Develop Reference

xml layout visibly different to code generated layout

Items will be displayed in a GridView:
<GridView
android:id="#+id/month_list"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:paddingLeft="#dimen/activity_half_horizontal_margin"
android:paddingRight="#dimen/activity_half_horizontal_margin"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:stretchMode="columnWidth"
android:horizontalSpacing="4dp"
android:verticalSpacing="4dp"/>
The layout for the items used to be generated in code:
private LinearLayout getMonthImageView() {
LinearLayout layout = new LinearLayout(context);
layout.setOrientation(LinearLayout.VERTICAL);
TextView text = new TextView(context);
text.setGravity(Gravity.CENTER);
text.setSingleLine();
layout.addView(text, 0);
ImageView image = new ImageView(context);
image.setScaleType(ImageView.ScaleType.CENTER_INSIDE);
image.setAdjustViewBounds(true);
layout.addView(image, 1);
return layout;
}
I've refactored that part to come from an xml layout file instead:
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="#+id/month_name"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:singleLine="true"/>
<ImageView
android:id="#+id/month_icon"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:scaleType="centerInside"
android:adjustViewBounds="true"/>
</LinearLayout>
This had an unwanted visible effect: the gap between the items in the GridView has grown larger, as if the items had acquired some padding or margin (which is clearly not the case). Why is that? What is the difference of the items being generated in code versus coming from an xml layout file? How can I make the items scale up again?
Before (code layout):
After (xml layout):

I see some potential issues, but it's hard for me to say exactly what, without an image description of your problem.
You might wanna check out these few things:
If you're inflating LinearLayout, you should probably avoid android:layout_height="match_parent", because it takes up maximum space (usually the whole screen) even though you might not need it.
I'm thinking ImageView probably shouldn't be equal to parent, but have a distinct size.
This way also, it takes up maximum space in its parent, which it might not need.
My advice is, try a RelativeLayout, with the android:layout_width="match_parent" and android:layout_height="wrap_content.
Then use different layout_align options to align everything on top, and give some specific dimensions to your ImageView.
That's just my guess, I might be wrong though.

Android: placing an ImageView on an exact location on the screen

I would like to use getLocationOnScreen to get the location of an ImageView, and then I would like to place another ImageView exactly at that place.
Assume they both are in the same layout. When the app starts only imgv1 is visible. The user can move and rotate that image. Then the user can press a button and second image, imgv2 should be placed exactly on top of imgv1 so it covers it. Both imgv1 and imgv2 have the same size.
For example, assume I have imgv1 and imgv2 as:
ImageView imgv1, imgv2;
int[] img_coordinates = new int[2];
imgv1.getLocationOnScreen(img_coordinates);
I wanted to use something like:
imgv2.setX(img_coordinates[0]);
imgv2.setY(img_coordinates[2]);
but this doesn't do what I need to do, which is to place the top left corner of imgv2 on the top left corner of imgv1.
Any other method that helps me to do so is fine too.
** Update **
This is the layout I have:
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/tools_root"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#android:color/transparent">
<ImageView
android:id="#+id/imgv1"
android:layout_width="300dp"
android:layout_height="200dp"
android:layout_gravity="center_vertical|center_horizontal"
android:visibility="gone"
app:cameraCropOutput="true"
app:cameraPlaySounds="false" />
<ImageView
android:id="#+id/imgv2"
android:layout_width="300dp"
android:layout_height="200dp"
android:adjustViewBounds="true"
android:scaleType="fitXY"
android:visibility="gone" />
</FrameLayout>

The javadoc for view says that setX and setY will offsett the image from it's original location. It looks like what you want to use is setLeft and setTop.
https://developer.android.com/reference/android/view/View#setleft

If i have overlapping views I generally put them in layout and show/hide them. However if you want to dit via code try setting layout params of second image like:
lp.addRule(RelativeLayout.ALIGN_LEFT, image1.getId());
lp.addRule(RelativeLayout.ALIGN_TOP, image1.getId());
...something like it.
Positioning depends a lot on parent of Image views. Relative Layout would be correct choice.

Step #1: Put imgv1 in a FrameLayout
Step #2: Put imgv2 in that same FrameLayout, with android:visibility="gone"
Step #3: When the user presses the button, call imgv2.setVisibility(View.VISIBLE)
<FrameLayout android:id="combined">
<ImageView android:id="imgv1" android:layout_width="match_parent" android:layout_height="match_parent" />
<ImageView android:id="imgv2" android:visibility="gone" android:layout_width="match_parent" android:layout_height="match_parent" />
</FrameLayout>
Missing are sizing/positioning rules for the FrameLayout, which would be whatever you are presently using for your starting conditions for imgv1, presumably.
Alternatively, have one ImageView, rather than two, and change the image on the button click. For example, you could use a LayerDrawable (or the equivalent resource) to layer two drawables on top of each other, and show that.

