自定义View控件

/*
* 自定义控件
* */
package com.frank.control;
import android.content.Context;
import android.graphics.*;
import android.util.AttributeSet;
import android.view.*;

public class DrawView extends View {
public float currentX = 40;
public float currentY = 50;
//定义、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 onDraw(Canvas canvas)
{
super.onDraw(canvas);
//设置画笔颜色
p.setColor(Color.RED);
//绘制一个小圆
canvas.drawCircle(currentX,currentY,15,p);
}
//为该组件的触碰事件重写事件处理方法
@Override
public boolean onTouchEvent(MotionEvent event)
{
currentX = event.getX();
currentY = event.getY();
//通知当前组件重绘自己
super.invalidate();
//返回true表明该处理方法已经处理该事件
return true;
}
}

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity"
android:id="@+id/root" >

</RelativeLayout>

package com.frank.userdfinedcontrol;

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.widget.*;
//引用自己定义控件包名
import com.frank.control.*;

public class MainActivity extends Activity {

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
RelativeLayout rl = (RelativeLayout)super.findViewById(R.id.root);
final DrawView draw = new DrawView(this);
draw.setMinimumWidth(300);
draw.setMinimumHeight(500);
rl.addView(draw);
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}

}