How to realize drawing in Android
This article mainly introduces the relevant knowledge of "how to draw in Android". The editor shows you the operation process through an actual case. The operation method is simple, fast and practical. I hope this article "how to draw in Android" can help you solve the problem.
In the development of Android operating system, it is a very common basic operation for the operation of graphical interface. We can first learn about the operation skills of the graphical interface through the related operations of Android drawing introduced in this article, so as to improve our understanding of this system.
Import java.io.InputStream
Import android.app.Activity
Import android.content.Context
Import android.graphics.Bitmap
Import android.graphics.BitmapFactory
Import android.graphics.Canvas
Import android.graphics.Color
Import android.graphics.LinearGradient
Import android.graphics.Paint
Import android.graphics.PorterDuff
Import android.graphics.PorterDuffXfermode
Import android.graphics.Shader
Import android.graphics.Typeface
Import android.os.Bundle
Import android.view.View
Public class AlphaBitmap extends Activity {
@ Override
Protected void onCreate (Bundle savedInstanceState) {
Super.onCreate (savedInstanceState)
SetContentView (new SampleView (this))
}
Private static class SampleView extends View {
Private Bitmap mBitmap
Private Bitmap mBitmap2
Private Bitmap mBitmap3
Private Shader mShader
Private static void drawIntoBitmap (Bitmap bm) {
Float x = bm.getWidth ()
Float y = bm.getHeight ()
/ / build a canvas with defined objects
Canvas c = new Canvas (bm)
Paint p = new Paint ()
/ / it is mainly used to remove edges. From the effect, it seems that false has rough edges.
P.setAntiAlias (true)
P.setAlpha (0x555555); / / Gray
C.drawCircle (XAGAR 2, YAGUAGAN 2, XAGUAGUBER 2, p)
P.setAlpha (0x0000ff); / / Blue
P.setXfermode (new PorterDuffXfermode (PorterDuff.Mode.SRC_OVER))
/ / the following are the settings for fonts
P.setTextSize (20)
String familyName = "Song style"
Typeface font = Typeface.create (familyName,Typeface.ITALIC)
P.setTypeface (font)
P.setTextAlign (Paint.Align.CENTER)
Paint.FontMetrics fm = p.getFontMetrics ()
C.drawText ("I love android", Xamp 2, (y-fm.ascent) / 2, p)
}
Public SampleView (Context context) {
Super (context)
SetFocusable (true)
/ / several methods to get an image
InputStream is = context.getResources ().
OpenRawResource (R.drawable.app_sample_code)
MBitmap = BitmapFactory.decodeStream (is)
/ / extract the color value from an image into a new image, usually the color of the brush is the same as below
P.setColor (Color.BLUE)
MBitmapmBitmap2 = mBitmap.extractAlpha ()
MBitmap3 = Bitmap.createBitmap (200,200, Bitmap.Config.ALPHA_8)
DrawIntoBitmap (mBitmap3)
/ / A gradient effect
MShader = new LinearGradient (0,0,150,70, new int [] {
Color.RED, Color.GREEN, Color.BLUE}
Null, Shader.TileMode.MIRROR)
}
@ Override protected void onDraw (Canvas canvas) {
Canvas.drawColor (Color.LTGRAY)
Paint p = new Paint ()
Float y = 10
P.setColor (Color.BLUE)
Canvas.drawBitmap (mBitmap, 10, y, p)
Y + = mBitmap.getHeight () + 10
Canvas.drawBitmap (mBitmap2, 10, y, p)
Y + = mBitmap2.getHeight () + 10
P.setShader (mShader)
Canvas.drawBitmap (mBitmap3, 10, y, p)
}
}
}
This is the end of the introduction of "how to draw in Android". Thank you for your reading. If you want to know more about the industry, you can follow the industry information channel. The editor will update different knowledge points for you every day.
