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I am trying to place a button at the bottom of LinearLayout. But it's not showing

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context=".MainActivity">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Quantity" />
<TextView
android:id="#+id/quantity_text_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:text="0"
android:textColor="#color/black"
android:textSize="16sp" />
<Button
android:id="#+id/button_id"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text=" Order" />
</LinearLayout>
I am new in Android. And I am learning Android at Udacity. But the course is way old that some errors are happening. I am not able to handle the errors.

Change quantity_text_view's layout_height from match_parent to wrap_content:
<TextView
android:id="#+id/quantity_text_view"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="0"
android:textColor="#color/black"
android:textSize="16sp" />
Or, the TextView should occupy rest of the height after the first TextView.

Dynamically updating table layout in android app

I am building an app for android that dynamically updates a table layout with table rows. The way I do this, is by having a fixed table row layout that I populate with content and then insert it to the table layout and it displays like seen below.
The problem I'm having is that when I add a row that contains content that is longer in the middle part and creates multiple lines on one of the text views, it somehow shortens the width of the layout that contains the two text views of the other rows (middle part), specifically those that have single lines, for example the first and second row in the image below.
You can find the code below. If you need any more code or examples, please tell me.
row_main.xml - The fixed layout of the row.
<?xml version="1.0" encoding="utf-8"?>
<merge xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/tableRowMain1"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginTop="10dp"
android:layout_marginBottom="10dp" >
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="vertical"
android:layout_margin="2dp"
android:gravity="center"
android:layout_gravity="center" >
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:gravity="center"
android:layout_gravity="center" >
<TextView
android:id="#+id/textViewEmployeeName"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="15sp"
android:layout_margin="2dp"
android:gravity="center"
android:layout_gravity="center"/>
<TextView
android:id="#+id/textViewClientId"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="15sp"
android:layout_margin="2dp"
android:gravity="center"
android:layout_gravity="center"/>
<TextView
android:id="#+id/textViewTable"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="15sp"
android:layout_margin="2dp"
android:gravity="center"
android:layout_gravity="center"/>
</LinearLayout>
<TextView
android:id="#+id/textViewTimeStamp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="12sp"
android:layout_margin="1dp"
android:gravity="center"
android:layout_gravity="center"/>
</LinearLayout>
<LinearLayout
android:id="#+id/linearLayoutOrder"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:layout_margin="2dp"
android:gravity="center"
android:layout_gravity="center"
android:layout_weight="1" >
<TextView
android:id="#+id/textViewOrder"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textSize="15sp"
android:textStyle="bold"
android:singleLine="true"
android:ellipsize="marquee"
android:layout_weight="1"
android:gravity="center"
android:layout_gravity="center" />
<TextView
android:id="#+id/textViewOrderDetails"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textSize="12sp"
android:layout_weight="1"
android:layout_margin="0dp"
android:gravity="center"
android:layout_gravity="center" />
</LinearLayout>
<Button
android:id="#+id/buttonDelete"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:clickable="true"
android:text="#string/cross"
android:textSize="25sp"
android:gravity="center"
android:layout_gravity="center" />
</merge>
MainActivity.xml (snippet) - Where the table row is inserted.
<ScrollView
android:layout_width="fill_parent"
android:layout_height="0dp"
android:scrollbars="vertical"
android:layout_weight="1"
android:layout_margin="10dp"
android:overScrollMode="always" >
<TableLayout
android:id="#+id/tableLayoutMain"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_margin="5dp" >
</TableLayout>
</ScrollView>
I really can't figure out how to solve this or what may be causing it... Please help!
Thank you in advance! :)
Note: The pink/red rectangles is the "Show layout bonds" tool from the developer options in android.
EDIT: I replaced the TableLayout with a Vertical LinearLayout and it works just fine. I guess I was overcomplicating it... :P

