blocks|key|1217966|text|scroll.fullScroll(View.FOCUS_DOWN)也应该可以工作。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1217967|将此代码放入scroll.Post(Runnable+run)中|1217968|Kotlin代码|1217969|scrollView.post+{
+++scrollView.fullScroll(View.FOCUS_DOWN)
}|code-block|syntax|javascript|1217970|entityMap^0|0|Y|0|6|P|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@$9|R|A|S|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|T|8|@$9|U|A|V|B|C]]|D|@]|E|$]]|$1|H|3|I|5|6|7|W|8|@]|D|@]|E|$]]|$1|J|3|K|5|L|7|X|8|@]|D|@]|E|$M|N]]|$1|O|3|-4|5|6|7|Y|8|@]|D|@]|E|$]]]|P|$]]

<code>scroll.fullScroll(View.FOCUS_DOWN)</code> also should work.

Put this in a <code>scroll.Post(Runnable run)</code>

Kotlin Code 

<pre><code>scrollView.post {
 scrollView.fullScroll(View.FOCUS_DOWN)
}
</code></pre>

blocks|key|1218011|text|您应该在scroll.post中运行代码，如下所示：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1218012|scroll.post(new+Runnable()+{++++++++++++
++++@Override
++++public+void+run()+{
+++++++++++scroll.fullScroll(View.FOCUS_DOWN);++++++++++++++
++++}
});|code-block|syntax|javascript|1218013|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

you should run the code inside the scroll.post like this:

<pre><code>scroll.post(new Runnable() { 
 @Override
 public void run() {
 scroll.fullScroll(View.FOCUS_DOWN); 
 }
});
</code></pre>

blocks|key|1218073|text|当视图尚未加载时，您不能滚动。你可以像上面那样“稍后”通过post或sleep调用来做这件事，但这不是很优雅。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1218074|最好是计划滚动，并在下一个onLayout()上执行。示例代码如下：|1218075|https://stackoverflow.com/a/10209457/1310343|offset|length|1218076|entityMap|0|LINK|mutability|MUTABLE|url^0|0|0|0|18|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|P|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|Q|8|@]|9|@$F|R|G|S|1|T]]|A|$]]|$1|H|3|-4|5|6|7|U|8|@]|9|@]|A|$]]]|I|$J|$5|K|L|M|A|$N|E]]]]

When the view is not loaded yet, you cannot scroll. You can do it 'later' with a post or sleep call as above, but this is not very elegant. 

It is better to plan the scroll and do it on the next onLayout(). Example code here:

<a href="https://stackoverflow.com/a/10209457/1310343">https://stackoverflow.com/a/10209457/1310343</a>

blocks|key|1003850|text|需要考虑的一件事是不设置什么。确保您的子控件(尤其是EditText控件)未设置RequestFocus属性。这可能是布局上最后解释的属性之一，它将覆盖其父级(布局或ScrollView)上的重力设置。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1003851|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

One thing to consider is what NOT to set. Make certain your child controls, especially EditText controls, do not have the RequestFocus property set. This may be one of the last interpreted properties on the layout and it will override gravity settings on its parents (the layout or ScrollView).

blocks|key|1218137|text|对我来说最有效的方法是|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1218138|scroll_view.post(new+Runnable()+{
+++++@Override
+++++public+void+run()+{
+++++++++//+This+method+works+but+animates+the+scrolling+
+++++++++//+which+looks+weird+on+first+load
+++++++++//+scroll_view.fullScroll(View.FOCUS_DOWN);

+++++++++//+This+method+works+even+better+because+there+are+no+animations.
+++++++++scroll_view.scrollTo(0,+scroll_view.getBottom());
+++++}
});|code-block|syntax|javascript|1218139|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

What worked best for me is 

<pre><code>scroll_view.post(new Runnable() {
 @Override
 public void run() {
 // This method works but animates the scrolling 
 // which looks weird on first load
 // scroll_view.fullScroll(View.FOCUS_DOWN);

