I am trying to create a custom dialog class with a custom layout, but, for reasons unknown to be, I am getting a null pointer exception when trying to access the buttons for the layout. Here is the XML for the dialog:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/enableTopRelativeLayout"
android:layout_width="460dp"
android:layout_height="wrap_content"
android:background="#drawable/dialog_background"
android:paddingBottom="15dp"
android:paddingLeft="15dp"
android:paddingRight="15dp"
android:paddingTop="15dp" >
<ImageView
android:id="#+id/imageView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_centerVertical="true"
android:src="#drawable/ic_launcher" />
<RelativeLayout
android:id="#+id/enableInnerRelativeLayout"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_toRightOf="#id/imageView1" >
<TextView
android:id="#+id/enableMessage"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_centerInParent="false"
android:paddingBottom="10dp"
android:text="Start service?"
android:textAppearance="?android:attr/textAppearanceMedium" />
<TextView
android:id="#+id/enableStrut"
android:layout_width="25dp"
android:layout_height="wrap_content"
android:layout_below="#id/enableMessage"
android:layout_centerHorizontal="true"
android:text=" " />
<Button
android:id="#+id/noenable"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#id/enableMessage"
android:layout_toLeftOf="#id/enableStrut"
android:background="#drawable/button_background"
android:text="No"
android:textColorLink="#color/color2"
android:textStyle="bold" />
<Button
android:id="#+id/enable"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#id/enableMessage"
android:layout_toRightOf="#id/enableStrut"
android:background="#drawable/button_background"
android:text="Yes"
android:textColorLink="#color/color2"
android:textStyle="bold" />
</RelativeLayout>
Here is the code for the class:
public class DialogStartService extends Dialog implements android.view.View.OnClickListener{
public Button yes;
public Button no;
public TextView tv;
public DialogStartService(Context context) {
super(context);
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.start_service_layout);
getWindow().setBackgroundDrawable(new ColorDrawable(android.graphics.Color.TRANSPARENT));
tv = (TextView) findViewById(R.id.enableMessage);
yes = (Button) findViewById(R.id.enable);
no = (Button) findViewById(R.id.noenable);
yes.setOnClickListener(this);
no.setOnClickListener(this);
}
#Override
public void onClick(View v) {
dismiss();
}
}
I instantiate the dialog with this code:
DialogStartService enableDialog = new DialogStartService(this);
Button enable = (Button) enableDialog.findViewById(R.id.enable);
enable.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
// Do stuff
}
});
Button noenable = (Button) enableDialog.findViewById(R.id.noenable);
noenable.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
// Do stuff
}
});
enableDialog.show();
The stack trace indicates the NPE occurs on this line:
enable.setOnClickListener(new OnClickListener() {
My question for the experts is... why is this code causing a NPE, and what is the best way to fix it? Thank you for any input you have.
According to documentation of findViewById() method:
Finds a child view with the given identifier. Returns null if the specified child view does not exist or the dialog has not yet been fully created (for example, via show() or create()).
In your code you call findViewById() before show() - that's why Button enable is null.
Related
I created a custom dialog fragment to be used as a YesNo Dialog Box for my project as shown below
I want to use it dynamically in where I can use it not only for one xml file.
Does anybody know how can I set the button click listener in the appcompact class from the dialogfragment on call?
I just want to set the buttonclick event of the dialogfragment in another xml file.
I tried using interface but it gives me a null pointer exception so I tried the code below.
