I'm following the accepted answer to this question:
ArrayList<EditText> myEditTextList = new ArrayList<EditText>();
for( int i = 0; i < myLayout.getChildCount(); i++ )
if( myLayout.getChildAt( i ) instanceof EditText )
myEditTextList.add( (EditText) myLayout.getChildAt( i ) );
How do you get myLayout, what does it actually represent? In my app I define linear_layout in activitymain.xml but can't seem to get it in MainActivity.java (I tried using R but it didn't work). I'm new to Android development and could really use some high level guidance.
Let Linear Layout be the root of your xml:
<LinearLayout android:id="#+id/my_layout" >
//your views goes here
</LinearLayout>
Then in your Activity you'll have to initialize the view once your layout gets inflated like this
LinearLayout myLayout = (LinearLayout) findViewById(R.id.my_layout);
Hope this helps.
You need to use myLayout as your root layout in your layout.xml file
the myLayout maybe a FrameLayout, LinearLayout, RelativeLayout or ConstraintLayout layout
SAMPLE CODE
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/myLayout"
android:orientation="vertical">
<!-- add your view here-->
</LinearLayout>
Now do findViewById in side your actvity
public class MyActivity extends AppCompatActivity {
LinearLayout myLayout;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_my);
myLayout = findViewById(R.id.myLayout);
}
}
You can try below code to get a reference of your LinearLayout in Java code.
LinearLayout myLayout=(LinearLayout) findViewById(R.id.your_linear_layout_id)
assuming your actiivtymain.xml looks like this
<?xml version="1.0" encoding="utf-8"?>
<SomeLayout
android:id="#+id/some_id"
...>
<EditText
...
/>
<EditText
...
/>
.
.
.
</SomeLayout>
mLayout you are referring is the parent of all your edit texts. It may not be the root of your layout but if you want to get a Java instance of it, you need to give it an id. and get the instance by using the code given by #Nilesh Rathod. One more thing to remember is to call the method findViewById(R.id.my_layout); only after setContentView(R.layout.activitymain);.
Related
I'm trying to load an existing layout from XML and then create dynamically a button and a Circle, the reason which I cannot include them onto the XML is because the purpose is to create Circles dynamically, actually the following code is a snippet of what I want to create.
I know the way I am doing this (adding the layout) is wrong, but after reading a lot of Internet content I failed to did it by myself, because that I request help.
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_etest);
LayoutInflater inflater;
inflater = this.getSystemService
(Context.LAYOUT_INFLATER_SERVICE);
LinearLayout layout = (LinearLayout)
inflater.inflate(R.layout.activity_etest ,
null);
LinearLayout viewGroup = layout;
Button b1 = new Button(this);
b1.setText("test");
viewGroup.addView(b1);
viewGroup.addView(new Circle(this));
}
}
And my class Circle, which extends from View and its method onDraw() consists of:
... onDraw(){
canvas.drawCircle(x, y, radius, paint);
}
The parameters of drawCircle are not rellevant to this question. I have defined them elsewhere.
I also add the XML:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="New Button"
android:id="#+id/button12"
android:layout_gravity="center_horizontal" />
</LinearLayout>
create one view group like linearlayout in your xml and using its instance add your dynamic views in that.
activity_etest.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout android:id="#+id/viewg" xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">
activity
setContentView(R.layout.activity_etest);
Linearlayout viewgroup = (LinearLayout)findViewById(R.id.viewg);
Button b1 = new Button(this);
b1.setText("test");
viewGroup.addView(b1);
viewGroup.addView(new Circle(this));
I want to create a layout which contain dynamic number of textviews, how to create the container layout to make it so it is possible to do something like this picture?
Use TokenAutoComplete library to do this:
Following link may solve your problem: https://github.com/splitwise/TokenAutoComplete
<com.tokenautocomplete.ContactsCompletionView
android:id="#+id/searchView"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</RelativeLayout>
You create a layout, where textviews should be added, in the xml of your activity file:
<LinearLayout
android:id="#+id/outerLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
</LinearLayout>
Then in Activity-Class in the onCreate-Method for example you.
- Get the LinearLayout from the xml
- Add as many items to the LinearLayout as you want.
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_load_selection);
// Get The Layout
LinearLayout l = (LinearLayout) findViewById(R.id.outerLayout);
// Adding 5 Textviews to the Layout
TextView tv ;
for(int i=0 ; i<5; i++){
tv = new TextView(this) ;
tv.setText("TextView No."+ i) ;
l.adView(tv) ;
} // for
}
Code not tested.
I just started android and I tried below questions to get this answer before posting it here:
Android - Adding layout at runtime to main layout
Add button to a layout programmatically
Dynamically adding a child to LinearLayout with getting each child's position
And I am still not able to add a button to linear layout :(
Below is the code for activity, please let me know where I am wrong:
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
LinearLayout layout = (LinearLayout) View.inflate(this, R.layout.activity_main, null);
Button btn = new Button(this);
btn.setId(123);
btn.setText("Welcome to WI FI World");
layout.addView(btn);
}
And xml looks like below:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent" >
</LinearLayout>
Try assigning an id to your layout then add the button to the layout.
Im pretty sure those 2 layouts are not the same, so you are infact adding a button to a layout that is never displayed.
