Develop Reference

create dynamic ImageViews during runtime on android

I got a bit of a problem with an app I'm building in Android. Previously we were showing 3 images in a LinearLayout, but now the amount of images has to vary. This means I have to make ImageViews during runtime, depending on how many I receive from the DB. This is how the ImageViews are defined right now:
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal" >
<ImageView
android:id="#+id/afbeelding1"
android:layout_width="250dp"
android:layout_height="200dp"
android:padding="1dp" />
<ImageView
android:id="#+id/afbeelding2"
android:layout_width="250dp"
android:layout_height="200dp"
android:layout_marginStart="30dp"
android:padding="1dp" />
<ImageView
android:id="#+id/afbeelding3"
android:layout_width="250dp"
android:layout_height="200dp"
android:layout_marginStart="30dp"
android:padding="1dp" />
</LinearLayout>
These ImageViews are filled at runtime, something I'll do with the new style as well. Does anybody know how I can achieve this? I'd also like to implement an OnClickListener on the ImageViews, so when you click on it, they get bigger.

Android, making a large background image scrollable

I am making an android app, and I want to set a large image as the background. However, I only want a small part of this image to display at the startup, and I want to be able to scroll to the rest of the image (by swiping)
This is what I have so far
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:background="#drawable/background"
>
<ImageButton
android:id="#+id/searchbutton"
android:contentDescription="#null"
android:scaleType="fitXY"
android:layout_height="50dp"
android:layout_width="55dp"
android:layout_gravity="left"
android:onClick="searchmethod"
android:src="#drawable/search" />
<ImageButton
android:id="#+id/filterbutton"
android:scaleType="fitXY"
android:contentDescription="#null"
android:state_pressed="true" android:drawable="#drawable/search"
android:layout_height="50dp"
android:layout_width="55dp"
android:layout_alignParentRight="true"
android:layout_alignTop="#+id/searchbutton"
android:onClick="choosefilter"
android:src="#drawable/filter" />
<ImageButton
android:id="#+id/Zoomoutbutton"
android:contentDescription="#null"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignRight="#+id/filterbutton"
android:layout_marginBottom="27dp"
android:src="#drawable/zoomout"
/>
<ImageButton
android:id="#+id/Zoominbutton"
android:contentDescription="#null"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignTop="#+id/Zoomoutbutton"
android:layout_toLeftOf="#+id/Zoomoutbutton"
android:src="#drawable/zoomin"
/>
</RelativeLayout>
This however just displays the entire image in the background, whereas I want a small part of it to display and then scroll across it. I apologize if this was asked already, but I couldn't find any answer that helped me.
EDIT: Ok, I can scroll the image now, but I want my buttons to stay in the corners of my screen at all times. Can anyone help? Currently when I scroll, I am scrolling away from my buttons.

Embed the RelativeLayout in a ScrollView. You don't specify vertical or horizontal, so you may need HorizontalScrollView (or both?)

You need to use a ScrollView object which will hold the image. The ScrollView dimensions can be set by you and the rest of the image will then become scrollable.

How can I evenly space my ImageViews in a RelativeLayout

I had a Android application built in which I had 3 ImageViews placed horizontally across a LinearLayout, they were placed with a android:layout_width="0dp" and android:layout_weight="1" such that they had an even spread in the layout.
Now I have to switch to use a RelativeLayout (because I want to overlap another image and that can't be done with a LinearLayout) so I want to start with replicating the same effect of having the 3 ImageViews evenly spread/scaled across the parent layout, but I'm not sure how to achieve this.
I feel like I need to make use of the android:scaleType... maybe center crop:
Scale the image uniformly (maintain the image's aspect ratio) so that both dimensions (width and height) of the image will be equal to or larger than the corresponding dimension of the view (minus padding).
Which sounds good but I can't seem to get it to work right... Any thoughts on how I would achieve this even spread of ImageViews across my RelativeLayout?
Snippet of code right now:
<RelativeLayout
android:layout_width="fill_parent"
android:layout_height="0dp"
android:layout_weight="1"
android:orientation="horizontal" >
<ImageView
android:id="#+id/dragcircle"
android:layout_width="wrap_content"
android:tag="circle"
android:layout_alignParentLeft="true"
android:layout_height="wrap_content"
android:adjustViewBounds="false"
android:scaleType="centerCrop"
android:src="#drawable/circle" />
<ImageView
android:id="#+id/dragsquare"
android:layout_width="wrap_content"
android:tag="square"
android:layout_height="wrap_content"
android:layout_toRightOf="#id/dragcircle"
android:adjustViewBounds="false"
android:src="#drawable/square" />
<ImageView
android:id="#+id/dragtriangle"
android:layout_width="wrap_content"
android:tag="triangle"
android:layout_height="wrap_content"
android:layout_toRightOf="#id/dragsquare"
android:adjustViewBounds="false"
android:src="#drawable/triangle" />
Note: I can't find a question with the same constraints as this one on SO. There are a number of questions like:
Android: how evenly space components within RelativeLayout?
and
android RelativeLayout, equal spacing?
But if you check out the details you'll see that they are people who have not considered the LinearLayout as an option for equal spacing and switching layout types ends up being the solution. I have, I was using it, but it does not work for me because I need to overlap an image:
Note the example, I have 3 ImageViews with basic shapes, but I also have a 4th ImageView (it starts hidden) which is overlapping the middle one. This is why I must use a RelativeLayout

