安卓：错误，当我设置的ImageView的大小内编程的TableRow [英] Android : Error when i set size of imageView inside TableRow programmatically

问题描述

当我尝试设置我的ImageView客体的大小，我总是同样的错误：

的尝试写入到外地'廉政android.view.ViewGroup $ LayoutParams.width对空对象引用的

我的一块code的：

  TableLayout TL =（TableLayout）findViewById（R.id.layoutDuNiveau）;
    对于（INT J = 0; J＆LT; hauteurDuNiveau; J ++）{
        TR的TableRow =新的TableRow（本）;
        tr.setLayoutParams（新TableLayout.LayoutParams（TableLayout.LayoutParams.WRAP_CONTENT，TableLayout.LayoutParams.WRAP_CONTENT））;
        的for（int i = 0; I＆LT; largeurDuNiveau;我++）{
            imageViewDuNiveau [I] [J] =新ImageView的（本）;
            imageViewDuNiveau [I] [J] .setImageResource（R.drawable.blanc）;
            imageViewDuNiveau [I] [J] .requestLayout（）;
            。imageViewDuNiveau [I] [J] .getLayoutParams（）宽= 20; // ERROR HERE
            。imageViewDuNiveau [I] [J] .getLayoutParams（）高度= 20; // ERROR HERE
            开关（tableauDuNiveau [I] [J]）{
                案件 '＃'：
                    imageViewDuNiveau [I] [J] .setImageResource（R.drawable.mur）;
                默认：
            }
            tr.addView（imageViewDuNiveau [I] [J]）;
        }
        tl.addView（TR）;
    }
 

解决方案

由于在这里看到：

View.getLayoutParams（）：

  

如果这个观点是没有连接到父此方法可能返回null
  的ViewGroup或setLayoutParams（android.view.ViewGroup.LayoutParams）是
  没有成功调用。当查看连接到父
  ViewGroup中，该方法不能返回null

要完成之前访问宽度和高度 TR code>：

  tr.addView（imageViewDuNiveau [I] [J]）;
。imageViewDuNiveau [I] [J] .getLayoutParams（）宽= 20;
。imageViewDuNiveau [I] [J] .getLayoutParams（）高度= 20;
 

When i try to set size of my ImageView objet, i have always same error :

Attempt to write to field 'int android.view.ViewGroup$LayoutParams.width' on a null object reference

A piece of my code :

    TableLayout tl = (TableLayout)findViewById(R.id.layoutDuNiveau);
    for(int j=0;j<hauteurDuNiveau;j++){
        TableRow tr = new TableRow(this);
        tr.setLayoutParams(new TableLayout.LayoutParams(TableLayout.LayoutParams.WRAP_CONTENT, TableLayout.LayoutParams.WRAP_CONTENT));
        for(int i=0;i<largeurDuNiveau;i++){
            imageViewDuNiveau[i][j] = new ImageView(this);
            imageViewDuNiveau[i][j].setImageResource(R.drawable.blanc);
            imageViewDuNiveau[i][j].requestLayout();
            imageViewDuNiveau[i][j].getLayoutParams().width = 20; // ERROR HERE
            imageViewDuNiveau[i][j].getLayoutParams().height = 20; // ERROR HERE


            switch(tableauDuNiveau[i][j]){
                case '#':
                    imageViewDuNiveau[i][j].setImageResource(R.drawable.mur);
                default:
            }
            tr.addView(imageViewDuNiveau[i][j]);
        }
        tl.addView(tr);
    }

解决方案

As see here:

View.getLayoutParams () :

This method may return null if this View is not attached to a parent ViewGroup or setLayoutParams(android.view.ViewGroup.LayoutParams) was not invoked successfully. When a View is attached to a parent ViewGroup, this method must not return null

To fix issue call add ImageView to tr before accessing width and height :

tr.addView(imageViewDuNiveau[i][j]);
imageViewDuNiveau[i][j].getLayoutParams().width = 20; 
imageViewDuNiveau[i][j].getLayoutParams().height = 20;

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