How would I display one view as an overlay of another? - android

I have two views that take the whole screen and I want to display both views at the same time, one on top of the other. My layout looks like this:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="vertical">
<WebView
android:id="#+id/webview"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
/>
<org.example.myCustomView
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
/>
</LinearLayout>
Note that myCustomView uses onDraw (this method last statement is invalidate()) to draw custom graphics. The problem I am getting is that it only displays myCustomView, WebView is hidden. I tried to change the background colour of mycustomView to transparent but this makes no difference.
I would also like to have the ability to make myCustomView as an overlay on WebView or vice versa.

Use a RelativeLayout for starters.
You could use the ViewGroup.addView(View child, int index, ViewGroup.LayoutParams params) or a variant along with ViewGroup.removeView(View view) or ViewGroup.removeViewAt(int index).
This would obviously require you to inflate the views manually using LayoutInflater but you could keep a global reference to each after inflating and just flip between the two.

I'm not sure if you can do this when they are in the same xml file, but I know that if you move:
<org.example.myCustomView
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent" />
to another xml file, and create another activity. set the content view to the xml file that contains the org.example.myCustomView and call that activity. in the manifest, when you add that activity, add a theme statement as so:
android:theme="#android:style/Theme.Dialog"
the full statement should look like this:
<activity android:name=".name_of_activity"
android:label="TextToBeOnTop"
android:theme="#android:style/Theme.Dialog">
</activity>
the result will look like this (only it will be with your components instead):
although it mabey possible to do it when they are still in the same xml file. if it is possible, it would likely be done by leaving the manifest alone, and editing your costomeView to the following:
<org.example.myCustomView
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:theme="#android:style/Theme.Dialog" />
(I added the theme statement into the CustomView )
if this isn't what you are looking for, than I would recoment something simmilar to what Nick Campion said, which was to change fillParent to wrapContent.
you could do that, or you could choose what size you wanted it to be. here are two options you could use:
<org.example.myCustomView
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="50dip"
android:layout_height="50dip" />
(you could change "50dip" to whatever number you want as long as it ends with dip)
or:
<org.example.myCustomView
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />

The term fill_parent means consume all the allowable space in the parent. Try setting it to wrap_content. Then you can try adding weight = 1 to both to try to evenly distribute the remaining space.

Related

fill_parent in LinearLayout isn't being honored

After much research on both SO and google, I haven't seen any one with exactly the same problem I am experiencing, so here it is:
I recently redid the entire UI on an android app. For the most part, I made only cosmetic changes to each of the screens. They appear in the UI editor of eclipse perfectly as expected. However, directly after doing this, two of the screens stopped being laid out correctly on both all tested devices and the emulator.
Now, the big problem one these two screens was that the root level LinearLayout didn't appear to be actually honoring the fill_parent for either layout_height or layout_width. it looks like it's being measured as if it were set to wrap_content instead. It only takes up about 70% of the screen - which is just enough to wrap the individual elements inside the root LinearLayout. I would post an image, but as a new user, I am not allowed to.
The layout isn't stretching to fill the screen. Here's the code for layout, except that there are a few more in the LinearLayouts containing a TextView and an EditText.
<?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:background="#FF000000"
android:orientation="vertical" >
<TextView
style="#style/sans.white.16.bold"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:paddingTop="4dp"
android:text="#string/edit_account" />
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="horizontal" >
<com.teamunify.ondeck.widget.TUTextView
style="#style/sans.white.14"
android:layout_width="100dp"
android:layout_height="wrap_content"
android:text="#string/first_name" />
<com.teamunify.ondeck.widget.TUEditText
android:id="#+id/acc_editor_first"
android:layout_width="fill_parent"
android:layout_height="40dp"
android:selectAllOnFocus="true"
android:singleLine="true" />
</LinearLayout>
I think the root LinearLayout should be filling both height and width. I've used this same layout many MANY times in our app without problems. (A quick count revealed that I used 76 LinearLayouts in our app, and all but two of them are working.)
At first, I suspected that perhaps our custom classes measure was wrecking things, so I changed the layout to use all plain EditTexts, but there was no change. I double checked the activity, but it isn't doing anything except to load this xml. So, in desperation, I redid the layout like so:
<?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:background="#FF000000"
android:orientation="vertical" >
<TextView
style="#style/sans.white.16.bold"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:gravity="center|top"
android:paddingTop="4dp"
android:text="#string/edit_account" />
</LinearLayout>
After that, The words Edit Account appear with a black background mashed into the upper left corner. Clearly, the LinearLayout isn't filling the parent.
Long story short, I am asking how to fix this so that the LinearLayout fills the screen as expected.
I am at a complete loss as to why this is happening, and I am certainly hoping that someone on SO has an idea. This has got me pulling my hair out!
Try setting fixed width and height for the root layout.
Then only you will be able to debug who is driving length and width. It is very much possible that parent activity or background activity is setting dimensions. Once you identify the root cause you can go back to original settings.
As of now from your code snippet given here, nothing wrong here
If you use a custom activity as a container to other activities for some reason (In our case, we were recreating the look of our iOS app, and needed a custom menu to show up along the button side of the screen) the window manager seems to get a bit confused with what the actual height and width of the nested activities should be. A call to fillparent or matchparent ends up wrapping the content instead.
We ended up changing the behavior of several methods in our container activity class to make this work.

