java - 如何测量宽度和高度，然后在添加 View 之前更改参数？

Question

我试图告诉我的标题尊重他旁边有一个日期，所以我想将他的宽度更改为背景的宽度，减去日期。但有时 getMeasuredWidth 会返回错误的值，或仅返回 0。我该怎么做呢？为每个项目调用此方法。

private void populateNewsItems(int pos, List<NewsItem> mFeedItems) {
    NewsItem newsItem = mFeedItems.get(pos);
    View newsContainer = getActivity().getLayoutInflater().inflate(R.layout.list_item_news, null);

    TextView background = (TextView) newsContainer.findViewById(R.id.background);
    TextView title = (TextView) newsContainer.findViewById(R.id.title);
    TextView colorBlock = (TextView) newsContainer.findViewById(R.id.colorBlock);
    TextView date = (TextView) newsContainer.findViewById(R.id.date);
    TextView description = (TextView) newsContainer.findViewById(R.id.description);

    title.setText(newsItem.getTitle());
    date.setText(newsItem.getDate());
    description.setText(newsItem.getDescription());

    title.measure(View.MeasureSpec.UNSPECIFIED, View.MeasureSpec.UNSPECIFIED);
    date.measure(View.MeasureSpec.UNSPECIFIED, View.MeasureSpec.UNSPECIFIED);
    background.measure(View.MeasureSpec.UNSPECIFIED, View.MeasureSpec.UNSPECIFIED);

    RelativeLayout.LayoutParams paramsTitle = (RelativeLayout.LayoutParams) title.getLayoutParams();
    paramsTitle.width = background.getMeasuredWidth() - date.getMeasuredWidth();
    title.setLayoutParams(paramsTitle);

    Log.e("LOG", String.format("background width:%d ; date width:%d", background.getMeasuredWidth(), date.getMeasuredWidth()));
    linearLayout.addView(newsContainer);
}

它读取的日期宽度绝对正确。但这可能是因为在填充 textview 之前它是相同的。

Answer 1

在您请求尺寸时，您的 View 还没有真正绘制出来。如果您的布局是静态的，最好在 XML 中进行，但如果它真的是动态的，那么您将需要使用 OnGlobalLayoutListener。等到 View 被第一次绘制然后调整它的大小。一些代码:

newsContainer.getViewTreeObserver().addOnGlobalLayoutListener(new OnGlobalLayoutListener() {
    @Override
    public void onGlobalLayout() {
        // title.measure(View.MeasureSpec.UNSPECIFIED, View.MeasureSpec.UNSPECIFIED);
        // date.measure(View.MeasureSpec.UNSPECIFIED, View.MeasureSpec.UNSPECIFIED);
        // background.measure(View.MeasureSpec.UNSPECIFIED, View.MeasureSpec.UNSPECIFIED);

        RelativeLayout.LayoutParams paramsTitle = (RelativeLayout.LayoutParams) title.getLayoutParams();
        // paramsTitle.width = background.getMeasuredWidth() - date.getMeasuredWidth();
        paramsTitle.width = background.getWidth() - date.getWidth();
        title.setLayoutParams(paramsTitle);
        title.requestLayout();
    }
});