的Android：動態生成的視圖添加，但沒有示出

Question

我有這種格式的UI組件：

<RelativeLayout 
     android:id="@+id/item_lists" 
     android:orientation="vertical" 
     android:layout_width="match_parent" 
     android:layout_height="match_parent" 
     android:weightSum="1" 
     android:paddingBottom="@dimen/activity_vertical_margin" 
     android:paddingLeft="@dimen/activity_horizontal_margin" 
     android:paddingRight="@dimen/activity_horizontal_margin" 
     android:paddingTop="@dimen/activity_vertical_margin"> 
     <TextView 
      android:id="@+id/first_list" 
      android:layout_width="match_parent" 
      android:layout_height="wrap_content" 
      android:visibility="visible" 
      android:text="First List"/> 

     <ListView 
      android:id="@+id/list_view" 
      android:layout_width="match_parent" 
      android:layout_height="wrap_content" 
      android:layout_below="@+id/first_list" 
      android:divider="@android:color/transparent" 
      android:dividerHeight="10dp" > 

     </ListView> 

    </RelativeLayout> 

外RelativeLayout的是我打算動態地生成的觀點和注入到包裝器，該邏輯動態地添加次（文本標題和另一個列表視圖）：

private void populateLists() { 
    View pre = firstList; // this points to the list view "list_view" 
    if(!titleMap.isEmpty()) { // titleMap is a hashmap that maps titles to lists 
     Set<String> titles = getTitles(); 

     for(String title : titles){ 
       List<Item> li = titleMap.get(title); 
       TextView tag = generateTitleTextView(title, pre); 
       ListView lv = generateListView(li, tag); 
       sceneLists.addView(tag); 
       sceneLists.addView(lv); 

       pre = lv; 
      } 
     } 

} 

generateTitleTextView(String title, View pre)和generateListView(List<Item> list, View pre)是生成的觀點和將View成分下所生成的視圖，通過使用

預兩種方法

layoutParams.addRule(RelativeLayout.BELOW, pre.getId()); 

代碼可以無例外地運行，但生成的視圖在頁面上不可見，我想知道可能是什麼問題？提前致謝！

編輯：爲generateTitleTextView代碼，generateListView類似於唯一的區別是它會產生一個ListView

private TextView generateTitleTextView(String title, View pre) { 
    TextView tag = new TextView(this); 
    tag.setId(generateRandomViewId());// generates a random int as Id 
    RelativeLayout.LayoutParams layoutParams = new RelativeLayout.LayoutParams(
      RelativeLayout.LayoutParams.MATCH_PARENT, 
      RelativeLayout.LayoutParams.MATCH_PARENT); 
    layoutParams.addRule(RelativeLayout.BELOW, pre.getId()); 
    tag.setLayoutParams(layoutParams); 

    tag.setText(title); 

    return tag; 
} 

Answer 1

你如何生成viewId？ 您可以在開發人員選項中使用HierarchyViewer或打開Show layout bounds進行調試。

我想你應該嘗試生成視圖ID與這段代碼：

public static int generateViewId() { 
    if (Build.VERSION.SDK_INT < Build.VERSION_CODES.JELLY_BEAN_MR1) { 
     for (; ;) { 
      final int result = sNextGeneratedId.get(); 
      // aapt-generated IDs have the high byte nonzero; clamp to the range under that. 
      int newValue = result + 1; 
      if (newValue > 0x00FFFFFF) { 
       newValue = 1; // Roll over to 1, not 0. 
      } 
      if (sNextGeneratedId.compareAndSet(result, newValue)) { 
       return result; 
      } 
     } 
    } else { 
     return View.generateViewId(); 
    } 
}