Develop Reference

Dynamically add element to layout

I am quite new to developing apps. Still I would have thought that this is a basic action, so if there is already a solved thread I would be OK with the link. But since I am searching for over 2 hours for this I am asking anyway:
I want to dynamically add an element to my layout every time the user clicks a button.
By now I have this:
XML (R.layout.game.xml)
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical">
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/submit_choice"
android:onClick="submitChoice"/>
</LinearLayout>
Java
public void submitChoice(View view)
{
TextView textView = new TextView(this);
textView.setTextSize(40);
textView.setText("text");
LinearLayout ll = new LinearLayout(this);
ll.addView(View.inflate(ll.getContext(), R.layout.game, null));
ll.addView(textView);
setContentView(ll);
}
Since the XML file does not change, it only works once.
So how can I add a second text when the user clicks the button a second time (without changing the XML file)? Examples are appreciated.

The problem comes from this line, that recreate the whole layout every time:
LinearLayout ll = new LinearLayout(this);
You should define it and setContentView(ll) outside the submitChoice function. Then on click only create and add the textView , then call ll.invalidate(); to see the changes.
Something like:
LinearLayout ll;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.game);
ll = (LinearLayout) findViewById(R.id.ll_game);
}
// More code...
public void submitChoice(View view) {
TextView textView = new TextView(this);
textView.setTextSize(40);
textView.setText("text");
ll.addView(textView);
ll.invalidate();
}
where ll_game is the id you have to set in xml for your LinearLayout.

Android:conditionally loading option into screen based on another field

Hi I am working on writing my first usable android app. I have the following query , is there a way to populate values of a flied , based on value selected in a spinner.
e.g When country A is selected , 3 values are shown .
But when country B is selected, only 2 values are shown.
Is there a way to achieve this on Android screen? can someone provide some examples or point me in the right direction.

I think this example can help you not sure. I am creating a linear layout on which I will add all option. I am managing options in a hashmap. You can change according to your requirement.
Here is my main Activity:
public class MainActivity extends Activity {
HashMap <String, CheckBox> options = new HashMap<String, CheckBox>();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
int number_of_options = 2;
for (int i = 0; i < number_of_options; i ++) {
create_view("option " + i);
}
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
private void create_view(String option)
{
LinearLayout layout = new LinearLayout(getApplicationContext());
layout.setOrientation(LinearLayout.VERTICAL);
TextView text_option = new TextView(getApplicationContext());
text_option.setText(option);
CheckBox check_box = new CheckBox(getApplicationContext());
layout.addView(text_option);
layout.addView(check_box);
LinearLayout inner_layout = (LinearLayout) findViewById(R.id.linear_layout);
inner_layout.addView(layout);
options.put(option, check_box);
}
}
create_view will create options for you.
Here is my XML layout:
<Spinner
android:id="#+id/spinner1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:layout_marginTop="28dp" />
<LinearLayout
android:id="#+id/linear_layout"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/spinner1"
android:layout_below="#+id/spinner1"
android:orientation="horizontal" >
</LinearLayout>
I am simply creating a linear layout and adding options on it. If you are having any doubt then you may ask I will try to help.
I am not managing margin between options.

How to scroll a HorizontalScrollView on button click in android?

