ScrollView doesn't show top part

问题:

Problem : ScrollView hides top part of its child view when it grows beyond certain height.

I have following layout defined in XML

<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"     android:layout_width="fill_parent"     android:layout_height="fill_parent" >      <LinearLayout         android:id="@+id/commandPanel"         android:layout_width="fill_parent"         android:layout_height="wrap_content"         android:layout_alignParentBottom="true"         android:paddingLeft="5dip"         android:paddingRight="5dip" >          <Button             android:id="@+id/button1"             android:layout_width="fill_parent"             android:layout_height="wrap_content"             android:layout_weight="1"             android:text="OK" />          <Button             android:id="@+id/button2"             android:layout_width="fill_parent"             android:layout_height="wrap_content"             android:layout_weight="1"             android:text="Back" />     </LinearLayout>      <RelativeLayout         android:id="@+id/mainContentPanel"         android:layout_width="fill_parent"         android:layout_height="fill_parent"         android:layout_above="@id/commandPanel"         android:background="@android:color/white" >          <ScrollView             android:id="@+id/formScrollView"             android:layout_width="fill_parent"             android:layout_height="fill_parent"             android:layout_gravity="center"             android:layout_marginTop="5dip"             android:layout_weight="1"             android:background="@android:color/darker_gray"             android:fillViewport="false"             android:paddingBottom="5dip"             android:scrollbarStyle="insideOverlay" >              <LinearLayout                 android:id="@+id/formContentLayout"                 android:layout_width="fill_parent"                 android:layout_height="fill_parent"                 android:layout_gravity="center"                 android:layout_marginTop="20dip"                 android:background="@android:color/black"                 android:gravity="center_horizontal|top"                 android:orientation="vertical"                 android:paddingLeft="5dip"                 android:paddingRight="5dip"                 android:paddingTop="20dip" >                  <LinearLayout                     android:id="@+id/tr"                     android:layout_width="fill_parent"                     android:layout_height="wrap_content"                     android:layout_marginTop="10dip"                     android:orientation="horizontal" >                      <TextView                         android:id="@+id/title"                         android:layout_width="fill_parent"                         android:layout_height="wrap_content"                         android:layout_weight="1"                         android:text="sample title" />                      <TextView                         android:id="@+id/value"                         android:layout_width="fill_parent"                         android:layout_height="wrap_content"                         android:layout_weight="1"                         android:text="sample value ......." />                 </LinearLayout>             </LinearLayout>         </ScrollView>     </RelativeLayout>  </RelativeLayout> 

---------- code ------

public void onCreate(Bundle savedInstanceState) {     super.onCreate(savedInstanceState);      setContentView(R.layout.scrollview);     updateUi(); }  //add few more rows here void updateUi() {     LinearLayout sampletr = (LinearLayout) findViewById(R.id.tr);     LinearLayout contentPane = (LinearLayout) findViewById(R.id.formContentLayout);     TextView title = (TextView) findViewById(R.id.title);     TextView value = (TextView) findViewById(R.id.value);     for (int i = 0; i < 25; i++) {         LinearLayout tr = new LinearLayout(this);         TextView t = new TextView(this);         t.setText("Sample title : " + i);         TextView v = new TextView(this);         v.setText("Sample value : " + i);          tr.addView(t, title.getLayoutParams());         tr.addView(v, value.getLayoutParams());         contentPane.addView(tr, sampletr.getLayoutParams());     } } 

Here top rows in LinearLayout (ScrollView's immediate child) start disappearing from top if no. of rows grows more than 15! Moreover I can not even scroll up manually to view them, Any pointer please, what's wrong with this layout?

回答1:

ok, I've solved it by removing following line from LinearLayout (Immediate child of ScrollView)

android:layout_gravity="center" 

ScrollView works perfectly now. Thanks everyone for suggestions.

回答2:

I would remove the Second RelativeLayout node, but keep the ScrollView. Then for the ScrollView I would add layout_alignParentTop=true and layout_above="@+id/commandPanel". The second RelativeLayout seems redundant and typically when you add children to a RelativeLayout they should use the layout options of the container, ie, layout_above, below, align, etc.

回答3:

it does seem as though your padding-top is a problem, try removing it first.

回答4:

jus write xml with lil change

<LinearLayout     android:id="@+id/commandPanel"     android:layout_width="fill_parent"     android:layout_height="wrap_content"     android:layout_alignParentBottom="true"     android:paddingLeft="5dip"     android:paddingRight="5dip" >      <Button         android:id="@+id/button1"         android:layout_width="fill_parent"         android:layout_height="wrap_content"         android:layout_weight="1"         android:text="OK" />      <Button         android:id="@+id/button2"         android:layout_width="fill_parent"         android:layout_height="wrap_content"         android:layout_weight="1"         android:text="Back" /> </LinearLayout>  <RelativeLayout     android:id="@+id/mainContentPanel"     android:layout_width="fill_parent"     android:layout_height="fill_parent"     android:layout_above="@id/commandPanel"     android:background="@android:color/white" >      <ScrollView         android:id="@+id/formScrollView"         android:layout_width="fill_parent"         android:layout_height="fill_parent"         android:layout_gravity="center"          android:layout_marginTop="0dp"    <--- --- change n remove this margin          android:layout_weight="1"         android:background="@android:color/darker_gray"         android:fillViewport="false"         android:paddingBottom="5dip"         android:scrollbarStyle="insideOverlay" >          <LinearLayout             android:id="@+id/formContentLayout"             android:layout_width="fill_parent"             android:layout_height="fill_parent"             android:layout_gravity="center"             android:layout_marginTop="20dip"             android:background="@android:color/black"             android:gravity="center_horizontal|top"             android:orientation="vertical"             android:paddingLeft="5dip"             android:paddingRight="5dip"             android:paddingTop="20dip" >              <LinearLayout                 android:id="@+id/tr"                 android:layout_width="fill_parent"                 android:layout_height="wrap_content"                 android:layout_marginTop="10dip"                 android:orientation="horizontal" >                  <TextView                     android:id="@+id/title"                     android:layout_width="fill_parent"                     android:layout_height="wrap_content"                     android:layout_weight="1"                     android:text="sample title" />                  <TextView                     android:id="@+id/value"                     android:layout_width="fill_parent"                     android:layout_height="wrap_content"                     android:layout_weight="1"                     android:text="sample value ......." />             </LinearLayout>         </LinearLayout>     </ScrollView> </RelativeLayout> 

文章来源: ScrollView doesn't show top part