blocks|key|4496426|text|我为AppBarLayout写了一个小的扩展。它允许在有或没有动画的情况下展开和折叠CollapsibleToolbarLayout。它似乎做得很对。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|4496427|Feel+free+to+try+it+out.|4496428|只需使用它而不是AppBarLayout，您就可以调用负责展开或折叠CollapsingToolbarLayout的方法。|4496429|它在我的项目中完全按照预期工作，但您可能需要调整perform...方法(特别是在performExpandingWithAnimation()中)中的翻转/滚动值，以完全适应您的CollapsibleToolbarLayout。|4496430|entityMap|0|LINK|mutability|MUTABLE|url|https://gist.github.com/blipinsk/3f8fb37209de6d3eea99^0|2|C|16|O|0|0|O|0|0|8|C|Y|N|0|O|A|15|V|2I|O|0^^$0|@$1|2|3|4|5|6|7|T|8|@$9|U|A|V|B|C]|$9|W|A|X|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|Y|8|@]|D|@$9|Z|A|10|1|11]]|E|$]]|$1|H|3|I|5|6|7|12|8|@$9|13|A|14|B|C]|$9|15|A|16|B|C]]|D|@]|E|$]]|$1|J|3|K|5|6|7|17|8|@$9|18|A|19|B|C]|$9|1A|A|1B|B|C]|$9|1C|A|1D|B|C]]|D|@]|E|$]]|$1|L|3|-4|5|6|7|1E|8|@]|D|@]|E|$]]]|M|$N|$5|O|P|Q|E|$R|S]]]]

I've written a small extension to <code>AppBarLayout</code>. It allows for expanding and collapsing of the <code>CollapsibleToolbarLayout</code> both with and without animation. It seems to be doing it quite right. 

<a href="https://gist.github.com/blipinsk/3f8fb37209de6d3eea99">Feel free to try it out.</a> 

Just use it instead of your <code>AppBarLayout</code>, and you can call methods responsible for expanding or collapsing of the <code>CollapsingToolbarLayout</code>.

It's working exactly as expected in my project, but you might need to tweak the fling/scroll values in the <code>perform...</code> methods (especially in <code>performExpandingWithAnimation()</code>) to fit perfectly with your <code>CollapsibleToolbarLayout</code>.

blocks|key|4497313|text|使用支持库v23，您可以调用appBarLayout.setExpanded(true/false)。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|4497314|进一步阅读：AppBarLayout.setExpanded(boolean)|4497315|entityMap|0|LINK|mutability|MUTABLE|url|http://developer.android.com/reference/android/support/design/widget/AppBarLayout.html#setExpanded(boolean)^0|E|10|0|6|X|0|0^^$0|@$1|2|3|4|5|6|7|P|8|@$9|Q|A|R|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|S|8|@]|D|@$9|T|A|U|1|V]]|E|$]]|$1|H|3|-4|5|6|7|W|8|@]|D|@]|E|$]]]|I|$J|$5|K|L|M|E|$N|O]]]]

Using Support Library v23, you can call <code>appBarLayout.setExpanded(true/false)</code>.

Further reading: <a href="http://developer.android.com/reference/android/support/design/widget/AppBarLayout.html#setExpanded(boolean)">AppBarLayout.setExpanded(boolean)</a>

blocks|key|4497337|text|您可以使用自定义动画工具定义它的展开或收拢程度。只需使用setTopAndBottomOffset(int)即可。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|4497338|下面是一个示例：|4497339|CoordinatorLayout.LayoutParams+params+=+(CoordinatorLayout.LayoutParams)+appBar.getLayoutParams();
final+AppBarLayout.Behavior+behavior+=+(AppBarLayout.Behavior)+params.getBehavior();
if+(behavior+!=+null)+{
++++ValueAnimator+valueAnimator+=+ValueAnimator.ofInt();
++++valueAnimator.setInterpolator(new+DecelerateInterpolator());
++++valueAnimator.addUpdateListener(new+ValueAnimator.AnimatorUpdateListener()+{
++++++++@Override
++++++++public+void+onAnimationUpdate(ValueAnimator+animation)+{
++++++++++++behavior.setTopAndBottomOffset((Integer)+animation.getAnimatedValue());
++++++++++++appBar.requestLayout();
++++++++}
++++});
++++valueAnimator.setIntValues(0,+-900);
++++valueAnimator.setDuration(400);
++++valueAnimator.start();
}|code-block|syntax|javascript|4497340|entityMap^0|S|Q|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|R|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|S|8|@]|D|@]|E|$K|L]]|$1|M|3|-4|5|6|7|T|8|@]|D|@]|E|$]]]|N|$]]

You can define how much it expands or collapses with your custom animator.
Just use the <code>setTopAndBottomOffset(int)</code>.

Here is an example:

<pre><code>CoordinatorLayout.LayoutParams params = (CoordinatorLayout.LayoutParams) appBar.getLayoutParams();
final AppBarLayout.Behavior behavior = (AppBarLayout.Behavior) params.getBehavior();
if (behavior != null) {
 ValueAnimator valueAnimator = ValueAnimator.ofInt();
 valueAnimator.setInterpolator(new DecelerateInterpolator());
 valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
 @Override
 public void onAnimationUpdate(ValueAnimator animation) {
 behavior.setTopAndBottomOffset((Integer) animation.getAnimatedValue());
 appBar.requestLayout();
 }
 });
 valueAnimator.setIntValues(0, -900);
 valueAnimator.setDuration(400);
 valueAnimator.start();
}
</code></pre>

