这篇文章主要介绍了Android如何实现自定义view圆并随手指移动，具有一定借鉴价值，感兴趣的朋友可以参考下，希望大家阅读完这篇文章之后大有收获，下面让小编带着大家一起了解一下。
具体内容如下
main代码
public class MainActivity extends AppCompatActivity { private int screenW; //屏幕宽度 private int screenH; //屏幕高度 @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); Display dis = this.getWindowManager().getDefaultDisplay(); // 设置全屏 requestWindowFeature(Window.FEATURE_NO_TITLE); this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN); // 获取屏幕宽度 screenW = dis.getWidth(); // 获取屏幕高度 screenH = dis.getHeight(); setContentView(new MyView(this)); } //自定义绘图类 class MyView extends View { private Paint paint; //定义画笔 private float cx = 50; //圆点默认X坐标 private float cy = 50; //圆点默认Y坐标 private int radius = 20; //定义颜色数组 private int colorArray[] = {Color.BLACK,Color.BLACK,Color.GREEN,Color.YELLOW, Color.RED}; private int paintColor = colorArray[0]; //定义画笔默认颜色 public MyView(Context context) { super(context); //初始化画笔 initPaint(); } private void initPaint(){ paint = new Paint(); //设置消除锯齿 paint.setAntiAlias(true); //设置画笔颜色 paint.setColor(paintColor); } //重写onDraw方法实现绘图操作 @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); //将屏幕设置为白色 canvas.drawColor(Color.WHITE); //修正圆点坐标 revise(); //随机设置画笔颜色 setPaintRandomColor(); //绘制小圆作为小球 canvas.drawCircle(cx, cy, radius, paint); } //为画笔设置随机颜色 private void setPaintRandomColor(){ Random rand = new Random(); int randomIndex = rand.nextInt(colorArray.length); paint.setColor(colorArray[randomIndex]); } //修正圆点坐标 private void revise(){ if(cx <= radius){ cx = radius; }else if(cx >= (screenW-radius)){ cx = screenW-radius; } if(cy <= radius){ cy = radius; }else if(cy >= (screenH-radius)){ cy = screenH-radius; } } @Override public boolean onTouchEvent(MotionEvent event) { switch (event.getAction()) { case MotionEvent.ACTION_DOWN: // 按下 cx = (int) event.getX(); cy = (int) event.getY(); // 通知重绘 postInvalidate(); //该方法会调用onDraw方法，重新绘图 break; case MotionEvent.ACTION_MOVE: // 移动 cx = (int) event.getX(); cy = (int) event.getY(); // 通知重绘 postInvalidate(); break; case MotionEvent.ACTION_UP: // 抬起 cx = (int) event.getX(); cy = (int) event.getY(); // 通知重绘 postInvalidate(); break; } //return super.onTouchEvent(event); return true; } }}布局
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:id="@+id/activity_main" android:layout_width="match_parent" android:layout_height="match_parent" tools:context="com.example.sn.MainActivity"> <com.example.sn.MainActivity.MyView android:id="@+id/myview" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerInParent="true" /></RelativeLayout>感谢你能够认真阅读完这篇文章，希望小编分享的“Android如何实现自定义view圆并随手指移动”这篇文章对大家有帮助，同时也希望大家多多支持编程网，关注编程网行业资讯频道，更多相关知识等着你来学习!
