You're calling findViewById() on your image view object, which looks among
the view's children. Since the progress bar is not a child of your image
view, this returns null. Look in the activity instead, or have the activity
provide the progress bar to the image view, or -- that's how I'd do it --
create a layout class that manages both image and progress views as its
children.
onMeasure may be called multiple times, yes.
-- K
2012/9/27 Serdel <adam.lichwierow...@gmail.com>
> Hi Kostya,
>
> I am not sure what is complicated here... I just want to place my progress
> bar in the exact location on my imageview. If do it 'hard coded' so i.e.
> the image is 200x400 and I place it 50px from left and 100px from bottom
> than it will be misplaced if the image is resized by android. Therefore I
> want to get new resized parameters so I can calculate my position
> dynamically not hard coded - it cannot be put more simple. I ahve now
> subclassed my ImageView on in the onMeasure I finally got the rescaled
> size. However inside that method I get null when I call:
>
> myCustomTwistedProgressBar = ((CustomTwistedProgressBar)
> findViewById(R.id.progressBar))
>
> Moreover I also need to get the screen density before placing my progress bar
> (I have different image sizes for different densities). So I am still stuck.
> I don't understand why is it soooooo difficult to get the rescaled dimensions
> of an imageView in android.
>
>
> Also one very strange thing is that my onMeasure is called a couple of
> times when the activity starts - first it seems that the image is spread
> (width and height are full screen values) and the 2nd time they are correct.
>
>
> W dniu środa, 26 września 2012 23:46:37 UTC+2 użytkownik Kostya Vasilyev
> napisał:
>>
>> Not sure what your requirements are, but the code below seems way too
>> complicated to me.
>>
>> Subclass ViewGroup, draw the image in onDraw, override onMeasure /
>> onLayout and position the progress bar (or skip the drawing and add an
>> image view as a child... you'd need to position it too...)
>>
>> -- K
>>
>> 2012/9/26 Serdel <adam.lich...@gmail.com>
>>
>>> The problem with properly handling multiple screen sizes on Android has
>>> been talked all over thousands of times. However I couldn't find a solution
>>> to m problem. In a nutshell I need to align my custom progress bar over an
>>> imageView. I've got 3 set of drawables for the imageView - ldpi(scaled for
>>> 240x400), mdpi(scaled for 320x480), hdpi(scaled for 480x800). I align my
>>> custom view in Java with the following code:
>>>
>>> //get screen density
>>> float density =
>>> getBaseContext().getResources(**).getDisplayMetrics().density;
>>>
>>> //set the progress bar position according to screen density
>>> if ( density == 1.0f)
>>>
>>> {
>>> ImageView micImage = ((ImageView)
>>> findViewById(R.id.imageViewClk**));
>>>
>>> Drawable drawing = micImage.getDrawable();
>>> Bitmap bitmap = ((BitmapDrawable)drawing).getB**itmap();
>>>
>>> // Get current dimensions
>>> int width = bitmap.getWidth();
>>>
>>> int height = bitmap.getHeight();
>>>
>>> LayoutParams params = new LayoutParams((int)(height/13.**94),
>>> (int)(height/13.94));
>>>
>>> params.setMargins((int)(width/**2.30), 0, 0,
>>> (int)(height/2.75));
>>>
>>> params.addRule(RelativeLayout.**ALIGN_LEFT,R.id.imageViewClk);
>>>
>>>
>>> params.addRule(RelativeLayout.**ALIGN_BOTTOM,R.id.imageViewClk**);
>>>
>>> myCustomTwistedProgressBar.set**LayoutParams(params);
>>> }else if ( density == 1.5f ){
>>>
>>> ImageView micImage = ((ImageView)
>>> findViewById(R.id.imageViewClk**));
>>>
>>> Drawable drawing = micImage.getDrawable();
>>> Bitmap bitmap = ((BitmapDrawable)drawing).getB**itmap();
>>>
>>> int width = bitmap.getWidth();
>>> int height = bitmap.getHeight();
>>>
>>> LayoutParams params = new
>>> LayoutParams((int)Math.round(h**eight/14.13),
>>> (int)Math.round(height/14.13))**;
>>>
>>> params.setMargins((int)Math.ro**und( width/2.27), 0, 0,
>>> (int)Math.round(height/2.91));
>>>
>>> params.addRule(RelativeLayout.**ALIGN_LEFT,R.id.imageViewClk);
>>>
>>>
>>> params.addRule(RelativeLayout.**ALIGN_BOTTOM,R.id.imageViewClk**);
>>>
>>> myCustomTwistedProgressBar.set**LayoutParams(params);
>>> }else if ( density == 0.75f ){
>>>
>>> ImageView micImage = ((ImageView)
>>> findViewById(R.id.imageViewClk**));
>>>
>>> Drawable drawing = micImage.getDrawable();
>>> Bitmap bitmap = ((BitmapDrawable)drawing).getB**itmap();
>>>
>>> // Get current dimensions
>>> int width = bitmap.getWidth();
>>>
>>> int height = bitmap.getHeight();
>>>
>>> LayoutParams params = new LayoutParams((int)(height/14.**88),
>>> (int)(height/14.88));
>>>
>>> params.setMargins((int)(width/**2.27), 0, 0,
>>> (int)(height/2.69));
>>>
>>> params.addRule(RelativeLayout.**ALIGN_LEFT,R.id.imageViewClk);
>>>
>>>