 // This method works even better because there are no animations.
 scroll_view.scrollTo(0, scroll_view.getBottom());
 }
});
</code></pre>

blocks|key|1218211|text|不完全是这个问题的答案，但我需要在EditText获得焦点后立即向下滚动。然而，公认的答案会使ET也立即失去焦点(我假设是ScrollView+)。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1218212|我的解决方法如下：|1218213|emailEt.setOnFocusChangeListener(new+View.OnFocusChangeListener()+{
++++@Override
++++public+void+onFocusChange(View+v,+boolean+hasFocus)+{
++++++++if(hasFocus){
++++++++++++Toast.makeText(getActivity(),+"got+the+focus",+Toast.LENGTH_LONG).show();
++++++++++++scrollView.postDelayed(new+Runnable()+{
++++++++++++++++@Override
++++++++++++++++public+void+run()+{
++++++++++++++++++++scrollView.fullScroll(ScrollView.FOCUS_DOWN);
++++++++++++++++}
++++++++++++},+200);
++++++++}else+{
++++++++++++Toast.makeText(getActivity(),+"lost+the+focus",+Toast.LENGTH_LONG).show();
++++++++}
++++}
});|code-block|syntax|javascript|1218214|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|L|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|M|8|@]|9|@]|A|$G|H]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

Not exactly the answer to the question, but I needed to scroll down as soon as an EditText got the focus. However the accepted answer would make the ET also lose focus right away (to the ScrollView I assume). 

My workaround was the following:

<pre><code>emailEt.setOnFocusChangeListener(new View.OnFocusChangeListener() {
 @Override
 public void onFocusChange(View v, boolean hasFocus) {
 if(hasFocus){
 Toast.makeText(getActivity(), "got the focus", Toast.LENGTH_LONG).show();
 scrollView.postDelayed(new Runnable() {
 @Override
 public void run() {
 scrollView.fullScroll(ScrollView.FOCUS_DOWN);
 }
 }, 200);
 }else {
 Toast.makeText(getActivity(), "lost the focus", Toast.LENGTH_LONG).show();
 }
 }
});
</code></pre>

blocks|key|1218249|text|有时scrollView.post无法工作|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1218250|+scrollView.post(new+Runnable()+{
++++++++@Override
++++++++public+void+run()+{
++++++++++++scrollView.fullScroll(ScrollView.FOCUS_DOWN);
++++++++}
++++});|code-block|syntax|javascript|1218251|但是如果你使用scrollView.postDelayed，它肯定可以工作|1218252|+scrollView.postDelayed(new+Runnable()+{
++++++++@Override
++++++++public+void+run()+{
++++++++++++scrollView.fullScroll(ScrollView.FOCUS_DOWN);
++++++++}
++++},1000);|1218253|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

Sometimes scrollView.post doesn't work

<pre><code> scrollView.post(new Runnable() {
 @Override
 public void run() {
 scrollView.fullScroll(ScrollView.FOCUS_DOWN);
 }
 });
</code></pre>

BUT if you use scrollView.postDelayed, it will definitely work

<pre><code> scrollView.postDelayed(new Runnable() {
 @Override
 public void run() {
 scrollView.fullScroll(ScrollView.FOCUS_DOWN);
 }
 },1000);
</code></pre>

blocks|key|1218362|text|在Kotlin协程中使用另一种很酷的方式来实现这一点。使用协程而不是带runnable+(post/postDelayed)的Handler的优点是，它不会启动昂贵的线程来执行延迟的操作。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1218363|launch(UI){
++++delay(300)
++++scrollView.fullScroll(View.FOCUS_DOWN)
}|code-block|syntax|javascript|1218364|将协程的HandlerContext指定为UI非常重要，否则可能无法从UI线程调用延迟的操作。|1218365|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

Using there is another cool way to do this with Kotlin coroutines. The advantage of using a coroutine opposed to a Handler with a runnable (post/postDelayed) is that it does not fire up an expensive thread to execute a delayed action.