I have horizontal scrollview in my android app with Next and Previous buttons.I want to show the these buttons only when the scollview needs scrolling.ie,width of scrollview content exceeds display width.Also want to hide previous and Next buttons when reaching first and last items respectively.How to to next/previous items when click on these buttons?
main.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/mainLayout"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:background="#ffffff" >
<Button
android:id="#+id/btnPrevoius"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_centerVertical="true"
android:text="Previous"
android:visibility="gone" />
<HorizontalScrollView
android:id="#+id/horizontalScrollView1"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_marginLeft="5dip"
android:layout_marginRight="5dip"
android:layout_toLeftOf="#+id/btnNext"
android:layout_toRightOf="#+id/btnPrevoius"
android:fillViewport="true" >
<LinearLayout
android:id="#+id/linearLayout1"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="horizontal" >
</LinearLayout>
</HorizontalScrollView>
<Button
android:id="#+id/btnNext"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_centerVertical="true"
android:text="Next"
android:visibility="gone" />
</RelativeLayout>
activity
public class SampleActivity extends Activity {
private static LinearLayout linearLayout;
private static HorizontalScrollView horizontalScrollView;
private static Button btnPrevious;
private static Button btnNext;
private static int displayWidth = 0;
private static int arrowWidth = 0;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
horizontalScrollView = (HorizontalScrollView) findViewById(R.id.horizontalScrollView1);
linearLayout = (LinearLayout) findViewById(R.id.linearLayout1);
btnPrevious = (Button) findViewById(R.id.btnPrevoius);
btnNext = (Button) findViewById(R.id.btnNext);
for (int i = 0; i < 15; i++) {
Button button = new Button(this);
button.setTag(i);
button.setText("---");
linearLayout.addView(button);
}
ViewTreeObserver vto = linearLayout.getViewTreeObserver();
vto.addOnGlobalLayoutListener(new OnGlobalLayoutListener() {
#Override
public void onGlobalLayout() {
ViewTreeObserver obs = linearLayout.getViewTreeObserver();
obs.removeGlobalOnLayoutListener(this);
Display display = getWindowManager().getDefaultDisplay();
displayWidth = display.getWidth();
if (linearLayout.getMeasuredWidth() > (displayWidth - 40)) {
btnPrevious.setVisibility(View.VISIBLE);
btnNext.setVisibility(View.VISIBLE);
}
}
});
btnPrevious.setOnClickListener(listnerLeftArrowButton);
horizontalScrollView.setOnTouchListener(listenerScrollViewTouch);
}
private OnTouchListener listenerScrollViewTouch = new OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
showHideViews();
return false;
}
};
private OnClickListener listnerLeftArrowButton = new OnClickListener() {
#Override
public void onClick(View v) {
horizontalScrollView.onKeyDown(KeyEvent.KEYCODE_DPAD_RIGHT, new KeyEvent(0, 0));
}
};
public static void showHideViews() {
int maxScrollX = horizontalScrollView.getChildAt(0).getMeasuredWidth()- displayWidth;
Log.e("TestProjectActivity", "scroll X = " +horizontalScrollView.getScrollX() );
Log.i("TestProjectActivity", "scroll Width = " +horizontalScrollView.getMeasuredWidth() );
Log.d("TestProjectActivity", "Max scroll X = " + maxScrollX);
if (horizontalScrollView.getScrollX() == 0) {
hideLeftArrow();
} else {
showLeftArrow();
}
if (horizontalScrollView.getScrollX() == maxScrollX) {
showRightArrow();
} else {
//hideRightArrow();
}
}
private static void hideLeftArrow() {
btnPrevious.setVisibility(View.GONE);
}
private static void showLeftArrow() {
btnPrevious.setVisibility(View.VISIBLE);
}
private static void hideRightArrow() {
btnNext.setVisibility(View.GONE);
}
private static void showRightArrow() {
btnNext.setVisibility(View.VISIBLE);
}
}
The 'maxScrollX' value is not correct for me.How to find maximum scrollvalue for this?
Thanks in Advance

This might come a bit late, but for anyone out there that will face this problem I suggest alternative solution(s).
First, use different component than HorizontalScrollView. Here are the options:
OPTION 1: Horizontal ListView - add this class to your project (create a separate package, something like com.yourproject.widgets). Also you'll need to create custom Adapter, see how that's done in this example. I suggest you create separate adapter class (exp. HorizontalListViewAdapter) and put it in already created com.yourproject.widgets package.
add this widget to your layout in the xml (put it between buttons that need to mimic the scrolling behavior) you'll need to add something like:
<com.yourproject.widgets.HorizontalListView
android:id="#+id/hList"
android:layout_width="match_parent"
android:layout_height="wrap_content"/>
reference this (along with the buttons) in the Activity/Fragment that utilizes the widget
HorizontalListView mHList = (HorizontalListView) findViewById (R.id.hList);
Button bPrevoius = (Button) findViewById (R.id.btnPrevoius);
Button bNext = (Button) findViewById (R.id.btnNext);
add onClickListeners to the Buttons. Use the scrollTo() function predefined in the HorizontalListView widget. As you can see in the code, it takes int dp value to scroll. Add positive values if you want to scroll in right (next), and use negative values if you want to scroll in left (previous):
bPrevoius.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
//value 500 is arbitrarily given. if you want to achieve
//element-by-element scroll you should get the width of the
//previous element dynamically or if the elements of the
//list have uniform width just put that value instead
mHList.scrollTo(-500);
//if it's the first/last element you can bPrevoius.setEnabled(false)
}
});
bNext.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
mHList.scrollTo(500);
}
});
OPTION 2: More up to date solution to this issue can be the new widget RecyclerView introduced in Android L (addition of android:scrollbars="vertical" seems that would do the trick; other than that should have conventional ListView behavior). For more info check the official documentation.

