Develop Reference

How do you put dynamically loaded radio buttons into a group?

Radio buttons are supposed to be mutually exclusive. But they need to be in a "radio group."
According to the docs, "By grouping them together, the system ensures that only one radio button can be selected at a time."
I made some radio buttons (dynamically loaded) and I made sure to put them in a group. However, they are not mutually exclusive and I can check all of them at once.
How do I fix this?
Here is the code:
public class MainActivity extends AppCompatActivity {
private LinearLayout candidatesLayout;
private String[] candidates = {"Smith","Johnson","Williams","Brown","Jones","Garcia","Miller","Davis","Rodriguez","Martinez"};
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
candidatesLayout = (LinearLayout) findViewById(R.id.candidatesLayout);
final int N = candidates.length; // total number of textviews to add
final TextView[] myTextViews = new TextView[N]; // create an empty array;
for (int i = 0; i < N; i++) {
// create a new textview
final TextView rowTextView = new TextView(this); //rowTextView is persons name
//create horizonal parent for radio buttons
LinearLayout radioButtons = new LinearLayout(this);
LinearLayout numbers = new LinearLayout(this);
radioButtons.setOrientation(LinearLayout.HORIZONTAL);
//create new radio buttons
final RadioGroup radioGroup = new RadioGroup(this);
RadioButton button;
for(int ii = 0; ii < N; ii++) {
button = new RadioButton(this); //I should not be able to click more than one of these!
radioButtons.addView(button);
}
candidatesLayout.addView(rowTextView);
candidatesLayout.addView(radioButtons);
}
}
}
I am guessing that they are not really in the group that I think they are in.

You have created RadioGroup, but didn't add it to the layout.
So, replace radio buttons adding with the following snippet:
for (int i = 0; i < N; i++) {
// create a new textview
final TextView rowTextView = new TextView(this); //rowTextView is persons name
//create horizonal parent for radio buttons
LinearLayout radioButtons = new LinearLayout(this);
LinearLayout numbers = new LinearLayout(this);
radioButtons.setOrientation(LinearLayout.HORIZONTAL);
//create new radio buttons
final RadioGroup radioGroup = new RadioGroup(this);
RadioButton button;
for(int ii = 0; ii < N; ii++) {
button = new RadioButton(this);
radioGroup.addView(button); // <-- Add to Group
}
candidatesLayout.addView(rowTextView);
candidatesLayout.addView(radioGroup); // Add Group itself
}

The ArrayList doesn't show in layout

I am trying to add items to array dynamically and then add these items in array of textviews but the layout doesn't show me any item. I need to know what is wrong with my code. Thanks in advance.
TextView[] tt;
LinearLayout testy;
List<String> x = new ArrayList<String>(99);
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_test);
testy=(LinearLayout) findViewById(R.id.testy);
tt=new TextView[100];
LinearLayout.LayoutParams dim=new
LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT,
LinearLayout.LayoutParams.WRAP_CONTENT);
x.add("hii");
for(int i=1;i<x.size();i++)
{
tt[i]=new TextView(this);
tt[i].setLayoutParams(dim);
x.add(i,"hello");
String data=x.get(i);
tt[i].setText(data);
testy.addView(tt[i]);
}
setContentView(testy);
}

You have only 1 item in your array list (which has an index of 0) but your loop starts at 1 which skips the whole for loop because 1<1 is false

R.layout.activity_test is a layout file that controls are how to display how to display the display interface of setContentView is to set a Activity, this sentence is the sentence and then set the Activity using main layout file under R.layout layout
remove this
setContentView(testy);
Edit
Try this .
TextView[] tt;
LinearLayout testy;
List<String> x = new ArrayList<String>(100);
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_test);
testy = (LinearLayout) findViewById(R.id.testy);
tt = new TextView[100];
LinearLayout.LayoutParams dim = new
LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT,
LinearLayout.LayoutParams.WRAP_CONTENT);
for (int i = 0; i < x.size(); i++) {
tt[i] = new TextView(this);
tt[i].setLayoutParams(dim);
x.add(i, "hello");
String data = x.get(i);
tt[i].setText(data);
testy.addView(tt[i]);
}
}

