ScrollBy（）滚动超过最大 [英] ScrollBy() scrolling over the maximum

问题描述

由于到Android不会让我就让它滚动处理上一个TextView（链接到这个问题，以尽快我写它补充说）我需要处理它自己。在code我使用非常简单，和它的作品在一定程度上，一个问题，它只是不断的最大后滚动（羯羊即顶部或底部）。我发现使用canScrollVertically（方向）的作品，但限制了我的API拉特14以上，这是我不想做的事。这是我目前的code：

Due to Android not allowing me to just let it handle scrolling on a TextView (link to that question to be added as soon as I write it) I need to handle it myself. The code i am using is quite simple, and it works to an extent, with a problem, it just keeps scrolling after the maximum (wether that is the top or the bottom). I found using canScrollVertically(direction) works, but that limits me to API lvl 14 and above, which is something i dont want to do. Here is my current code:

float prevY;

@Override
public boolean onTouch(View v, MotionEvent event) {
    if (event.getAction() == MotionEvent.ACTION_MOVE) {
        int dy = (int) (prevY - event.getY());
        if (myView.canScrollVertically(dy)) { //This is the line i want to get rid of
            myView.scrollBy(0, dy);
        }
    }
    prevY = event.getY();

    return true;
}

此外，有没有使其行为completelly像任何滚动视图的方法吗？我的意思是，当你快速滑动并放开，它doesent STO inmediatly，它使速度一段时间，所以滚动长距离doesent采取青睐。

Also, is there any way of making it behave completelly like any Scrolling view? I mean when you swipe quickly and let go, it doesent sto inmediatly, it keeps the speed for a while, so scrolling long distances doesent take ages.

推荐答案

从大卫的回答，以及大量的试验和错误的开始，这里就是doesent允许滚动过去的顶部和底部的一个版本，并从onTouch作品（ ）我alredy有。

Starting from David's answer, and a lot of trial and error, here is a version that doesent allow scrolling past the top and bottom, and works from the onTouch() I alredy have.

float prevY;

@Override
public boolean onTouch(View v, MotionEvent event) {
    if (event.getAction() == MotionEvent.ACTION_MOVE) {
        int dy = (int) (prevY - event.getY());
        if (dy < 0) {
            int distanceToTop = myView.getScrollY();
            if (-distanceToTop < dy) {
                myView.scrollBy(0, dy);
            } else {
                myView.scrollTo(0, 0);
            }
        } else {
            int realHeight = (myView.getLineCount() + 1)
                    * myView.getLineHeight();
            int distanceToBottom = myView.getScrollY() - realHeight
                    + myView.getHeight();
            if (-distanceToBottom > dy) {
                myView.scrollBy(0, dy);
            } else {
                myView.scrollTo(0, realHeight - myView.getHeight());
            }
        }
    }
    prevY = event.getY();
    return true;
}

请注意，我允许滚动一行比最大进一步发展，从视图底线的底部一定的空间。

Note that i allow scrolling to one line further than the maximum to let some space from the bottom of the view to the bottom line.

但是，它不是一个正常的滚动视图呢，因为它doesent时进行刷卡不断滚动，但它是配不上我，如果没有对方的回答让我这样做。

It is however not what a normal scrolling view does, as it doesent keep scrolling when a swipe is performed, but it is good enough for me if no other answer allows me to do that.

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