Android MotionEvent ACTION_MOVE的效率.如何提高性能? [英] Android MotionEvent ACTION_MOVE efficiency. How to improve performance?

问题描述

我目前正在开发允许自由绘图的应用程序.

I am currently working on an app that allows for free-drawing.

我当前使用的方法如下:

The current method I am using is as follows:

currentLine是一个列表，其中保留了 ACTION_MOVE 返回的所有点的历史记录.

currentLine is a list that keeps a history of all points that ACTION_MOVE returns.

public boolean onTouchEvent (MotionEvent event) {

        switch (event.getAction()) {
            case MotionEvent.ACTION_MOVE:
                Point p = new Point(event.getX(),event.getY());
                currentLine.addPoint(p);
                    invalidate();
                break;
        }

        return true;

}

然后我将这些要点放在我班的 onDraw 方法中.

I then take these points and draw them in the onDraw method of my class.

@Override
protected void onDraw(Canvas c) {
    super.onDraw(c);

    //Draw Background Color
    c.drawColor(Color.BLUE);

    //Setup Paint
    Paint p = new Paint();
    p.setStyle(Style.FILL);
    p.setColor(COLOR.WHITE);

    //iterate through points
    if(currentLine.size()>0){
        for(int x = 0;x<currentLine.size();x++){
            c.drawCircle(currentLine.get(x).getX(), currentLine.get(x).getY(), 3, p);
        }
    }

}

这种方法效果很好，没有滞后或其他任何情况.

And this method works great, with no lag or anything.

除了，它没有足够所需的点数.

Except, it does not get enough of the points that it needs to.

例如，如果我要在整个屏幕上快速拖动手指，则可能只会绘制整个事件的15个点.

For example, if I am to drag my finger quickly across the entire screen, it may only draw 15 points of the whole event.

如何提高MotionEvent的性能/速度?我如何获得更多积分?还是我应该做些其他事情?

How can I improve the performance/speed of the MotionEvent? How can I get more points? Or is there something else I should be doing?

----编辑----

我设法自己解决了.

我没有使用 drawCircle ，而是切换到 drawLine .

Instead of using drawCircle, I switched to drawLine.

示例:

if(points.size()>0){
        for(int x = 0;x<points.size()-1;x++){
            c.drawLine(points.get(x).getX(), points.get(x).getY(), points.get(x+1).getX(), points.get(x+1).getY(), p);
        }
}

这会产生实线，这正是我想要的.

This produces solid lines, which is what I wanted.

但是，出于知识的考虑，我仍然想知道如何加快MotionEvents的速度.

一个详细的答案，将不胜感激

A detailed answer would be appreciated

推荐答案

显然，瓶颈是绘制方法.

The bottleneck is the drawing method, obviously.

如果您使用的是Android 3.0+，请在GPU上绘制所有这些疯狂的东西.添加属性

If you are working on android 3.0+, draw all those crazy things on the GPU. Add the attribute

android:hardwareAccelerated="true"

到清单中的< application> 标记.这将令人难以置信的增加绘图时间.

to the <application> tag in your manifest. This will unbelievably increase drawing time.

此外，如果只需要更新一点，请尝试不要重绘整个内容.调用invalidate(Rectdirty)而不是invalidate().

Additionally, try to not redraw the whole thing if only a little needs to be updated. Invoke invalidate(Rect dirty) instead of invalidate().

这篇关于Android MotionEvent ACTION_MOVE的效率.如何提高性能?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！