A simple way to realize the effect of image paging in Android _android

Copy Code code as follows:

public class Pagewidget extends View {
Private Bitmap foreimage;
Private Bitmap bgimage;
Private PointF Touchpt;
private int screenwidth;
private int screenheight;
Private Gradientdrawable Shadowdrawablerl;
Private Gradientdrawable SHADOWDRAWABLELR;
Private Colormatrixcolorfilter Mcolormatrixfilter;
Private Scroller Mscroller;
private int Lasttouchx;

Public Pagewidget {
Super (context);
TODO auto-generated Constructor stub
TOUCHPT = new PointF ( -1,-1);

ARGB A (0-transparent, 255-opaque)
int[] color = {0xb0333333, 0x00333333};
Shadowdrawablerl = new Gradientdrawable (GradientDrawable.Orientation.RIGHT_LEFT, color);
Shadowdrawablerl.setgradienttype (gradientdrawable.linear_gradient);

SHADOWDRAWABLELR = new Gradientdrawable (GradientDrawable.Orientation.LEFT_RIGHT, color);
Shadowdrawablelr.setgradienttype (gradientdrawable.linear_gradient);

Float array[] = {0.55f, 0, 0, 0, 80.0f,
, 0.55f, 0, 0, 80.0f,
, 0,0.55f, 0, 80.0f,
, 0, 0, 0.2f, 0};
ColorMatrix cm = new ColorMatrix ();
Cm.set (array);
/*
* | a*0.55 + 80|
* | r*0.55 + 80|
* | g*0.55 + 80|
* | b*0.2|
*/
Cm.setsaturation (0);
Mcolormatrixfilter = new Colormatrixcolorfilter (cm);

Using the scroll bar to realize the animation effect of contact point release
Mscroller = new Scroller (context);
}

    @Override
    public void Computescroll () {
        //TODO auto-generated method stub
        if ( Mscroller.computescrolloffset ()) {
            Touchpt.x = Mscroller.getcurrx ();
            touchpt.y = Mscroller.getcurry ();

            postinvalidate ();
       }
        else{
//             touchpt.x =-1;
//            touchpt.y = -1;            
       }

Super.computescroll ();
}

public void Setscreen (int screenwidth,int screenheight) {
This.screenwidth = ScreenWidth;
This.screenheight = ScreenHeight;
}

Public Bitmap Getforeimage () {
return foreimage;
}

public void Setforeimage (Bitmap foreimage) {
This.foreimage = Foreimage;
}

Public Bitmap Getbgimage () {
return bgimage;
}

    public void Setbgimage (Bitmap bgimage) {
        This.bgimage = Bgimage;
   }

    @Override
    protected void OnDraw (Canvas Canvas) {
        //TODO auto-generated method stub
        Drawpageeffect (canvas);
        Super.ondraw (canvas);
   }

   /**
     * Picture foreground picture
     * @param canvas
     */
    private void Drawforceimage (Canvas Canvas) {
        //TODO auto-generated method stub
        Paint Mpaint = new Paint ();

        if (foreimage!=null) {
             Canvas.drawbitmap (foreimage, 0, 0, mpaint);
       }       
    }

   /**
     * picture background picture
     * @param canvas
     */
    private void Drawbgimage (Canvas canvas,path Path) {
        //TODO auto-generated method stub
        Paint mpaint = new Paint ();

        if (bgimage!=null) {
             Canvas.save ();

           //Paint only at the intersection of Paths
             Canvas.clippath (Path,op.intersect);
            canvas.drawbitmap (bgimage, 0, 0, mpaint);
            Canvas.restore ();
       }
   }

/**
* Picture Page effect
* @param canvas
*/
private void Drawpageeffect (Canvas Canvas) {
TODO auto-generated Method Stub
Drawforceimage (canvas);
Paint mpaint = new Paint ();
if (touchpt.x!=-1 && touchpt.y!=-1) {
Flip the left side of the book
Canvas.drawline (touchpt.x, 0, Touchpt.x,screenheight, mpaint);

