Develop Reference

getLayoutParam returning width as -1

I am trying to set the layout width programatically .
ViewTreeObserver vtoRecyclerView = mMainLayout.getViewTreeObserver();
vtoRecyclerView.addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
#Override
public void onGlobalLayout() {
mMainLayout.getViewTreeObserver().removeGlobalOnLayoutListener(this);
ViewGroup.LayoutParams lpView = mMainLayout.getLayoutParams();
lpView.width = ViewGroup.LayoutParams.MATCH_PARENT-20;
mMainLayout.requestLayout();
}
});
but mMainLayout.getLayoutParams() is returning width as -1 .so when I set width as match_parent - 20 it becomes -21. I want to set the width as match_parent - 20.
What is wrong with the approach.

The root problem with your code here, is because you set the width with:
lpView.width = ViewGroup.LayoutParams.MATCH_PARENT-20;
while ViewGroup.LayoutParams.MATCH_PARENT is a constant.
You can find the constant on ViewGroup class
public static final int MATCH_PARENT = -1;
So that is obvious, because -1 - 20 is -21
What you can do here is, you can change the line to
lpView.width = mMainLayout.getWidth()-20;

try this.
DisplayMetrics displaymetrics = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(displaymetrics);
int height = displaymetrics.heightPixels;
int width = displaymetrics.widthPixels;
ViewTreeObserver vtoRecyclerView = mMainLayout.getViewTreeObserver();
vtoRecyclerView.addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
#Override
public void onGlobalLayout() {
mMainLayout.getViewTreeObserver().removeGlobalOnLayoutListener(this);
ViewGroup.LayoutParams lpView = mMainLayout.getLayoutParams();
lpView.width = width -20;
mMainLayout.requestLayout();
}
});

Try this.
ViewTreeObserver vtoRecyclerView = mMainLayout.getViewTreeObserver();
vtoRecyclerView.addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
#Override
public void onGlobalLayout() {
if(mMainLayout.getWidth > 10 && mMainLayout.getHeight() > 10) // you can modify this value.
{
mMainLayout.getViewTreeObserver().removeGlobalOnLayoutListener(this);
ViewGroup.LayoutParams lpView = mMainLayout.getLayoutParams();
lpView.width = ViewGroup.LayoutParams.MATCH_PARENT-20; // This seems to be wrong;
ViewParent parent = mMainLayout.getParent();
if(parent != null) {
lpView.width = (View)parent.getWidth();
}
mMainLayout.requestLayout();
}
}
});

I had the same problem while setting width as match_parent, I had resolved this by getting the phone screen width as follows:
Display display = ((Activity) context).getWindowManager().getDefaultDisplay();
Point size = new Point();
display.getSize(size);
int width = size.x;
int ActualWidth=width-(`margin you set for view`);
Hope it will help :)

As ViewGroup.LayoutParams.MATCH_PARENT constant predefined numeric value is -1 so you are getting -21 as result. and what you want can be achieved by defining margin to a layout rather than using that approach.

Changing WRAP_CONTENT to a set number using LinearLayout.LayoutParams

I have set up some LinearLayout.LayoutParams to set up some buttons just using java. But I want to change it from WRAP_CONTENT to a height and width of my choice.
//LinearLayout.LayoutParams top;
//this is declared at the top as it is used by different bits of the code.
top = new LinearLayout.LayoutParams
(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT);
top.topMargin = 100;
top.leftMargin = 120;

top = new LinearLayout.LayoutParams
(90, 80);
// whatever u like
this is from documentation:
public LayoutParams(int width, int height) {
super(width, height);
weight = 0;
}

According to ViewGroup.MarginLayoutParams.html#setMargins you have to use this:
LinearLayout layout = (LinearLayout)findViewById(R.id.yourLinear_Layout);
LayoutParams params = new LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT);
params.setMargins(120, 100, 0, 0); //Here your custom margin (int left, int top, int right, int bottom)
layout.setLayoutParams(params);

Have you tried?
top.getLayoutParams().height = 256;
top.getLayoutParams().width= 256;
top.requestLayout();

try like this..
LinearLayout layout = (LinearLayout)findViewById(R.id.numberPadLayout);
// Gets the layout params that will allow you to resize the layout
LayoutParams params = layout.getLayoutParams();
// Changes the height and width to the specified *pixels*
params.height = 100;
params.width = 100;
layout.setLayoutParams(params);

