android学习笔记3：自定义view

在android的程序开发中我们可以根据需要开发出属于我们自己的view，来丰富我们的页面布局和功能，此时我们只需集成View这个基类，再重写其中的相关方法即可。接下来实现的这个程序，实现了一个随手指移动的小球的自定义view。

/**
*
*/
package snoopy.android;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.view.View;

public class DrawView extends View
{
    public float currentX = 40;
    public float currentY = 50;
    /**
     * @param context
     */
    public DrawView(Context context)
    {
        super(context);
        // TODO Auto-generated constructor stub
    }
    @Override
    public void onDraw (Canvas canvas)
    {
        super.onDraw(canvas);
        //创建画笔
        Paint p = new Paint();
        //设置画笔的颜色
        p.setColor(Color.RED);
        //绘制一个小圆（作为小球）
        canvas.drawCircle(currentX , currentY , 15 , p);
    }
}
/**
*
*/
package snoopy.android;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.view.View;

public class DrawView extends View
{
public float currentX = 40;
public float currentY = 50;
/**
* @param context
*/
public DrawView(Context context)
{
  super(context);
  // TODO Auto-generated constructor stub
}
@Override
public void onDraw (Canvas canvas)
{
  super.onDraw(canvas);
  //创建画笔 www.zzzyk.com
  Paint p = new Paint();
  //设置画笔的颜色
  p.setColor(Color.RED);
  //绘制一个小圆（作为小球）
  canvas.drawCircle(currentX , currentY , 15 , p);
}
}

package snoopy.android;

import android.app.Activity;
import android.os.Bundle;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.widget.LinearLayout;

public class CustomView extends Activity
{
    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        //获取布局文件中的LinearLayout容器
        LinearLayout root = (LinearLayout)findViewById(R.id.root);
        //创建DrawView组件
        final DrawView draw = new DrawView(this);
        //设置自定义组件的最大宽度、高度
        draw.setMinimumWidth(300);
        draw.setMinimumHeight(500);
        //为draw组件绑定Touch事件
        draw.setOnTouchListener(new OnTouchListener()
        {
            @Override
            public boolean onTouch(View arg0, MotionEvent event)
            {
                //修改draw组件的currentX、currentY两个属性
                draw.currentX = event.getX();
                draw.currentY = event.getY();
                //通知draw组件重绘
                draw.invalidate();
                //返回true表明处理方法已经处理该事件
                return true;
            }
        });
        root.addView(draw);
    }
}

摘自 hn307165411的专栏

补充：移动开发 , Android ,