如何测量宽度和高度，然后在添加视图之前更改参数？

Question

I'm trying to tell my title to respect that there's a date next to him, so I want to change his width to that of the background, minus the date. But sometimes getMeasuredWidth returns wrong values, or just 0. How do I go about doing this? This method is called for every item.

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);
}

It reads the date width absolutely correct. But that's probably because it's the same before that textview gets filled.

Answer 1

There is a much simpler solution than trying to manually calculate the width. In your xml document containing R.id.title and R.id.background , try structuring the views a little something like this:

<RelativeLayout // this is built to match the width of the background
 android:width="wrap_content"
 android:height="wrap_content"/>
     <TextView
      android:width="wrap_content"
      android:height="wrap_content"
      android:id="@+id/background"/>
     <RelativeLayout
      android:width="match_parent"
      android:height="wrap_content"/>
           <TextView
            android:width="wrap_content"
            android:height="wrap_content"
            android:id="@+id/date"
            android:layout_alignParentRight="true"/> // This aligns the date to the 
                                                     // right side of the view
           <TextView
            android:width="match_parent" // this fills the container which matches the width of background, currently
            android:height="wrap_content"
            android:id="@+id/title"
            android:layout_alignLeft="@id/date"/> // and this makes sure the view doesn't overlap the date.

The ordering in this actually does matter. You want to list the title after the date so you can reference the date view in the title view. Let me know if you have any more questions and good luck!

Answer 2

At the point that you're asking for the dimensions, your view hasn't been actually drawn yet. If your layout is static, it's best to do it in the XML, but if it's truly dynamic, then you'll want to use an OnGlobalLayoutListener to wait until the view has been first drawn and then resize it. Some code:

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();
    }
});