Replace
for(int i=1;i<x.size();i++)
{
tt[i]=new TextView(this);
tt[i].setLayoutParams(dim);
x.add(i,"hello");
String data=x.get(i);
tt[i].setText(data);
testy.addView(tt[i]);
}
By
for(int i=0;i<tt.length;i++)
{
tt[i]=new TextView(this);
tt[i].setLayoutParams(dim);
x.add(i,"hello");
String data=x.get(i);
tt[i].setText(data);
testy.addView(tt[i]);
}
And
List<String> x = new ArrayList<String>(99);
By
List<String> x = new ArrayList<String>(100);

Android How to change data of Textview by clicking on button

First of all, the app looks like this.
How to make - if I click on Add, on its column the textview is updated with value + 1?
I'm creating TextView and Button in a Loop;
for(int i = 0;i < playercountint; i++)
{
LinearLayout layout = new LinearLayout(this);
layout.setOrientation(LinearLayout.VERTICAL);
layout.setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT,(100/playercountint)));
layout.setGravity(Gravity.CENTER_HORIZONTAL);
TextView tt = new TextView(this);
tt.setText("0");
tt.setTextSize(14);
tt.setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
tt.setGravity(Gravity.CENTER_HORIZONTAL);
Button btadd = new Button(this);
btadd.setText("Add");
btadd.setId(2);
btadd.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
????? what here?
}
});
}
What should be written in onClick function , so only TextView value which is in buttons column is changed.
There is one outer LinearLayout which is horizontally oriented, and those which are created within a loop is vertical Linear Layouts.
Maybe i should create a template for 1 loop iteration?

First make your textview final and them set it's value in onClick
for(int i = 0;i < playercountint; i++)
{
LinearLayout layout = new LinearLayout(this);
layout.setOrientation(LinearLayout.VERTICAL);
layout.setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT,(100/playercountint)));
layout.setGravity(Gravity.CENTER_HORIZONTAL);
final TextView tt = new TextView(this);
tt.setText("0");
tt.setTextSize(14);
tt.setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
tt.setGravity(Gravity.CENTER_HORIZONTAL);
Button btadd = new Button(this);
btadd.setText("Add");
btadd.setId(2);
btadd.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
tt.setText(String.valueOf(Integer.parseInt(tt.getText())+1));
}
});
}
You can write one function that returns linearlayout:
public View getPlayerView(){
LinearLayout layout = new LinearLayout(this);
layout.setOrientation(LinearLayout.VERTICAL);
layout.setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT,(100/playercountint)));
layout.setGravity(Gravity.CENTER_HORIZONTAL);
final TextView tt = new TextView(this);
tt.setText("0");
tt.setTextSize(14);
tt.setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
tt.setGravity(Gravity.CENTER_HORIZONTAL);
Button btadd = new Button(this);
btadd.setText("Add");
btadd.setId(2);
btadd.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
tt.setText(String.valueOf(Integer.parseInt(tt.getText())+1));
}
});
layout.add(tt);
layout.add(btadd);
return layout;
}
Call this function in a loop.

tt.setText("something");
tt.invalidate();
my bad I didn't even notice it was a for loop uh you need to hold a reference to the text view.. make your textview final

tt.setText(Integer.parse(tt.getText().toString()) + 1);
But, I strongly recommend you design UI (layout) in the *.xml file!
See more: http://developer.android.com/guide/topics/ui/declaring-layout.html

You should provide your TextView with an unique id (.setId(...)). Having this, in your onClick method simply use something like this:
final TextView tv = (TextView) findViewById(R.id.your_textview_id);
final String cur_text = tv.getText();
Integer plus_one = Integer.valueOf(cur_text);
plus_one++;
tv.setText(plus_one.toString());
Didn't try it but should work.

static int counter = 0;
btn_Add.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
counter ++;
tv_Display.setText("Your Total is : " + counter);
}
});

Scroll TextView to text position

I want to scroll my TextView to make visible a specific position in the text. How can I do that? I tried bringPointIntoView (int offset) but without success.
Source code:
public class TextScrollActivity extends Activity {
public void onCreate (final Bundle savedInstanceState) {
super.onCreate (savedInstanceState);
final int position = 500;
final TextView textView = new TextView (this);
final ScrollView scrollView = new ScrollView (this);
scrollView.addView (textView);
Button button = new Button (this);
button.setText ("Scroll to " + position);
LinearLayout layout = new LinearLayout (this);
layout.setOrientation (LinearLayout.VERTICAL);
layout.addView (scrollView,
new LayoutParams (LayoutParams.FILL_PARENT, 200));
layout.addView (button, new LayoutParams (LayoutParams.FILL_PARENT,
LayoutParams.WRAP_CONTENT));
StringBuilder builder = new StringBuilder ();
for (int i = 0; i < 1000; i++)
builder.append (String.format ("[ %05d ] ", i));
textView.setText (builder);
setContentView (layout);
button.setOnClickListener (new OnClickListener () {
public void onClick (View v) {
System.out.println (textView.bringPointIntoView (position * 10));
// scrollView.scrollTo (0, position * 10); // no
}
});
}
}

