Develop Reference

Set gravity of dynamic textview

I have created a text view dynamically.I want to set its gravity to right.I have used textview.setGravity(Gravity.RIGHT) but its not working.When I am using it the text view is aligned to left direction only.How can I set the gravity of textview?I dont want to use setPadding().
textMore[i]=new TextView(this);
textMore[i].setGravity(Gravity.Right);
textMore[i].setText("more....");
textMore[i] .setTextColor(Color.BLUE);

you can't change alignment of TextView by setGravity , it changes the TextView contents alignment.

You can do
LinearLayout.LayoutParams textParams = (LinearLayout.LayoutParams) textMore[i].getLayoutParams();
textParams.gravity = Gravity.RIGHT;
textMore[i].setLayoutParams(textParams);
and then add the view in your dynamic LinearLayout

If the parent of your text view is RelativeLayout(Prefer this)
set : alignParentRight
If the parent of your text view is LinearLayout
set : setLayoutGravity(Gravity.Right)
or
LinearLayout.LayoutParams textParams = (LinearLayout.LayoutParams)textMore[i].getLayoutParams();
textParams.gravity = Gravity.RIGHT;
textMore[i].setLayoutParams(textParams);
setGravity(Gravity.Right) ==> This property will align the text inside your textView, rather than aligning the view in its parent.

Firstly set your textView Width property to fill parent then you can set it gravity to right
if you are using linear layout

The View Scroll when the keyboard is showing

In Android, I have a RelativeLayout named A. It has a view named B in the top of A. It has a view named C in the bottom of A.
Code I have so far:
RelativeLayout A = new RelativeLayout(context);
View B = new View(context);
LayoutParams paramsB = new LayoutParams(LayoutParams.FILL_PARENT, 40);
paramsB.addRule(RelativeLayout.ALIGN_PARENT_TOP);
View C = new View(context);
LayoutParams paramsC = new LayoutParams(LayoutParams.FILL_PARENT, 40);
paramsC.addRule(RelativeLayout.ALIGN_PARENT_BOTTOM);
A.addView(B,paramsB);
A.addView(C,paramsC);
How do I adjust the RelativeLayout size when the keyboard shows?

I think you can set layout parameters of 'A' relative layout to WRAP_CONTENT so that when keyboard comes from bottom then it will adjust the height with relative layout.I doubt about the rules you added to 'B' and 'C' relative layout because you have added Align_parent_bottom and Align_parent_top to true.

There are two ways to achieve that:
First you can define the following attribute in of AndroidManifest.xml
android:windowSoftInputMode="stateVisible|adjustResize"
Second you can add scrollview as your parent view of your whole view.

Why can't I set the gravity for my view

I want to set the gravity of a view (in my .java file) but for some reason it can't be done this time (it states that there is no such method). But normally setGravity(Gravity.CENTER); will just be considered valid code.
So why can't it be done all the time? What should I do when I can't set the gravity of a view but I still want to align it to mid( like setGravity(Gravity.CENTER);)?
AScrollView middle = new AScrollView(context);
RelativeLayout.LayoutParams formid =
new RelativeLayout.LayoutParams(width,LayoutParams.WRAP_CONTENT);
middle.setLayoutParams(formid);
middle.setGravity(Gravity.CENTER); //This can't be done..

I can't say exactly why you can't set Gravity on ScrollView but I'm pretty sure you can't. However, if you have a ScrollView then you should have some Layout or content inside of it to scroll. Simply set the Gravity on that Layout and it should give you the effect you want

use this way..First add the view middle then after try to set gravity
formid.addView(middle) ;
middle.setGravity(Gravity.CENTER);

Layout Gravity is not supported by RelativeLayout. It is supported e.g. by LinearLayout where you can set it via the public property gravity of the LinearLayout.LayoutParams class.

try this code.
ScrollView middle = new ScrollView(this);
middle.setLayoutParams(newLayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT,Gravity.CENTER));
let me know the status.

RelativeLayout add rule "RelativeLayout.LEFT_OF" not working

I have a relativeLayout like below:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="horizontal"
android:id="#+id/parent" >
<ListView
android:layout_width="360dp"
android:layout_height="600dp"
android:id="#+id/list"
android:inputType="text"
android:maxLines="1"
android:layout_margin="50dp"
android:layout_alignParentRight="true"
/>
</RelativeLayout>
In the java code, I want to add a view to the left of the listview, but it didn't worked:
m_relativeLayout = (RelativeLayout)findViewById(R.id.parent);
RelativeLayout.LayoutParams layoutParams = new RelativeLayout.LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT);
layoutParams.addRule(RelativeLayout.LEFT_OF, m_listView.getId());
Button button2 = new Button(this);
button2.setText("I am button 2");
m_relativeLayout.addView(button2, layoutParams);
only if I set the listview to alignParentRight, it will work. Is this an android bug or I'm missing something?
I always try addView(View child, int index, LayoutParams params), but it might only work in the linearlayout. So is there an normal solution to make the RelativeLayout.LEFT_OF work?
EDIT
I have tried RelativeLayout.BELOW and RelativeLayout.RIGHT_OF, and they worked perfectly, so it means I don't have enough place to get the button? I tried to give more space, but it still not work.
I use Toshiba AT100 (1280*800) and landscape, so the space is enough. Test below and right just same as the left. I think If i put an control A in the relativelayout, then I add control B and decalare it's on the left of the control A, the result should be the control B will push the control A to its right, right?

