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POHelp with Android UI ListView problems
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copied!<p>To understand this question, <a href="http://developer.android.com/reference/android/widget/AbsListView.html#onInterceptTouchEvent%28android.view.MotionEvent%29" rel="noreferrer">first read how this method works.</a></p> <p>I am trying to implements a drag and drop <a href="http://developer.android.com/reference/android/widget/ListView.html" rel="noreferrer">ListView</a>, it's going alright but have run into a road block. So I don't have to handled everything, I am intercepting(but returning false) <a href="http://developer.android.com/reference/android/view/MotionEvent.html" rel="noreferrer">MotionEvents</a> sent to the ListView, letting it handle scrolling and stuff. When I want to start dragging a item, I then return true and handled all the dragging stuff. Everything is working fine except for one thing. The drag(drag and drop) is started when it is determined that a long press as a occurred(in onInterceptTouchEvent). I get the <a href="http://developer.android.com/reference/android/graphics/Bitmap.html" rel="noreferrer">Bitmap</a> for the image that I drag around like so. itemPositition being the index of the item that was selected.</p> <p>(omitting irrelevant parts)</p> <pre><code>... View dragItem = mListView.getChildAt(itemPosition); dragItem.setDrawingCacheEnabled(true); Bitmap bitmap = Bitmap.createBitmap(dragItem.getDrawingCache()); mDragImage = new ImageView(mContext); mDragImage.setImageBitmap(bitmap); ... </code></pre> <p>The problem is, mDragImage is a solid black like this. <img src="https://i.stack.imgur.com/RbqY2.jpg" alt="A solid back bitmap"></p> <p>But, if I don't let ListView handle anything. As in, I start the drag on <a href="http://developer.android.com/reference/android/view/MotionEvent.html#ACTION_DOWN" rel="noreferrer">ACTION_DOWN</a> and stop on <a href="http://developer.android.com/reference/android/view/MotionEvent.html#ACTION_UP" rel="noreferrer">ACTION_UP</a>, mDragImage looks has expected(but I obviously lose scrolling abilities).</p> <p><img src="https://i.stack.imgur.com/820Cc.jpg" alt="A good bitmap"></p> <p>Since the drag is started with a long press, the ListView is given the opportunity to do things before the long press occurs. This is my guess as to why this is happening. When a item is pressed, it is highlighted by the ListView. Somewhere in doing so, it is messing with the bitmap. So when I go to get it, it's in a weird state(all black). </p> <p>I see two options for fixing this, neither of which I know how to do.</p> <ol> <li><p>Create a image from scratch.</p></li> <li><p>Handle the highlighting myself(if that is the problem).</p></li> </ol> <p>Option two seems a better one to me, except that I looked at the documentation and the source code and could not find out how to do so. Here are some things I have done/tried.</p> <ul> <li><p>I set <a href="http://developer.android.com/reference/android/widget/AdapterView.html#setOnItemClickListener%28android.widget.AdapterView.OnItemClickListener%29" rel="noreferrer">setOnItemClickListener(...)</a> and <a href="http://developer.android.com/reference/android/widget/AdapterView.html#setOnItemSelectedListener%28android.widget.AdapterView.OnItemSelectedListener%29" rel="noreferrer">setOnItemSelectedListener</a>(...) with a empty method(highlighting still happens). (Before anyone suggests it, calling <a href="http://developer.android.com/reference/android/widget/AdapterView.html#setOnClickListener%28android.view.View.OnClickListener%29" rel="noreferrer">setOnClickListener</a> results in a runtime error.)</p></li> <li><p>I also looked into trying to get the ListView to make a new item (for option 2), but could not find a way.</p></li> <li><p>Spent 45ish minutes looking through the source code and documentation trying to pinpoint where the highlighting was happening(I never found it).</p></li> </ul> <p>Any help fixing this would be appreciated.</p> <p>(EDIT1 START)</p> <p>So I don't actually know if onLongClickListener is working, I made an error before thinking it was. I am trying to set it up right now, will update when I find out if it does.</p> <p>(EDIT1 END)</p> <p>Last minute edit before post. I tried using <a href="http://developer.android.com/reference/android/widget/AdapterView.OnItemClickListener.html" rel="noreferrer">onLongClickListener</a> just now, and the image is good. I would still like to know if there is another way. How I have to use onLongClickListener to get things working is ugly, but it works. I also spent so much time trying to figure this out, it would be nice to find out the answer. I still want to be able to change/handle the highlight color, the default orangeish color is not pretty. Oh and sorry about the length of the post. I could not think of way of making it shorter, while supplying all the information I thought was needed.</p>

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