我遇到了性能问题,我认为这是由于对我的观点进行衡量所致.
我的布局是通过编程方式构建的,因此无法显示我的布局的xml.但是,这里有一些可能导致此问题的观点:
>一个用于包装所有内容的ScrollVIEw(宽度:MATCH_PARENT,高度:MATCH_PARENT)
>包含所有不同内容部分的linearLayout(宽度:MATCH_PARENT,高度:MATCH_PARENT,前一个视图的子级)
>两个异步填充的LinearListViews(linearLayout)(宽度:MATCH_PARENT,高度:WRAP_CONTENT,上一个视图的子代)
当我填充linearListVIEw时,似乎只会出现此问题.添加视图似乎会触发VIEw.measure被多次调用:
为什么多次调用VIEw.measure? linearLayout的大小为MATH_PARENT,这意味着在添加子项时不必再次对其进行测量,对吗?
我不太确定如何防止这种情况的发生或如何调试问题.我尝试将linearListVIEw的可见性设置为GONE,直到添加了所有项目,但这并没有改变.
我希望我能提供足够的信息,以便有人指出正确的方向.
编辑#1(07/01):
这是用于linearListVIEws的适配器基类的某些部分:
public abstract class DataProvIDerAdapter<T> extends BaseAdapter{ ... @OverrIDe public VIEw getVIEw(int position, VIEw convertVIEw, VIEwGroup parent) { VIEw row = convertVIEw; T item = getItem(position); Log.d(TAG, "getVIEw(): position: " + position + ", ConvertVIEw: " + (convertVIEw == null ? "null" : convertVIEw) + ", TotalCount: " + getCount()); if (row == null) { row = buildrow(position); markRowAsLoading(row); } if (item == null) { if (convertVIEw != null) { markRowAsLoading(row); } int skip; if (itemsRequestParams != null) { int pageSize = itemsRequestParams.getTake(); // determine how many items to skip skip = position - (position % pageSize); } else { skip = 0; } // if the page isn't already being fetched if (!pagesReceiving.contains(skip)) { pagesReceiving.add(skip); AsyncTaskUtil.executeMultiThreaded(new ReceiveItemsTask(), skip); } } else { Log.d(TAG, getClass().getSimplename() + " - PrepareRow: " + getItemID(position) + ", Pos: " + position); prepareRow(row, item, position); } return row; } protected voID processDataResult(int skip, DataResult<T> result) { if (result instanceof GroupedDataResult<?>) { GroupedDataResult<T> groupedResult = (GroupedDataResult<T>)result; totalitemCount = groupedResult.getTotalGroupCount() + groupedResult.getTotalitemCount(); } else { totalitemCount = result.getTotalitemCount(); } for (int i = 0; i < result.getItems().size(); i++) { itemList.put(skip + i, result.getItems().get(i)); } Log.d(TAG, "processDataResult(" + skip + ")"); notifyDataSetChanged(); } static protected class CellHolder { public Progressbar Progressspinner; public List<androID.Widget.ImageVIEw> Images; public List<TextVIEw> Labels; private final HashMap<String, Object> _extras = new HashMap<String, Object>(); public voID putExtra(String key, Object value) { _extras.put(key, value); } @SuppressWarnings("unchecked") public <T> T getExtra(String key) { return _extras.containsKey(key) ? (T)_extras.get(key) : null; } } ... private class ReceiveItemsTask extends AsyncTask<Integer, VoID, DataResult<T>> { private int skip; @OverrIDe protected DataResult<T> doInBackground(Integer... params) { skip = params[0]; DataResult<T> items = getItems(skip); Log.d(TAG, "doInBackground(" + skip + ")"); return items; } @OverrIDe protected voID onPostExecute(DataResult<T> result) { Log.d(TAG, "onPostExecute(" + (result == null ? "null" : result.getItems().size() + "/" + result.getTotalitemCount()) + ")"); if (result == null) { return; } processDataResult(skip, result); Log.d(TAG, "onPostExecute end"); } }}
编辑#2(07/01):
我将relativeLayout子类化,并覆盖了onMeasure,以便我可以记录正在测量哪些视图以及以什么顺序进行记录.
