錯誤的圖像出現在Android的按鈕背景

我在使用按鈕和圖像時遇到了一些困難。我有兩個按鈕，一個緊挨着另一個，但第二個出現錯誤的圖像。它用一些工具顯示圖像。錯誤的圖像出現在Android的按鈕背景

這裏是我的代碼：

TextView categoriaText = new TextView(this); 
RelativeLayout.LayoutParams params = new RelativeLayout.LayoutParams(LayoutParams.FILL_PARENT, 
      LayoutParams.WRAP_CONTENT); 
params.addRule(RelativeLayout.ALIGN_PARENT_LEFT); 
// use same id as defined when adding the button 
params.addRule(RelativeLayout.LEFT_OF, 1001); 
params.topMargin = top; 
params.leftMargin = 30; 
categoriaText.setLayoutParams(params); 
categoriaText.setText(_listaCategorias.get(i).getNome()); 
categoriaText.setTextSize(20); 


Button deleteBtn = new Button(this); 
RelativeLayout.LayoutParams params2 = new RelativeLayout.LayoutParams(60, 
      60); 
params2.addRule(RelativeLayout.ALIGN_PARENT_RIGHT); 
params2.rightMargin = 80; 
params2.topMargin = top; 
deleteBtn.setLayoutParams(params2); 

deleteBtn.setBackgroundResource(R.drawable.ic_coleccao); 
// give the button an id that we know 
deleteBtn.setId(1001); 


Button editBtn = new Button(this); 
RelativeLayout.LayoutParams params3 = new RelativeLayout.LayoutParams(60, 
      60); 
// params2.addRule(RelativeLayout.RIGHT_OF, 1001); 
params3.addRule(RelativeLayout.ALIGN_PARENT_RIGHT); 
params3.topMargin = top; 
editBtn.setLayoutParams(params3); 
editBtn.setBackgroundResource(R.drawable.ic_edit);

這裏是一個screenshoot： Screen Shot