<pre><code>launch(UI){
 delay(300)
 scrollView.fullScroll(View.FOCUS_DOWN)
}
</code></pre>

It is important to specify the coroutine's HandlerContext as UI otherwise the delayed action might not be called from the UI thread.

blocks|key|1218453|text|实际上，我发现调用fullScroll两次可以做到这一点：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1218454|myScrollView.fullScroll(View.FOCUS_DOWN);

myScrollView.post(new+Runnable()+{
++++@Override
++++public+void+run()+{
++++++++myScrollView.fullScroll(View.FOCUS_DOWN);
++++}
});|code-block|syntax|javascript|1218455|这可能与在执行第一次(不成功)滚动后立即激活post()方法有关。我认为这种行为发生在之前对myScrollView的任何方法调用之后，因此您可以尝试将第一个fullScroll()方法替换为与您相关的任何其他方法。|1218456|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

I actually found that calling fullScroll twice does the trick:

<pre><code>myScrollView.fullScroll(View.FOCUS_DOWN);

myScrollView.post(new Runnable() {
 @Override
 public void run() {
 myScrollView.fullScroll(View.FOCUS_DOWN);
 }
});
</code></pre>

It may have something to do with the activation of the post() method right after performing the first (unsuccessful) scroll. I think this behavior occurs after any previous method call on myScrollView, so you can try replacing the first fullScroll() method by anything else that may be relevant to you.

blocks|key|1218547|text|即使包装在.post()中，scroll.fullScroll(View.FOCUS_DOWN)也可能无法工作，一个可能的原因是视图没有布局。在这种情况下，View.doOnLayout()可能是更好的选择：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1218548|scroll.doOnLayout(){
++++scroll.fullScroll(View.FOCUS_DOWN)
}|code-block|syntax|javascript|1218549|或者，为勇敢的灵魂做更详细的介绍：https://chris.banes.dev/2019/12/03/suspending-views/|1218550|entityMap|0|LINK|mutability|MUTABLE|url|https://developer.android.com/reference/kotlin/androidx/core/view/package-summary#doonlayout|1|https://chris.banes.dev/2019/12/03/suspending-views/^0|5|7|E|Y|26|H|0|0|0|H|1G|1|0^^$0|@$1|2|3|4|5|6|7|W|8|@$9|X|A|Y|B|C]|$9|Z|A|10|B|C]]|D|@$9|11|A|12|1|13]]|E|$]]|$1|F|3|G|5|H|7|14|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|15|8|@]|D|@$9|16|A|17|1|18]]|E|$]]|$1|M|3|-4|5|6|7|19|8|@]|D|@]|E|$]]]|N|$O|$5|P|Q|R|E|$S|T]]|U|$5|P|Q|R|E|$S|V]]]]

One possible reason of why <code>scroll.fullScroll(View.FOCUS_DOWN)</code> might not work even wrapped in <code>.post()</code> is that the view is not laid out. In this case <a href="https://developer.android.com/reference/kotlin/androidx/core/view/package-summary#doonlayout" rel="nofollow noreferrer">View.doOnLayout()</a> could be a better option:
<pre><code>scroll.doOnLayout(){
 scroll.fullScroll(View.FOCUS_DOWN)
}
</code></pre>
Or, something more elaborated for the brave souls: <a href="https://chris.banes.dev/2019/12/03/suspending-views/" rel="nofollow noreferrer">https://chris.banes.dev/2019/12/03/suspending-views/</a>

blocks|key|1218601|text|我试过了，成功了。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1218602|scrollView.postDelayed(new+Runnable()+{
++++@Override
++++public+void+run()+{
++++++++scrollView.smoothScrollTo(0,+scrollView.getHeight());
++++}
},+1000);|code-block|syntax|javascript|1218603|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

i tried that successful.

<pre><code>scrollView.postDelayed(new Runnable() {
 @Override
 public void run() {
 scrollView.smoothScrollTo(0, scrollView.getHeight());
 }
}, 1000);
</code></pre>

blocks|key|1218646|text|如果您的最低SDK为23或更高，您可以使用以下代码：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1218647|View+childView+=+findViewById(R.id.your_view_id_in_the_scroll_view)
if(childView+!=+null){
++scrollview.post(()+->+scrollview.scrollToDescendant(childView));
}|code-block|syntax|javascript|1218648|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