ImageView dynamic position

i'm using the following code to position ImageView
DisplayMetrics displayMetrics = new DisplayMetrics();
getActivity().getWindowManager().getDefaultDisplay().getMetrics(displayMetrics);
int height = displayMetrics.heightPixels;
int width = displayMetrics.widthPixels;
bg = (ImageView) rootView.findViewById(R.id.rectimage);
bg.getLayoutParams().width = width;
bg.getLayoutParams().height = 500;
MarginLayoutParams params = (MarginLayoutParams)bg.getLayoutParams();
params.setMargins(0, height - 510, 0, 0);
i want to place ImageView always at the bottom of screen but screenHeight - image_height is not working Any ideas?

Try to add
android:layout_alignParentBottom="true"
to your ImageView in your layout xml file

Layout params getWidth() returns zero

i have a RelativeLayout here's the code :
<RelativeLayout
android:id="#+id/camerapreview"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_margin="10dp"
android:background="#000">
</RelativeLayout>
its a camera preview for the camera application, i set the width to match_parent.
and here is my java code :
RelativeLayout preview = (RelativeLayout) findViewById(R.id.camerapreview);
int w = preview.getWidth();
LayoutParams params = preview.getLayoutParams();
params.width = w;
params.height = w;
preview.addView(mPreview);
basically i decalaired the width of the RelativeLayout to match_parent to be dynamic to the width of any device. But i want the view to be square so i used the java code abave, but every time i ran the program this line int w = preview.getWidth(); returns zero. I must have missed something, help please :D thank you.

The size of view cannot be calculated until its parent is calculated you can force that with following code:
view.measure(MeasureSpec.UNSPECIFIED, MeasureSpec.UNSPECIFIED);
int widht = view.getMeasuredWidth();
int height = view.getMeasuredHeight();
there is three way to do this, see this link
EDIT
you can use this too.
RelativeLayout layout = (RelativeLayout) findViewById(R.id.camerapreview);
ViewTreeObserver vto = layout.getViewTreeObserver();
vto.addOnGlobalLayoutListener(new OnGlobalLayoutListener() {
#Override
public void onGlobalLayout() {
hs.getViewTreeObserver().removeGlobalOnLayoutListener(this);
int width = layout.getMeasuredWidth();
int height = layout.getMeasuredHeight();
}
});

this may help you...
RelativeLayout preview = (RelativeLayout) findViewById(R.id.camerapreview);
int width = getResources().getDisplayMetrics().widthPixels;
ViewGroup.LayoutParams params = preview.getLayoutParams();
params.width = width;
params.height = width;
preview.setLayoutParams(params);
here preview will occupy entire screen width... and it will be square shaped...

Layout has width 'match parent' . So if it hasn't views (is empty) width = 0.
Solution:
Add views to layout
Or set width to 'fill parent'

Get screen sizes & set them in carousel view android

Here you can see my carousel layout xml file.
<com.touchmenotapps.carousel.simple.HorizontalCarouselLayout
android:id="#+id/carousel_layout_event"
android:layout_width="600dp"
android:layout_height="500dp"
android:layout_above="#+id/relativeLayout1"
android:layout_alignTop="#+id/carousel_layout" >
</com.touchmenotapps.carousel.simple.HorizontalCarouselLayout>
I want to set the running android simulator screen width & height to the android:layout_width & android:layout_height...
can anyone help me. thanks

HorizontalCarouselLayout hcl=(HorizontalCarouselLayout)findViewById(R.id.carousel_layout_event);
Display display = getWindowManager().getDefaultDisplay();
Point size = new Point();
display.getSize(size);
int width = size.x;
int height = size.y;
hcl.setLayoutParams(new LayoutParams(width,height));

Firs you get the divice size i.e.
Display display = getWindowManager().getDefaultDisplay();
Point size = new Point();
display.getSize(size);
int divWidth= size.x;
int divHeight = size.y;
Create a function to set the layout params. i.e.
public void setWidthHeight(View v, int width, int height){
LayoutParams lp;
lp = v.getLayoutParams();
lp.width = width;
lp.height = height;
v.setLayoutParams(lp);
}
then call this function as,
setWidthHeight(yourView,divWidth,divHeight);