In other words,LayoutInflater.from(...).inflate() require either a XmlPullParser or an Resource Locator. How can I instruct it to inflate a default View such as a TextView or a Button ?
Well, turns out that on runtime, the instantiation of a View object already inflates it.
In the end, the whole expression:
LayoutInflater.from(...).inflate()
can be replaced with the widget itself:
TextView(parent.context) (for a TextView)
Related
I notice that there is a tag <view>(not <View>) which can be used in Android layout xml. When I add such a tag in a layout xml, the app can be successfully compiled but crashes when running. So what is this <view> used for?
view is an alternative way for specifying a view to inflate. You need to combine it with class attribute to specify the class name.
This is "useful" if your view class is an inner class and you cannot use something with a $ in the tag name in XML. (Having inner classes as Views you inflate is not a very good idea though.)
For example:
<view class="your.app.full.package.Something$InnerClass" ... />
Reference: http://androidxref.com/5.0.0_r2/xref/frameworks/base/core/java/android/view/LayoutInflater.java#696
View is widget of android that is use to add any kind of view.Like in problems when we use scrollView in a activity and at bottom of activity there is buttons ,That time we add view to looks better.We can set any kind of color to View .
for exp
This will make a View of 20dp height.
I've read this answer : https://stackoverflow.com/a/5027921/1364174
And wonder why depending on the root parameter inflate method changes its behavior such drastically creating confusion.
According to that answer this code:
view = LayoutInflater.from(getBaseContext()).inflate(R.layout.smallred, null);
parent.addView(view);
Will create will create view specified in smallred.xml completely ignoring the properties of tags replacing them with some mysterious defaults values.
But this code will respect the properties from smallred.xml
view = LayoutInflater.from(getBaseContext()).inflate(R.layout.smallred, parent, false);
parent.addView(view);
Why is that ? Why we need to specify root/parent to which we later insert our view to, nflate" method?
Why is that necessary ? Why if we wouldn't we won't get the properties from .xml file ?
Probably because attributes are read only when you are actually inflating the view, so once you inflate it without providing the parent you will be missing information inside the inflated view. Then it doesn't matter if you add it to a parent, the data isn't there so the layout won't be as you expected it to be.
The layoutinflater doesn't know about your parent when he's inflating your view. So it doesn't even know its class. If you notice, every layout has its own LayoutParams class inside it, and you have to tell the layoutinflater which one it has to use or they will be simply discarded.
I know in my onCreate() I can inflate a view from XML by something like:
loadingScreen = (RelativeLayout) findViewById(R.id.loadingScreen);
But how could I do this from another view? Im trying to call up a loading screen by setting its visibility from GONE to VISIBLE but cant seem to figure out how to do this from my glSurfaceView
If you want to inflate a layout the code looks like this:
LayoutInflater inflater = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
LinearLayout myRoot = new LinearLayout(context);
View itemView = inflater.inflate(R.layout.layout_details, myRoot);
Here you first create a new LinearLayout an then inflate the layout with id R.layout.layout_details into it. The inflate method then returns the myRoot view.
Here is a tutorial about the LayoutInflater:
Layout resources in Android
Thats actually not inflating. Inflating is the process that parses a XML layout file and creates a structure of View and ViewGroup class instances out of it (setContentView() does this for you in the background for example).
What you do is getting a reference to a view in code that you have defined in your XML layout file. To change the visibility of your GLSurfaceView you have to reference it like you did above. But remember that the View (GLSurfaceView in this case) has to be defined in your layout file.
After referencing you have to call GLSurfaceView.setVisibility() to change it's visibility.
Here's an example:
GLSurfaceView glsurface = (GLSurfaceView) findViewById(R.id.myglsurfaceid);
glsurface.setVisibility(View.VISIBLE);
Of course you can use View.INVISIBLE or View.GONE either, depending on what you want to do.
If you reference a layout (such as a RelativeLayout), you may find children of this layout with the findViewById() of your RelativeLayout instance:
RelativeLayour rl = (RelativeLayout) findViewById(R.id.mylayout);
(Button) mybutton = (Button) rl.findViewById(R.id.mybutton);
But thats usually not neccessary (at least when you just started with Android) because the activities findViewById() finds all Views that are displayed, even in sublayouts. You only have to use it if you have duplicate ids in your ui structure (tbh I never had that case yet) and want to specifiy where to look for your particular View.
You can't get a reference to a View that's doesn't exists in your current Layout, or your current View, (your current Activity content) , but you can create a new View from another XML layout, using LayoutInflater from current Activity.
you can add to you current Activity content, a new View, that's what you mentioned as " loading screen ", even by showing it as a Dialog or by creating View and then add it to root layout in your Activity
I hope I helped you
If I correctly understood what you wanna do:
Supposing you have a glSurfaceView object and you wanna grab a view that's inside that one.
You'll do just the same thing you did for you normal view. Let's say a button:
Button button = (Button) glSurfaceView.findViewById(R.id.buttonid);
If you meant something different let me know in the comments.