devu
Plz have a look at the following links
1) http://android-er.blogspot.in/2012/07/implement-gallery-like.html
2) http://androiddreamers.blogspot.in/2012/09/horizontal-scroll-view-example.html
3)http://code.google.com/p/mobyfactory-uiwidgets-android/
Let me know if u r facing any issues
Thanks

In titanium appcelerator, you can do this using scrollableView
var scrollableView = Ti.UI.createScrollableView({
showPagingControl:true,
scrollingEnabled: true,
top: 360
});
Then, you can run a loop of all images or any content that you have, and add them to this view.
for(loop) {
eval("var view"+i+"=Ti.UI.createView();");
profile_image = Ti.UI.createImageView({
image: result[0]['profile_image'],
left:15,
width:82,
height:104,
top: 0
});
eval("view"+i+".add(profile_image);");
eval("scrollableView.addView(view"+i+");");
}
mywin.add(scrollableView);

Android: programmatically adding buttons to a layout

I'm trying to get an add button to add another button to the layout, based on the edittext to the left of the button. The point is for a person to list the rooms in their house, and then when they type in each room, a new button is generated so they can click the room, and then start working on the next page.
I had an xml layout all done, and then I realized I'm "programmatically" adding buttons, so I redid the layout programmatically, and then in the switch/case (that's how I do onclicks) for the add button I tried to add a button to the view, but it's getting very tricky. I'd like to have a scrollview below the edittext and add buttons, and as they add all the rooms to their house it eventually is populated with a scrollable list of buttons for their entire home. Is there a way to add buttons programmatically to an xml'd layout. I was thinking you can but everything I'm trying just isn't working.
Thanks for your help everybody, any recommendations you have would be greatly appreciated.
First Edit (in response to Tanuj's solution)
My XML file (not sure if we're going to use this or just use the java):
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<TextView
android:id="#+id/tvAddARoom"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/tvAddARoom" />
<EditText
android:id="#+id/etAddARoom"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="#string/etAddARoom" />
<Button
android:id="#+id/btnAddARoom"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/btnAdd" />
<TextView
android:id="#+id/tvSelectARoom"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/tvSelectARoom" />
<TextView
android:id="#+id/tvNoRooms"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/tvNoRooms" />
<Button
android:id="#+id/btnViewAll"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/btnViewAll" />
</LinearLayout>
And the Java. This isn't at all correct, as in the java I'm creating the whole layout instead of using the layout above. Just not sure if I can bridge the two.
package com.bluej.movingbuddy;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup.LayoutParams;
import android.widget.Button;
import android.widget.EditText;
import android.widget.LinearLayout;
//import android.widget.ScrollView;
import android.widget.TextView;
public class EstimatorByRoom extends Activity implements OnClickListener {
String roomName;
EditText etAddARoom;
LinearLayout layout;
LinearLayout.LayoutParams layoutParam;
#Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
//setContentView(R.layout.estimatorbyroom);
LayoutParams params =
new LinearLayout.LayoutParams(
LayoutParams.FILL_PARENT,
LayoutParams.WRAP_CONTENT);
//create a layout
LinearLayout layout = new LinearLayout(this);
layout.setOrientation(LinearLayout.VERTICAL);
//create a text view
TextView tvAddARoom = new TextView(this);
tvAddARoom.setText("Add a Room");
tvAddARoom.setLayoutParams(params);
//create an edittext
EditText etAddARoom = new EditText(this);
etAddARoom.setHint("Living Room, Dining Room, etc.");
etAddARoom.setLayoutParams(params);
//create a button
Button btnAddARoom = new Button(this);
btnAddARoom.setText("Add");
btnAddARoom.setLayoutParams(params);
//adds the textview
layout.addView(tvAddARoom);
//add the edittext
layout.addView(etAddARoom);
//add the button
layout.addView(btnAddARoom);
//create the layout param for the layout
LinearLayout.LayoutParams layoutParam = new LinearLayout.LayoutParams(
LayoutParams.FILL_PARENT,
LayoutParams.WRAP_CONTENT);
this.addContentView(layout, layoutParam);
}
public void onClick(View v) {
// TODO Auto-generated method stub
switch (v.getId()) {
case R.id.btnAddARoom:
//add a room
//this part isn't working!
roomName = etAddARoom.getText().toString();
Button createdButton = new Button(this);
createdButton.setText(roomName);
layout.addView(createdButton);
this.addContentView(layout, layoutParam);
//if no rooms make tvnorooms disappear
break;
}
}
}