I think you're going to want to go back to your original LinearLayout to meet all of your needs here.
If the size of your fourth image must match one of your existing image then either you'd want to create a resource that is a composite of the two images to swap to when it needs to be overlaid or replace your center ImageView with a RelativeLayout or FrameLayout that contains the ImageView. When you need to add the fourth image, add it to that layout.
Something like:
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="horizontal" >
<ImageView
android:id="#+id/dragcircle"
android:layout_width="0dp"
android:layout_weight="1"
android:tag="circle"
android:layout_height="wrap_content"
android:scaleType="centerCrop"
android:src="#drawable/circle" />
<FrameLayout
android:id="#+id/centerimagewrapper"
android:layout_height="wrap_content"
android:layout_width="0dp"
android:layout_weight="1" >
<ImageView
android:id="#+id/dragsquare"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:tag="square"
android:src="#drawable/square" />
<ImageView
android:id="#+id/arrow"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:src="#drawable/arrow"
android:visibility="invisible" />
</FrameLayout>
<ImageView
android:id="#+id/dragtriangle"
android:layout_width="0dp"
android:layout_weight="1"
android:tag="triangle"
android:layout_height="wrap_content"
android:src="#drawable/triangle" />

You could hide the icon you want to place on existing images and keep your previous LinearLayout to achieve this. Each component of your LinearLayout would be a custom layout (inflated):
<RelativeLayoutxmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/relativeLayout"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="#android:color/transparent"
>
<ImageView
android:id="#+id/img"
android:layout_width="100dip"
android:layout_height="100dip"
android:layout_centerInParent="true"
android:scaleType="fitXY"
android:background="#android:color/transparent"
android:src="img1_src"
/>
<ImageView
android:id="#+id/imgOverlap"
android:layout_width="50dip"
android:layout_height="50dip"
android:layout_centerInParent="true"
android:scaleType="fitXY"
android:adjustViewBounds="true"
android:background="#android:color/transparent"
android:src="img2_src"
android:visibility="gone"
/>
</RelativeLayout>
It appears not possible to use "layout_weight" in a RelativeLayout.
You could also consider a GridView and set its number of columns; each item of the GridView would be the inflated layout above.

you could also do it programatically and tell them to be 33% of the screen width. Look at DisplayMetrics and the attributes of each ImageView if you want to achieve this.

Try this
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="fill_parent"
android:layout_height="wrap_content" >
<ImageView
android:id="#+id/dragcircle"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:scaleType="fitXY"
android:src="#drawable/circle"
android:tag="circle" />
<ImageView
android:id="#+id/dragtriangle"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:src="#drawable/triangle"
android:scaleType="fitXY"
android:tag="triangle" />
<ImageView
android:id="#+id/dragsquare"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_toLeftOf="#+id/dragtriangle"
android:layout_toRightOf="#id/dragcircle"
android:src="#drawable/square"
android:scaleType="fitXY"
android:tag="square" />
</RelativeLayout>

How do you layer imageViews in an android application?