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
LinearLayout layout = (LinearLayout) findViewById(R.id.lnr_main);
Button btn = new Button(this);
btn.setId(123);
btn.setText("Welcome to WI FI World");
layout.addView(btn);
}
With Layout assigned an id
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/lnr_main"
android:layout_width="match_parent"
android:layout_height="match_parent" >
</LinearLayout>
Take the Id for LinearLayout in XML and in jave code use that id of LinearLayout from XML
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/linear" >
</LinearLayout>
In onCreate():
LinearLayout linear=(LinearLayout)findViewById(R.id.linear);
//Select widgets
linear.addView()
Give an id to your linearLayout.
Then in your code
LinearLayout layout = (LinearLayout)findViewById(R.id.given_id);
Keep the rest the same, should work.
I'm trying to add a bunch of TextViews at runtime to a scrollview but I get The specified child already has a parent. You must call removeView on the child's parent first.
main.xml
<?xml version="1.0" encoding="utf-8"?>
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/layout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical" >
</LinearLayout>
</ScrollView>
testapp
#Override
public void onCreate(Bundle savedInstanceState) {
TextView[] data;
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
View layout = findViewById(R.id.layout);
.......................................
data = new TextView[10];
for (int i = 0; i < 10; i++) {
data[i] = new TextView(this);
data[i].setText("data = " + i);
((ViewGroup) layout).addView(data[i]);
}
setContentView(layout);
}
You cannot use setContentView() twice in a single Activity like this. That's the problem.
Look at this answer here:
A view can only have a single parent. The view that you are adding (I am guessing re-using) is already part of another view hierarchy. If you really want to reuse it (I would suggest you probably don't) then you have to detach it from its parent in its existing view hierarchy.
I think the problem is of layout variable.
it already has a parent ScrollView view as per XML now when you are using this setContentView(layout); so this try to add layout in different parent ..
I have an android xml layout, main.xml. I would like to add controls to this layout at runtime (I would like to add a series of additional linear layouts that contain buttons controls). Can I do that and if yes, how?
Thanks
I see the error u r doing here
LinearLayout mainLayout = (LinearLayout) findViewById(R.layout.main);
You r taking the layout as Linearlayout object, you should take the LinearLayout id
Try this
LinearLayout lnr = (LinearLayout) findViewById(R.id.LinearLayout01);
Button b1 = new Button(this);
b1.setText("Btn");
lnr.addView(b1);
You can add controls programmatically if you want in your code, or even another XML with a View and an Inflater.
Here you can read the basics: http://developer.android.com/guide/topics/ui/declaring-layout.html
Ok, I have got it to work.
The steps are the following:
First inflate the xml layout, ie,
View view = View.inflate(this, R.layout.main, null);
Then instantiate the container object from the xml layout into a ViewGroup class, ie,
ViewGroup container = (ViewGroup) view.findViewById(R.id.myContainer);
Then create a linearLayout object, create and add onto that any controls needed, add the linearLayout to the container object and use setContentView on the view object, ie,
container.addView(buttonsLayout);
this.setContentView(view);
You can do this quite easy by setting an id on the layout on which you want to add views to. Say your main.xml look like this:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<TextView android:id="#+id/label"
android:layout_width="fill_parent"/>
<LinearLayout android:id="#+id/container"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
</LinearLayout>
</LinearLayout>
Lets assume that you want to add your additional views to the LinearLayout with id id/container. In your onCreate method you could retrieve that object for later use:
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mContainer = (ViewGroup)view.findViewById(R.id.container);
}
Now you are all set to add other views to your container ViewGroup:
LinearLayout theButtons = getButtons()
mContainer.addView(theButtons);
In the getButtons method you need to create your LinearLayout containing the buttons you need. Either you do this programmatically or by inflating a view defined in an XML file. See LayoutInflater.inflate.
just try this:
LinearLayout mainLinearLayout = (LinearLayout) findViewById(R.layout.llmain);
now create button dynamically like this
Button btn1 = new Button(this);
btn1.setText=("Button 1");
mainLinearLayout .addView(btn1);
now if you want to add onether linearlayout then add it below button then
LinearLayout llinner = new LinearLayout(this);
Button btn2 = new Button(this);
btn2.setText=("Button 2");
mainLinearLayout .addView(btn2);
llinner.addView(btn2 );
mainLinearLayout .addView(llinner);
Try this :
LinearLayout ll =(LinearLayout)findViewById(R.id.linlay);
Button b = new Button(this);
b.setText("Hello");
l.addView(b);
This might help you
Here is what I did to display a set of runtime buttons on table layout.
MainActivity.java
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
View view = View.inflate(this, R.layout.activity_main, null);
TableRow myrow = (TableRow) view.findViewById(R.id.myrow);
Button btn1 = new Button(this);
btn1.setText("Button 1");
myrow .addView(btn1);
Button btn2 = new Button(this);
btn2.setText("Button 2");
myrow .addView(btn2);
this.setContentView(view);
}
}
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Hello World!"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<ScrollView
android:id="#+id/myview"
android:layout_width="404dp"
android:layout_height="691dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
<TableLayout
android:id="#+id/mylayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<TableRow android:id="#+id/myrow"></TableRow>
</TableLayout>
</ScrollView>
</androidx.constraintlayout.widget.ConstraintLayout>
AVD Pixel4API30
Output screenshot