Avoid to rewrite code for activities with the same layout

I'd like to run several Activities on my Application;I'd like each Activity to have a Linear Layout and to show an image as heading; basically I'd like every layout to start like this:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#color/Grey"
>
<ImageView android:id="#+id/imageHeader" android:src="#drawable/tf_header" android:layout_height="wrap_content" android:layout_width="fill_parent"
android:background="#color/Black" android:scaleType="fitXY"></ImageView>
Is it possible not to reapeat this code for each layout? Could I use themes or styles to avoid it? Thank you for your replies.
Yes thats possible use the <include> tag as described in Layout Tricks.
For your example I would add the image as <include> and have a LinearLayout in each Activity layout xml
One of my apps uses the same xml file for 30 or so classes, i just modify it in code to customize it. That approach may work, just leave every label in the xml blank and set it in the .class

What are the different ways to design layouts in android?

I'm fairly new to Android development. I'm wondering what are the different ways that are used to design XML layouts. Ive been using the eclipse drag and drop interface and I've seen http://droiddraw.org/ while doing some searching. Just wondering if there are any other possibly better ways out there to design layouts that professions use because I'm having a hard time with the eclipse interface making complex designs?
First of all check out the android developer site user interface page
http://developer.android.com/guide/topics/ui/index.html
There are basically three different ways you can make an android layout:
XML
http://developer.android.com/guide/topics/ui/declaring-layout.html
You can define a static layout using XML. Perhaps a good way to think of it is a sort of shorthand. It is very easy to declare Views and attributes, and the hierarchical format of XML makes it a bit easier to visualize.
This is a typical layout
<?xml version="1.0" encoding="utf-8"?>
<ViewGroup xmlns:android="http://schemas.android.com/apk/res/android"
android:attribute="value" >
<ViewGroup android:attribute="value" >
<View android:attribute="value" />
</ViewGroup>
<View android:attribute="value" />
</ViewGroup>
Then you use setContentView(R.layout.layout) in your activity and go about your business.
Java
You can do everything you would do in XML, plus add things like listeners, or do other dynamic things that you cannot in XML. Here is how you might declare a typical layout (ViewGroup is abstract so you would have to use a subclass. The same goes for XML)
ViewGroup parent = new ViewGroup(this);
ViewGroup vg1 = new ViewGroup(this);
View v1 = new View(this);
View v2 = new View(this);
parent.addView(vg1);
vg1.addView(v1);
parent.addView(v2);
v1.setOnAwesomeListener(new AwesomeListener() {
onAwesome(View v) {
doDynamicThings();
}
}
setContentView(parent);
Hybrid
This is the case used most often in my opinion. Declare a layout in XML with an id, like android:id="#+id/v1" then load Views from XML into Java
setContentView(R.layout.layout);
View v1 = findViewById(R.id.v1);
// dynamically change v1
How to design a layout using XML
So the lack of GUI designer tools has left you no choice but to dive into coding up your layout by hand. Good news is that once you get the hang of it you should be able to tackle any layout you wish. Let's look at the building blocks
ViewGroup
First off you need to choose a ViewGroup to define the structure of the layout, or section of the layout. Remember that these can be nested, so design top-down and try to classify sections of the layout based on the form you want them to have. There are two main options:
LinearLayout
As the name implies, useful for arranging items in a line. Choose an orientation, horizontal or vertical, and simply add items. They will be added in top to bottom or left to right ordering.
RelativeLayout
Useful for placing an item in a specific location on the screen. So if you want to put a button in the top-left, or a bar across the top, this is your ViewGroup.
Layout Parameters
