Develop Reference

How to know if widgets width is set to wrap_content

I am creating a custom view which extends LinearLayout. I'm adding some shapes to the linear layout, currently with a fixed value of space between them. I'm doing so by defining a LayoutParams and setting the margins to create the space between the shapes.
What I want to do is span them at an equal space across the entire screen so they would fill it, but only if the width of the view is set to either match_parent or fill_parent. If it's set to wrap_content then the original fixed value of space should be set.
I've tried doing:
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
{
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
int parentWidth = MeasureSpec.getSize(widthMeasureSpec);
spaceBetweenShapesPixels = (parentWidth - shapeWidth * numberOfShapes) / numberOfShapess;
}
However, the method seems to be called twice - Once for the width and height of the parent and after that for the View's itself and when it's for the view itself, the space gets a 0 value.
So how can I just make this logic:
if(width is wrap_content)
{
space = 10;
}
else
{
space = (parentWidth - shapeWidth * numberOfShapes) / numberOfShapess;
}

You should use WidthMode and HeightMode
In the onMeasure() method. Below is sample a from one of my projects
#Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
int widthMode = MeasureSpec.getMode(widthMeasureSpec);
int heightMode = MeasureSpec.getMode(heightMeasureSpec);
int measuredWidth = 0, measuredHeight = 0;
if (widthMode == MeasureSpec.EXACTLY || widthMode == MeasureSpec.AT_MOST) {
measuredWidth = MeasureSpec.getSize(widthMeasureSpec);
}
if (heightMode == MeasureSpec.EXACTLY) {
measuredHeight = MeasureSpec.getSize(heightMeasureSpec);
} else if (heightMode == MeasureSpec.AT_MOST) {
double height = MeasureSpec.getSize(heightMeasureSpec) * 0.8;
measuredHeight = (int) height;// + paddingTop + paddingBottom;
}
}
MeasureSpec.EXACTLY - A view should be exactly this many pixels regardless of how big it actually wants to be.
MeasureSpec.AT_MOST - A view can be this size or smaller if it measures out to be smaller.
MeasureSpec.UNSPECIFIED - A view can be whatever size it needs to be in order to show the content it needs to show.
Refer this for more details https://stackoverflow.com/a/16022982/2809326

How to cut off an unused space in a custom view?

I have a custom View which has bigger height than its inner drawn content. I tried to set desired content height manually in code like this:
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
int widthMode = MeasureSpec.getMode(widthMeasureSpec);
int widthSize = MeasureSpec.getSize(widthMeasureSpec);
int heightMode = MeasureSpec.getMode(heightMeasureSpec);
int heightSize = MeasureSpec.getSize(heightMeasureSpec);
int chosenWidth = chooseDimension(widthMode, widthSize);
int chosenHeight = chooseDimension(heightMode, heightSize);
int chosenDimension = Math.min(chosenWidth, chosenHeight);
centerX = chosenDimension / 2 - offsetCenterX;
centerY = chosenDimension / 2 - offsetCenterY;
setMeasuredDimension(chosenDimension, chosenDimension - 200); //IN HERE I`M TRYING TO CROP THE VIEWS HEIGHT
}
But it appears that my View scales down. I do not need this.
My solution to this was to reset ALL the dimensions in dimen.xml, but it kinda wrong. Any idea how to crop it in a right and easy way?
Here it is a picture what I want to cut off

Well, I would not have to cut off that space. Just set the correct values in onMesaure(). And to scale all dimens in dimens.xml

How to fit png/jpg images on any screen without decreasing quality?

I know it's bit tricky and still thinking whether is it possible or not, but i want to make my image to adjust without decreasing in image quality on any android device when i used vector Drawable it was pretty convenient but sometimes size of vectors are not memory efficient so i don't want to use them.Though i want to know if there is any way to adjust simple PNG or JPEG files irrespective of resolution and screen size in Android?
If anyone can give me way,it would be great help !!