结果如下:
07-01 15:37:37.434: V/DefaultLayout(8172): DefaultLayout.onMeasure07-01 15:37:37.434: V/DefaultLayout(8172): TabVIEw.onMeasure07-01 15:37:37.434: V/DefaultLayout(8172): ItemDetailsContainerVIEw.onMeasure07-01 15:37:37.438: V/DefaultLayout(8172): headerVIEw.onMeasure07-01 15:37:37.438: V/DefaultLayout(8172): ItemDetailsInfoFIEldsLayout.onMeasure07-01 15:37:37.438: V/DefaultLayout(8172): ItemRevIEwtableVIEw.onMeasure07-01 15:37:37.438: V/DefaultLayout(8172): InfoFIEldsLayout.onMeasure07-01 15:37:37.438: V/DefaultLayout(8172): InfoFIEldsLayout.onMeasure07-01 15:37:37.442: V/DefaultLayout(8172): InfoFIEldsLayout.onMeasure07-01 15:37:37.442: V/DefaultLayout(8172): InfoFIEldsLayout.onMeasure07-01 15:37:37.442: V/DefaultLayout(8172): InfoFIEldsLayout.onMeasure07-01 15:37:37.442: V/DefaultLayout(8172): InfoFIEldsLayout.onMeasure07-01 15:37:37.442: V/DefaultLayout(8172): InfoFIEldsLayout.onMeasure07-01 15:37:37.442: V/DefaultLayout(8172): InfoFIEldsLayout.onMeasure07-01 15:37:37.446: V/DefaultLayout(8172): ItemRevIEwtableVIEw.onMeasure07-01 15:37:37.446: V/DefaultLayout(8172): InfoFIEldsLayout.onMeasure07-01 15:37:37.446: V/DefaultLayout(8172): InfoFIEldsLayout.onMeasure07-01 15:37:37.446: V/DefaultLayout(8172): InfoFIEldsLayout.onMeasure07-01 15:37:37.446: V/DefaultLayout(8172): InfoFIEldsLayout.onMeasure07-01 15:37:37.450: V/DefaultLayout(8172): InfoFIEldsLayout.onMeasure07-01 15:37:37.450: V/DefaultLayout(8172): InfoFIEldsLayout.onMeasure07-01 15:37:37.450: V/DefaultLayout(8172): InfoFIEldsLayout.onMeasure07-01 15:37:37.450: V/DefaultLayout(8172): InfoFIEldsLayout.onMeasure07-01 15:37:37.450: V/DefaultLayout(8172): RelatedItemstableVIEw.onMeasure07-01 15:37:37.454: V/DefaultLayout(8172): ratingVIEw.onMeasure07-01 15:37:37.458: V/DefaultLayout(8172): ratingVIEw.onMeasure07-01 15:37:37.462: V/DefaultLayout(8172): ratingVIEw.onMeasure07-01 15:37:37.466: V/DefaultLayout(8172): ratingVIEw.onMeasure07-01 15:37:37.470: V/DefaultLayout(8172): ratingVIEw.onMeasure07-01 15:37:37.474: V/DefaultLayout(8172): ratingVIEw.onMeasure07-01 15:37:37.478: V/DefaultLayout(8172): ratingVIEw.onMeasure07-01 15:37:37.478: V/DefaultLayout(8172): ratingVIEw.onMeasure07-01 15:37:37.482: V/DefaultLayout(8172): ratingVIEw.onMeasure07-01 15:37:37.482: V/DefaultLayout(8172): ratingVIEw.onMeasure07-01 15:37:37.486: V/DefaultLayout(8172): ratingVIEw.onMeasure07-01 15:37:37.486: V/DefaultLayout(8172): ratingVIEw.onMeasure07-01 15:37:37.490: V/DefaultLayout(8172): ratingVIEw.onMeasure07-01 15:37:37.490: V/DefaultLayout(8172): ratingVIEw.onMeasure07-01 15:37:37.494: V/DefaultLayout(8172): ratingVIEw.onMeasure07-01 15:37:37.494: V/DefaultLayout(8172): ratingVIEw.onMeasure07-01 15:37:37.498: V/DefaultLayout(8172): RelatedItemstableVIEw.onMeasure07-01 15:37:37.498: V/DefaultLayout(8172): ratingVIEw.onMeasure07-01 15:37:37.498: V/DefaultLayout(8172): ratingVIEw.onMeasure07-01 15:37:37.502: V/DefaultLayout(8172): ratingVIEw.onMeasure07-01 15:37:37.502: V/DefaultLayout(8172): ratingVIEw.onMeasure07-01 15:37:37.506: V/DefaultLayout(8172): ratingVIEw.onMeasure07-01 15:37:37.506: V/DefaultLayout(8172): ratingVIEw.onMeasure07-01 15:37:37.510: V/DefaultLayout(8172): ratingVIEw.onMeasure07-01 15:37:37.510: V/DefaultLayout(8172): ratingVIEw.onMeasure07-01 15:37:37.514: V/DefaultLayout(8172): ratingVIEw.onMeasure07-01 15:37:37.514: V/DefaultLayout(8172): ratingVIEw.onMeasure07-01 15:37:37.518: V/DefaultLayout(8172): ratingVIEw.onMeasure07-01 15:37:37.518: V/DefaultLayout(8172): ratingVIEw.onMeasure07-01 15:37:37.522: V/DefaultLayout(8172): ratingVIEw.onMeasure07-01 15:37:37.522: V/DefaultLayout(8172): ratingVIEw.onMeasure07-01 15:37:37.526: V/DefaultLayout(8172): ratingVIEw.onMeasure07-01 15:37:37.526: V/DefaultLayout(8172): ratingVIEw.onMeasure...
此列表会持续一段时间.但是对我来说似乎很奇怪,它始于测量顶视图(DefaultLayout.onMeasure),然后还测量所有子视图(因此所有视图).它多次这样做!
是什么导致onMeasure在顶视图上被调用?
编辑#3(07/02):
可能是notifyDataSetChanged()触发了顶视图的测量?
编辑#4(07/03):
是的,似乎notifyDataSetChanged()触发了要测量的顶级视图(我能够在新的测试项目中重现此视图).并且由于我的适配器的工作方式,notifyDataSetChanged()被多次调用.
当我调用notifyDataSetChanged()时,测量所有视图的原因是什么?有什么方法可以防止这种情况发生吗?
解决方法:
您没有说相对布局的位置,这是列表的包装器吗?
根据罗曼·盖伊(Romain Guy)的说法,相对布局始终执行两次度量传递,因此这可能会导致某些速度降低.您是否甚至有嵌套的相对布局?显然,这可能具有指数的时间复杂度.
请参阅以下答案以供参考(以及指向他实际说过的Google io视频的链接):
https://stackoverflow.com/a/17496262/1281144
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