I'm trying to create my first real Android app, the code seems easy enough, but the layout is giving me problems.
My app will be a drag and drop application, very simple, just drag shapes to the correct place in the "puzzle". Here's an example of how it looks right now:
What I have currently is 4 ImageViews, one for the "empty puzzle" at the top, then 1 for each of the shapes below. I think the correct way to do this is to have each of the empty spots in the puzzle be an ImageView (what the arrow is pointing to, for example, should be an ImageView)
If I am correct on this, I need to "layer" ImageViews, put 3 "empty shape" image views over the "puzzle" image view at the top. The problem is I can't find any examples or suggestions for this anywhere online. So my questions are:
Does it make sense to have 3 ImageViews sitting on top of a "background" ImageView, or is there a more correct way to do this?
If I'm heading in the right direction, could someone explain/examplify how one builds ImageView layers?
XML for my current screen:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<ImageView
android:id="#+id/emptyPuz"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="#drawable/EmptyPuzzle" />
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="horizantal" >
<ImageView
android:id="#+id/imageView1"
android:layout_width="0dp"
android:layout_weight="1"
android:layout_height="wrap_content"
android:adjustViewBounds="false"
android:src="#drawable/Circle" />
<ImageView
android:id="#+id/imageView2"
android:layout_width="0dp"
android:layout_weight="1"
android:layout_height="wrap_content"
android:adjustViewBounds="false"
android:src="#drawable/Square" />
<ImageView
android:id="#+id/imageView3"
android:layout_width="0dp"
android:layout_weight="1"
android:layout_height="wrap_content"
android:adjustViewBounds="false"
android:src="#drawable/Triangle" />
</LinearLayout>
</LinearLayout>

The solution I ended up using was to add a new LinearLayout with the background set to a "puzzle base" image and added three new images with "empty puzzle" pieces on it. Ie: I broke up each of the 3 "empty" puzzle slots into individual images like in this example:
Then used them as backgrounds to a new layout, so where I had this code before:
<ImageView
android:id="#+id/emptyPuz"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="#drawable/EmptyPuzzle" />
I now have:
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="0dp"
android:layout_weight="1"
android:background="#drawable/emptypuzzle"
android:orientation="horizontal" >
<ImageView
android:id="#+id/dropsquare"
android:layout_width="0dp"
android:layout_weight="1"
android:tag="square"
android:layout_height="wrap_content"
android:adjustViewBounds="false"
android:src="#drawable/emptysquare" />
<ImageView
android:id="#+id/droptriangle"
android:layout_width="0dp"
android:layout_weight="1"
android:tag="triangle"
android:layout_height="wrap_content"
android:adjustViewBounds="false"
android:src="#drawable/emptytriangle" />
<ImageView
android:id="#+id/dropcircle"
android:layout_width="0dp"
android:layout_weight="1"
android:tag="circle"
android:layout_height="wrap_content"
android:adjustViewBounds="false"
android:src="#drawable/emptycircle" />
</LinearLayout>
Ending with a resultant drag and drop game looking like:
It's not pretty, but my toddler likes it. :)

creating arrow keys on center of screen

i am writing an application to control a robot
for controlling i need ( up, down , right, left ) keys
i used eclipse designer to create it but maybe it is not possible
i want to create something like this :
how can i create buttons like this in center of screen ?
is there a better way to create arrow keys on android ?

Here you go :
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent" >
<View
android:id="#+id/view1"
android:layout_width="30dp"
android:layout_height="30dp"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true" />
<ImageView
android:id="#+id/imageView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#+id/view1"
android:layout_centerHorizontal="true"
android:src="#drawable/ic_launcher" />
<ImageView
android:id="#+id/imageView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="#+id/view1"
android:layout_centerHorizontal="true"
android:src="#drawable/ic_launcher" />
<ImageView
android:id="#+id/imageView3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_toRightOf="#+id/view1"
android:src="#drawable/ic_launcher" />
<ImageView
android:id="#+id/imageView4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_toLeftOf="#+id/view1"
android:src="#drawable/ic_launcher" />
</RelativeLayout>
Of course, you can replace ImageView with anything else like an ImageButton.
Be sure, if you change the name of the first view, tu update the name in the 4 ImageView.
And be aware that the corners of each image are overlapping each other.

I suggest using ImageButtons and setting the background for each to a State List Drawable xml file. This will change the image between states(focused, pressed, etc).
The tricky part would be positioning each so that they orient themselves in this sort of "box" you have above.
Just create some PNGs of each button in their positions. Up button points up, left points left etc. Then use RelativeLayout to position them with respect to each other. You can also use Buttons as well