FrameLayout borders in Android app

What I have to implement in order to limit the max size of a FrameLayout or the View inside it?
I am using a FrameLayout for my Android app:
<?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" >
<FrameLayout
android:id="#+id/dog_holder"
android:layout_width="match_parent"
android:layout_height="match_parent">
</FrameLayout>
</LinearLayout>
I have added a View to it:
FrameLayout frame = (FrameLayout) findViewById(R.id.dog_holder);
dog = new DogView(this);
frame.addView(dog);
(DogView extends View)
I am initializing the View with a bitmap:
my_dog = BitmapFactory.decodeResource(getResources(), R.drawable.dog);
I want to move around the picture (I have implemented the touch controls) but not to be able to move outside it. Good example is a picture gallery app: while a picture is zoomed you can go around it but on the borders there is bouncy effect which doesn't allow to go into the dark side.
What I have to implement to stop me when I try to go outside the dimension of the bitmap?

Centering a custom view in a RelativeLayout using LayoutParams

I'm trying to center a custom view in relative layout. This image rotates so it needs to be in the center of the layout so it doesn't go out of the layout bounds. Right now its displaying in the top left corner. Here is my code:
container = (RelativeLayout) findViewById(R.id.lay_container);
bmap = BitmapFactory.decodeResource(this.getResources(), R.drawable.charlie_sheen);
rotate_view = new RotationView(this, bmap);
RelativeLayout.LayoutParams params = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.WRAP_CONTENT, RelativeLayout.LayoutParams.WRAP_CONTENT);
params.addRule(RelativeLayout.CENTER_IN_PARENT);
rotate_view.setLayoutParams(params);
container.addView(rotate_view);
Here is my relative xml layout
<RelativeLayout
android:id="#+id/lay_container"
android:layout_width="200dip"
android:layout_height="200dip"
android:layout_alignParentRight="true"
android:layout_below="#+id/txt_1"
android:layout_marginRight="45dp"
android:layout_marginTop="56dp"
android:padding="10dip" />
Do you have any ideas? I know that there is probably a simple solution to this problmem, but I can't seem to find the answer. Setting the LayoutParameter to center should center the view in the layour right?
Thanks in advance for any help or suggestions

Overall the code to add the custom view looks correct. This may be a weak suggestion, but to rule out any issues that may have been cause by the view customization you could try modifying the code in one of two ways.
Option 1: Use the explicit form of addRule(), i.e.
params.addRule(RelativeLayout.CENTER_IN_PARENT, RelativeLayout.TRUE);
Option 2: Use the explicit form of addView() and don't set the params on the view itself, i.e.
//Omit the line above this one
container.addView(rotate_view, params);
Beyond that, perhaps some insight into the custom view, specifically how it measures itself (it's not trying to fill parent is it)?
HTH

Ok Devunwired I will do that.
Here is how I am centering the image now.
1) I am centering the image in my canvas using a BitmapDrawable setGravity(Gravity.CENTER) property.
2) I'm centering the RotationView in my Relative Layout:
<RelativeLayout
android:id="#+id/image_container"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_below="#+id/txt_1"
android:layout_centerHorizontal="true" >
<com.mobicartel.acceldatatester.RotationView
android:id="#+id/rotate_view"
android:layout_centerInParent="true"
android:layout_height="wrap_content"
android:layout_width="wrap_content" />
</RelativeLayout>
I'll add the background and let you know. (Right now the image isn't displaying at all. Sometimes you have to take a step backward to take two in the right direction!)

Android horizontal LinearLayout with wrapped text in TextView

I've observed a behavior with layout_weight that I can't explain. The following is a trivial example:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_vertical"
android:text="This is a very very very very very very very very very very very very very very very long string."
android:layout_weight="1"
/>
<View
android:layout_width="32dp"
android:layout_height="32dp"
android:layout_gravity="center_vertical"
android:background="#ffffffff"
/>
</LinearLayout>
In a QVGA display, the TextView wraps the text. The white square is displayed to the right of the text.
However, if I remove android:layout_weight="1" from the TextView, the TextView now takes up the entire display width. The white square is no longer displayed.
Why would layout_weight in the TextView affect whether or not the white square is displayed? Shouldn't the View with the white background always be assigned 32dpx32dp first? (It makes no difference if the view were any other types - ImageView or TextView).
The problem I was working on is that I want the white square to always be displayed to the right of the TextView (whether or not the text is wrapped), but I don't want any empty space between the TextView and the white square. (If I add android:layout_weight="1" to the TextView, then there is a gap if the text is not wrapped.)
Any help would be appreciated!

