自定义view 小球的移动

自定义View 继承View

package com.mrli.rk03;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.support.annotation.Nullable;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;

/**
* Created by MRli on 2017/11/2.
*/

public class MyView extends View {
public int currentX = 100;
public int currentY = 100;
Context context;
//创建画笔
Paint p  = new Paint();

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

public MyView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}

public MyView(Context context, @Nullable AttributeSet attrs) {
super(context, attrs);
}

@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
//设置画笔的颜色
p.setColor(Color.RED);
//绘制一个小球
//参数分别是：圆心坐标，半径，所使用的画笔
canvas.drawCircle(currentX,currentY,45,p);
}

@Override
public boolean onTouchEvent(MotionEvent event) {

this.currentX = (int) event.getX(); //触摸座标X
this.currentY = (int) event.getY(); //触摸座标Y
this.invalidate();
// 自己处理触摸事件
return true;
}

}

在xml文件中引入

<com.mrli.rk03.MyView
android:layout_width="wrap_content"
android:id="@+id/circle"
android:layout_height="wrap_content" />