If your minimum SDK is 23 or upper you could use this:
<pre><code>View childView = findViewById(R.id.your_view_id_in_the_scroll_view)
if(childView != null){
 scrollview.post(() -&gt; scrollview.scrollToDescendant(childView));
}
</code></pre>

blocks|key|1218678|text|所有答案的组合为我做了这个把戏：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1218679|扩展函数PostDelayed|1218680|private+fun+ScrollView.postDelayed(
++++time:+Long+=+325,+//+ms
++++block:+ScrollView.()+->+Unit
)+{
++++postDelayed({block()},+time)
}|code-block|syntax|javascript|1218681|扩展函数measureScrollHeight|1218682|fun+ScrollView.measureScrollHeight():+Int+{
++++val+lastChild+=+getChildAt(childCount+-+1)
++++val+bottom+=+lastChild.bottom+%2B+paddingBottom
++++val+delta+=+bottom+-+(scrollY%2B+height)
++++return+delta
}|1218683|扩展函数ScrolltoBottom|1218684|fun+ScrollView.scrollToBottom()+{
++++postDelayed+{
++++++++smoothScrollBy(0,+measureScrollHeight())
++++}
}|1218685|请注意，最小延迟应至少为325ms，否则滚动会出错(不会滚动到整个底部)。当前高度和底部之间的增量越大，延迟时间就越大。|1218686|entityMap^0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|V|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|W|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|X|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|Y|8|@]|9|@]|A|$G|H]]|$1|M|3|N|5|6|7|Z|8|@]|9|@]|A|$]]|$1|O|3|P|5|F|7|10|8|@]|9|@]|A|$G|H]]|$1|Q|3|R|5|6|7|11|8|@]|9|@]|A|$]]|$1|S|3|-4|5|6|7|12|8|@]|9|@]|A|$]]]|T|$]]

A combination of all answers did the trick for me:
<h2>Extension Function PostDelayed</h2>
<pre><code>private fun ScrollView.postDelayed(
 time: Long = 325, // ms
 block: ScrollView.() -&gt; Unit
) {
 postDelayed({block()}, time)
}
</code></pre>
<h2>Extension Function measureScrollHeight</h2>
<pre><code>fun ScrollView.measureScrollHeight(): Int {
 val lastChild = getChildAt(childCount - 1)
 val bottom = lastChild.bottom + paddingBottom
 val delta = bottom - (scrollY+ height)
 return delta
}
</code></pre>
<h2>Extension Function ScrolltoBottom</h2>
<pre><code>fun ScrollView.scrollToBottom() {
 postDelayed {
 smoothScrollBy(0, measureScrollHeight())
 }
}
</code></pre>
Be aware that the minimum delay should be at least 325ms or the scrolling will be buggy (not scrolling to the entire bottom). The larger your delta between the current height and the bottom is, the larger should be the delayed time.

blocks|key|1004338|text|这里的一些人说scrollView.post不起作用。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1004339|如果您不想使用scrollView.postDelayed，另一种选择是使用侦听器。下面是我在另一个用例中所做的：|1004340|ViewTreeObserver.OnPreDrawListener+viewVisibilityChanged+=+new+ViewTreeObserver.OnPreDrawListener()+{
++++@Override
++++public+boolean+onPreDraw()+{
++++++++if+(my_view.getVisibility()+==+View.VISIBLE)+{
++++++++++++scroll_view.smoothScrollTo(0,+scroll_view.getHeight());
++++++++}
++++++++return+true;
++++}
};|code-block|syntax|javascript|1004341|您可以通过以下方式将其添加到视图中：|1004342|my_view.getViewTreeObserver().addOnPreDrawListener(viewVisibilityChanged);|1004343|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|P|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|Q|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|R|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|S|8|@]|9|@]|A|$G|H]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

Some people here said that scrollView.post didn't work.
If you don't want to use scrollView.postDelayed, another option is to use a listener. Here is what I did in another use case :
<pre><code>ViewTreeObserver.OnPreDrawListener viewVisibilityChanged = new ViewTreeObserver.OnPreDrawListener() {
 @Override
 public boolean onPreDraw() {
 if (my_view.getVisibility() == View.VISIBLE) {
 scroll_view.smoothScrollTo(0, scroll_view.getHeight());
 }
 return true;
 }
};
</code></pre>
You can add it to your view this way :
<pre><code>my_view.getViewTreeObserver().addOnPreDrawListener(viewVisibilityChanged);
</code></pre>

I would like a ScrollView to start all the way at the bottom. Any methods?

Android: ScrollView force to bottom

我想让ScrollView从最底层开始。有什么方法吗？

问安卓: ScrollView强制到底部
EN

社区

活动

资源

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问安卓: ScrollView强制到底部EN

社区

活动

资源

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问安卓: ScrollView强制到底部
EN