点画一个直线到a点
  path.close();
  paint.setstyle(paint.style.fill);
  paint.setcolor(color.black);
  canvas.drawpath(path,paint);
  canvas.restore();
  //旋转的度数一个一个度数增加, 如果乘以一个速度的话,按一个速度速度增加
  currentdegree+=1*currentspeed;
  if (!ispause){
   invalidate();
  }
 }
 public void speed(){
  ++currentspeed;
  if (currentspeed>=10){
   currentspeed=10;
   toast.maketext(getcontext(),"我比闪电还快",toast.length_short).show();
  }
 }
 public void slowdown(){
  --currentspeed;
  if (currentspeed<=1){
   currentspeed=1;
  }
 }
 public void pauseorstart(){
  //如果是开始状态的话去重新绘制
  if (ispause){
   ispause=!ispause;
   invalidate();
  }else {
   ispause=!ispause;
  }
 }
}
//主页面
public class mainactivity extends appcompatactivity {
 //全局变量
 private mycircleview my_view;
 @override
 protected void oncreate(bundle savedinstancestate) {
  super.oncreate(savedinstancestate);
  setcontentview(r.layout.activity_main);
  //找控件
  my_view = (mycircleview) findviewbyid(r.id.my_view);
 }
 public void onclick(view view){
  my_view.setcolor(color.blue);
 }
 public void add(view view){
  my_view.speed();
 }
 public void slow(view view){
  my_view.slowdown();
 }
 public void pauseorstart(view view){
  my_view.pauseorstart();
 }
}
主页面布局
<relativelayout
 xmlns:android="http://schemas.android.com/apk/res/android"
 xmlns:tools="http://schemas.android.com/tools"
 xmlns:app="http://schemas.android.com/apk/res-auto"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 tools:context="com.example.lx_20170928.mainactivity">
 <button
  android:id="@+id/set_color_btn"
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  android:layout_centerhorizontal="true"
  android:onclick="onclick"
  android:text="设置颜色" />
 <button
  android:id="@+id/add"
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  android:layout_below="@id/set_color_btn"
  android:layout_centerhorizontal="true"
  android:onclick="add"
  android:text="加速" />
 <button
  android:id="@+id/slow"
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  android:layout_below="@+id/add"
  android:layout_centerhorizontal="true"
  android:onclick="slow"
  android:text="减速" />
 <button
  android:id="@+id/pause_or_start"
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  android:layout_below="@+id/slow"
  android:layout_centerhorizontal="true"
  android:onclick="pauseorstart"
  android:text="暂定/开始" />
  <com.example.lx_20170928.mycircleview
   android:layout_width="wrap_content"
   android:layout_height="wrap_content"
   android:id="@+id/my_view"
   android:layout_centerinparent="true"
   app:circlr_bound_color="@color/coloraccent"
   app:circlr_bound_width="3dp"
   />
</relativelayout>
//在values建一个attrs.xml
<resources>
 <declare-styleable name="mycustomcirclearrowview">
  <attr name="circlr_bound_width" format="dimension"></attr>
  <attr name="circlr_bound_color" format="color"></attr>
 </declare-styleable>
</resources>

效果图如下所示：

总结

以上所述是小编给大家介绍的android自定义view实现箭头沿圆转动实例代码，希望对大家有所帮助