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
Related
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
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.
I've created a custom View that implements onMeasure:
#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( width / height > aspectRatio //too wide
&& (
widthMode == MeasureSpec.AT_MOST ||
widthMode == MeasureSpec.UNSPECIFIED
)
) {
width -= (width - height * aspectRatio);
}
if( width / height < aspectRatio //too tall
&& (
heightMode == MeasureSpec.AT_MOST ||
heightMode == MeasureSpec.UNSPECIFIED
)
) {
height -= (height - width / aspectRatio);
}
setMeasuredDimension((int)width, (int)height);
}
The intention is, where possible, to create a rectangle whose aspect ratio is the same as the one specified by nominalheight and nominalwidth. Obviously if the function is passed MeasureSpec.EXACTLY then it should lay out with the dimension given in that direction.
I'm laying this View out with WRAP_CONTENT in the xml in both directions. What's puzzling me is that, stepping through the onMeasure calls, half of them show MeasureSpec.AT_MOST and the routine calculates the correct rectangle, and the other half show MeasureSpec.EXACTLY and it obviously uses the given dimensions. Even more puzzlingly, if I disable the conditionality (I would assume, from documentation and the example code, incorrectly) it works fine.
Why am I getting these alternating calls with different values, and how can I persuade Android to lay my View out in the correct dimensions?
The way I solved this problem is by creating a custom view for the child views, and then overriding onMeasure() for the custom view. The new onMeasure() sets the width and height to be as large as possible.
The problem is when you show the soft keyboard and rotate the phone. With the orientation change and the keyboard showing, onMeasure() sets the "largest" available height to be something ridiculously small, so when I hide the keyboard, the child views have the wrong size.
Is there a way to tell the views to recompute the layout when the keyboard goes away? Or am I doing onMeasure() wrong? Here's the code:
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec){
int parentWidth = MeasureSpec.getSize(widthMeasureSpec);
int parentHeight = MeasureSpec.getSize(heightMeasureSpec);
setMeasuredDimension(measureWidth(widthMeasureSpec),
measureHeight(heightMeasureSpec));
setLayoutParams(new LinearLayout.LayoutParams(
measureWidth(widthMeasureSpec), measureHeight(heightMeasureSpec))
);
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
}
public int measureWidth(int measureSpec) {
int result = 0;
int specMode = MeasureSpec.getMode(measureSpec);
int specSize = MeasureSpec.getSize(measureSpec);
Display display = ( (WindowManager)getContext().getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay();
int screenWidth = display.getWidth();
if (specMode == MeasureSpec.EXACTLY) {
// We were told how big to be
result = specSize;
} else {
// Measure the view
result = screenWidth;
if (specMode == MeasureSpec.AT_MOST) {
// Respect AT_MOST value if that was what is called for by measureSpec
result = Math.min(result, specSize);
}
}
Log.d(TAG, "Width: "+String.valueOf(result));
return result;
}
measureHeight() is done the same way.
Your super.onMeasure(widthMeasureSpec, heightMeasureSpec) uses the passed in values I would think you would want these to be the actual measured width and height:
super.onMeasure(measureWidth(widthMeasureSpec), measureHeight(heightMeasureSpec));
I made a custom view. If I add the view to the layout XML file and I set the height to fill_parent "specSize" return 0. Why?
Code:
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
int measuredHeight = 90;
int specMode = MeasureSpec.getMode(heightMeasureSpec);
int specSize = MeasureSpec.getSize(MeasureSpec.getMode(heightMeasureSpec));
if(specMode != MeasureSpec.UNSPECIFIED){
measuredHeight = specSize;
}
setMeasuredDimension(60, measuredHeight);
}
Does anyone know how I can get the height of fill_parent?
You don't need to call MeasureSpec.getMode inside of call to 'getSize' whole idea of measure spec is to combine way of measuring ( knowing as Spec) and associated Size. See documentation for MeasureSpec.makeMeasureSpec method.So correct code will look something like:
int widthSpec = MeasureSpec.getMode(widthMeasureSpec);
int width = MeasureSpec.getSize(widthMeasureSpec);
The correct code will be:
int specMode = MeasureSpec.getMode(heightMeasureSpec); ----This was already correct
int specSize = MeasureSpec.getSize(heightMeasureSpec); ----This is corrected.