图形编程——Paint和Canvas的基本使用

1、MainActivity

package com.njupt.shudhu02;

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

public class MainActivity extends Activity {

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

	@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;
	}

}

2、MyView

package com.njupt.shudhu02;

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);
	}

	@Override
	protected void onDraw(Canvas canvas) {
		Paint paint = new Paint();
		paint.setARGB(150, 0, 100, 200);
		
//		paint.setStyle(Paint.Style.STROKE);//这时候画笔画出来的东西都是空心的
		paint.setStrokeWidth(10);
		paint.setTextSize(100);//
		
		/**
		 * canvas.drawRect(100, 300,300,500,paint)
		 * 该函数的4个参数分别为距离左边的距离,上,右,下
		 */
//		canvas.drawRect(100, 300,300,500,paint);//画矩形
		
		/**
		 * 前3个参数的意思是:前两个是圆心的坐标,第三个是半径...
		 */
//		canvas.drawCircle(200, 200, 150, paint);//画圆形
		
		/**
		 * canvas.drawText("apple", 50, 200, paint)
		 * 这四个参数分别为:要绘制的文本,X轴的坐标,基准线,所使用的画笔
		 */
//		canvas.drawText("apple", 50, 200, paint);//绘制文本
		
		
		/**
		 * canvas.drawBitmap(BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher), 100,300, paint)
		 * 前四个参数为:要显示的图形,图片左边界,图片的上边界,所使用的画笔
		 * 
		 */
		canvas.drawBitmap(BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher), 100,300, paint);//绘制图形
		super.onDraw(canvas);
	}
	
	
}