Android开发之初级开发_Paint和canvas浅谈

//这儿只是简单的介绍Paint和canvas的使用，详细的属性，请百度

MainActivity.java:

import android.os.Bundle;
import android.app.Activity;

public class MainActivity extends Activity
{

    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        MyView myView=new MyView(this);
        setContentView(myView);
    }

}

MyView.java:

import android.annotation.SuppressLint;
import android.content.Context;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.view.View;

public class MyView extends View
{

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

    @SuppressLint("DrawAllocation")
    protected void onDraw(Canvas canvas)
    {
        Paint paint = new Paint();
        // 设置画笔颜色，分别为：透明度，红，绿，蓝
        paint.setARGB(150, 0, 150, 150);
        // 设置画笔空心
        paint.setStyle(Paint.Style.STROKE);
        // 设置画笔边框宽度
        paint.setStrokeWidth(4);
        // 绘制一个矩形
        canvas.drawRect(10, 10, 60, 60, paint);
        // 绘制圆形
        canvas.drawCircle(70, 70, 50, paint);
        paint.setTextSize(20);
        // 文本，X坐标起点，Y表示基准线,画笔
        canvas.drawText(" I love you", 200, 60, paint);
        // 绘制一张图片
        canvas.drawBitmap(BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher), 60, 60, paint);
        super.onDraw(canvas);
    }

}

//绘制图形，得重写onDraw方法。