Used for defining the width, height, weight, and other aspects of a view.
There are two options for width and height: fill_parent (replaced with match_parent in API level 8) and wrap_content. The view can choose to either fill the parent view's width, or take only the space it needs.
There is another useful layout parameter, unique to LinearLayout, called weight. It is useful for letting views share space in ratios, or letting one view take the space left over after other views in the LinearLayout take their share.
Example
Let's try to design the layout for Google Maps. Pretend it is a layout that I have in my head, and I want to implement it. Here is a screenshot
I will try to break this down:
Looking at it, there is a bar across the top and a map underneath it. I believe this could be implemented with either a LinearLayout or a RelativeLayout. However, the buttons in the bottom right and left scream RelativeLayout, so I will go with that.
<?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="fill_parent" >
<TODO:BAR
android:id="#+id/bar"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_alignParentTop="true">
</TODO:BAR>
<MapView
android:id="#+id/map"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_below="#+id/bar" />
<ImageButton
android:id="#+id/latitude"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentLeft="true"
android:layout_marginBottom="20dp"
android:layout_marginLeft="20dp" />
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentRight="true"
android:layout_marginBottom="20dp"
android:layout_marginRight="20dp"
android:orientation="vertical" >
<ImageButton
android:id="#+id/zoom_in"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<ImageButton
android:id="#+id/zoom_out"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</LinearLayout>
</RelativeLayout>
Now some explanation. In RelativeLayout you use alignParent[direction] to specify where the view goes. I also wanted some space on the sides, so I used margin[direction] to specify in dp or density-independent pixels. As you can see, wrap_content is used most of the time, so the buttons would acquire the size of the image used on them.
Now everything is defined but the bar at the top. I'm going to break it up into four different Views: The dropdown menu view, the search view, the layers button and the my location button. The way I would like it to work is put the menu at the far left, and the layers and my location buttons on the right, with the search box taking up the remaining space. This sounds like a job for LinearLayout and weight! Here is how I define the bar, which can be inserted into the placeholder above to get the final layout
<LinearLayout
android:id="#+id/bar"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_alignParentTop="true" >
<ImageButton
android:id="#+id/dropdown_menu"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<EditText
android:id="#+id/search"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1" />
<ImageButton
android:id="#+id/layers"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<ImageButton
android:id="#+id/my_location"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</LinearLayout>
Setting the width of the search bar to 0dp means let the other views take what they need, then the weight says take the remaining space.
And there you have it. A recreation of the basic layout for the Google Maps app (minus button images and other niceties like custom views), showing how you might use various layouts and XML fairly painlessly. Hopefully this was useful.
The tool chain is a little weak in this area. I don't really care for DroidDraw, and the Eclipse GUI editor is not very good for anything more than simple layouts. It often renders RelativeLayouts incorrectly for example.
Personally I do almost everything directly in XML. You have to understand how all the different Layout classes work to do anything complex anyway. The only real downside to XML is that all of the extra cruft from tags, attributes, etc. makes for a lot of extra stuff to type, but the editor takes care of most of that for you.

What should my Android Layout look like?

