In develepoers guide it is advised to use the following layout for App Widgets.
<FrameLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:padding="#dimen/widget_margin">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal"
android:background="#drawable/my_widget_background">
</LinearLayout>
</FrameLayout>
Naturally Eclipse have the warning This LinearLayout layout or its FrameLayout parent is useless.
is it correct? Can I remove the LinearLayout?
It really depends on what the content of your widget is. Do you need a LinearLayout or a FrameLayout to position your content correctly? From you question one can't answer that question. But if it's a LinearLayout then the following is identical to the layout above:
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal"
android:layout_margin="#dimen/widget_margin"
android:background="#drawable/my_widget_background">
</LinearLayout>
Please note that I added the layout_margin attribute instead of using the padding because the background will be drawn regardless of what padding you define.
Related
Does anyone know how to have a floating Cardview like this?
http://chairnerd.seatgeek.com/images/autocomplete_checkout.gif
The background image should be able to change programmatically and the cardviews should be scrollable. And the position of the first Cardview should be somewhere below the image. Thanks in advance!
I figured it out myself and I will post my solution here in case anyone run into the same situation.
Here how the layout file should look like:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:focusableInTouchMode="true"
android:background="#color/bgGrey">
<ImageView
android:layout_width="match_parent"
android:layout_height="125dp"
app:srcCompat="#drawable/soccer"
android:id="#+id/imageView"
android:scaleType="centerCrop"/>
<ScrollView
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:layout_marginTop="120dp">
<android.support.v7.widget.CardView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_margin="6dp">
EDIT: Within the LinearLayout, something like a place holder should be added. Otherwise a part of the content at the end would not be shown. So I used a textview to do so.
<TextView
android:layout_width="match_parent"
android:layout_height="120dp" />
Note: The height here should match the marginTop in the LinearLayout
Yes it is a cardView directly on a ScrollView, or a ListView simply with the item's layout with background transparency.
The scrollview/listview is placed on a FrameLayout or RelativeLayout. Either there is a padding/margin on top, or a "stub" first element which is transparent".
Bellow (declared first in the parent layout) the scrollview/listview you can place an image or any other static component whatsoever.
And above you can place other floating components (like the Check-out button on your example)
Is there any way to put my FrameLayout between 1.1 and 1.3.
I tried to use layout_below and layout_above for it, but it doesn't work together.
1.RelativeLayout
1.1RelativeLayout (strict_size)
1.2FrameLayout (match_parent)
1.3RelativeLayout(strict_size)
I would use a LinearLayout. Assuming you are talking about heights:
<LinearLayout
android:orientation="vertical">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="20dp">
<FrameLayout
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="20dp">
</LinearLayout>
When using layout_weight like that, LinearLayout will first lay out views with fixed dimensions, and then assign all the remaining space to the layout_weight="1" view.
I have a RelativeLayout with a match_parent main LinearLayout view and a secondary wrap_content LinearLayout which is initially not visible (gone).
The secondary one has to be shown at the top of the screen but declaring it at the beginning of the xml file, it is not shown even when set to visible because it's behind the main one.
That's why it's declared after the main LinearLayout.
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<LinearLayout
android:id="#+id/main_layout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<!-- FULL SCREEN CONTENT -->
</LinearLayout>
<LinearLayout
android:id="#+id/secondary_layout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#color/f_white_transparent"
android:gravity="center"
android:visibility="gone">
<TextView
android:id="#+id/myText"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="10dp" />
</LinearLayout>
</RelativeLayout>
I would like to create a custom RelativeLayout to be used in all the xml files where I can obtain the same behavior and I can be able to put whatever content under the main layout.
Is there any way to do it still using xml?
You are using a RelativeLayout but do not use the benefits of it. You can declare the wrap_content-Layout in first place and add the parameter android:layout_alignParentBottom="true" to it.
In your match_parent-LinearLayout you can add the parameter android:layout_above="#+id/secondary_layout" to make sure it will give space to the secondary Layout. This way gone will work, too.
I want to use two child layout (one linear layout and one relative layout) inside a parent layout (relative layout) in such a way that both of the child layout will take exactly half of the screen and items inside of each child layout will not cause one child layout to get more width than another one!
It is pretty easy, use parameter layout_weight in children of LinearLayout, something like this:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="match_parent">
<RelativeLayout
android:layout_weight="1"
android:layout_width="0dp"
android:layout_height="match_parent">
</RelativeLayout>
<RelativeLayout
android:layout_weight="1"
android:layout_width="0dp"
android:layout_height="match_parent">
</RelativeLayout>
</LinearLayout>
If I understand correctly from your illustration, the red box is a RelativeLayout, whereas the green boxes are a LinearLayout and a RelativeLayout.
A simple solution would be to center an empty View inside the RelativeLayout and align the two child Views against it:
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent" >
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_toLeftOf="#+id/v_center" />
<View
android:id="#+id/v_center"
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_centerInParent="true" />
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_toRightOf="#+id/v_center" />
</RelativeLayout>
A nice little bonus here is that you can provide some spacing between the two by specifying the View's dimensions.
Beware, however, that RelativeLayouts aren't very efficient, and nesting them is an especially bad idea. I suggest using the hierarchy viewer tool to inspect the layout timings to make sure it's relatively fast, and to try to avoid nesting the layouts in this fashion.
Margins in group layouts do not seem to work.
For example,
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_margin="40dip"
android:layout_width="match_parent"
android:layout_height="match_parent">
<Button
android:id="#+id/button"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:text="I'm a button" />
</LinearLayout>
should display a button with 40p margins on all sides. However, it has 80p margins on the right and bottom.
Am I doing something wrong?
Is this a bug?
A workaround would be to use gravity, but this only works with even margins.
BTW, there is a similar question posted here but has not been answered.
android:padding="40dp" on the LinearLayout or android:layout_margin="40dp" on the Button will give you the effect you want. Padding defines the space between a views edges and its content, layout margin defines extra space on the sides of a view.
The problem is actually the way FrameLayout interprets margins. setContentView() attaches your "main" layout to a FrameLayout, which is the actual root of the view hierarchy (you can see that with Hierarchy Viewer) and is offered to you by the phone.
Margins are managed by the parent layout, so in this case that main FrameLayout. I don't know if it's a feature or a bug, but that's how this layout interprets margins.
So well, the solution was already posted while I was typing: use padding instead.
if you need set margin for a layout, simply wrap it with another linear or relative layout
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<LinearLayout android:layout_margin="40dip"
android:layout_width="match_parent"
android:layout_height="match_parent">
<Button android:id="#+id/button"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:text="I'm a button" />
</LinearLayout>
</LinearLayout>
Wrapping the Linear Layout with another layout is the best strategy.