>>> params.addRule(RelativeLayout.**ALIGN_BOTTOM,R.id.imageViewClk**);
>>>
>>> myCustomTwistedProgressBar.set**LayoutParams(params);
>>> }
>>>
>>>
>>> The problem with properly handling multiple screen sizes on Android
>>> has been talked all over thousands of times. However I couldn't find a
>>> solution to m problem. In a nutshell I need to align my custom progress bar
>>> over an imageView. I've got 3 set of drawables for the imageView -
>>> ldpi(240x400), mdpi(320x480), hdpi(480x800). I align my custom view in Java
>>> with the following code:
>>>
>>> //get screen density
>>> float density =
>>> getBaseContext().getResources(**).getDisplayMetrics().density;
>>>
>>> //set the progress bar position according to screen density
>>> if ( density == 1.0f)
>>>
>>> {
>>> ImageView micImage = ((ImageView)
>>> findViewById(R.id.imageViewClk**));
>>>
>>> Drawable drawing = micImage.getDrawable();
>>> Bitmap bitmap = ((BitmapDrawable)drawing).getB**itmap();
>>>
>>> // Get current dimensions
>>> int width = bitmap.getWidth();
>>>
>>> int height = bitmap.getHeight();
>>>
>>> LayoutParams params = new LayoutParams((int)(height/13.**94),
>>> (int)(height/13.94));
>>>
>>> params.setMargins((int)(width/**2.30), 0, 0,
>>> (int)(height/2.75));
>>>
>>> params.addRule(RelativeLayout.**ALIGN_LEFT,R.id.imageViewClk);
>>>
>>>
>>> params.addRule(RelativeLayout.**ALIGN_BOTTOM,R.id.imageViewClk**);
>>>
>>> myCustomTwistedProgressBar.set**LayoutParams(params);
>>> }else if ( density == 1.5f ){
>>>
>>> ImageView micImage = ((ImageView)
>>> findViewById(R.id.imageViewClk**));
>>>
>>> Drawable drawing = micImage.getDrawable();
>>> Bitmap bitmap = ((BitmapDrawable)drawing).getB**itmap();
>>>
>>> int width = bitmap.getWidth();
>>> int height = bitmap.getHeight();
>>>
>>> LayoutParams params = new
>>> LayoutParams((int)Math.round(h**eight/14.13),
>>> (int)Math.round(height/14.13))**;
>>>
>>> params.setMargins((int)Math.ro**und( width/2.27), 0, 0,
>>> (int)Math.round(height/2.91));
>>>
>>> params.addRule(RelativeLayout.**ALIGN_LEFT,R.id.imageViewClk);
>>>
>>>
>>> params.addRule(RelativeLayout.**ALIGN_BOTTOM,R.id.imageViewClk**);
>>>
>>> myCustomTwistedProgressBar.set**LayoutParams(params);
>>> }else if ( density == 0.75f ){
>>>
>>> ImageView micImage = ((ImageView)
>>> findViewById(R.id.imageViewClk**));
>>>
>>> Drawable drawing = micImage.getDrawable();
>>> Bitmap bitmap = ((BitmapDrawable)drawing).getB**itmap();
>>>
>>> // Get current dimensions
>>> int width = bitmap.getWidth();
>>>
>>> int height = bitmap.getHeight();
>>>
>>> LayoutParams params = new LayoutParams((int)(height/14.**88),
>>> (int)(height/14.88));
>>>
>>> params.setMargins((int)(width/**2.27), 0, 0,
>>> (int)(height/2.69));
>>>
>>> params.addRule(RelativeLayout.**ALIGN_LEFT,R.id.imageViewClk);
>>>
>>>
>>> params.addRule(RelativeLayout.**ALIGN_BOTTOM,R.id.imageViewClk**);
>>>
>>> myCustomTwistedProgressBar.set**LayoutParams(params);
>>> }
>>>
>>> Everything worked fined on different screen sizes however when I tried
>>> to check on 480x854 resolution the vertical alignment of the custom view
>>> was incorrect. Checked with 480x800 on the same screen size and it again
>>> works. I than went for a big jump and checked in GalaxyTab and the
>>> horizontal and vertical alignments were wrong. Now my first though was that
>>> the bitmap width and height were the one of the image not the actual
>>> resized imageview. So I spent a lot of time on trying to get the real size
>>> of the imageview and even went for viewTreeObserver but the results were
>>> all the same - the correct, unchanged (unscaled?) bitmap size. So being
>>> positive that the problem is not here I couldn't get through further. I see
>>> 2 options here:
>>>
>>> -either I still can't get the true 'real' size of the imageview
>>> (although I think I have ruled this out by checking the size by adding
>>> listeners to biewTreeObserver)
>>> -or, although I get the right size and calculate the alignment
>>> parameters correctly, they are somehow 'incorrectly' (differently) used in
>>> the layout.
>>>
>>>
>>> Does anyone have an idea why the alignment is not working correctly?
>>>
>>> PS: as for the image view in layout xml file I have 2 configurations for
>>> long and notlong but this image has the same description in both:
>>>
>>> <ImageView
>>> android:src="@drawable/**cloking"
>>>
>>> android:id="@+id/**imageViewClk"
>>> android:layout_height="wrap_**content"
>>> android:layout_width="wrap_**content"
>>>
>>> android:layout_**centerHorizontal="true"
>>> android:layout_above="@+id/**imageViewProcess"
>>> android:adjustViewBounds="**true"
>>>
>>> android:cropToPadding="false"
>>> android:layout_marginTop="**60dp"
>>> android:scaleType="fitXY">
>>> </ImageView>
>>>
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>>
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