I recently asked a question about how to add a view on top of a view, after asking that I realized I needed to added a better layout to my app before proceeding further.
I was reading Android Layout Tricks but noticed it was specifically for text views and image views. I'm looking to do it with two custom views. So I decided to whip up a quick image in paint to hopefully show more clearly of what I'm wanting to do.
This is how I want my layout to split the views. :
This is how it would look with the views drawn. Obviously the purple and blue boundaries would be the background color (greyish). The data above simply displays the y-intercept of the graph drawn with respective color. (So there would be multiple graph views drawn on top of each other)
So my question is, what would my main content view look like? I assume it would have a Linear layout but I'm rather new to these layouts.
EDIT
Using TextViews I'm able to come up with something similar using the following XML:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<LinearLayout
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<TextView
android:text="Data Placeholder"
android:background="#733674"
android:textSize="15pt"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="20"/>
<TextView
android:text="Graph Placeholder"
android:background="#374F82"
android:textSize="15pt"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="80"/>
</LinearLayout>
</LinearLayout>
So The only question that really remains is, am I supposed to use TextViews? Meaning in my Activity am I able to add my custom views where these TextViews are? Or am I supposed to add my custom view to the XML?
Ie.
<DataView
android:text="Data Placeholder"
android:background="#733674"
android:textSize="15pt"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="20"/>
<GraphView
android:text="Graph Placeholder"
android:background="#374F82"
android:textSize="15pt"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="80"/>
My custom views are written in Java and I'm not sure how I would let the layout know where the views are located if I was to do it this way.
Try this: http://developer.android.com/resources/tutorials/views/hello-linearlayout.html
It has some very useful information which might help you out in regards to layout_weight as Michell Bak mentioned in the comment.
And here's the page for the Hello Views:
http://developer.android.com/resources/tutorials/views/index.html
Not to be rude, but it would be much better for you to peruse these and learn the xml on your own. That way you can actually understand it and be better able to re-create it later.
I was quite overwhelmed at first with all the code I didn't understand (including xml files), but with a little practice it becomes very easy - just time consuming.
The main thing I'm confused about is what kind of View to put in the
layout. In the examples they use TextView or ImageView, but mine is a
custom view
Well, for your "Custom Data View", you would use a LinearLayout with android:layout_width="fill_parent" and android:layout_height="fill_parent" and android:layout_weight="1" and android:background="#BA4AAB" (See http://www.colorpicker.com/)
Then for your Custom Graph View, I would use:
android:layout_width="fill_parent" android:layout_height="fill_parent" android:layout_weight="4" android:background="#7D4ABA"
Note the layout_weight and background values I put are kind of guesses, you might have to tweak them some to match what you want.
The two linearlayouts that I mentioned would be inside one larger LinearLayout with android:orientation="vertical"
Then for the data in the top, you would use 4 text Views, and in code, you'd use setText(...) on those text views to put your data in.
In the xml for textview1, you would add android:id="#+id/textview1" then in code add TextView textview1 = (TextView)findviewbyId(R.id.textview1); then textview1.setText(myString);
For the graph in the bottom part, you would use 2 views for the base of the graph, and set there android:layout_width and android:layout_height to whatever suits you using dip, dp, or px units.
For the lines that you draw, I believe you would have to use the canvas class with a bitmap and call canvas.drawLine(...) (see http://developer.android.com/reference/android/graphics/Canvas.html)

How does Android determine whether to move the layout up when showing the softkeyboard?

How does Android determine whether to move the layout up when showing the softkeyboard?
Note: I am aware that the activity property android:windowSoftInputMode="adjustResize|adjustResize|adjustUnspecified"
exists, as described here http://developer.android.com/guide/topics/manifest/activity-element.html#wsoft
, but in my case it doesn't seem to have any effect. This is my problem:
I have two activities, pretty much the same layout, but the first one is using a ListView that holds a list of buttons. The second activity holds a scrollview with buttons.
The rest is the same, same number of buttons, same height of elements, etc.
Now, when I press the search button to open the search input bar, in my first activity, the entire layouts gets moved up.
While on the second activity, the layout is not being moved up but the softkeyboard just displays on top of it. This is actually how I want it to behave. How can I achieve the same with my activity that's using the ListView?
In my manifest, initially I didn't specify any android:windowSoftInputMode attribute, but even if I do, it doesn't make any difference; I tried all three values (adjustPan, adjustResize, adjustUndefined, without any difference).
This is my layout:
1) http://pastebin.com/5zzVxjbK
2) http://pastebin.com/KFtPuHvP
Interestingly though: when I set my ListView visibility in my layout 1 (left) to View.INVISIBLE, then the layout doesn not get moved up!
I can achieve this with a RelativeLayout and setting android:windowSoftInputMode="adjustPan" like so:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent" android:layout_height="fill_parent" >
<include android:id="#+id/Header" layout="#layout/header"
android:layout_width="fill_parent" android:layout_height="wrap_content" />
<ListView android:id="#+id/android:list" android:layout_width="fill_parent"
android:layout_height="wrap_content" android:layout_below="#id/Header"
android:layout_above="#+id/Footer" />
<include android:id="#id/Footer" layout="#layout/footer"
android:layout_width="fill_parent" android:layout_height="wrap_content"
android:layout_alignParentBottom="true" />
</RelativeLayout>
You may be able to achive this by setting the footer gravity (or layout_gravity) to "bottom", if you want to keep the LinearLayout, but I am not sure.

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