Android Scrollview doesn't wrap child

Here's the Layout xml file:
<?xml version="1.0" encoding="utf-8"?>
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_height="wrap_content"
android:layout_width="match_parent"
android:scrollbars = "vertical">
<LinearLayout
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
tools:context="factory.Settings"
android:layout_height="fill_parent"
android:layout_width="fill_parent"
android:orientation="vertical">
<LinearLayout
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<TextView
android:id="#+id/lblShopID"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/ShopId"
android:textAppearance="?android:attr/textAppearanceMedium" />
<EditText
android:id="#+id/txtShopID"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:inputType="text"
android:layout_weight="1" />
</LinearLayout>
<LinearLayout
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<TextView
android:id="#+id/lblShopname"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_below="#+id/lblShopID"
android:layout_marginTop="36dp"
android:text="#string/ShopName"
android:textAppearance="?android:attr/textAppearanceMedium" />
<Spinner
android:id="#+id/spinShopName"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBottom="#+id/lblShopname"
android:layout_toRightOf="#+id/lblShopname" />
</LinearLayout>
<Button
android:id="#+id/btnSaveChanges"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentEnd="true"
android:layout_alignParentRight="true"
android:layout_below="#+id/spinShopName"
android:layout_marginTop="22dp"
android:onClick="saveData"
android:text="Save Changes" />
<TextView
android:id="#+id/txtChangePassword"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_centerVertical="true"
android:text="#string/ChangePassword"
android:textAppearance="?android:attr/textAppearanceMedium"
android:layout_marginTop="30px" />
<LinearLayout
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:layout_marginTop="30px">
<TextView
android:id="#+id/lblOldPassword"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/OldPassword"
android:textAppearance="?android:attr/textAppearanceMedium" />
<EditText
android:id="#+id/txtOldPassword"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:ems="10"
android:inputType="textPassword" />
</LinearLayout>
<LinearLayout
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<TextView
android:id="#+id/lblNewPassword"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/NewPassword"
android:textAppearance="?android:attr/textAppearanceMedium" />
<EditText
android:id="#+id/txtNewPassword"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:ems="10"
android:inputType="textPassword" />
</LinearLayout>
<LinearLayout
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<TextView
android:id="#+id/lblRetypePassword"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/RetypePassword"
android:textAppearance="?android:attr/textAppearanceMedium" />
<EditText
android:id="#+id/txtRetypePassword"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:ems="10"
android:inputType="textPassword" />
</LinearLayout>
<Button
android:id="#+id/btnChangePassword"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:onClick="changePassword"
android:text="Change Password" />
<ListView
android:id="#+id/lstUsers"
android:layout_width="340dp"
android:layout_height="wrap_content" />
</LinearLayout>
</ScrollView>
And Here's the expecting output:
The expected output is : I have some items in lstUsers and there wouldn't be enough space for displaying all the users, so I would like to add a scrollview to the Layout to let users scroll down.
But the problem is: the scrollview doesn't wrap any controls at all, the outcome is:
As you can see, the scrollview is unable to wrap the lstUser
Is there anything wrong with the layout file?

I don't think you are allowed to put a listview in a scrollview. Listview implements its own scroller so it doesn't like being in a scrollview. Take a look at this link
How can I put a ListView into a ScrollView without it collapsing?

Scrollview and Listview do not work well with each other.
What I would suggest u is to make 'lstUsers' Listview the main content of the layout file.
Create a separate layout file with the views that are above the listview.
Then inflate this layout file and add it as a header view to the listview.

Unable To Center Objects Within Two Relative Layouts

I'm attempting to split the UI for my horizontal layout into two halves each with it's own realative layout so I am able to center text and graphics within the two left and right halves of the screen. The problem is when I attmept to do so - the go button still ends up in the middle of the screen instead of centered on the right hand of the screen.
(If I can figure out how to center correctly I'm sure I'll be able to apply the same technique to the other elements to achieve the result I desire.
SOURCE:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginBottom="8sp"
android:layout_marginLeft="8sp"
android:layout_marginRight="8sp"
android:layout_marginTop="8sp"
android:background="#drawable/background"
android:orientation="vertical" >
<RelativeLayout
android:id="#+id/start"
android:layout_width="wrap_content"
android:layout_height="wrap_content" >
<ImageView
android:id="#+id/emblem"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
android:layout_marginTop="24dp"
android:gravity="center"
android:scaleType="fitStart"
android:src="#drawable/apn_app_logo" />
</RelativeLayout>
<RelativeLayout
android:id="#+id/start2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_centerVertical="true" >
<TextView
android:id="#+id/text"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_below="#+id/go_button"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
android:gravity="center"
android:text="#string/start_text2"
android:textColor="#000000"
android:textSize="18sp" />
<Button
android:id="#+id/go_button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
android:background="#drawable/apn_app_go_button" />
</RelativeLayout>
</RelativeLayout>
EDIT: (in response to Kuba's answer)
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal"
tools:context=".MainActivity" >
<LinearLayout
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:background="#drawable/background"
android:gravity="center"
android:orientation="horizontal" >
<ImageView
android:id="#+id/emblem"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:layout_marginTop="24dp"
android:gravity="center"
android:scaleType="fitStart"
android:src="#drawable/apn_app_logo" />
</LinearLayout>
<LinearLayout
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:background="#drawable/background"
android:gravity="center_horizontal"
android:orientation="horizontal" >
<Button
android:id="#+id/go_button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="#drawable/apn_app_go_button"
android:gravity="center_horizontal" />
<TextView
android:id="#+id/text"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:gravity="center_horizontal"
android:text="#string/start_text2"
android:textColor="#000000"
android:textSize="18sp" />
</LinearLayout>
</LinearLayout>