blocks|key|4496496|text|适用于像我这样想要使用onNestedPreScroll并遇到错误的人。我在onCreate中获得了NullPointerException，但没有这行|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4496497|++++CoordinatorLayout+coordinator+=(CoordinatorLayout)findViewById(R.id.tab_maincontent);
++++CoordinatorLayout.LayoutParams+params+=+(CoordinatorLayout.LayoutParams)+appBarLayout.getLayoutParams();
++++//below+line
++++params.setBehavior(new+AppBarLayout.Behavior()+{});|code-block|syntax|javascript|4496498|在这种情况下无法正常工作。但是我解决这个问题的方法是|4496499|在onCreate中：|4496500|++++++++scrollToolbarOnDelay();|4496501|还有..。|4496502|++++public+void+scrollToolbarOnDelay()+{
++++++++++++final+Handler+handler+=+new+Handler();
++++++++++++handler.postDelayed(new+Runnable()+{
++++++++++++++++@Override
++++++++++++++++public+void+run()+{
++++++++++++++++++++AppBarLayout+appBarLayout+=+(AppBarLayout)+findViewById(R.id.tab_appbar);
++++++++++++++++++++CoordinatorLayout+coordinator+=+(CoordinatorLayout)+findViewById(R.id.tab_maincontent);
++++++++++++++++++++CoordinatorLayout.LayoutParams+params+=+(CoordinatorLayout.LayoutParams)+appBarLayout.getLayoutParams();
++++++++++++++++++++AppBarLayout.Behavior+behavior+=+(AppBarLayout.Behavior)+params.getBehavior();
+++++++++if(behavior!=null)
++++++++++++++++++++behavior.onNestedPreScroll(coordinator,+appBarLayout,+null,+0,+100,+new+int[]{0,+0});
+++++++++else
++++++++++++scrollToolbarOnDelay()
++++++++++++++++}
++++++++++++},+100);


++++++++}|4496503|entityMap^0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|U|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|V|8|@]|9|@]|A|$]]|$1|K|3|L|5|D|7|W|8|@]|9|@]|A|$E|F]]|$1|M|3|N|5|6|7|X|8|@]|9|@]|A|$]]|$1|O|3|P|5|D|7|Y|8|@]|9|@]|A|$E|F]]|$1|Q|3|-4|5|6|7|Z|8|@]|9|@]|A|$]]]|R|$]]

for the ones who wants to work with onNestedPreScroll and get error like me.
i get NullPointerException in onCreate with out this line

<pre><code> CoordinatorLayout coordinator =(CoordinatorLayout)findViewById(R.id.tab_maincontent);
 CoordinatorLayout.LayoutParams params = (CoordinatorLayout.LayoutParams) appBarLayout.getLayoutParams();
 //below line
 params.setBehavior(new AppBarLayout.Behavior() {});
</code></pre>

and doesn't work properly with this.
but i work around this problem with 

in onCreate :

<pre><code> scrollToolbarOnDelay();
</code></pre>

and...

<pre><code> public void scrollToolbarOnDelay() {
 final Handler handler = new Handler();
 handler.postDelayed(new Runnable() {
 @Override
 public void run() {
 AppBarLayout appBarLayout = (AppBarLayout) findViewById(R.id.tab_appbar);
 CoordinatorLayout coordinator = (CoordinatorLayout) findViewById(R.id.tab_maincontent);
 CoordinatorLayout.LayoutParams params = (CoordinatorLayout.LayoutParams) appBarLayout.getLayoutParams();
 AppBarLayout.Behavior behavior = (AppBarLayout.Behavior) params.getBehavior();
 if(behavior!=null)
 behavior.onNestedPreScroll(coordinator, appBarLayout, null, 0, 100, new int[]{0, 0});
 else
 scrollToolbarOnDelay()
 }
 }, 100);


 }
</code></pre>

blocks|key|4497394|text|这可能有助于展开或折叠：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4497395|appBarLayout.setActivated(true);
appBarLayout.setExpanded(true,+true);|code-block|syntax|javascript|4497396|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|$]]

This may help to expand or collapse : 

<pre><code>appBarLayout.setActivated(true);
appBarLayout.setExpanded(true, true);
</code></pre>

blocks|key|4496534|text|我用的是这个|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4496535|+private+fun+collapseAppbar()+{
++++++++scrollView.postDelayed(Runnable+{
++++++++++++scrollView?.smoothScrollTo(50,+50)
++++++++},+400)
++++}|code-block|syntax|javascript|4496536|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 have using this

<pre><code> private fun collapseAppbar() {
 scrollView.postDelayed(Runnable {
 scrollView?.smoothScrollTo(50, 50)
 }, 400)
 }
</code></pre>

blocks|key|4497452|text|要以编程方式展开/折叠AppBarLayout：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4497453|fun+expandAppBarLayout(expand:+Boolean,+isAnimationEnabled:+Boolean){
++++appBarLayout.setExpanded(expand,+isAnimationEnabled);
}|code-block|syntax|javascript|4497454|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|$]]

To expand/collapse AppBarLayout programmatically:

<pre><code>fun expandAppBarLayout(expand: Boolean, isAnimationEnabled: Boolean){
 appBarLayout.setExpanded(expand, isAnimationEnabled);
}
</code></pre>

Simple question, but I can't find an answer. How can I collapse or expand the <code>CollapsingToolbarLayout</code> programmatically?

<img src="https://i.stack.imgur.com/rSzUr.png" alt="collapsed toolbar">

↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓

<img src="https://i.stack.imgur.com/AMDbK.png" alt="expanded toolbar">

Programmatically collapse or expand CollapsingToolbarLayout

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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很简单的问题，但我找不到答案。如何以编程方式折叠或展开CollapsingToolbarLayout？​​↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓​​

问以编程方式折叠或展开CollapsingToolbarLayout
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