android开发之实现动态打勾效果(DrawHookView)

今天产品中要实现这样的需求，想了想还是把它给整出来了！ 

第一步：自定义View 
实现步骤： 
1、先画好圆弧 
2、再画第一根线 
3、最后再画第二根线

 /**
  * DrawHook
  * Created by Zane on 2015/3/4.
  */
 public class DrawHookView extends View {
     //绘制圆弧的进度值
     private int progress = 0;
     //线1的x轴
     private int line1_x = 0;
     //线1的y轴
     private int line1_y = 0;
     //线2的x轴
     private int line2_x = 0;
     //线2的y轴
     private int line2_y = 0;

     public DrawHookView(Context context) {
         super(context);
     }

     public DrawHookView(Context context, AttributeSet attrs) {
         super(context, attrs);
     }

     public DrawHookView(Context context, AttributeSet attrs, int defStyle) {
         super(context, attrs, defStyle);
     }

     //绘制

     @Override
     protected void onDraw(Canvas canvas) {
         super.onDraw(canvas);

         progress++;

         /**
          * 绘制圆弧
          */
         Paint paint = new Paint();
         //设置画笔颜色
         paint.setColor(getResources().getColor(R.color.arc_blue));
         //设置圆弧的宽度
         paint.setStrokeWidth(5);
         //设置圆弧为空心
         paint.setStyle(Paint.Style.STROKE);
         //消除锯齿
         paint.setAntiAlias(true);

         //获取圆心的x坐标
         int center = getWidth() / 2;
         int center1 = center - getWidth() / 5;
         //圆弧半径
         int radius = getWidth() / 2 - 5;

         //定义的圆弧的形状和大小的界限
         RectF rectF = new RectF(center - radius -1, center - radius -1 ,center + radius + 1, center + radius + 1);

         //根据进度画圆弧
         canvas.drawArc(rectF, 235, -360 * progress / 100, false, paint);

         /**
          * 绘制对勾
          */
         //先等圆弧画完，才话对勾
         if(progress >= 100) {
             if(line1_x < radius / 3) {
                 line1_x++;
                 line1_y++;
             }
             //画第一根线
             canvas.drawLine(center1, center, center1 + line1_x, center + line1_y, paint);

             if (line1_x == radius / 3) {
                 line2_x = line1_x;
                 line2_y = line1_y;
                 line1_x++;
                 line1_y++;
             }
             if (line1_x >= radius / 3 && line2_x <= radius) {
                 line2_x++;
                 line2_y--;
             }
             //画第二根线
             canvas.drawLine(center1 + line1_x - 1, center + line1_y, center1 + line2_x, center + line2_y, paint);
         }

         //每隔10毫秒界面刷新
         postInvalidateDelayed(10);
     }
 }

第二步：布局文件引用自定义View

 xml version="1.0" encoding="utf-8"?>
 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
               android:orientation="vertical"
               android:layout_width="fill_parent"
               android:layout_height="fill_parent"
               android:background="@color/color_fff"
         >
     <com.offcn.DrawHookViewDemo.DrawHookView
             android:layout_width="90dp"
             android:layout_height="90dp"
             android:layout_centerInParent="true"
             />
 RelativeLayout>

附colors.xml:

 xml version="1.0" encoding="utf-8"?>
 <resources>
     <color name="arc_blue">#10a679color>
     <color name="color_fff">#ffffffcolor>
 resources>

示例代码戳Here

https://github.com/ZaneLove/DrawHookView