天天向上

package com.example.drawrandcircle;

import java.util.ArrayList;

import java.util.List;

import android.content.Context;

import android.graphics.Canvas;

import android.graphics.Paint;

import android.view.View;

public class CircleCanvas extends View

{

    public List<CircleInfo> mCircleInfos = new ArrayList<CircleCanvas.CircleInfo>();

    public static class CircleInfo

    {

        private float x;

        private float y;

        private float radius;

        private int color;

        public float getX()

        {

            return x;

        }

        public void setX(float x)

        {

            this.x = x;

        }

        public float getY()

        {

            return y;

        }

        public void setY(float y)

        {

            this.y = y;

        }

        public float getRadius()

        {

            return radius;

        }

        public void setRadius(float radius)

        {

            this.radius = radius;

        }

        public int getColor()

        {

            return color;

        }

        public void setColor(int color)

        {

            this.color = color;

        }

    }

    public CircleCanvas(Context context)

    {

        super(context);

    }

    @Override

    protected void onDraw(Canvas canvas)

    {

        super.onDraw(canvas);

        for (CircleInfo circleInfo : mCircleInfos)

        {

            Paint paint = new Paint();

            paint.setColor(circleInfo.getColor());

            canvas.drawCircle(circleInfo.getX(), circleInfo.getY(),

                    circleInfo.getRadius(), paint);

        }

    }

}

package com.example.drawrandcircle;

import java.util.Random;

import com.example.drawrandcircle.CircleCanvas.CircleInfo;

import android.app.Activity;

import android.os.Bundle;

import android.view.Menu;

import android.view.MenuItem;

import android.graphics.Color;

import android.util.Log;

import android.view.View;

import android.view.ViewGroup;

import android.view.ViewGroup.LayoutParams;

public class MainActivity extends Activity {

    //------------插入[開始]---------------

    private CircleCanvas mCircleCanvas;

    //------------插入[結束]----------------

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        //------------插入[開始]---------------

        ViewGroup viewGroup = (ViewGroup) getLayoutInflater().inflate(

                R.layout.activity_main, null);

        mCircleCanvas = new CircleCanvas(this);

        viewGroup.addView(mCircleCanvas, new LayoutParams(

                LayoutParams.FILL_PARENT, 650));

        setContentView(viewGroup);

        //------------插入[結束]----------------

        //setContentView(R.layout.activity_main);

    }

    public void button1_Click(View view)

    {

        Random random = new Random();

        float randomX = (float) (100 + random.nextInt(100));

        float randomY = (float) (100 + random.nextInt(100));

        float randomRadius = (float) (20 + random.nextInt(40));

        int randomColor = 0;

        if (random.nextInt(100) > 50)

        {

            randomColor = Color.BLUE;

        }

        else

        {

            if (random.nextInt(100) > 50)

                randomColor = Color.RED;

            else

                randomColor = Color.GREEN;

        }

        CircleInfo circleInfo = new CircleInfo();

        circleInfo.setX(randomX);

        circleInfo.setY(randomY);

        circleInfo.setRadius(randomRadius);

        circleInfo.setColor(randomColor);

        mCircleCanvas.mCircleInfos.add(circleInfo);

        mCircleCanvas.invalidate();

        // 輸出偵錯資訊

        Log.v("VERBOSE_randomX", String.valueOf(randomX));

        Log.d("DEBUG_randomY", String.valueOf(randomY));

        Log.i("INFO_randomRadius", String.valueOf(randomRadius));

        Log.w("WARN_randomColor", String.valueOf(randomColor));

        Log.e("ERROR_area", String.valueOf(3.14 * randomRadius * randomRadius));

        Log.println(Log.VERBOSE, "VERBOSE_println", "VERBOSE_println");

    }

    public void button2_Click(View view)

    {

        mCircleCanvas.mCircleInfos.clear();

        mCircleCanvas.invalidate();

    }

    @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;

    }

    @Override

    public boolean onOptionsItemSelected(MenuItem item) {

        // Handle action bar item clicks here. The action bar will

        // automatically handle clicks on the Home/Up button, so long

        // as you specify a parent activity in AndroidManifest.xml.

        int id = item.getItemId();

        if (id == R.id.action_settings) {

            return true;

        }

        return super.onOptionsItemSelected(item);

    }

}