Develop Reference

Android - GridView doesn't get centered in the screen

I came across this problem while making a launch pad activity. I have a GridView layout that is populated with app icons. I want to center it on the screen but just can not no matter what I've tried. If the icons are not enough to cover the whole screen width the GridView is aligned to the left. I put a white background in the GridView Layout to show the problem.
I change programmaticaly the size of the ImageView and the widthof the GridView column to offer more functionality so I see that increaasing the image size enough makes it look centered. But I want it to be centered regardless of the icons number or size. Can someone help?
(I also tried using a linear layout instead of a reletive for the GridView. no difference)
GridView Layout
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="#ffffff" >
<GridView
android:id="#+id/gridView1"
android:numColumns="auto_fit"
android:gravity="center"
android:layout_gravity="center"
android:columnWidth="70dp"
android:stretchMode="columnWidth"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true" >
</GridView>
</RelativeLayout>
Single grid-item layout
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="vertical" >
<ImageView
android:id="#+id/grid_item_image"
android:layout_width="wrap_content"
android:layout_gravity="center"
android:gravity="center"
android:layout_height="wrap_content" >
</ImageView>
</LinearLayout>

For centering in the middle of another layout (RelativeLayout), use
android:layout_centerVertical="true"
android:layout_centerHorizontal="true"
e.g. for a GridView:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="wrap_content"
android:layout_height="wrap_content" >
<GridView
android:id="#+id/gridView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_centerHorizontal="true" >
</GridView>
</RelativeLayout>
In order to make your Items fill the whole screen at all times, use match_parent for your item-width and use weights.

Grid view overlapping other views android

I need to have a button, a grid view and a button, arranged vertically. I can see the Button and the GridView but can't see the button declared after the grid view. Why's that? This happens with any view below the grid view declaration.
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="vertical" >
<TextView
android:id="#+id/text_view"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_gravity="center_horizontal|center_vertical"
android:layout_marginTop="20dip"
android:text="Fragment1"
android:textAppearance="?android:attr/textAppearanceLarge"
android:textSize="30dip" />
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Button1"/>
<GridView
android:id="#+id/gridview"
android:layout_width="wrap_content"
android:layout_height="match_parent"overla
android:columnWidth="90dp"
android:numColumns="auto_fit"
android:verticalSpacing="10dp"
android:horizontalSpacing="10dp"
android:stretchMode="columnWidth"
android:gravity="center"/>
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Button1"/>
</LinearLayout>

As you have taken LinearLayout with vertical orientation, give wrap_content to the height of GridView.
Now, if you want last button at below to the screen, then include android:layout_weight="1" in GridView.

try this
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<Button
android:id="#+id/button1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Button1"/>
<Button
android:id="#+id/button2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:text="Button1"/>

as you have declared height of gridview as match_parent it should overlap the views declared below it if it can not find enough screen space available to show it.
You should try calling bringtoFront() method on the view declared below gridview.
Other thing from my viewpoint is to try relativeLayout if possible and use android:layout_above and android:layout_below with gridview.

Stretch image background of a linear layout which serves as cell in gridview

I have this cell item:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<TextView android:id="#+id/titleText"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_marginTop="50dp"
android:background="#AA000000"
android:gravity="center"
android:textColor="#FFFFFF"/>
</LinearLayout>
and this GridView:
<GridView android:id="#+id/gridView"
android:layout_width="fill_parent"
android:layout_height="0dp"
android:numColumns="auto_fit"
android:gravity="center"
android:columnWidth="100dp"
android:layout_weight="1"/>
I want to set linear layout's background image but, according to image size, I get different heigths for cells (I use different images) which is not very good looking...how can I stretch the background to a fixed heigth?
Unfortunately gridview seems not have a columnHeigth attribute...

Solved thanks to chet 's advice: I set heigth and width of linear layout.

