Develop Reference

Cannot center text when programmatically creating view from adaptor

I am using an adaptor to generate a view for each of several items. The view needs to show an image with centered text below it. I create a linear layout and add an image view and text view.
To show the problem I have changed the background colors to green for the linear layout and red for the text view...
Obviously the text is showing left aligned instead of centered. Here is the simple code in the adaptor GetView method...
public override View GetView(int position, View convertView, ViewGroup parent)
{
ImageView imageView = new ImageView(_context);
LinearLayout.LayoutParams imageViewParam = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.MatchParent, LinearLayout.LayoutParams.WrapContent);
imageView.LayoutParameters = imageViewParam;
imageView.Id = 1000 + position;
imageView.SetImageResource(Resource.Drawable.Code);
TextView textView = new TextView(_context);
LinearLayout.LayoutParams textViewParam = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.MatchParent, LinearLayout.LayoutParams.WrapContent);
textView.LayoutParameters = textViewParam;
textView.Text = OPTIONS_TEXT[position];
textView.SetBackgroundColor(Color.Red);
textView.SetForegroundGravity(GravityFlags.CenterHorizontal);
LinearLayout linear = new LinearLayout(_context);
linear.LayoutParameters = new GridView.LayoutParams(200, 172);
linear.SetBackgroundColor(Color.Green);
linear.Orientation = Orientation.Vertical;
linear.AddView(imageView);
linear.AddView(textView);
return linear;
}
As far as I can work out, you cannot set the layout_gravity setting when generating the view programmatically and so I tried setting the foreground gravity but has no effect at all.
I have tried everything I can think of but nothing gets that text centered!

Set gravity center to LinearLayout.LayoutParams of TextView i.e.
textViewParam.gravity = Gravity.CENTER;

How to place center of a view inside FrameLayout

I have a FrameLayout which already holds a child view, and I know its width and height in pixels. I want to programmatically add a new view so that its center is at the specific point of the frame layout. Size of the view is not known and its FrameLayout.LayoutParams is set to WRAP_CONTENT, WRAP_CONTENT. How can I do it?

Say you want to position a TextView in the middle of a FrameLayout.
TextView text = (TextView)frame.findViewById(R.id.text);
FrameLayout frame = (FrameLayout)findViewById(R.id.frame1);
FrameLayout.LayoutParams params = new FrameLayout.LayoutParams(LayoutParams.WRAP_CONTENT,
LayoutParams.WRAP_CONTENT);
Now add your TextView to your FrameLayout and set gravity to center
frame.addView(text);
params.gravity=Gravity.CENTER;
I haven't tried it but I think it should work.

In KOTLIN
viewToADD?.layoutParams = FrameLayout.LayoutParams
(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT).
apply {gravity = Gravity.CENTER and Gravity.CENTER_VERTICAL}
frameLayout.addView(viewToADD)

How to dynamically wrap root layout in a ScrollView

I want to add a scroll view to all the layouts that I have. But dynamically. Because the app will run in different screen sizes, and when I will get a screen size smaller than a specific size, then I want to show the layout in a scroll view.
So I made this method, it will be called on the check that the screen is small. I will pass my activity and I want to change the root layout to scroll view or just add a ScrollView as the root layout. So if the root layout is a LinearLayout, then I want to put that layout in the ScrollView. And I have not named all the layouts, meaning that I didn't give an ID to the layout, so I cannot use findViewById.
public static void SetActivityRoot(Activity c) {
View v = c.getWindow().getDecorView();
// View v = v.getRootView();
ScrollView sv = new ScrollView(c);
LayoutParams lp = new LayoutParams(LayoutParams.MATCH_PARENT,
LayoutParams.MATCH_PARENT);
sv.setLayoutParams(lp);
((ViewGroup)v.getParent()).removeView(v);
sv.addView((View) v);
((ViewGroup)v.getParent()).addView(sv);
}
It's giving me an error saying that "you cannot remove view from null" etc. Or that "you cannot add view to layout as it already has parent view". How can I make this work?

Finally solved my problem.
public static void SetActivityRoot(Activity c) {
View v = ((ViewGroup)c.findViewById(android.R.id.content)).getChildAt(0);
ScrollView sv = new ScrollView(c);
LayoutParams lp = new LayoutParams(LayoutParams.MATCH_PARENT,
LayoutParams.MATCH_PARENT);
sv.setLayoutParams(lp);
((ViewGroup) v.getParent()).removeAllViews();
sv.addView((View) v);
c.addContentView(sv, lp);
}

Set framelayout margin and its children width, height and position

I am currently having a programatically created framelayout with a imageview and a text view. By original layout is relative layout.
RelativeLayout layout = (RelativeLayout) findViewById(R.id.rel);
FrameLayout fr = new FrameLayout(this);
fr.setBackgroundResource(R.drawable.question_bar_icon);
ImageView b1 = new ImageView(this);
TextView b2 = new TextView(this);
b1.setBackgroundResource(R.drawable.mcq);
fr.addView(b1);
fr.addView(b2);
layout.addView(fr);
Now i am unable to resize the imageview and the button, also m unable to position them, in the sence textview in the center and imageview in the verticle center and left positioned.
I tried layout params, but not working, any help would be greatly appreciated!

Try using the overloaded version of addView that takes a LayoutParameter as well in every case you are programatically adding a view, otherwise it is inserted to the ViewGroup with default layout parameters. (P.S. you can also control the order of insertion).
For example for the ImageView you wanted to be in the center of the frame layout:
int width = FrameLayout.LayoutParams.WRAP_CONTENT; //or whatever you want
int height= FrameLayout.LayoutParams.WRAP_CONTENT; //or whatever you want
FrameLayout.LayoutParams lp = new FrameLayout.LayoutParams(width, height, Gravity.CENTER);
fr.addView(b1,lp);
Do the same for the other view, and most importantly, do the same, using RelativeLayout.LayoutParams for inserting the frame element itself into your RelativeLayout.

How to programmatically set weight for Button

I need to implement Dialog for my Android app through Java code, so I can't use XML.
I have root LinearLayout where I implement range seek bar, then I have another LinearLayout under root layout, with horizontal orientation, where I want to add two buttons in same row. So I need to set weight to 1, and width to FILL_PARENT and height to WRAP_CONTENT.
How I can do that with Java code?

LinearLayout.LayoutParams p = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.LayoutParams.WRAP_CONTENT);
p.weight = 1;
rangeSeekBar.setLayoutParams(p);
I'm not sure which view you want to set the layout params on. I just assumed the rangeSeekbar to show an example. Change if you need.
When using the layout params always use the root's param type..
Ex. if you have a View you want to apply params to within a RelativeLayout use RelativeLayout.LayoutParams..

You can pass it in as part of the LinearLayout.LayoutParams constructor:
Did you mean wrap_content?
LayoutParams param = new LinearLayout.LayoutParams(
LayoutParams.MATCH_PARENT,
LayoutParams.WRAP_CONTENT, 1.0f);
1.0f is the weight

Is not using XML a requirement? If not, you could always build your layout in XML and then use a LayoutInflater at run-time to build up your view hierarchy and pass that to setView() on your dialog.
For example:
LayoutInflater inflater = LayoutInflater.from(getActivity());
View v = inflater.inflate(R.layout.my_dialog_layout, null);
AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
builder.setView(v);

an easier way:
public static void setLayoutWeight(View view , float weight)
{
((LinearLayout.LayoutParams) view.getLayoutParams()).weight = weight;
view.requestLayout();
}