本文实例讲述了Android开发实现跟随手指的小球效果。分享给大家供大家参考，具体如下：
配置DrawView类用于绘制小球
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public class DrawView extends View { public float currentX = 40; public float currentY = 50; //定义并创建画笔 Paint p = new Paint(); public DrawView(Context context) { super(context); } public DrawView(Context context , AttributeSet set) { super(context,set); } @Override public void onDrawForeground(Canvas canvas) { super.onDrawForeground(canvas); //设置画笔颜色 p.setColor(Color.RED); //绘制一个小球 canvas.drawCircle(currentX , currentY , 30 , p); } //为组建的触碰实践重写处理方法 @Override public boolean onTouchEvent(MotionEvent event) { //修改currentX,currentY的两个属性 currentX = event.getX(); currentY = event.getY(); //通知当前组建重绘自己 invalidate(); //放回true表明该处理方法已经处理该事件 return true; }} |
MainActivity
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public class MainActivity extends AppCompatActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); //获取Linearlayout布局容器 LinearLayout root = (LinearLayout) findViewById(R.id.root); //创建DrawView组件 final DrawView draw = new DrawView(this); //设定自定义组件的最小宽度、高度 draw.setMinimumWidth(300); draw.setMinimumHeight(500); root.addView(draw); }} |
xml文件
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<?xml version="1.0" encoding="utf-8"?><LinearLayout 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:id="@+id/root" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical"> <com.example.a30797.myapplication.DrawView android:layout_width="match_parent" android:layout_height="match_parent" /></LinearLayout> |
**注：**由上面布局，已经添加了自定义组件，因此Activity代码可简化为：
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public class MainActivity extends AppCompatActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); }} |
示例：
希望本文所述对大家Android程序设计有所帮助。
原文链接：https://blog.csdn.net/qq_43377749/article/details/83720642