Android some of the view elements not visible

I am creating a layout as below but the checkbox element is not visible on the scren where am i goign wrong ?
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="match_parent">
<SeekBar android:id="#+id/seek"
android:layout_width="300dip"
android:layout_height="wrap_content"
android:progress="50"/>
...and a few more elements here.
</LinearLayout>
<CheckBox android:id="#+id/CheckBox"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:text="somestring" />
</LinearLayout>

The LinearLayout before the CheckBox has its height set to MATCH_PARENT(and it fills all the parent's height) and the parent LinearLayout of both has the orientation set to vertical so the CheckBox is pushed out of the screen.
Set the height of the LinearLayout containing the SeekBar to WRAP_CONTENT for example.

You need to set your inner Linear Layout's height and width to wrap content.
Try this.
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal" >
<SeekBar
android:id="#+id/seek"
android:layout_width="300dip"
android:layout_height="wrap_content"
android:progress="50" />
</LinearLayout>
<CheckBox
android:id="#+id/CheckBox"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="somestring" />
</LinearLayout>

Try This :
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical"
android:weightSum="10" >
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_weight="9"
android:orientation="horizontal" >
<SeekBar
android:id="#+id/seek"
android:layout_width="300dip"
android:layout_height="wrap_content"
android:progress="50" />
</LinearLayout>
<CheckBox
android:id="#+id/CheckBox"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="somestring" />
</LinearLayout>

In your layout chose one element that you want to be flexible in size, say height wise. Then make its height="0dp" and weight="1". Make heights of rest of elements: height="wrap_content".
Also you may have given discreet size of some dp to your other elements, and hence their total height runs out of available screen space OR there are too many elements that they go beyond your screen height. In this case, wrap your layout in a ScrollView.

change your LinerLayout definition it cannot be android:layout_height="match_parent"
<LinearLayout android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="0px"
android:layout_weight="1">
if you set match_parent for linearlayout it consumes all content so wrap_content is better.
But if you set it as I wrote checkbox will be at bottom page a linearlayout will consumes remaing part of screen.

android:layout_height 50% of the screen size

I just implemented a ListView inside a LinearLayout, but I need to define the height of the LinearLayout (it has to be 50% of the screen height).
<LinearLayout
android:id="#+id/widget34"
android:layout_width="300px"
android:layout_height="235px"
android:orientation="vertical"
android:layout_below="#+id/tv_scanning_for"
android:layout_centerHorizontal="true">
<ListView
android:id="#+id/lv_events"
android:textSize="18sp"
android:cacheColorHint="#00000000"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_below="#+id/tv_scanning_for"
android:layout_centerHorizontal="true">
</ListView>
</LinearLayout>
Is that possible?
I did something similar for a button and an EditText, but doesn't seem to work on Layouts.
This is my Code:
//capture the size of the devices screen
Display display = getWindowManager().getDefaultDisplay();
double width = display.getWidth();
//my EditText will be smaller than full screen (80%)
double doubleSize = (width/5)*4;
int editTextSize = (int) doubleSize;
//define the EditText
userName = (EditText) this.findViewById(R.id.userName);
password = (EditText) this.findViewById(R.id.password);
//set the size
userName.setWidth(editTextSize);
password.setWidth(editTextSize);

Set its layout_height="0dp"*, add a blank View beneath it (or blank ImageView or just a FrameLayout) with a layout_height also equal to 0dp, and set both Views to have a layout_weight="1"
This will stretch each View equally as it fills the screen. Since both have the same weight, each will take 50% of the screen.
*See adamp's comment for why that works and other really helpful tidbits.

This is easy to do in xml. Set your top container to be a LinearLayout and set the orientation attribute as you wish. Then inside of that place two linearlayouts that both have "fill parent" on width and height. Finally, set the weigth attribute of those two linearlayouts to 1.

