Android Canvas 两种使用方式

From:http://blog.csdn.net/androiddevelop/article/details/8267312

一、Canvas第一种使用方式

最简单的使用Canvas， 画一个方形，一行字。 下面是效果图



[java]
view plaincopyprint?





public class CustomView extends View {

private Paint mPaint;

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

public CustomView(Context context, AttributeSet attrs) {
super(context, attrs);

mPaint = new Paint();
mPaint.setColor(Color.GREEN);
mPaint.setTextSize(36);

}

@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);

mPaint.setStyle(Style.FILL); //设置填充

canvas.drawRect(10, 10, 200, 200, mPaint); //绘制矩形

mPaint.setColor(Color.BLUE);
canvas.drawText("我不是自定义View", 10, 120, mPaint);
}

public class CustomView extends View {

private Paint mPaint;

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

public CustomView(Context context, AttributeSet attrs) {
super(context, attrs);

mPaint = new Paint();
mPaint.setColor(Color.GREEN);
mPaint.setTextSize(36);

}

@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);

mPaint.setStyle(Style.FILL); //设置填充
canvas.drawRect(10, 10, 200, 200, mPaint); //绘制矩形

mPaint.setColor(Color.BLUE);
canvas.drawText("我不是自定义View", 10, 120, mPaint);
}

参考资料：

android图形系统详解一：Canvas

android Canvas类介绍

Android Graphic ： apk and Skia/OpenGL|ES

二、Canvas第二种使用方式

Canvas的使用通常只有两种形式：

1. 在已有的Canvas上绘制图形或文字，通过VIew.onDraw回调获取Canvas对象。Canvas第一种使用方式

2. 图形或文字直接绘制到View上（本文使用此种方式）

[java]
view plaincopyprint?





public class MainActivity extends Activity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); Bitmap b =Bitmap.createBitmap(100, 100, Bitmap.Config.ARGB_8888); Canvas canvas =new Canvas(b); Paint paint = new Paint(); paint.setColor(Color.BLUE); canvas.drawText("love_world_", 20, 20, paint); ImageView imageView = (ImageView) findViewById(R.id.image_view); BitmapDrawable bitmapDrawable = new BitmapDrawable(b); imageView.setBackgroundDrawable(bitmapDrawable); } }

public class MainActivity extends Activity {

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

Bitmap b =Bitmap.createBitmap(100, 100, Bitmap.Config.ARGB_8888);
Canvas canvas =new Canvas(b);

Paint paint = new Paint();
paint.setColor(Color.BLUE);
canvas.drawText("love_world_", 20, 20, paint);

ImageView imageView = (ImageView) findViewById(R.id.image_view);
BitmapDrawable bitmapDrawable = new BitmapDrawable(b);
imageView.setBackgroundDrawable(bitmapDrawable);
}

}

效果图



Android入门第十四篇之画图

http://blog.csdn.net/hellogv/article/category/761980

Andriod中绘(画)图----Canvas的使用详解

/article/1390946.html

Android图像处理之Bitmap类
http://blog.csdn.net/thl789/article/details/6762030
Android利用canvas画各种图形(点、直线、弧、圆、椭圆、文字、矩形、多边形、曲线、圆角矩形)

/article/2742974.html

画了个Android——Canvas类的使用

http://blog.sina.com.cn/s/blog_61ef49250100qw9x.html

Android Canvas rotate

http://verydemo.com/demo_c131_i3507.html

Android入门第十四篇之画图

http://blog.csdn.net/hellogv/article/category/761980

Andriod中绘(画)图----Canvas的使用详解

/article/1390946.html

Android图像处理之Bitmap类
http://blog.csdn.net/thl789/article/details/6762030
Android利用canvas画各种图形(点、直线、弧、圆、椭圆、文字、矩形、多边形、曲线、圆角矩形)

/article/2742974.html

画了个Android——Canvas类的使用

http://blog.sina.com.cn/s/blog_61ef49250100qw9x.html

Android Canvas rotate

http://verydemo.com/demo_c131_i3507.html