For those who have the same problem, I finally made my own implementation of bringPointIntoView:
public static void bringPointIntoView (TextView textView,
ScrollView scrollView, int offset)
{
int line = textView.getLayout ().getLineForOffset (offset);
int y = (int) ((line + 0.5) * textView.getLineHeight ());
scrollView.smoothScrollTo (0, y - scrollView.getHeight () / 2);
}
Don't hesitate if you have a better solution.

Does adding a movement method to the text view solve the problem?
textView.setMovementMethod(new ScrollingMovementMethod());

Just FYI for anyone else with the same problem, on a listView with large listItems, the overloaded bringPointIntoView can be passed a ListView instead of a ScrollView and use the ScrollTo method instead of smoothScrollTo.

Create a new TextView programmatically then display it below another TextView

String[] textArray={"one","two","asdasasdf asdf dsdaa"};
int length=textArray.length;
RelativeLayout layout = new RelativeLayout(this);
RelativeLayout.LayoutParams relativeParams = new RelativeLayout.LayoutParams(
LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
for(int i=0;i<length;i++){
TextView tv=new TextView(getApplicationContext());
tv.setText(textArray[i]);
relativeParams.addRule(RelativeLayout.BELOW, tv.getId());
layout.addView(tv, relativeParams);
}
I need to do something like that.. so it would display as
one
two
asdfasdfsomething
on the screen..

If it's not important to use a RelativeLayout, you could use a LinearLayout, and do this:
LinearLayout linearLayout = new LinearLayout(this);
linearLayout.setOrientation(LinearLayout.VERTICAL);
Doing this allows you to avoid the addRule method you've tried. You can simply use addView() to add new TextViews.
Complete code:
String[] textArray = {"One", "Two", "Three", "Four"};
LinearLayout linearLayout = new LinearLayout(this);
setContentView(linearLayout);
linearLayout.setOrientation(LinearLayout.VERTICAL);
for( int i = 0; i < textArray.length; i++ )
{
TextView textView = new TextView(this);
textView.setText(textArray[i]);
linearLayout.addView(textView);
}

Try this code:
final String[] str = {"one","two","three","asdfgf"};
final RelativeLayout rl = (RelativeLayout) findViewById(R.id.rl);
final TextView[] tv = new TextView[10];
for (int i=0; i<str.length; i++)
{
tv[i] = new TextView(this);
RelativeLayout.LayoutParams params=new RelativeLayout.LayoutParams
((int)LayoutParams.WRAP_CONTENT,(int)LayoutParams.WRAP_CONTENT);
params.leftMargin = 50;
params.topMargin = i*50;
tv[i].setText(str[i]);
tv[i].setTextSize((float) 20);
tv[i].setPadding(20, 50, 20, 50);
tv[i].setLayoutParams(params);
rl.addView(tv[i]);
}

public View recentView;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//Create a relative layout and add a button
relativeLayout = new RelativeLayout(this);
btn = new Button(this);
btn.setId((int)System.currentTimeMillis());
recentView = btn;
btn.setText("Click me");
relativeLayout.addView(btn);
setContentView(relativeLayout);
btn.setOnClickListener(new View.OnClickListener() {
#Overr ide
public void onClick(View view) {
//Create a textView, set a random ID and position it below the most recently added view
textView = new TextView(ActivityName.this);
textView.setId((int)System.currentTimeMillis());
layoutParams = new RelativeLayout.LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT);
layoutParams.addRule(RelativeLayout.BELOW, recentView.getId());
textView.setText("Time: "+System.currentTimeMillis());
relativeLayout.addView(textView, layoutParams);
recentView = textView;
}
});
}
This can be modified to display each element of a String array in different TextViews.

You're not assigning any id to the text view, but you're using tv.getId() to pass it to the addRule method as a parameter. Try to set a unique id via tv.setId(int).
You could also use the LinearLayout with vertical orientation, that might be easier actually. I prefer LinearLayout over RelativeLayouts if not necessary otherwise.