Android TV for full screen drawing vertical line

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With canvas double buffering, you can reduce the time of drawing and improve performance.

Staggeredview.java

The source code is as follows:

Package Com.xxx.demo;import Android.content.context;import Android.graphics.bitmap;import Android.graphics.Canvas; Import Android.graphics.color;import Android.graphics.paint;import Android.view.view;import    Android.view.windowmanager;public class Staggeredview extends view {int width;    int height;    Paint p;    Bitmap Bitmap = null;    Canvas x = null;        Public Staggeredview (Context context) {super (context);        WindowManager wm = (WindowManager) getcontext (). Getsystemservice (Context.window_service);        width = Wm.getdefaultdisplay (). GetWidth ();        Height = Wm.getdefaultdisplay (). GetHeight ();    p = new Paint (); private void Initmycanvas () {p.setcolor (color.white);//Set Green bitmap = Bitmap.createbitmap (bitm Ap.        config.argb_8888);        Create Canvas.        x = new Canvas ();        X.setbitmap (bitmap);        P.setstyle (Paint.Style.STROKE);        P.setantialias (TRUE); for (int i = 0; I <=20; i++) {           ChangeColor (I, p); X.drawline (i, 0, I, p),//Draw line}} @Override protected void OnDraw (canvas canvas) {Super.ondraw (        Canvas);        Canvas.drawcolor (Color.White);        Create a brush long starttime=system.currenttimemillis ();        Initmycanvas ();        int bitwidth = Bitmap.getwidth ();        int bitheight = Bitmap.getheight ();                for (int i = 0; i < height; i + = Bitheight) {for (int j = 0; J < width; j + = Bitwidth) {//                ChangeColor (i,j,p);//Canvas.drawpoint (i, J, p);            Canvas.drawbitmap (Bitmap, J, I, p);    }} System.out.println ("time = = =" + (System.currenttimemillis ()-starttime)); }/** * Change the color of the brush * * @param i * @param p */private void ChangeColor (int i, Paint p) {SWI                TCH (i% 2) {case 0:p.setcolor (color.white);            Break Case 1:p.setcolor (Color.blacK);        Break }    }}

First, draw a small rectangular area, create a canvas to draw on the bitmap, then use the system Canavas reuse the front bitmap, can improve the efficiency of processing.

Mainactivity.java

public class Mainactivity extends Activity {    @Override    protected void onCreate (Bundle savedinstancestate) {        super.oncreate (savedinstancestate);        Requestwindowfeature (window.feature_no_title);        Setcontentview (New Staggeredview (This));}    }

The results are printed as follows:
I/system.out: Time ===91

Method Two:

Staggeredview2.java

In the default way, it is a loop that draws a vertical line with a width. The efficiency is still very low.

public class StaggeredView2 extends View {int width;    int height;    Paint p;    Bitmap Bitmap = null;    Canvas x = null;        Public StaggeredView2 (Context context) {super (context);        WindowManager wm = (WindowManager) getcontext (). Getsystemservice (Context.window_service);        width = Wm.getdefaultdisplay (). GetWidth ();        Height = Wm.getdefaultdisplay (). GetHeight ();        p = new Paint ();    Initmycanvas (); private void Initmycanvas () {p.setcolor (color.white);//Set Green bitmap = Bitmap.createbitmap (bitm Ap.        config.argb_8888);        Create Canvas.        x = new Canvas ();        X.setbitmap (bitmap);        P.setstyle (Paint.Style.STROKE);        P.setantialias (TRUE);            for (int i = 0; I <=; i++) {ChangeColor (I, p); X.drawline (i, 0, I, +, p);//Draw line}} @Override protected void OnDraw (canvas canvas) {Super.ondraw (        Canvas); Canvas.drawcolor (Color.White);        Create a brush long starttime=system.currenttimemillis ();            for (int i = 0; i < width; i++) {ChangeColor (I, p);        Canvas.drawline (i,0, I, height-1, p);    } System.out.println ("time = = =" + (System.currenttimemillis ()-starttime)); }/** * Change the color of the brush * * @param i * @param p */private void ChangeColor (int i, Paint p) {SWI                TCH (i% 2) {case 0:p.setcolor (color.white);            Break                Case 1:p.setcolor (Color.Black);        Break }    }}

The result is:

I/system.out: Time ===277

Relative to the previous approach, efficiency is very low ...