Develop Reference

Centering multiple textViews programmatically on Android

I have an Open GL ES 2.0 app and am displaying an Android TextView over the top of my GLSurfaceView.
I have the actual textviews displaying OK but now I need to try to centre them.
This is what I have so far:
text1 = new TextView(this);
text1.setText("This is some sample text");
text1.setTextColor(Color.WHITE);
text1.setTextSize(textSize);
text2= new TextView(this);
text2.setText("And this is some more sample text");
text2.setTextColor(Color.WHITE);
text2.setTextSize(textSize);
RelativeLayout.LayoutParams textParams = new RelativeLayout.LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.MATCH_PARENT);
lp.addRule(RelativeLayout.CENTER_HORIZONTAL);
textLayout = new RelativeLayout(this);
textLayout.setLayoutParams(textParams);
textLayout.addView(text1);
textLayout.addView(text2);
mainLayout.addView(textLayout);
However, when I run this, only text1 is centered. Text 2 isn't, and starts at the left side of the first (correctly centered) textView. Try as I might, I can't seem to get both of them centered. The following graphic describes what I mean:
(Please note re vertical placement - in my actual results, both TextViews are at the same vertical/'y' position and therefore overlapping - obviously this is expected as I haven't changed the vertical position of the 2nd TextView, but to make things clearer to illustrate, I've moved the 2nd one down manually.......)
The idea I was going with was creating a 'textLayout' to which I could add all of my textViews, then just add that textLayout to my main layout. Thus facilitating the addition and removal of all of the textViews with a single line of code.
Please note that I am not using, and do not wish to use, XML for this - I would like to know how to do this programmatically.
What am I missing?
Edit Here is how I am creating my Main Layout to which I am adding the textView.....
layout = new RelativeLayout(this);
layout.setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));

When you are adding "RelativeLayout.CENTER_HORIZONTAL" as a rule to your layout params, what you are actually doing is telling textLayout that it should be centered horizontally in your mainLayout (see http://developer.android.com/reference/android/widget/RelativeLayout.LayoutParams.html#attr_android:layout_centerHorizontal). In code you should actually do text1.setGravity(Gravity.CENTER) and text2.setGravity(Gravity.CENTER).

Handling an EditText that was added programatically

I've been making all of my views dynamically, and now I've come to the point where I want to add an EditText for people to write in.
I've been able to accomplish this for the most part, but it doesn't look right. I have a linear layout that I'm adding a relative layout to. I'm making the relative layout have a white background, then adding the EditText. Problem is, it always adds it to the direct center of the relative layout, and options to align it vertically to the top have so far failed.
I also need to be able to pull the text from it later when a separate button was pressed (I know how to make the button work, it's the pulling text from it part I'm a bit iffy on). Here's my code so far:
public void addEditText(LinearLayout L){
EditText myEditText = new EditText(c);
myEditText.setSingleLine(false);
RelativeLayout l1 = new RelativeLayout(c);
LinearLayout.LayoutParams lp=new LinearLayout.LayoutParams(scWidth1, 300);
lp.gravity=Gravity.CENTER;
l1.setLayoutParams(lp);
l1.setBackgroundColor(Color.WHITE);
l1.setGravity(Gravity.CENTER_VERTICAL);
l1.addView(myEditText);
L.addView(l1);
}

l1.setGravity(Gravity.CENTER_VERTICAL); places the EditText in center vertical of the parent container i.e RelativeLayout, remove that line.

Building a simple Group Chat View in Android

I'm building a very simple online chat room App. What I have achieved is something like below right now:
Robert:blah..
Tom: yes blah..
David(You): That sounds cool!
Lily: Do you know blah...
Robert:blah..
Robert:blah..
David(You): Wow! Blah...
The new feature/problem I'm facing is that I want current user's talks to show on the right.
Like below(this is what David see on his screen):
Robert:blah..
Tom: yes blah..
That sounds cool! : David(You)
Lily: Do you know blah...
Robert:blah..
Robert:blah..
Wow! Blah... : David(You)
Each line above is a TextView, and I'm dynamically creating TextView whenever there's new message, then adding them to the LinearLayout that contains these TextView. In order to make David(current user)'s talk on the right, I tried to set align right and I change the LinearLayout to RelativeLayout. But then I realize once I use RelativeLayout, all talks are in the same line overlapping each other since I didn't set their height.. Can anyone shed some light on how to achieve this please? My codes below:
...
//new messages are stored in lines[]
for (int i = 0; i < lines.length; i++) {
TextView newLine = new TextView(getBaseContext());
newLine.setText(lines[i]);
// check if the speaker of this line is user himself
if (speakerName.equals(userName)) {
//change the layout of this textView to make it align right..
}
myLinearView.addView(newLine);//add to linearView that contains these talks
}

