1.写一个继承View的类
public class MyCustomCircleArrowView extends View { //从xml中获取的颜色 private int circleBoundColor; private float circleBoundWidth; //当前画笔画圆的颜色 private int CurrenCircleBoundColor; private Paint paint; public MyCustomCircleArrowView(Context context) { super(context); initVeiw(context); } public MyCustomCircleArrowView(Context context, @Nullable AttributeSet attrs) { super(context, attrs); initVeiw(context); TypedArray typedArray = context.obtainStyledAttributes(attrs, R.styleable.MyCustomCircleArrowView); 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.MyCustomCircleArrowView_circlr_bound_color: circleBoundColor = typedArray.getColor(attr, Color.RED); CurrenCircleBoundColor = circleBoundColor; break; case R.styleable.MyCustomCircleArrowView_circlr_bound_width: circleBoundWidth = typedArray.getDimension(attr, 3); break; } } } private void initVeiw(Context context) { paint = new Paint(); } public void setColor(int color) { if (CurrenCircleBoundColor != color) { CurrenCircleBoundColor = color; } else { CurrenCircleBoundColor = circleBoundColor; } } //圆心 private float pivotX; private float pivotY; private float radius = 130; private float currentDegree = 0; @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(); } } private int currentSpeed = 1; private boolean isPause = false; 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; } } } 2.在values下,新建attrs文件,用来定义属性
<declare-styleable name="MyCustomCircleArrowView">
<attr name="circlr_bound_width" format="dimension"></attr>
<attr name="circlr_bound_color" format="color"></attr>
</declare-styleable>
3.activity_main.xml布局中进行引用,并写一些按钮用来控制
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.mycustomcirclearrowviewdemo.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.mycustomcirclearrowviewdemo.view.MyCustomCircleArrowView
android:id="@+id/my_view"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
app:circlr_bound_color="@color/colorAccent"
app:circlr_bound_width="3dp" />
</RelativeLayout>
4.Activity中的写法
import android.graphics.Color; import android.os.Bundle; import android.support.v7.app.AppCompatActivity; import android.view.View; import com.example.mycustomcirclearrowviewdemo.view.MyCustomCircleArrowView;
public class MainActivity extends AppCompatActivity { private MyCustomCircleArrowView myCustomCircleArrowView; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); myCustomCircleArrowView = (MyCustomCircleArrowView) findViewById(R.id.my_view); } public void onClick(View view) { myCustomCircleArrowView.setColor(Color.BLUE); } public void add(View view) { myCustomCircleArrowView.speed(); } public void slow(View view) { myCustomCircleArrowView.slowDown(); } public void pauseOrStart(View view) { myCustomCircleArrowView.pauseOrStart(); } }
以上就是带箭头圆旋转的代码
那我们看一下效果吧!!!