Android for Scratch effect

Just a few months ago, when I was in touch with Android, I did a little project, which also used a scratch-like effect, and now put the code out.

First, do something like an eraser, and then erase the handwriting on the paper.

/** * FileName:SplashActivity.java * * @desc eraser function, similar to scratch effect * @author HTP * @Date 20140311 * @version 1.00 */public class Text_rubbler extends TextView {private float touch_tolerance;//fill the distance, make the line more natural, softer, the smaller the value, the softer. Private final int bgcolor;//bitmap private Bitmap mbitmap;//canvas private canvas mcanvas;//brush private Paint mpaint;private Pat  H mpath;private Float MX, my;private boolean isdraw = False;public Text_rubbler (context context) {/** * @param context context */super (context);} Public Text_rubbler (context context, AttributeSet attrs, int defstyle) {Super (context, attrs, defstyle);//BgColor =//att Rs.getattributeintvalue ("http://schemas.android.com/apk/res/android",//"TextColor", 0xFFFFFF);// System.out.println ("Color:" +bgcolor);} Public Text_rubbler (context context, AttributeSet Attrs) {Super (context, attrs);//BgColor =// Attrs.getattributeintvalue ("http://schemas.android.com/apk/res/android",//"TextColor", 0xFFFFFF);// System.out.println (BgColor);//System.out.println (Attrs.getattributevaluE ("http://schemas.android.com/apk/res/android",//"Layout_width");} @Overrideprotected void OnDraw (canvas canvas) {Super.ondraw (canvas), if (Isdraw) {Mcanvas.drawpath (MPath, mpaint);// Mcanvas.drawpoint (MX, MY, Mpaint); Canvas.drawbitmap (mbitmap, 0, 0, null);}} /** * Turn on erase function * * @param bgColor * Cover background color * @param paintstrokewidth * Contact (RUBBER) Width * @param touchtolera NCE * Fills the distance, the lower the value, the softer. */public void Beginrubbler (final int bgColor, final int paintstrokewidth,float touchtolerance) {touch_tolerance = Touchto lerance;//Set Brush mpaint = new Paint ();//Mpaint.setalpha (0);//brush across the traces will become transparent color mpaint.setcolor (color.black); This cannot be a transparent color mpaint.setxfermode (new Porterduffxfermode (PorterDuff.Mode.DST_OUT));//or//Mpaint.setalpha (0);// Mpaint.setxfermode (New Porterduffxfermode (PorterDuff.Mode.DST_IN)); Mpaint.setantialias (true); Mpaint.setdither ( true); Mpaint.setstyle (Paint.Style.STROKE); Mpaint.setstrokejoin (Paint.Join.ROUND); Front fillet mpaint.setstrokecap (Paint.Cap.ROUND); Rear Fillet mpaint.setsTrokewidth (Paintstrokewidth); Pen width//Trace MPath = new Path ();; /overwrite//if (Getlayoutparams (). width = = layoutparams.fill_parent) {////}mbitmap = Bitmap.createbitmap (Getlayoutparams (). Width,getlayoutparams (). Height, config.argb_8888) Mcanvas = new Canvas (MBITMAP); Mcanvas.drawcolor (bgColor); Isdraw = true;} @Overridepublic boolean ontouchevent (Motionevent event) {if (!isdraw) {return true;} Switch (event.getaction ()) {case Motionevent.action_down://Contact Press//TouchDown (EVENT.GETRAWX (), Event.getrawy ()); TouchDown (Event.getx (), event.gety ()); invalidate (); Break;case motionevent.action_move://Contact Move touchmove (event.getx (), event.gety ()); invalidate (); Break;case motionevent.action_up://Contacts Bounce Touchup (Event.getx (), event.gety ()); Invalidate (); break;default:break;} return true;} private void TouchDown (float x, float y) {mpath.reset (); Mpath.moveto (x, y); MX = X;my = y;} private void TouchMove (float x, float y) {float dx = math.abs (x-mx); float dy = Math.Abs (y-my); if (DX >= touch_toler ance | | Dy >= TOUCH_tolerance) {mpath.quadto (MX, my, (x + MX)/2, (y + MY)/2), mx = X;my = y;}} private void TouchUp (float x, float y) {mpath.lineto (x, y); Mcanvas.drawpath (MPath, Mpaint); Mpath.reset ();}}