the YesNoDialogFragment Class
public class DialogYesNo extends DialogFragment {
LayoutInflater inflater;
View v;
#NonNull
#Override
public Dialog onCreateDialog(#Nullable Bundle savedInstanceState) {
inflater = getActivity().getLayoutInflater();
v = inflater.inflate(R.layout.dialog_yesno,null);
AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
builder.setView(v);
return builder.create();
}
}
the XML file of the DialogFragment
<?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="wrap_content"
android:orientation="vertical"
android:layout_marginLeft="10dp"
android:layout_marginRight="10dp"
android:layout_marginTop="10dp"
android:background="#drawable/dialog_background"
android:layout_gravity="center">
<TextView
android:id="#+id/yesno_title"
android:layout_height="wrap_content"
android:layout_width="match_parent"
android:text="TITLE"
android:textAlignment="center"
android:textAllCaps="true"
android:textSize="10pt"
android:background="#1b1b01"
android:textColor="#fff"
android:layout_marginLeft="10dp"
android:layout_marginRight="10dp"
android:layout_marginTop="7dp"
android:paddingLeft="10dp"
android:textStyle="bold"/>
<View
android:id="#+id/divider"
android:layout_width="match_parent"
android:layout_height="5dp"
android:background="?android:attr/listDivider" />
<ScrollView
android:layout_width="match_parent"
android:layout_height="100dp"
android:layout_marginLeft="10dp"
android:layout_marginRight="10dp"
android:background="#520456">
<TextView
android:id="#+id/yesno_message"
android:layout_height="wrap_content"
android:layout_width="match_parent"
android:text="Message"
android:textAllCaps="true"
android:textSize="12dp"
android:textColor="#fff"
android:paddingLeft="10dp"
android:textStyle="bold"/>
</ScrollView>
<View
android:id="#+id/divider1"
android:layout_width="match_parent"
android:layout_height="10dp"
android:background="?android:attr/listDivider" />
<LinearLayout
android:orientation="horizontal"
android:layout_height="wrap_content"
android:layout_width="match_parent"
android:gravity="center">
<Button
android:id="#+id/dialog_No"
android:layout_height="wrap_content"
android:layout_width="wrap_content"
android:text="NO"
android:background="#drawable/dialog_background"
android:textColor="#000"
android:textStyle="bold"
android:textSize="10pt"/>
<Button
android:id="#+id/dialog_Yes"
android:layout_height="wrap_content"
android:layout_width="wrap_content"
android:text="YES"
android:layout_marginLeft="8dp"
android:background="#drawable/dialog_background"
android:textColor="#000"
android:textStyle="bold"
android:textSize="10pt"/>
</LinearLayout>
this is the code in the MainActivity
btnYes = dialogYesNo.getActivity().findViewById(R.id.dialog_Yes);
btnNo = dialogYesNo.getActivity().findViewById(R.id.dialog_No);
btnYes.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent = new Intent(MainActivity.this,TutwithNavigation.class);
startActivity(intent);
}
});
btnNo.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
// code here
}
});
try findViewById in your DialogYesNo, and add setListener for it
like this:
private OnClickListener onYesClick;
private OnClickListener onNoClick;
public Dialog onCreateDialog(#Nullable Bundle savedInstanceState) {
inflater = getActivity().getLayoutInflater();
v = inflater.inflate(R.layout.dialog_yesno,null);
AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
builder.setView(v);
View btnYes = v.findViewById(R.id.dialog_Yes);
View btnNo = v.findViewById(R.id.dialog_No);
btnYes.setOnClickListener(onYesClick);
btnNo.setOnClickListener(onNoClick);
return builder.create();
}
}
public void setOnYesClick(OnClickListener listener){
onYesClick = listener
}
public void setOnNoClick(OnClickListener listener){
onNoClick = listener
}
use setOnYesClick and setOnNoClick instead
I am trying to make a popup window in an activity. The popup window shows up when we click a button in the activity. The layout for popup window is to show a radio group containing 4 radio buttons, a button and a seek bar and has to return a value to the main activity based on the selected radio button when the button in the pop up window is pressed.
