title: My RecyclerView has many rows but shows only one row?
body: <p>its  recyclerview inside recyclerview inside recyclerview 
  it seems to be OK even the row is added but it doesn't show any thing.
  many questions like this asked already and answered  but none solved mine</p>
  
  <pre><code>&lt;android.support.v7.widget.CardView 
       xmlns:android="http://schemas.android.com/apk/res/android"
          xmlns:card_view="http://schemas.android.com/apk/res-auto"
          android:id="@+id/fn_file_field_card_view"
          android:layout_width="match_parent"
          android:layout_height="wrap_content"
        card_view:cardElevation="0dp"&gt;
  
       &lt;LinearLayout
          android:layout_width="match_parent"
          android:layout_height="match_parent"
          android:layout_marginLeft="@dimen/fn_field_margin_right_and_left"
          android:layout_marginTop="@dimen/fn_field_margin_top_or_bottom"
          android:layout_marginRight="@dimen/fn_field_margin_right_and_left"
          android:orientation="vertical"&gt;
  
          &lt;ir.tenthwindow.lbs.views.PersianTextView
              android:id="@+id/fn_file_field_title"
              android:layout_width="match_parent"
              android:layout_height="wrap_content"
              android:padding="10dp"
              android:text="btn"
              android:textColor="@color/black"
              android:textSize="@dimen/fn_field_text_size"
              android:textStyle="bold" /&gt;
  
           &lt;ir.tenthwindow.lbs.views.PersianTextView
               android:id="@+id/fn_file_field_btn"
               android:layout_width="match_parent"
               android:layout_height="wrap_content"
               android:background="@drawable/button_green"
               android:gravity="center"
               android:maxLines="1"
               android:padding="10dp"
               android:text="@string/upload_file"
               android:textColor="@color/white"
               android:textSize="@dimen/fn_field_text_size" /&gt;
             &lt;android.support.v7.widget.RecyclerView
              android:id="@+id/fn_field_images_RecyclerView"
              android:layout_width="match_parent"
              android:layout_height="wrap_content"&gt;
  
  
          &lt;/android.support.v7.widget.RecyclerView&gt;
  
           &lt;View
              android:layout_width="match_parent"
              android:layout_height="1dp"
              android:layout_marginTop="@dimen/fn_field_line_margin_top"
              android:background="@color/fn_grey_line_border"&gt;
           &lt;/View&gt;
       &lt;/LinearLayout&gt;
    &lt;/android.support.v7.widget.CardView&gt;
  </code></pre>
  
  <p>Thx in advance for helping me</p>