The next step is to erase with Eraser

/** * FileName:RubblerAct.java * @Desc This class will show a scratch area on the activity by calling Text_rubbler, can start touch event * @author HTP * @Date 2014  0312 * @version 1.00 */public class Rubbleract extends Activity {//After scraping the text shows private TextView tv_rubbler;//get scraped content private Sentence msentence;//next private TextView tv_next; @Overridepublic void OnCreate (Bundle savedinstancestate) { Super.oncreate (savedinstancestate);//Setcontentview (new rubble (this, "Thank you", New Rect (200,//300,250), 2,1f,14)) ;///////////////////////////////////////////setcontentview (R.layout.rubbler);//The color set must be transparent. ((Text_rubbler) Findviewbyid (R.id.rubbler)). Beginrubbler (0xFFFFFFFF, 20,1f);//Set the width of the eraser, etc. msentence = new sentence (); /random Initialization text Tv_rubbler = (TextView) Findviewbyid (R.id.rubbler); String str = msentence.getsentence (); Tv_rubbler.settext (str); tv_next = (TextView) Findviewbyid (r.id.tv_next);// Click Next Tv_next.setonclicklistener (New Onclicklistener () {@Overridepublic void OnClick (View v) {//TODO auto-generated Method stubstring str = msentence.Getsentence (); Tv_rubbler.settext (str);((Text_rubbler) Findviewbyid (R.id.rubbler))//Initialize state. Beginrubbler ( 0xFFFFFFFF, 1f);});} Class Rubble extends View {private final int paint_stroke_width;private final float touch_tolerance;//fill the distance to make the line more natural, softer, less value , the more gentle. Private final int text_size;private Bitmap mbitmap;//canvas private canvas mcanvas;//brush private Paint mpaint;private Path Mpat h;private float MX, my;private final int X, Y, W, h;private final Rect touchrect;public Rubble (context context, String BgT Ext, Rect rect,int paintstrokewidth, float touchtolerance, int textSize) {super (context); setfocusable (true); Touchrect = Rect W = Rect.right-rect.left; H = Rect.bottom-rect.top; X = Rect.left; Y = Rect.top; Text_size = textSize; Paint_stroke_width = Paintstrokewidth; Touch_tolerance = Touchtolerance;setbackground (Touchrect, Bgtext); Initdrowtools ();} private void SetBackground (rect rect, String bgtext) {displaymetrics dm = new Displaymetrics ();d m = this.getresources (). GE Tdisplaymetrics (); Bitmap Bitmap = Bitmap.createbitmap (Dm.widthpixels,dm.heightpixels, config.argb_8888); Canvas canvas = new canvas (bitmap); Paint paint = new paint ();p aint.setcolor (0x88000000);//Paint.setstyle (Style.stroke);//Paint.settextalign ( Align.center);p aint.settextsize (text_size);//Paint.settextscalex (1.5f); Canvas.drawcolor (color.white);// Stooped coordinates are not well controlled int x = rect.left+ (Rect.right-rect.left-bgtext.length () * text_size)/2;int y = rect.top + (rect.bottom-re ct.top-text_size)/2;//int y = 218+25;canvas.drawtext (Bgtext, x, y, paint);D rawable drawable = new Bitmapdrawable (bitm AP); setbackgrounddrawable (drawable);} private void Initdrowtools () {//set brush Mpaint = new Paint ();//Mpaint.setalpha (0);//brush across the traces will become transparent color mpaint.setcolor ( Color.Black); This cannot be a transparent color mpaint.setxfermode (new Porterduffxfermode (PorterDuff.Mode.DST_OUT));//or//Mpaint.setalpha (0);// Mpaint.setxfermode (new//porterduffxfermode (PorterDuff.Mode.DST_IN)); Mpaint.setantialias (true); Mpaint.setdither (true); Mpaint.setstyle (Paint.Style.STROKE); mpaint.seTstrokejoin (Paint.Join.ROUND); Front fillet mpaint.setstrokecap (Paint.Cap.ROUND); Posterior fillet mpaint.setstrokewidth (paint_stroke_width); Pen width//Trace MPath = new Path ();; /Overwrite Mbitmap = Bitmap.createbitmap (W, H, config.argb_8888); Mcanvas = new Canvas (MBITMAP); Mcanvas.drawcolor (0x88000000);} @Overrideprotected void OnDraw (canvas canvas) {super.ondraw (canvas); Mcanvas.drawpath (MPath, mpaint);// Mcanvas.drawpoint (MX, MY, Mpaint); Canvas.drawbitmap (Mbitmap, X, Y, null);} @Overridepublic boolean ontouchevent (Motionevent event) {System.out.print ("x--" + event.getx ()); System.out.println ("y--" + event.gety ()), if (!touchrect.contains (int) event.getx (), (int) event.gety ())) {return false;} Switch (event.getaction ()) {//Contacts press case Motionevent.action_down: {TouchDown (EVENT.GETRAWX (), Event.getrawy ()); TouchDown (Event.getx ()-Touchrect.left, Event.gety ()-touchrect.top); invalidate (); break;} Case Motionevent.action_move://Contact Move touchmove (Event.getx ()-Touchrect.left, Event.gety ()-touchrect.top); invalidate (); Break;case MOTIONEVENT.ACTION_UP://Contacts Bounce Up Touchup (Event.getx ()-Touchrect.left, Event.gety ()-touchrect.top); invalidate (); break; Default:break;} return true;} private void TouchDown (float x, float y) {mpath.reset (); Mpath.moveto (x, y); MX = X;my = y;} private void TouchMove (float x, float y) {float dx = math.abs (x-mx); float dy = Math.Abs (y-my); if (DX >= touch_toler ance | | Dy >= touch_tolerance) {mpath.quadto (MX, my, (x + MX)/2, (y + MY)/2), mx = X;my = y;}} private void TouchUp (float x, float y) {mpath.lineto (x, y); Mcanvas.drawpath (MPath, Mpaint); Mpath.reset ();}} /** * Keyboard event, when the back button is pressed to ask whether to press the exit program again *///exit time private long exittime = 0; @Overridepublic boolean onKeyDown (int keycode, Keyev Ent event) {if (keycode = = keyevent.keycode_back&& event.getaction () = = Keyevent.action_down) {if ( System.currenttimemillis ()-Exittime) > {toast.maketext (Getapplicationcontext (), "Press again to exit the program", Toast.length_ Short). Show (); exittime = System.currenttimemillis ();} else {finish (); System.exit (0);} Returntrue;} Return Super.onkeydown (KeyCode, event);}}

The implementation results are as follows:

Android for Scratch effect