When i run the app and open the pop up window it is giving we this error:
"java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.RadioGroup.setOnCheckedChangeListener(android.widget.RadioGroup$OnCheckedChangeListener)' on a null object reference "
The code for my main activity is:
public class CustomMenuActivity extends Activity
{
String ingredientName;
String ingredientQuantity;
private PopupWindow pw;
Button setQuantity;
#Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_custom_menu);
setQuantity = (Button) findViewById(R.id.btnSetQty);
setQuantity.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v)
{
initiatePopupWindow();
}
});
}
private void initiatePopupWindow()
{
try {
//We need to get the instance of the LayoutInflater, use the context of this activity
LayoutInflater inflater = (LayoutInflater) CustomMenuActivity.this
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
//Inflate the view from a predefined XML layout
View layout = inflater.inflate(R.layout.set_quantity_popup,
(ViewGroup) findViewById(R.id.popupElementid));
// create a 600px width and 570px height PopupWindow
pw = new PopupWindow(layout, 600, 570, true);
// display the popup in the center
pw.showAtLocation(layout, Gravity.CENTER, 0, 0);
RadioGroup radioGroup;
radioGroup = (RadioGroup) findViewById(R.id.radioGroupid);
final String[] tempQtyVar = new String[1];
radioGroup.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
#Override
public void onCheckedChanged(RadioGroup group, int checkedId) {
switch (checkedId){
case R.id.rbqty30id:
tempQtyVar[0] = "30";
break;
case R.id.rbqty60id:
tempQtyVar[0] = "60";
break;
case R.id.rbqty90id:
tempQtyVar[0] = "90";
break;
case R.id.rbqtycutomid:
tempQtyVar[0] = "120";
break;
}
}
});
Button setQtyBtn = (Button) layout.findViewById(R.id.buttonOkSetQtyid);
setQtyBtn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
ingredientQuantity = tempQtyVar[0];
Toast.makeText(getApplicationContext(),ingredientQuantity,Toast.LENGTH_LONG).show();
pw.dismiss();
}
});
} catch (Exception e) {
e.printStackTrace();
}
}
}
The layout.xml for my pop up window is:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content" android:layout_height="wrap_content"
android:background="#fd050505"
android:padding="30dp"
android:id="#+id/popupElementid">
<RelativeLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
android:id="#+id/relativeLayout">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="SET QUANTITY"
android:textColor="#84e9e6"
android:textSize="20sp"
android:layout_centerHorizontal="true"
android:layout_marginTop="20dp"
android:textStyle="bold"
android:id="#+id/popupTitleid"/>
<LinearLayout
android:layout_width="600dp"
android:layout_height="wrap_content"
android:layout_below="#+id/popupTitleid"
android:orientation="horizontal"
android:background="#drawable/btn_rounded_boarder"
android:layout_centerHorizontal="true"
android:layout_marginTop="20dp">
<RadioGroup
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:id="#+id/radioGroupid"
android:layout_marginTop="20dp"
android:layout_marginBottom="20dp"
android:orientation="horizontal"
>
<RadioButton
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text=" 30ml "
android:textColor="#84e9e6"
android:id="#+id/rbqty30id"
android:checked="true" />
<RadioButton
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:textColor="#84e9e6"
android:text=" 60ml "
android:id="#+id/rbqty60id" />
<RadioButton
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:textColor="#84e9e6"
android:text=" 90ml "
android:id="#+id/rbqty90id" />
<RadioButton
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:textColor="#84e9e6"
android:text=" Custom Value "
android:id="#+id/rbqtycutomid"
/>
</RadioGroup>
</LinearLayout>
<LinearLayout
android:layout_width="600dp"
android:layout_height="wrap_content"
android:layout_marginTop="50dp"
android:layout_centerHorizontal="true">
<SeekBar
android:id="#+id/customqtySBid"
android:layout_height="fill_parent"
android:layout_width="600dp"
android:textColor="#84e9e6"
android:layout_marginLeft="30dp"
android:layout_marginRight="30dp"
android:layout_marginTop="150dp"
android:paddingBottom="10dp"/>
</LinearLayout>
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="20dp"
android:layout_centerHorizontal="true">
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/buttonOkSetQtyid"
android:textColor="#84e9e6"
android:text="OK"
android:background="#drawable/btn_rounded_boarder"
android:layout_marginTop="275dp"/>
</LinearLayout>
</RelativeLayout>
</RelativeLayout>
I tried looking for answer online but didn't really find solution specific to my problem. Please suggest any solutions.