You definitely need to use a ListView, as Chor WaiChun mentioned. However, the way you would do this with a relative layout would be to set the RelativeLayout.layoutParams for the view with a rule that sets it to layout_below the previous view. Just like you would in XML.
Also, even if you insist on adding 1 view per line (which as previously stated is wrong, use a ListView), there's no reason not to use the LinearLayout. You can have a LinearLayout with right justified text, just set the gravity to right.

Android Making a table look like I want

I am having a little bit of trouble making the table look like I intend to.
These are a few questions, but since they all refer to the picture below and the details I provide I thought they should all be in a single post.
Here is what I achieved so far:
The header row contains one element of type Button.
TableRow.LayoutParams params = new TableRow.LayoutParams(TableRow.LayoutParams.MATCH_PARENT, TableRow.LayoutParams.WRAP_CONTENT);
Button bt = new Button(getContext());
bt.setText("Column1");
mHeader.addView(bt, params);
mHeader.setLayoutParams(new TableRow.LayoutParams(TableRow.LayoutParams.WRAP_CONTENT, TableRow.LayoutParams.WRAP_CONTENT));
addView(mHeader);
The rest of the table is poulated like this:
(Messagerow extends TableRow and has a TextView member)
for(int i = 0; i < 100; i++) {
MessageRow mr = new MessageRow(getContext());
// stuff to set the TexView text and color
mr.setLayoutParams(new TableRow.LayoutParams(TableRow.LayoutParams.WRAP_CONTENT, TableRow.LayoutParams.WRAP_CONTENT));
this.addView(mr);
}
1. How can I make the header row height be more like the rows?
2. How can I make the button occupy the full width of the row?
If the table is empty, no text rows just header, then the button matches the row width. As soon as I add a row of text, the column width is adapted but the button width is not.
3. How can I make the row fill the screen width? (MATCH_PARENT does not do it)
4. How can I draw a thin line between the table rows?
I tried to override the onDraw() function on MessageRow, but it never gets called, not even once.
Don't get me wrong. I am not asking that you do my work for me. These are issues I tried to solve by myself and googled them and read similar posts, but did not find an answer.Note: I find that UI design in Javascript for Android lacks clear control and clear documentation over all these little details.
Edit
This is how I create the table:
TableLayout mTable = new TableLayout(this);
HorizontalScrollView hview = (HorizontalScrollView) findViewById(R.id.hscroll);
populate(mTable);
mTable.setLayoutParams(new TableLayout.LayoutParams( TableLayout.LayoutParams.MATCH_PARENT, TableLayout.LayoutParams.WRAP_CONTENT));
mTable.setBackgroundColor(Color.WHITE);
hview.addView(mTable);