This is my android:layout_height=50%
activity:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<LinearLayout
android:id="#+id/alipay_login"
style="#style/loginType"
android:background="#27b" >
</LinearLayout>
<LinearLayout
android:id="#+id/taobao_login"
style="#style/loginType"
android:background="#ed6d00" >
</LinearLayout>
</LinearLayout>
style:
<style name="loginType">
<item name="android:layout_width">match_parent</item>
<item name="android:layout_height">match_parent</item>
<item name="android:layout_weight">0.5</item>
<item name="android:orientation">vertical</item>
</style>

best way is use
layout_height="0dp"
layout_weight="0.5"
for example
<WebView
android:id="#+id/wvHelp"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="0.5" />
<TextView
android:id="#+id/txtTEMP"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="0.5"
android:text="TextView" />
WebView,TextView have 50% of the screen height

To make sure the height of a view is 50% of the screen then we can create two sub LinearLayouts in a LinearLayout. Each of the child LinearLayout should have "android:layout_weight" of 0.5 to cover half the screen
the parent LinearLAyout should have "android:orientation" set to vertical
.
.
here is code for your reference....
this code contains two buttons of height half the screen
<LinearLayout
android:orientation="vertical"
android:layout_height="match_parent">
<LinearLayout
android:layout_weight="0.5"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<Button
android:padding="10dp"
android:layout_weight="0.5"
android:layout_width="wrap_content"
android:layout_height="fill_parent"
android:text="button1"
android:id="#+id/button1"
android:layout_alignParentTop="true"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_alignParentBottom="true"
/>
<Button
android:padding="10dp"
android:layout_weight="0.5"
android:layout_width="wrap_content"
android:layout_height="fill_parent"
android:text="button2"
android:id="#+id/button2"
android:layout_alignParentTop="true"
android:layout_alignParentRight="true"
android:layout_alignParentEnd="true"
android:layout_alignParentBottom="true"
/>
</LinearLayout>
<LinearLayout
android:layout_weight="0.5"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
</LinearLayout>
</LinearLayout>

This kind of worked for me.
Though FAB doesn't float independently, but now it isn't getting pushed down.
Observe the weights given inside the LinearLayout
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:id="#+id/andsanddkasd">
<android.support.v7.widget.RecyclerView
android:id="#+id/sharedResourcesRecyclerView"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="4"
/>
<android.support.design.widget.FloatingActionButton
android:id="#+id/fab"
android:layout_width="wrap_content"
android:layout_height="0dp"
android:layout_gravity="bottom|right"
android:src="#android:drawable/ic_input_add"
android:layout_weight="1"/>
</LinearLayout>
Hope this helps :)

You should do something like that:
<LinearLayout
android:id="#+id/widget34"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical"
android:layout_below="#+id/tv_scanning_for"
android:layout_centerHorizontal="true">
<ListView
android:id="#+id/lv_events"
android:textSize="18sp"
android:cacheColorHint="#00000000"
android:layout_height="1"
android:layout_width="fill_parent"
android:layout_weight="0dp"
android:layout_below="#+id/tv_scanning_for"
android:layout_centerHorizontal="true"
/>
</LinearLayout>
Also use dp instead px or read about it here.

it's so easy if you want divide your screen two part vertically ( top30% + bottom70%)
<LinearLayout
android:id="#+id/LinearLayoutTop"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_weight="2">
</LinearLayout>
<LinearLayout
android:id="#+id/LinearLayoutBottom"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_weight="1">
</LinearLayout>

To achieve this feat, define a outer linear layout with a weightSum={amount of weight to distribute}.
it defines the maximum weight sum. If unspecified, the sum is computed by adding the layout_weight of all of the children. This can be used for instance to give a single child 50% of the total available space by giving it a layout_weight of 0.5 and setting the weightSum to 1.0.Another example would be set weightSum=2, and if the two children set layout_weight=1 then each would get 50% of the available space.
WeightSum is dependent on the amount of children in the parent layout.

You can use android:weightSum="2" on the parent layout combined with android:layout_height="1" on the child layout.
<LinearLayout
android:layout_height="match_parent"
android:layout_width="wrap_content"
android:weightSum="2"
>
<ImageView
android:layout_height="1"
android:layout_width="wrap_content" />
</LinearLayout>