To answer my question #1: One thing I learned by looking at the source for LinearLayout: Not only does layout_weight assign unused space to a child, it also shrinks a child with layout_weight if the child extends beyond the bounds of the LinearLayout. That explains why a TextView with wrapped text is shrunk in my layout.
As for the answer to my question #2, I think you meant android:toRigthOf instead of android:layout_alignRight. Using a RelativeLayout instead of a LinearLayout doesn't change the layout behavior. The tricky part is placing a view immediately to the right of a TextView, without gaps, whether or not the text is wrapped. Setting a maxWidth would limit the TextView's width, but that solution doesn't scale across portrait/landscape and different display dimensions.
Solution - Looks like Dyarish's solution is the best available. My layout problem exists regardless of the layout you use. The key is to set a maxWidth for the TextView so that it doesn't take up the all of the horizontal space in the layout. Because hardcoding a android:maxWidth value in the TextView doesn't scale across different displays, setting the maxWidth at runtime, as Dyarish suggested, is a good solution.

Hopefully this is what you are looking for.
First off, here is a great resource I found for Creating UI's.
layout_weight - Specifies how much of the extra space in the layout to be allocated to the View.
If you want to ensure that the white square is always to the right of the textview, you can use a Relative View, and add the parameter to the view. android:layout_alignRight="+id#yourTextViewID". This should always make the box appear right beside the textView area. You should probably also add something like android:maxWidth="250px" This will ensure that you don't push the white box completely out of the screen.
Here is a code sample:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
>
<TextView
android:layout_width="wrap_content"
android:maxWidth="250px"
android:id="#+id/TextForWhiteBox"
android:layout_height="wrap_content"
android:layout_gravity="center|left"
android:text="This is a very very very very very very very very very very very very very very very long string."
/>
<View android:background="#ffffffff" android:layout_width="32dp" android:layout_height="32dp" android:id="#+id/view1" android:layout_toRightOf="#+id/TextForWhiteBox"></View>
</RelativeLayout>
You could also add to the View:
android:layout_alignTop="#+id/TextForWhiteBox" android:layout_alignBottom="#+id/TextForWhiteBox"
to make the white box the same size as the TextView.

Firstly I've tested the code from my other answer and it does exactly what you've described you've wanted. (unless I'm misunderstanding what you are asking for). You definitely do not want to use the android:layout_alignRight which is not what is in the code sample. That would simply keep the box on the right hand of the screen and not be affected by the textview at all. This sample uses android:layout_toRightOf="#+id/TextForWhiteBox" which is possible due to it being a relative layout. Since the Relative Layout allows you to place objects in relation to others. That line will always place the box just to the right of the textview with no gaps.
As for the screen orientation changes:
When the orientation changes it creates a new instance of the view.
Here is a simple solution.
//Add to oncreate in your Activity
private TextView textStatus;
textStatus = (TextView) findViewById(R.id.TextForWhiteBox);
// This get's the width of your display.
DisplayMetrics displaymetrics = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(displaymetrics);
int width = displaymetrics.widthPixels;
// Now you know the screen orientation, and it's width. So just set the maxwidth of the text view to match the display width - the pixels of your white box.
textStatus.setMaxWidth(width - 32); // 32 is here because you already know the size of the white box. More logic is needed to dynamically get this value, because you would need to wait for the activity to be fully created.
}
Here is the main.xml I used:
<?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="wrap_content"
android:orientation="horizontal"
>
<TextView
android:layout_width="wrap_content"
android:id="#+id/TextForWhiteBox"
android:layout_height="wrap_content"
android:layout_gravity="center|left"
android:text="This is a very very very very very very very very very very very very very very very very very very very long string."
/>
<View android:background="#ffffffff" android:layout_width="32px" android:layout_height="32px" android:id="#+id/view1" android:layout_toRightOf="#+id/TextForWhiteBox"></View>
</RelativeLayout>
You might need some additional logic to keep screen values.
This code has been tested, you should be able to literally copy and paste this to work as you asked.
Also depending on your logic you could use something like this to return the screen orientation.
int orient = getResources().getConfiguration().orientation;
Hope this helps!
If this helped you, please click the accepted button. =) Cheers!