Use Resize Image View (Custom Image View)
public class ResizableImageView extends ImageView {
public ResizableImageView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public ResizableImageView(Context context) {
super(context);
}
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
Drawable d = getDrawable();
// get drawable from imageview
if (d == null) {
super.setMeasuredDimension(widthMeasureSpec, heightMeasureSpec);
return;
}
int imageHeight = d.getIntrinsicHeight();
int imageWidth = d.getIntrinsicWidth();
// get height and width of the drawable
int widthSize = MeasureSpec.getSize(widthMeasureSpec);
int heightSize = MeasureSpec.getSize(heightMeasureSpec);
// get width and height extracts the size from the supplied measure specification.
float imageRatio = 0.0F;
if (imageHeight > 0) {
imageRatio = imageWidth / imageHeight;
}
float sizeRatio = 0.0F;
if (heightSize > 0) {
sizeRatio = widthSize / heightSize;
}
int width;
int height;
if (imageRatio >= sizeRatio) {
// set width to maximum allowed
width = widthSize;
// scale height
height = width * imageHeight / imageWidth;
} else {
// set height to maximum allowed
height = heightSize;
// scale width
width = height * imageWidth / imageHeight;
}
setMeasuredDimension(width, height);
// This method must be called to store the measured width and measured height. Failing to do so will trigger an exception at measurement time
}
}

Telling the Android layout inflater how large "wrap_content" should be

I want to create a custom View, such that when it is inflated with wrap_content as one of the dimension parameters and match_parent as the other, it will have a constant aspect ratio, filling whichever dimension is set to match_parent, but providing the layout inflater with the other dimension to be "wrapped". I presume this is possible because, for example, a full screen width TextView would obviously be able to demand that it have space for two, three or any arbitrary number of lines of text (depending on width), but would not necessarily know this until inflation-time.
Ideally what I want to do is override layout methods in the View subclass such that when the view is inflated, I get the layout information, and supply my own dimensions for the "content" to be wrapped (ie my fixed-ratio rectangle).
I will need to create a lot of these custom views and put them in various different types of layout—sometimes using an Adapter—so really I want to have the maximum control over their inflation I can. What's the best technique for doing this?

You can always check for compliance to aspect ratio in onMeasure.
not a full answer I know, but it should lead you there ;)

I've now solved this with the following code. It's worth mentioning in passing that the class I'm overriding is a custom ViewGroup with custom children, all using the inherited onMeasure. The children are created and added at construction-time, and I would assume as a matter of course that this is necessary.
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
float width = MeasureSpec.getSize(widthMeasureSpec);
final int widthMode = MeasureSpec.getMode(widthMeasureSpec);
float height = MeasureSpec.getSize(heightMeasureSpec);
final int heightMode = MeasureSpec.getMode(heightMeasureSpec);
float nominalHeight = getResources().getInteger(R.integer.nominalheight);
float nominalWidth = getResources().getInteger(R.integer.nominalwidth);
float aspectRatio = nominalWidth / nominalHeight;
if( widthMode == MeasureSpec.UNSPECIFIED ) { //conform width to height
width = height * aspectRatio;
}
else if (heightMode == MeasureSpec.UNSPECIFIED ) { //conform height to width
height = width / aspectRatio;
}
else if( width / height > aspectRatio //too wide
&& ( widthMode == MeasureSpec.AT_MOST )
) {
width -= (width - height * aspectRatio);
}
else if( width / height < aspectRatio //too tall
&& ( heightMode == MeasureSpec.AT_MOST )
) {
height -= (height - width / aspectRatio);
}
int newWidthMeasure = MeasureSpec.makeMeasureSpec((int)width, MeasureSpec.AT_MOST);
int newHeightMeasure = MeasureSpec.makeMeasureSpec((int)height, MeasureSpec.AT_MOST);
measureChildren(newWidthMeasure, newHeightMeasure);
setMeasuredDimension((int)width, (int)height);
}
I'm defining the aspect ratio in terms of a nominal rectangle in resources, but obviously there are plenty of other ways to do this.
With thanks to Josephus Villarey who pointed me at onMeasure(...) in the first place.

What's a simple way to make a view's layout_width="match_parent" and make the height equal to its width?

I would like a view styled similar to the album art in the Rdio app (img)
I don't know how I should be going about this. I want to load a bitmap into the view, if that affects the solution at all.

In this case (where the control has the full width of the device) you can always just use getWindowManager().getDefaultDisplay().getWidth(); to get the width and then manually set the height.
If you're not using the full display width then you'll probably need to override onMeasure in the View class and set the height to match the width in there, perhaps like this:
#Override protected void onMeasure( int widthMeasureSpec, int heightMeasureSpec )
{
viewWidth = MeasureSpec.getSize( widthMeasureSpec );
viewHeight = MeasureSpec.getSize( heightMeasureSpec );
if(viewWidth != 0) viewHeight = viewWidth;
setMeasuredDimension( viewWidth, viewHeight );
}