I have a small xml file called 'xmlview.xml' which is something like:
<tablelayout>
<tablerow>
<view id="view1" />
I created a class which extends view, and I inflated that xml file and now i have a view obtained due to inflation.
xmlView = layoutInflater.inflate(R.layout.xmlview, this);
I am wondering is there a way to draw on the view 'view1' inside the view 'xmlview'
I tried something like:
View view1 = (View)xmlview.findById(R.Id.view1);
and then I tried in the overriden onDraw to draw on view1 but nothing worked,
any ideas ??
Seems to me maybe you should try something like this:
<TableLayout>
<TableRow>
<com.yourdomain.yourproject.ViewClassName>
Then you can create a class ViewClassName that extends View and, on that class, override the onDraw method. This is explained in detail here: http://developer.android.com/guide/topics/ui/custom-components.html. You can go directly the topic Modifying an Existing View Type
See, you don't need to inflate the view if the only reason to do this is to try and manipulate the view's drawing. And if it is the only reason, you really shouldn't.
hope I helped
I'm not sure what exactly you mean by "draw on the view", but it sounds like you should be looking into the Canvas. You should not arbitrarily override the onDraw method, this is what causes your widgets to appear on the screen.
Related
I have a custom view that, on a high level, takes whatever drawable one might pass into it and draws a ring around it, the ring is animated, and comes with a whole set of parameters; things such as ringWidth, gradient colors, etc.
Currently, to show/specify this view in my XML, my markup looks a lot like this:
<RingedImageView
android:id="#+id/ringedImageView"
android:layout_height="#dimen/image_gigantic"
android:layout_width="#dimen/image_gigantic"
app:source="#drawable/ic_icon_1"
app:ringWidth="2dp" />
This is all well and good. However, instead of passing in a drawable as the image in the middle, what I would like is to be able to pass in a whole view, entirely seperate from #id/ringedImageView.
Ideally, I'd like this to look as follows in my XML:
<RingedImageView
android:id="#+id/ringedImageView"
android:layout_height="#dimen/image_gigantic"
android:layout_width="#dimen/image_gigantic" ...>
<ImageView
android:id="#+id/imageView" .../>
</RingedImageView>
My question then is, can I access that nested ImageView in my RingedImageView.java class? How can I specify how to handle this situation?
Some answers point to having to extend ViewGroup instead of View, but as this isn't a layout manager per se, and the component comes with its own rules for displaying content, a View seems more appropriate. Would appreciate a pointer.
Thanks all
I want to draw animations over a webview. My activity's xml structure looks like the structure below:
<FrameLayout>
<LinearLayout>
</LinearLayout>
<WebView/>
<LinearLayout>
</LinearLayout>
</FrameLayout>
Is it possible somehow to create a transparent canvas in order to draw my animation over the webview?
Thanks in advance!
If you use a RelativeLayout as a parent of the WebView you would be able to add some other view above it, order of declaration in the XML file determines the way it is drawn, so if the WebView is drawn first then the next view will be on top of it, make the background of this view transparent and you should be good to go, you may have some problems with interacting with the WebView however, I would make the visibility of this view View.GONE while it is not needed.
Ok... Actually done it by creating a CustomWebView object that extends WebView and add it to the layout programmaticaly. The CustomWebView objects overrides onDraw(Canvas canvas) method, and there I do my animation...
When declaring custom view in xml, what is the difference between declaring a View of a custom class, or declaring a completely custom view:
<LinearLayout>
<view class="packageName.MyView" android:id="#+id/myView" />
</LinearLayout>
and
<LinearLayout>
<packageName.myView android:id="#+id/myView" />
</LinearLayout>
?
I've created a subclass of EditText, and when instatiating it as View class=".." my Activity crashes with ClassCastException when trying to access MyView:
(MyView) myView = (MyView) findViewById(R.id.myView);
When declared as second option, everything works as expected.
I'm not 100% sure on this, but let me give it a go. A couple of things could be happening. The parser might not understand the class attribute correctly (e.g. it thinks it is part of a stylesheet). I am not sure how the parser handles the class attribute, since I have never seen or used it (in fact, I've never seen the <View> tag used either). A better explanation, though, might be this: the parser is trying to down-cast your View into packageName.myView class and fails (down-casting is always risky; up-casting is always safe).
Regardless of what is happening, I would always use the second option you listed, <packageName.myView android:id...>, instead of using the <View> tag. Reason being, it's redundant to use the <View> tag. Everything in this xml file must be a view (LinearLayout, Button, TextView, etc. are all descendants of the View class).
Hope that helps. If you're really, really curious, you could always download the source code for the parser...
Im kind of new to Android.
I am playing around with the Android FingerPaint API Sample. I have figured out how to add buttons and functions to the Menu, but how do I get buttons on the actual screen?
Is it possible to place buttons over the drawing surface? Or would I need a linear (Vertical) layout on the left, and place buttons in there. Either would be fine.
Help? Thanks.
The Android FingerPaint sample code does not use a layout; it instead just has a subclass of View called MyView, and then the Activity sets its content view to be an instance of MyView.
If you want to have more than one View on the screen, you'll need to use some sort of layout. You could use a LinearLayout if you want the MyView for painting to be above, below, or to the side of the buttons; if you want the buttons to be on top of the MyView, take a look at using a FrameLayout or RelativeLayout.
You can either then define the layout in XML or create it manually in code. The former is more flexible and maintainable, but there will be a few hiccups.
First, create a layout XML showing how you want your components to be laid out. For this example, we'll call it finger_paint.xml. Make sure you have a MyView in there somewhere, something like:
<view class="com.example.android.apis.graphics.FingerPaint$MyView"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
Then, replace the line that looks like
setContentView(new MyView(this));
with
setContentView(R.layout.finger_paint);
Note that because MyView does not (yet) have the proper constructor for being instantiated by the LayoutInflater, this will not work yet, so let's fix that. Add an additional import near the top of the file:
import android.util.AttributeSet;
and then add an AttributeSet parameter to the constructor of MyView:
public MyView(Context c, AttributeSet as) {
super(c, as);
// rest of constructor is same as in the sample
}
You will also have to change MyView to be a static inner class of FingerPaint.
You may find the Building Custom Components document and the NotePad sample useful as you figure this out.
Good luck!
Are you trying to dynamically position your buttons?
If so, you can use setLayoutParams to set the layout properties of the button.
In an Android application, I have created a custom view extending the View class. I want to declare an object of my class in the xml layout file but, even after many tries, the application unexpectedly stops when the setContentView call is executed (that's what the popup windows which appears says).
In my view class, which is declared in my MainActivity file as public, I have two constructors : one with only the Context as parameter and one with a Context and an AttributeSet parameters. And I have overridden the onDraw function.
This class is in my source package, named org.me.myapp.
In the layout file, I declare the object I want to insert like this :
<org.me.myApp.MainActivity.myView"
android:id="#+id/View"
android:layout_below="#id/toto"
android:layout_width="300dip"
android:layout_height="100dip"/>
Can anyone tell me what is wrong?
Thanks in advance for the time you will spend trying to help me.
What Yar said, you should extend View or ViewGroup to create custom layout element, and use that class name in your layout xml. Not member variable what it looks you're trying to do. After inflating your layout you can access your custom view with;
org.me.myapp.MyView myView = (org.me.myapp.MyView) findViewById(R.id.MYVIEWID);
I think you need to declare your custom layout as a separate class, for example: org.me.myapp.MyView and relate to it in your xml file like this:
<org.me.myapp.MyView
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
...
/>