Thanks in advance.
You seem to be inflating the wrong layout. Change the correct layout.xml in
setContentView(R.layout.activity_custom_menu);
I have a following layout in main_view.xml which contains a ImageButton in it, button when i click/touch the button the ButtonListener function never gets called.
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/relativeLayoutFragment"
android:layout_width="match_parent"
android:layout_height="fill_parent" >
<fragment
android:id="#+id/mapArea"
android:name="com.google.android.gms.maps.MapFragment"
android:layout_width="match_parent"
android:layout_height="match_parent" >
</fragment>
<RelativeLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="horizontal" >
<TextView
android:id="#+id/locate"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_gravity="center_horizontal"
android:layout_marginTop="10dp"
android:background="#80000000"
android:gravity="center"
android:padding="10dp"
android:text="#string/findingLocation"
android:textColor="#FFFFFF"
android:textSize="12sp" />
<ImageButton
android:id="#+id/Button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentLeft="true"
android:layout_marginBottom="#dimen/rightLeftMargin"
android:layout_marginLeft="#dimen/rightLeftMargin"
android:background="#null"
android:clickable="true"
android:contentDescription="#string/button1text"
android:src="#drawable/ic_feed_active" />
<ImageButton
android:id="#+id/Button2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true"
android:layout_marginBottom="#dimen/rightLeftMargin"
android:background="#null"
android:contentDescription="#string/button2"
android:src="#drawable/ic_button2" />
<ImageButton
android:id="#+id/Button3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentRight="true"
android:layout_marginBottom="#dimen/rightLeftMargin"
android:layout_marginRight="#dimen/rightLeftMargin"
android:background="#null"
android:contentDescription="#string/button3View"
android:src="#drawable/ic_settings_active" />
</RelativeLayout>
And following code in MainActivity.Java
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
User usrObj = new User();
if (usrObj.authenticateUser())
setContentView(R.layout.main_view);
else
setContentView(R.layout.login);
}
public void ButtonListener() {
ImageButton oggleButton = (ImageButton) findViewById(R.id.Button1);
ToggleButton.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View arg0) {
Toast.makeText(MainActivity.this, "ImageButton is clicked!",
Toast.LENGTH_SHORT).show();
}
});
}
}
please help.
you forget to call ButtonListener method when usrObj.authenticateUser() is true. do it as:
if (usrObj.authenticateUser())
{
setContentView(R.layout.main_view);
ButtonListener (); << call here
}
else
setContentView(R.layout.login);
and also attach setOnClickListener to oggleButton instead of ToggleButton
apart from above suggestions from ρяσѕρєя K, here is one more thing you have to take care is.
instead of this below code.
oggleButton.setOnClickListener(new OnClickListener() {
use this one
oggleButton.setOnClickListener(new View.OnClickListener() { // use View.oncli......
Good day everyone,
I'm learning Android development and I try to build some dynamic lists for my application. And I'm stuck... like for 4 hours already.
