本文分享了解决surfaceview触摸轨迹闪烁问题的方法,供大家参考,具体内容如下
第一种解决surfaceview触摸轨迹闪烁问题的方法:
由于surfaceview使用双缓存机制,两张画布轮流显示到屏幕上。那么,要存储触摸轨迹并避免两张画布内容不一致造成的闪烁问题,完全可以利用保存绘制过程并不断重新绘制的方法解决闪烁,而且这样还顺带解决了多次试验中偶尔出现的因为moveto()函数不能读取到参数执行默认设置(参数设为上次的触摸点)而出现的断线连接闪烁问题,详细代码如下:
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package com.tobacco.touchdraw; import java.util.arraylist; import android.content.context; import android.graphics.canvas; import android.graphics.color; import android.graphics.paint; import android.graphics.path; import android.view.motionevent; import android.view.surfaceholder; import android.view.surfaceview; import android.view.view; import android.view.surfaceholder.callback; import android.view.view.ontouchlistener; public class lsurfaceview extends surfaceview implements callback,ontouchlistener,runnable{ private surfaceholder sfh; private canvas canvas; private paint paint; private path path; private arraylist<path> paths; private boolean flag; public lsurfaceview(context context) { super (context); sfh= this .getholder(); sfh.addcallback( this ); paint= new paint(); paint.setcolor(color.red); paint.setantialias( true ); paint.setstrokewidth( 4 ); paint.setstyle(paint.style.stroke); paint.setstrokecap(paint.cap.round); paths= new arraylist<path>(); path= new path(); } public void mydraw(motionevent e){ int action=e.getaction(); switch (action){ case motionevent.action_down: path.moveto(e.getx(),e.gety()); break ; case motionevent.action_move: path.lineto(e.getx(),e.gety()); break ; case motionevent.action_up: //path.close(); path path1= new path(path); paths.add(path1); path.reset(); break ; } } @override public void surfacechanged(surfaceholder arg0, int arg1, int arg2, int arg3) { } @override public void surfacecreated(surfaceholder holder) { flag= true ; setontouchlistener( this ); new thread( this ).start(); } @override public void surfacedestroyed(surfaceholder holder) { flag= false ; } @override public boolean ontouch(view v, motionevent event) { mydraw(event); return true ; } @override public void run() { while (flag){ long start=system.currenttimemillis(); canvas=sfh.lockcanvas(); if (canvas!= null ){ canvas.drawcolor(color.black); for ( int i= 0 ;i<paths.size();i++) canvas.drawpath(paths.get(i),paint); canvas.drawpath(path,paint); sfh.unlockcanvasandpost(canvas); } long end=system.currenttimemillis(); try { if (end-start< 30 ){ thread.sleep( 30 -(end-start)); } } catch (exception e){ } } } } |
这里还要注意的是:arraylist保存的是对象的引用,所以要在每次添加时都新建一个对象实体。
第二种解决surfaceview触摸轨迹闪烁问题的方法:
处理触屏轨迹的绘制时,用到了surfaceview,建立path对象,在点击时开始设置path对象,滑动过程中记录触摸点,离开后重新设置path对象,因不能阻塞主线程,所以新建了一个子线程来不断刷新屏幕,也就是将path不断绘制。但是,接着就出现了一个问题:屏幕中每条轨迹线的终点都会有一小段直线段不断闪烁。猜测可能是lockcanvas()获取的对象区域不一样,就试着使用了lockcanvas(rect re),但是,运行后发现还是没有解决问题;接着想到可能是因为每次lockcanvas()后获取的对象不同,就在主线程中添加了一个canvas对象,每次都在canvas对象中修改画面,然后提交显示,但是,程序运行后效果丝毫没有改变!程序代码如下:
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package com.tobacco.touchdraw; import android.content.context; import android.graphics.canvas; import android.graphics.color; import android.graphics.paint; import android.graphics.path; import android.view.motionevent; import android.view.surfaceholder; import android.view.surfaceview; import android.view.view; import android.view.surfaceholder.callback; import android.view.view.ontouchlistener; public class mysurfaceview extends surfaceview implements callback,ontouchlistener,runnable{ private surfaceholder sfh; private canvas canvas; private paint paint; private float lastx,lasty; private path path; private boolean flag; public mysurfaceview(context context) { super (context); sfh= this .getholder(); sfh.addcallback( this ); paint= new paint(); paint.setcolor(color.red); paint.setantialias( true ); paint.setstrokewidth( 5 ); paint.setstyle(paint.style.stroke); paint.setstrokecap(paint.cap.round); path= new path(); } public void mydraw(motionevent e){ int action=e.getaction(); switch (action){ case motionevent.action_down: path.moveto(e.getx(),e.gety()); lastx=e.getx(); lasty=e.gety(); break ; case motionevent.action_move: path.quadto(lastx,lasty,e.getx(),e.gety()); lastx=e.getx(); lasty=e.gety(); break ; case motionevent.action_up: //path.quadto(lastx,lasty,e.getx(),e.gety()); path.reset(); break ; } } @override public void surfacechanged(surfaceholder arg0, int arg1, int arg2, int arg3) { } @override public void surfacecreated(surfaceholder holder) { flag= true ; setontouchlistener( this ); new thread( this ).start(); } @override public void surfacedestroyed(surfaceholder holder) { flag= false ; } @override public boolean ontouch(view v, motionevent event) { mydraw(event); return true ; } @override public void run() { while (flag){ long start=system.currenttimemillis(); canvas=sfh.lockcanvas(); if (canvas!= null ){ canvas.drawpath(path,paint); sfh.unlockcanvasandpost(canvas); } long end=system.currenttimemillis(); try { if (end-start< 100 ){ thread.sleep( 100 -(end-start)); } } catch (exception e){ } } } } |
以上就是本文的全部内容,希望能够帮助大家轻松解决surfaceview触摸轨迹闪烁问题。