Try this :
//the layout on which you are working
LinearLayout layout = (LinearLayout) findViewById(R.id.linear_layout_tags);
//set the properties for button
Button btnTag = new Button(this);
btnTag.setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
btnTag.setText("Button");
btnTag.setId(some_random_id);
//add button to the layout
layout.addView(btnTag);

Try this code:
LinearLayout l_layout = (LinearLayout) findViewById(R.id.linear_layout);
l_layout.setOrientation(LinearLayout.VERTICAL); // or HORIZONTAL
Button btn1 = new Button(this);
btn1.setText("Button_text");
l_layout.addView(btn1);
btn1.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
// put code on click operation
}
});
that is a way to create button dynamically and add in Layout.
remember that when you create button programmatically you just use this not Class_name.this

public class AndroidWalkthroughApp1 extends Activity implements View.OnClickListener {
final int TOP_ID = 3;
final int BOTTOM_ID = 4;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
// create two layouts to hold buttons
LinearLayout top = new LinearLayout(this);
top.setId(TOP_ID);
LinearLayout bottom = new LinearLayout(this);
bottom.setId(BOTTOM_ID);
// create buttons in a loop
for (int i = 0; i < 2; i++) {
Button button = new Button(this);
button.setText("Button " + i);
// R.id won't be generated for us, so we need to create one
button.setId(i);
// add our event handler (less memory than an anonymous inner class)
button.setOnClickListener(this);
// add generated button to view
if (i == 0) {
top.addView(button);
}
else {
bottom.addView(button);
}
}
// add generated layouts to root layout view
LinearLayout root = (LinearLayout)this.findViewById(R.id.root_layout);
root.addView(top);
root.addView(bottom);
}
#Override
public void onClick(View v) {
// show a message with the button's ID
Toast toast = Toast.makeText(AndroidWalkthroughApp1.this, "You clicked button " + v.getId(), Toast.LENGTH_LONG);
toast.show();
// get the parent layout and remove the clicked button
LinearLayout parentLayout = (LinearLayout)v.getParent();
parentLayout.removeView(v);
}
}

Each button needs to have an onclicklistener to tell it what to do. this can be added to your java code under where you state your button.
Button createdButton = new Button(this);
createdButton.setOnClickListener(new OnClickListener()
{
code you want implemented
}

I would add an id to your LinearLayout in xml:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#id/llContainer"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
And then change your onClick to this:
public void onClick(View v) {
switch (v.getId()) {
case R.id.btnAddARoom:
//add a room
//Find you parent layout which we'll be adding your button to:
LinearLayout layout = (LinearLayout) findViewById(R.id.llContainer);
roomName = etAddARoom.getText().toString();
Button createdButton = new Button(this);
createdButton.setText(roomName);
createdButton.setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
layout.addView(createdButton);
//if no rooms make tvnorooms disappear
break;
}
}

Unable to set background resource on a Button

I have an application on which I apply some resources to buttons to modify their backgrounds.
All work well, but when my application goes to onResume after onPause, I'm not able to set the background anymore.
I have a set of 18 buttons, and when I am in onResume, i call:
for (int i = 0; i < max; i++) {
Button b = l.get(i);
b.setBackgroundResource(R.color.green);
}
In l i have the list of all buttons got from findViewById().
This works only for the last element of the for, but not for the others.
Any idea?
** Edit **
This is the code I use for populating the array
btn_1 = (Button)findViewById(R.id.btn_1);
btn_1.setOnClickListener(this);
l.add(btn_1);
this is repeated for all my buttons.
** Second edit **
public void onResume() {
btn_1 = (Button)findViewById(R.id.btn_1);
btn_1.setOnClickListener(this);
l = new ArrayList<Button>();
l.add(btn_1);
...
for (int i = 0; i < max; i++) {
Button b = l.get(i);
b.setBackgroundResource(R.color.green);
}
}
The same is done in onCreate().