EDIT: And then you can just set the button's visibility:
button.setVisibility(Button.GONE)
I am new to android development and keep coming across references to Inflating views from a layout xml file. I googled and searched the development guide but still wasn't able to pick up a sense for what it means. If someone could provide a very simple example, it'd be much appreciated.
When you write an XML layout, it will be inflated by the Android OS which basically means that it will be rendered by creating view object in memory. Let's call that implicit inflation (the OS will inflate the view for you). For instance:
class Name extends Activity{
public void onCreate(){
// the OS will inflate the your_layout.xml
// file and use it for this activity
setContentView(R.layout.your_layout);
}
}
You can also inflate views explicitly by using the LayoutInflater. In that case you have to:
Get an instance of the LayoutInflater
Specify the XML to inflate
Use the returned View
Set the content view with returned view (above)
For instance:
LayoutInflater inflater = LayoutInflater.from(YourActivity.this); // 1
View theInflatedView = inflater.inflate(R.layout.your_layout, null); // 2 and 3
setContentView(theInflatedView) // 4
"Inflating" a view means taking the layout XML and parsing it to create the view and viewgroup objects from the elements and their attributes specified within, and then adding the hierarchy of those views and viewgroups to the parent ViewGroup. When you call setContentView(), it attaches the views it creates from reading the XML to the activity. You can also use LayoutInflater to add views to another ViewGroup, which can be a useful tool in a lot of circumstances.
Inflating is the process of adding a view (.xml) to activity on runtime. When we create a listView we inflate each of its items dynamically. If we want to create a ViewGroup with multiple views like buttons and textview, we can create it like so:
Button but = new Button();
but.setText ="button text";
but.background ...
but.leftDrawable.. and so on...
TextView txt = new TextView();
txt.setText ="button text";
txt.background ... and so on...
Then we have to create a layout where we can add above views:
RelativeLayout rel = new RelativeLayout();
rel.addView(but);
And now if we want to add a button in the right-corner and a textview on the bottom, we have to do a lot of work. First by instantiating the view properties and then applying multiple constraints. This is time consuming.
Android makes it easy for us to create a simple .xml and design its style and attributes in xml and then simply inflate it wherever we need it without the pain of setting constraints programatically.
LayoutInflater inflater =
(LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View menuLayout = inflater.inflate(R.layout.your_menu_layout, mainLayout, true);
//now add menuLayout to wherever you want to add like
(RelativeLayout)findViewById(R.id.relative).addView(menuLayout);
A layman definition for inflation might be to convert the XML code to Java code. Just a way to understand, e.g., if we have a tag in XML, OS has to create a corresponding Java object in memory, so inflatter reads the XMLtags, and creates the corresponding objects in Java.
I think here "inflating a view" means fetching the layout.xml file drawing a view specified in that xml file and POPULATING ( = inflating ) the parent viewGroup with the created View.
Because we make UI into XML but view objects is what we display so we somehow need to convert xml into view objects so inflating means we are converting xml into view objects so that it can be displayed, for this we need a service called layout inflator service and give it an xml and it will be convert for you.
In the iOS UIKit universe, this means getting the reference to the .Xib (which is XML, just like android) file and adding it to the current ViewController's view hierarchy.
Can anybody please tell What Inflator is and how it is being used in an Android application?
I don't know the exact use of it and Why it is being used.
My preferred way to handle inflation:
//First get our inflater ready, you'll need the application/activity context for this
LayoutInflater mInflater;
mInflater = LayoutInflater.from(mContext);
//Inflate the view from xml
View newView = mInflater.inflate(R.layout.my_new_layout, null);
//Then you'll want to add it to an existing layout object
mMainLayout.add(newView);
//Or perhaps just set it as the main view (though this method can also
// inflate the XML for you if you give it the resource id directly)
setContentView(newView);
Basically, you use it to inflate existing xml layouts at runtime. Usually you go ahead and insert those new views into previously defined ViewGroups or List objects.
Not quite sure what you mean, but if its related with inflating views, its used to load layout xml files into your application. e.g by
View myWelcome = View.inflate(this, R.layout.welcome, null);
Its easier and consider best practice to have you view definition inside layout xml files, instead of creating your views fully by code.
layout inflator is used to return a java object of your complete layout
suppose you have a layout xml file in which the root element is relative layout and it contains a imageview and textview then using layout inflator you can return a view object that refers to entire layout.
this basically is used in list view and grid view to plug into them a layout object of single row or element which is to be repeated.
you were asking for use of Inflator..
basically when you want to use two xml files in one java class ,inflator is used and its code is simple which is given below..
TextView text;
View layout;
LayoutInflater inflator=getLayoutInflater();
layout =inflator.inflate(R.layout.new_xml_that you want to use in that java class,null);
text=(TextView)layout.findViewById(R.id.text);
text.setText("progressing");
here i use textview,this is present in next xml with id=text
thats it..
if you find this worthy then please like this..
thanks