How can I make the header row height be more like the rows?
Using the default Button there isn't much to do. The Button uses a nine-patch image that has some space between the button's text and the borders that you see. You could use a smaller font but that you'll probably look ugly. Another thing to try is using your own background for the Button and get rid of the default extra space(of the default nine-patch image) so the final height is near the height of the text from the TextViews. Or try to enforce a standard height for all rows using a fixed value.
How can I make the button occupy the full width of the row?
I think that you have more then one TextView in MessageRow so when you add the Button it moves to the first column(corresponding to the first TextView). If this is the case, make your Button span across the number of columns representing the number of TextViews in MessageRow:
TableRow.LayoutParams params = new TableRow.LayoutParams(TableRow.LayoutParams.MATCH_PARENT, TableRow.LayoutParams.WRAP_CONTENT);
params.span = 3; // if you have 3 `TextView` in the MessageRow
Button bt = new Button(getContext());
bt.setText("Column1");
mHeader.addView(bt, params);
If this is not the case add more details.
How can I make the row fill the screen width? (MATCH_PARENT does not do it)
As I said on one of your previous questions, I don't know why that happens(but I gave you some solutions there to overcome this issue). Also:
mHeader and the other MessageRow are children of a Tablelayout and the correct LayoutParams to use on them is the LayoutParams of the parent: TableLayout.LayoutParams and not TableRow.LayoutParams.
You add some TextView in the MessageRow(from what I seen in your previous questions), add those child views with TableRow.LayoutParams to MessageRow.
You use only WRAP_CONTENT for your LayoutParams everywhere in your code, you might want to set the width(the first parameter in the constructor) to FILL_PARENT/MATCH_PARENT
How can I draw a thin line between the table rows?
You could use a simple View that will act as a separator:
for(int i = 0; i < 100; i++) {
MessageRow mr = new MessageRow(getContext());
// stuff to set the TexView text and color
mr.setLayoutParams(new TableLayout.LayoutParams(TableLayout.LayoutParams.FILL_PARENT, TableLayout.LayoutParams.WRAP_CONTENT));
this.addView(mr);
View separator = new View(getContext());
separator.setLayoutParams(new TableLayout.LayoutParams(TableLayout.LayoutParams.FILL_PARENT, 3)));
separator.setBackgroundColor(Color.RED);
this.addView(separator);
}
Because you have 100 rows you could try to set a drawable with a separator line as the background for theTableRow(header and MessageRow) instead of the above method that adds another 100 Views to the layout.
Extra Note:
You have a lot of views to add to a single activity layout, you are talking about 100 rows, and if your MessageRow is more complex than a simple TextView(and I think it is) you could get in some performances problems. I suggest you take a look at the wonderful ListView widget.

Don't have a programming environment here, but I'll try and answer some of your questions.
The reason your header row (button) is taller than your test based rows is because the button requires more space and the row accomodates it. The default button has padding on both the top/bottom of the text. I think your best option is to create your own button, which gives you the additional benefit of being able to control the look and feel. It seems like other people have had this issue before: Can't get rid of bottom padding on button
Your button is set to wrap_content which means it won't be any bigger than it needs to be (It will grow/shrink so it can fit the text "Column1" or whatever you put there). Instead of making the Button WRAP, I suspect you'll need to make it FILL_PARENT.
It's not your Table Row that needs to fill the screen width, it's your table that needs to fill the screen. Wherever you define your table, it's probably set to WRAP_CONTENT for the Horizontal dimension. Set it to FILL_PARENT and your table should expand to the full width of whatever it's container is (In this case, it should expand the full width of the screen)
There are probably several different ways you can do this. One method I used somewhat recently is to utilize the View tag which essentially looks like a horizontal bar across the screen. Below is a link to how to implement it.
http://sonnygill.net/android/horizontal-rule/

Setting button alignment programmatically

I'm creating some 50 button dynamically.
Text is getting set as followed:
btn.Text=result.Rows[i]["Col1"].ToString()+"\n"+result.Rows[i]["Col2"].ToString()
+"\n"+result.Rows[i]["Col3"].ToString();
where result is DataTable & btn is object for button.
Now the problem is some of the buttons are not getting displayed appropriately.
Referring to screenshot below,
in img1 - An unnecessary blank line is getting displayed after the first row.
in img2 - Text is not center aligned.
in img3 - TATAMOTORS is not getting displayed in single line even though there is a space on either side of t he button.
Please note that I'm not setting padding which can be the reason for this.
Any idea how to solve this?
Also, how alignment of text of a button can be set programmatically?
I know that this is not the Best of the question, but after spending hours on it, I'm unable to crack it.
Any help appreciated...

You can set the gravity of the button to customize how the text is aligned. This is exposed on the button by using the Gravity property. From the docs:
Sets the horizontal alignment of the text and the vertical gravity that will be used when there is extra space in the TextView beyond what is required for the text itself.
The values you can assign are found in the GravityFlags enum. For example:
button.Gravity = GravityFlags.Center;

Alignment of button content can be set with .setGravity(int)

In the original question, I wonder if the source text contained some extra space characters? That would explain img1 and img2.
Anyway, my need to left-align the text in a button led me to this page, and here's the solution I ended up with, based on Alix Bloom's answer:
Button myButton = new Button(getActivity());
myButton(Gravity.LEFT);

Button myButton = new Button();
myButton.setGravity(Gravity.RIGHT); //LEFT
Hope this help you. Worked for my (i was also strugling with this issue for some time)