I have two layouts:
1. main.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent" >
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:id="#+id/action_buttons"
android:layout_alignParentTop="true"
android:layout_alignParentLeft="true"
android:gravity="center"
>
<Button
android:id="#+id/button_count"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/button_calculate" />
<Button
android:id="#+id/button_add"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_toRightOf="#+id/button_count"
android:text="#string/button_add" />
</LinearLayout>
<ScrollView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_below="#+id/action_buttons"
>
<LinearLayout
android:id="#+id/action_list"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="vertical" >
</LinearLayout>
</ScrollView>
</RelativeLayout>
action_list_item.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/action_list_item_root"
android:layout_width="fill_parent"
android:layout_height="wrap_content" >
<EditText
android:id="#+id/action_list_item_edittext_drinkName"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBottom="#+id/action_list_item_button_remove"
android:layout_alignParentTop="true"
android:layout_toRightOf="#+id/action_list_item_title"
android:padding="10dp" />
<EditText
android:id="#+id/action_list_item_edittext_drinkPercent"
android:text="40"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_toLeftOf="#+id/action_list_item_edittext_drinkAmount"
android:inputType="number"
android:padding="10dp"/>
<EditText
android:id="#+id/action_list_item_edittext_drinkAmount"
android:text="0.0"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_toLeftOf="#+id/action_list_item_button_remove"
android:layout_alignBottom="#+id/action_list_item_button_remove"
android:inputType="numberDecimal"
android:width="50dp"
android:padding="10dp" />
<Button
android:id="#+id/action_list_item_button_remove"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:text="#string/action_list_item_button_remove" />
And code that creates dynamic list:
public class MainActivity extends Activity {
LinearLayout actionList = null;
private Button btnAdd;
private Button btnCalculate;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
initActivityElements();
}
private void initActivityElements() {
initAddButton();
initCalculateButton();
}
private void initCalculateButton() {
btnCalculate = (Button) findViewById(R.id.button_count);
btnCalculate.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
TextView amount = (TextView) findViewById(R.id.action_list_item_edittext_drinkAmount);
//this retrives TextView value from first list
Toast.makeText(getApplicationContext(), amount.getText().toString(),
Toast.LENGTH_SHORT)
.show();
}
});
}
private void initAddButton() {
actionList = (LinearLayout) findViewById(R.id.action_list);
btnAdd = (Button) findViewById(R.id.button_add);
btnAdd.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
RelativeLayout listItem = (RelativeLayout) View.inflate(
MainActivity.this, R.layout.action_list_item, null);
TextView name = (TextView) listItem
.findViewById(R.id.action_list_item_edittext_drinkName);
name.setText("Here is the Title " + actionList.getChildCount());
listItem.findViewById(R.id.action_list_item_button_remove)
.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
actionList.removeView((View) v.getParent());
}
});
actionList.addView(listItem);
}
});
}
My problem is that I need to get all data from TextView boxes (Amount, Percent), but I can retrive that data only from first item of a list (look at onClickListener for btnCalculate) and can't figure out how to do it, but tried to add 'unique ids' for view (but that brakes layout, badly), tried setting Tags but again with no luck.
Maybe anyone can give a tip? I bet there is some easy way to do it, but I'm failing to find it and google is no help here.
Thanks
I'm not really sure what exactly you are trying to do but it sounds like you are trying to take in information and populate it into a view. I would recommend having a static text box that takes in your information and builds that into a listview. A good example of how to do that is located here http://developer.android.com/resources/tutorials/notepad/notepad-ex1.html.
I'm a beginner in android and making my first app. Here, I had taken 3 textViews and a button named Add. When I click on this button, I need to show the content of 2 textViews on third textView. I used eventListener and buttonClick event but it doesn't work. Please guide me with the code of Add button.
First create the xml as below:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_height="fill_parent"
android:layout_width="fill_parent"
android:layout_gravity="center_horizontal"
android:orientation="horizontal"
android:layout_weight="1"
android:id="#+id/singleEmployee"
android:background="#ffffff">
<TextView
android:text="TextView"
android:id="#+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
<TextView
android:text="TextView"
android:id="#+id/textView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
<TextView
android:text="TextView"
android:id="#+id/textView3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
<Button
android:text="Button"
android:id="#+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
</LinearLayout>
And then use this Java code to done your desire action:
public class MainActivity extends Activity {
/** Called when the activity is first created. */
TextView tv1,tv2,tv3;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.testing);
tv1 = findViewById(R.id.textView1);
tv2 = findViewById(R.id.textView2);
tv3 = findViewById(R.id.textView3);
tv1.setText("Hello");
tv2.setText("World");
Button add = findViewById(R.id.button1);
add.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
tv3.setText("");
String tvValue1 = tv1.getText().toString();
String tvValue2 = tv2.getText().toString();
tv3.setText("Value of First Text is: "+tvValue1+".And the value of second TextView is: "+tvValue2);
}
});
}