I think If i put an control A in the relativelayout, then i add control B and declare it's on the left of the control A, the result should be the control B will push the control A to its right, right?
Your assumption is incorrect, the control A will not be pushed to the right unless you specified this with a RelativeLayout.LayoutParams rule. RelativeLayout places its children one one top of each other starting at the top-left corner of the screen if you don't specify placement rules for them. When you add the View A to the RelativeLayout without any rules(like layout_alignParentRight) it will be placed starting from the top-left corner of the screen. Then, when you add the View B, the rule to_leftOf will apply to this View position but this rule doesn't mean anything for the View A who will maintain its position on the screen. This will make View B to be place to the left of View A but outside of the screen as View A bounds start from the left border of the screen.
The Button will be placed to the left of the ListView when you use layout_alignParentRight="true" because there is now space to actually see the Button(it's not outside anymore). addView(View child, int index, LayoutParams params) works in a LinearLayout because the LinearLayout arranges its children in a row or column(depending on orientation) so when you add a View at a specific position, it will push the other Views after it to the right or below(depending on orientation)(there is no relative positioning of the views in a LinearLayout, the only rule is that the children come one after the other).
Starting with the ListView without any rules set on it, here is an example on how to make the Button to appear on the left of the ListView:
RelativeLayout.LayoutParams layoutParams = new RelativeLayout.LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT);
Button button2 = new Button(this);
button2.setText("I am button 2");
button2.setId(1000);
m_relativeLayout.addView(button2, layoutParams);
RelativeLayout.LayoutParams rlp = (RelativeLayout.LayoutParams) m_listView
.getLayoutParams();
rlp.addRule(RelativeLayout.RIGHT_OF, button2.getId());
The Button will be added as normal to the screen and it will appear starting from the top-left corner of the screen. Without the two lines from the code above the Button and ListView will overlap as this is the normal behavior of RelativeLayout for children without any rules on them. We then explicitly modify the position of the ListView to move it to the right(with the last two line from the code above).

If your variable names are indicative, it's because you are adding the widget to a LinearLayout, so tags for a RelativeLayout get ignored.
This line is the one I'm talking about:
m_linearLayout.addView(button2, layoutParams);
EDIT
You say alignParentRight works... the only difference there is that ot doesn't take an anchor parameter. Perhaps m_listView.getId() isn't returning the proper id. You could step through with the debugger and see if it's returning a proper value.
Maybe you could try calling the id specifically...
layoutParams.addRule(RelativeLayout.LEFT_OF, R.id.list);

To perform it, use predefined view ID or declare one. In values folder create ids.xml then add a Item like this:
<item name="imageViewID" type="id"/>
use this id in your code where you are creating new Instance of view like this:
RelativeLayout layout=new RelativeLayout(context);
ImageView imageView = new ImageView(context);
imageView.setId(R.id.imageViewID);
RelativeLayout.LayoutParams layoutParams = new LayoutParams(50, 50);
layoutParams.addRule(RelativeLayout.CENTER_HORIZONTAL);
layout.addView(imageView, layoutParams);
TextView textView = new TextView(context);
RelativeLayout.LayoutParams textViewParams= new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
textViewParams.addRule(RelativeLayout.CENTER_HORIZONTAL);
textViewParams.addRule(RelativeLayout.BELOW, imageView.getId());
layout.addView(nameView, nameLayoutParams);
or we can directly use this function View.generateViewId() to perform the same. Like this:
imageView.setId(View.generateViewId());

I think you might have forgotten to add m_listView to the RelativeLayout or m_listView's visibility would be GONE.
Can you please check for that?

setId before align is called, especially for the new object view.

If you are using a custom id and not a regular generated Android id (eg. R.id.my_id), make sure that the id is not equal to 0 (or negative), otherwise the rule will be ignored.

dynamically adding a view to activity layout

I have a custom view (an extension of a TextView) that I want to dynamically add to my Layout (don't want to include it in the main.xml file).
The book says to fetch the RelativeLayout using findViewById() in my java code then create a new instance of my custom view, then use addView on the RelativeLayout to add the new view.
I'm not getting any errors, but when I click my button to add the new view, nothing is happening (view isn't being added). Do I need to set additional properties on my custom view (layout width, layout height for example) in order for it to be shown?
EDIT: adding code
// changed to an imageview as I thought it might be easier to see an image
RelativeLayout rel = (RelativeLayout) findViewById(R.id.rellay);
MyCustomImageView mciv = new MyCustomImageView(null);
mciv.setId(5);
LayoutParams p = new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
mciv.setLayoutParams(p);
mciv.setImageResource(R.drawable.someImage);
rel.Addview(mciv);

Please post your code where you add the view.
But yes, you might be missing the params for width and height. Try something like
LayoutParams p = new LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.FILL_PARENT);
txtView.setLayoutParams(p);
or what you would like the width and height to be. Also in xml layout, layout_width and layout_height are required attributes.