android 自定义组件随着手指自动画圆
16lz
2021-12-04
首先自定义一个View子类:
package com.example.androidtest0.myView;import android.content.Context;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.util.AttributeSet;import android.view.MotionEvent;import android.view.View;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 attrs) {super(context, attrs);}@Overrideprotected void onDraw(Canvas canvas) {super.onDraw(canvas);//设置画笔的颜色p.setColor(Color.RED);//绘制一个小球canvas.drawCircle(currentX, currentY, 15, p);}/** * 为该组件的触碰事件重写事件处理方法 */@Overridepublic boolean onTouchEvent(MotionEvent event) {//修改currentX、currentY两个属性currentX = event.getX();currentY = event.getY();//通知当前组件重绘自己invalidate();return true;} }主界面XML：
custom_layout.xml
<?xml version="1.0" encoding="utf-8"?>
主activity:
package com.example.androidtest0;import com.example.androidtest0.myView.DrawView;import android.app.Activity;import android.os.Bundle;import android.widget.LinearLayout;public class CustomView extends Activity {@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.custom_layout);//获取布局文件中LinearLayout容器LinearLayout root = (LinearLayout)findViewById(R.id.root);//创建DrawView组件final DrawView drawView = new DrawView(this);//设置自定义组件的最小宽度、高度drawView.setMinimumWidth(10);drawView.setMinimumHeight(10);root.addView(drawView);}}除此之外：
还可以用XML的方式：也是首先建一个View的子类，和上面一样。然后主界面XML如下：
<?xml version="1.0" encoding="utf-8"?> 主activity文件如下：
package com.example.androidtest0;import com.example.androidtest0.myView.DrawView;import android.app.Activity;import android.os.Bundle;import android.widget.LinearLayout;public class CustomView extends Activity {@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.custom_layout);}}更多相关文章
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