Left side of the book Side painting Shadow
Shadowdrawablerl.setbounds ((int) touchpt.x-20, 0, (int) touchpt.x, screenheight);
Shadowdrawablerl.draw (canvas);

Flip the fold in the corner
Float Halfcut = touchpt.x + (screenwidth-touchpt.x)/2;
Canvas.drawline (halfcut, 0, Halfcut, ScreenHeight, Mpaint);

Fold the left side of the page to picture the back
Rect Backarea = new Rect (int) touchpt.x,0, (int) halfcut,screenheight);
Paint backpaint = new Paint ();
Backpaint.setcolor (0XFFDACAB0);
Canvas.drawrect (Backarea, backpaint);

Flip the front of the page image horizontally and pan to the touchpt.x point
Paint fbpaint = new Paint ();
Fbpaint.setcolorfilter (Mcolormatrixfilter);
Matrix matrix = new Matrix ();

Matrix.prescale ( -1,1);
Matrix.posttranslate (Foreimage.getwidth () + touchpt.x,0);

Canvas.save ();
Canvas.cliprect (Backarea);
Canvas.drawbitmap (Foreimage, Matrix, fbpaint);
Canvas.restore ();

Draw left Shadow in fold
Shadowdrawablerl.setbounds ((int) halfCut-50, 0, (int) halfcut, screenheight);
Shadowdrawablerl.draw (canvas);

Path Bgpath = new Path ();

An area that can display a background image
Bgpath.addrect (New RECTF (halfcut,0,screenwidth,screenheight), DIRECTION.CW);

Fold the right drawing background
Drawbgimage (Canvas,bgpath);

Draw the right shadow in the fold
Shadowdrawablelr.setbounds ((int) halfcut, 0, (int) Halfcut +, screenheight);
Shadowdrawablelr.draw (canvas);
}
}

@Override
public boolean ontouchevent (Motionevent event) {
TODO auto-generated Method Stub
if (event.getaction () = = Motionevent.action_down) {
Touchpt.x = Event.getx ();
Touchpt.y = Event.gety ();
}
else if (event.getaction () = = Motionevent.action_move) {
LASTTOUCHX = (int) touchpt.x;
Touchpt.x = Event.getx ();
Touchpt.y = Event.gety ();

Postinvalidate ();
}
else if (event.getaction () = = motionevent.action_up) {
int dx,dy;

DY = 0;

Slide Right
if (lasttouchx<touchpt.x) {
DX = Foreimage.getwidth ()-(int) touchpt.x + 30;
}
else{
Slide Left
DX =-(int) touchpt.x-foreimage.getwidth ();
}

Mscroller.startscroll ((int) touchpt.x, (int) touchpt.y,dx,dy,1000);
Postinvalidate ();
}

Must be true otherwise the action_move and ACTION_UP events cannot be obtained
return true;
}
}

public class Pageactivity extends activity {
protected void OnCreate (Android.os.Bundle savedinstancestate) {
Requestwindowfeature (Window.feature_no_title);

Pagewidget pagewidget = new Pagewidget (this);

Display display = Getwindowmanager (). Getdefaultdisplay ();
int width = display.getwidth ();
int height = display.getheight ();

Pagewidget.setscreen (width, height);

Bitmap bm1 = Bitmapfactory.decoderesource (Getresources (), r.drawable.pre7);
Bitmap bm2 = Bitmapfactory.decoderesource (Getresources (), r.drawable.after7);

Bitmap foreimage = Bitmap.createscaledbitmap (bm1, Width, height,false);
Bitmap bgimage = Bitmap.createscaledbitmap (bm2, Width, height,false);

Pagewidget.setbgimage (Bgimage);
Pagewidget.setforeimage (Foreimage);

Setcontentview (Pagewidget);

Super.oncreate (savedinstancestate);
};
}