I want to measure the height of the ListView (getHight() = 0)

问题

I can not decide for himself the task will be to ask

I want to measure the height of the ListView. Can not catch the moment of rendering ListView (rssListView.getHight(); = 0 )

public class RSSactivity extends Activity {

    public static RssItem selectedRssItem = null;
    String feedUrl = "";
    ListView rssListView = null;
    ArrayList<RssItem> rssItems = new ArrayList<RssItem>();
    ArrayAdapter<RssItem> aa = null;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        rssListView = (ListView) findViewById(R.id.rssListView);
        aa = new ArrayAdapter<RssItem>(this, R.layout.list_item, rssItems);
        rssListView.setAdapter(aa); 
        feedUrl = rssURLTV.getText().toString();
        refressRssList();
        rssListView.getWidth(); // = 0 ,    
    }

    private void refressRssList() {

        ArrayList<RssItem> newItems = RssItem.getRssItems(feedUrl);
        rssItems.clear();
        rssItems.addAll(newItems);
        aa.notifyDataSetChanged();

    }

}

target to calculate the number of items intermeddle ListView screen

回答1:

In onCreate:

rssListView.getViewTreeObserver().addOnGlobalLayoutListener(
    new ViewTreeObserver.OnGlobalLayoutListener() {
      @Override
      public void onGlobalLayout() {
        // If you need this to be called again, then run again addOnGlobalLayoutListener.
        mainPanel.getViewTreeObserver().removeGlobalOnLayoutListener(this);
        rssListView.getWidth(); // It's available here.
      }
    });

回答2:

why you need Listview's Height()? if u want to check empty Listview then you can do using setEmptyListview().

回答3:

You can Measure the height of listview by using size method.

rssItems.size();

Hope it helps you.

回答4:

When onCreate method is called the screen is not loaded so every layout component has height = 0 and width = 0. If you want to know the height or width do it before the screen is loaded. The way I use is make a thread that starts running on onCreate. The thread asks for layout object height, while it is 0 I know that the screen components are not loaded yet. When the height is greater than 0 I commit to UI thread the task I want to do.

Edit: Try to do get the height inside onStart method, but I'm not sure about the screen is loaded yet.

Some Code example:

public void onCreate(Bundle savedBundle){
    super.onCreate(savedBundle);
    setContentView(R.layout.main);
    final ListView lv = (ListView) findViewById(R.id.my_list_view);
    Thread thr = new Thread(new Runnable(){
        public void run(){
            while(lv.getHieght() <= 0){
                try{
                    Thread.sleep(10);
                } catch(Exception e) {
                }
            }   //while ends
            final int height = lv.getHight();
            MyActivity.this.runOnUiThread(new Runnable(){
                public void run(){
                    myMethod(height);
                } //UI thread runnable-run method ends
            }); //UI Runnable declaration ends
        } //thread runnable-run method ends
    }); //Thread Runnable declaration ends
    thr.start();
} // onCreate ends.


public void myMethod(int height){
    //opeate with valid height
}

来源：https://stackoverflow.com/questions/11795862/i-want-to-measure-the-height-of-the-listview-gethight-0