如何检索视图的尺寸? [英] How to retrieve the dimensions of a view?

问题描述

我有一个由TableLayout, TableRow and TextView组成的视图.我希望它看起来像一个网格.我需要获取此网格的高度和宽度.方法getHeight()和getWidth()始终返回0.这在我动态格式化网格以及使用XML版本时会发生.

I have a view made up of TableLayout, TableRow and TextView. I want it to look like a grid. I need to get the height and width of this grid. The methods getHeight() and getWidth() always return 0. This happens when I format the grid dynamically and also when I use an XML version.

如何检索视图的尺寸?

How to retrieve the dimensions for a view?

这是我在Debug中用于检查结果的测试程序:

Here is my test program I used in Debug to check the results:

import android.app.Activity;
import android.os.Bundle;
import android.widget.TableLayout;
import android.widget.TextView;

public class appwig extends Activity {  
    @Override
    public void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.maindemo);  //<- includes the grid called "board"
      int vh = 0;   
      int vw = 0;

      //Test-1 used the xml layout (which is displayed on the screen):
      TableLayout tl = (TableLayout) findViewById(R.id.board);  
      tl = (TableLayout) findViewById(R.id.board);
      vh = tl.getHeight();     //<- getHeight returned 0, Why?  
      vw = tl.getWidth();     //<- getWidth returned 0, Why?   

      //Test-2 used a simple dynamically generated view:        
      TextView tv = new TextView(this);
      tv.setHeight(20);
      tv.setWidth(20);
      vh = tv.getHeight();    //<- getHeight returned 0, Why?       
      vw = tv.getWidth();    //<- getWidth returned 0, Why?

    } //eof method
} //eof class

推荐答案

我相信OP已经不复存在了，但是如果此答案能够为将来的搜索者提供帮助，我想我应该发布一个找到的解决方案.我已将此代码添加到我的onCreate()方法中:

I believe the OP is long gone, but in case this answer is able to help future searchers, I thought I'd post a solution that I have found. I have added this code into my onCreate() method:

已 11年7月5日，包括注释中的代码:

EDITED: 07/05/11 to include code from comments:

final TextView tv = (TextView)findViewById(R.id.image_test);
ViewTreeObserver vto = tv.getViewTreeObserver();
vto.addOnGlobalLayoutListener(new OnGlobalLayoutListener() {

    @Override
    public void onGlobalLayout() {
        LayerDrawable ld = (LayerDrawable)tv.getBackground();
        ld.setLayerInset(1, 0, tv.getHeight() / 2, 0, 0);
        ViewTreeObserver obs = tv.getViewTreeObserver();

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
            obs.removeOnGlobalLayoutListener(this);
        } else {
            obs.removeGlobalOnLayoutListener(this);
        }
    }

});

首先，我获得了对我的TextView的最终引用(要在onGlobalLayout()方法中进行访问).接下来，我从TextView中获取ViewTreeObserver，并添加一个OnGlobalLayoutListener，覆盖onGLobalLayout(似乎不是在这里调用的超类方法...)并添加需要了解查看此侦听器的视图的大小.一切都按我的预期进行，因此希望对您有所帮助.

First I get a final reference to my TextView (to access in the onGlobalLayout() method). Next, I get the ViewTreeObserver from my TextView, and add an OnGlobalLayoutListener, overriding onGLobalLayout (there does not seem to be a superclass method to invoke here...) and adding my code which requires knowing the measurements of the view into this listener. All works as expected for me, so I hope that this is able to help.

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