Android各种单位转换&&Android的View用到的部分代码

Resources r = getResources(); 
float px = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 14, r.getDisplayMetrics());

这种神奇的代码很有用（dp to px,sp to px...）

TypedValue有很多单位

    /** {@link #TYPE_DIMENSION} complex unit: Value is raw pixels. */
    public static final int COMPLEX_UNIT_PX = 0;
    /** {@link #TYPE_DIMENSION} complex unit: Value is Device Independent
     *  Pixels. */
    public static final int COMPLEX_UNIT_DIP = 1;
    /** {@link #TYPE_DIMENSION} complex unit: Value is a scaled pixel. */
    public static final int COMPLEX_UNIT_SP = 2;
    /** {@link #TYPE_DIMENSION} complex unit: Value is in points. */
    public static final int COMPLEX_UNIT_PT = 3;
    /** {@link #TYPE_DIMENSION} complex unit: Value is in inches. */
    public static final int COMPLEX_UNIT_IN = 4;
...

发现于：http://stackoverflow.com/questions/4605527/converting-pixels-to-dp-in-android

Android View用到的一些代码

填充图形:setStyle(Style.FILL);
不进行填充:setStyle(Style.STROKE);
抗锯齿：paint.setAntiAlias(true);   
 canvas.setDrawFilter(new PaintFlagsDrawFilter(0, Paint.ANTI_ALIAS_FLAG|Paint.FILTER_BITMAP_FLAG)); 
设置笔触宽度（线的宽度）:paint.setStrokeWidth(float width); 
绘制圆形:canvas.drawCircle(float cx, float cy, float radius, Paint paint);
绘制矩形:canvas.drawRect(float left, float top, float right, float bottom, Paint paint);
绘制圆角矩形:canvas.drawRoundRect(RectF rect, float rx, float ry, Paint paint);
绘制文字：canvas.drawText(String text, float x, float y, Paint paint);
绘制椭圆:canvas.drawOval(RectF oval, Paint paint);
绘制弧：canvas.drawArc(oval, startAngle, sweepAngle, useCenter, paint);
绘制多边形:path.moveTo(float x, float y);
    path.linTo(float x, float y);
    path.close();
    canvas.drawPath(Path path, Paint paint);