try the d following.. this will works fine.
List<Button> mButtonList = new ArrayList<Button>();
onCreate() {
mButtonList.add((Button) findViewById(R.id.btn_1));
mButtonList.add((Button) findViewById(R.id.btn_2));
mButtonList.add((Button) findViewById(R.id.btn_3));
....
for(Button b : mButtonList) {
b.setOnClickListener(this);
}
}
onResume() {
for(Button b : mButtonList) {
b.setBackgroundResource(R.color.green);
}
}

Simple example:
Activity
public class StackOverFlowActivity extends Activity {
private ArrayList<Button> myArray = new ArrayList<Button>();
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
myArray.add((Button)findViewById(R.id.btn_1));
myArray.add((Button)findViewById(R.id.btn_2));
myArray.add((Button)findViewById(R.id.btn_3));
myArray.add((Button)findViewById(R.id.btn_4));
myArray.add((Button)findViewById(R.id.btn_5));
}
#Override
protected void onResume() {
super.onResume();
for (Button b : myArray) {
b.setBackgroundColor(getResources().getColor(R.color.blue));
}
}
}
XML main
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<Button
android:id="#+id/btn_1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Button 1" />
<Button
android:id="#+id/btn_2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Button 2" />
<Button
android:id="#+id/btn_3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Button 3" />
<Button
android:id="#+id/btn_4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Button 4" />
<Button
android:id="#+id/btn_5"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Button 5" />
</LinearLayout>
My color in the Strings.xml
<color name="blue">#0099CC</color>

Use this instead:
for (int i = 0; i < max; i++) {
Button b = l.get(i);
b.setBackgroundColor(getResources().getColor(R.color.green));
}
If max is really big you might want to cache the getColor result before the loop.
EDIT:
According to the docs: setBackgroundResource is to be used with drawable ids only, and setBackgroundColor seems to be exactly what you need, so maybe another part of your code isn't working well, maybe the loop, the above line for setBackgroundColor works well on my app.

You've said:
": the ... code is the same for btn_1, just swap btn_1 with btn_2, btn_3 and so on. "
if so, than these lines are resetting your Array every time you try and add a new button.
l = new ArrayList<Button>();
l.add(btn_1);
P.S. you should avoid using a manual creation of buttons array - instead use some Parenting Layout such as LinearLayout and then fetch his button son's using getChildAt(i), It's much cleaner. Example:
// Register all the buttons in the layout to the OnClickListener
LinearLayout lin = (LinearLayout)findViewById(R.id.linear_buttons);
int childcount = lin.getChildCount();
for (int i=0; i < childcount; i++){
View v = lin.getChildAt(i);
v.setOnClickListener(this);
}

Try this --
for (int i = 0; i < l.getChildCount(); i++)
{
Button b = (Button) l.getChildAt(i);
b.setBackgroundResource(R.color.green);
}

try this. its working for me
for (int i = 0; i < count; i++) {
btn_title[i] = new Button(ActivityName.this);
btn_title[i].setText(menu.menu_title[i]);
btn_title[i].setId(i);
btn_title[i].setTextColor(Color.BLACK);
btn_title[i].setBackgroundColor(Color.parseColor(dataxml
.getMenucolor()));
btn_title[i]
.setTextSize(Integer.parseInt(dataxml.getFontsize()));
btn_title[i].setGravity(Gravity.CENTER_VERTICAL
| Gravity.CENTER_HORIZONTAL);
btn_title[i].setSingleLine();
btn_title[i].setEllipsize(TruncateAt.END);
btn_title[i].setOnClickListener(new ButtonListner());
}
hope this will help

why don't extend Button class, set its color, then use that new class?

It wont work obviously , let me explain why it has set last value of button .
you are using of one button reference (whatever u got from (Button)findViewById(R.id.btn_1) )
and untimely there is a one button reference and u just change its value using l.add(btn_1);
what you need to do is , do create a new button instance for each button and inflate it in proper view .
here is the small tick for that
for (int i==0 ; i < length; i++ ){
Button button = new Button(context);
collectionOfButton.add(button) ;
}
use that buttons collection using inflate if u try to integrate in some xml layout file .