Instead of Relative layout, I would recommend using LinearLayout.
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal"
tools:context=".MainActivity" >
<LinearLayout
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:orientation="horizontal"
android:background="#00dd00"
android:gravity="center"
>
<Button
android:text="Button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
/>
</LinearLayout>
<LinearLayout
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:orientation="horizontal"
android:background="#dd0000"
android:gravity="center_horizontal"
>
<Button
android:text="Button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
/>
</LinearLayout>
</LinearLayout>
In the inner LinearLayout you can either use android:gravity="center" to have its children centered vertically and horizontally. Or use use android:gravity="center_horizontal" to center in only horizontal way.
EDIT: Added the textview, which was discussed in the comments.
To have the textView appear underneath the button, you must change the orientation of the LinearLayout from horizontal to vertical. Please see the developer site .
The inner LinearLayout thus looks like this.
<LinearLayout
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:orientation="vertical"
android:background="#dd0000"
android:gravity="center"
>
<Button
android:text="Button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="text here"
/>
</LinearLayout>
How can I use android:layout_below="#+id/go_button" in a linear layout?
You can't. These relationships only work in relative layout where you place views in relation to each other or the parent view. In linear layout items are stacked either vertically or horizontally.

Set android:gravity="center" in
<Button
android:id="#+id/go_button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
android:background="#drawable/apn_app_go_button" />
Maybe its work.

how to center two textViews with different font-size

<LinearLayout
android:id="#+id/layout_information"
android:layout_width="0dp"
android:layout_height="fill_parent"
android:layout_weight="0.17"
android:gravity="center"
android:orientation="horizontal" >
<TextView
android:id="#+id/text_view_destination"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="\# Home in"
android:textColor="#color/solid_white"
android:textSize="19sp"
android:textStyle="bold"
android:layout_gravity="bottom"
/>
<TextView
android:id="#+id/text_view_time"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="30dp"
android:textColor="#color/solid_white"
android:textSize="25sp"
android:textStyle="normal"
android:layout_gravity="bottom"
/>
</LinearLayout>
I want to center the two textViews vertically,
but I want them to be aligned to one line at their bottom.
Now they are alined to the same bottom,
but they are at the bottom of their parent layout.
How can I do this?
I have thought to wrap their current layout parent ("parent1") with another layout
("parent2")
and make "parent1" be in the center of "parent2".
Is there another way without adding elements?

If your problem is that both views are aligned at the bottom of their parent you can use this.
Both views are still aligned to the same bottom and centered on the screen.
Your layout looks like a part of a bigger XML (weight=0.17), that is why I have used fill_parent on layout_width.
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/layout_information"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_weight="0.17"
android:gravity="center"
android:orientation="horizontal" >
<TextView
android:id="#+id/text_view_destination"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:text="\# Home in"
android:textColor="#color/solid_white"
android:textSize="19sp"
android:textStyle="bold" />
<TextView
android:id="#+id/text_view_time"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="30dp"
android:text="\# Home in"
android:textColor="#color/solid_white"
android:textSize="25sp"
android:textStyle="normal"
android:layout_alignParentBottom="true"
android:layout_toRightOf="#id/text_view_destination"
android:layout_alignBaseline="#id/text_view_destination" />
</RelativeLayout>

try this way
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/layout_information"
android:layout_width="match_parent"
android:layout_height="fill_parent"
android:gravity="center_vertical|bottom"
android:orientation="horizontal" >
<TextView
android:id="#+id/text_view_destination"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:gravity="center"
android:text="HOme in"
android:textColor="#color/solid_white"
android:textSize="19sp"
android:textStyle="bold" />
<TextView
android:id="#+id/text_view_time"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:gravity="center"
android:textColor="#color/solid_white"
android:textSize="25sp"
android:text="Home out"
android:textStyle="normal" />
</LinearLayout>