Develop Reference

With FrameLayout as root layout, add view on top of another one, with offset of X,Y

I'd like to place a view on top of an existing view. The view I'm targeting is inside a LinearLayout, which resides in a FrameLayout.
I'm thinking there's a way to do this with RelativeLayout because I already have it partially working. I'd like to align the new view to the bottom-left or top-left (as the origin) and then offset X and Y to some precise value that I specify.
How can this be achieved?
Here's the idea:
public static void placeTextRelativeToBottomLeftOfViewAtXY(final FrameLayout layout, View component, int x, int y, String text) {
final TextView textView = new TextView(getContext());
textView.setId((int)System.currentTimeMillis());
final RelativeLayout relativeLayout = new RelativeLayout(getContext());
RelativeLayout.LayoutParams params = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.MATCH_PARENT, RelativeLayout.LayoutParams.MATCH_PARENT);
params.setMargins(x, y, 0,0);
params.addRule(RelativeLayout.LEFT_OF, component.getId());
relativeLayout.setLayoutParams(params);
relativeLayout.setBackgroundColor(Color.TRANSPARENT);
textView.setText("+500 points!");
textView.bringToFront();
relativeLayout.addView(textView, params);
layout.addView(relativeLayout);
}

Based on the additional information in comments, even if it is possible to overlap a different layouts inside a FrameLayout, those layouts will only be able to position their own children.
A RelativeLayout won't be able to position one of its child views relative to a view in a different sibling or parent Layout.
The way to go would be to flattern the heierarchy of Layouts, setting the root layout to a RelativeLayout or a ConstraintLayout.
ConstraintLayout is more flexible in terms of positioning views, but it is also more difficult to learn.
Here I am leaving an alternative to be used with RelativeLayout as the root view. The important items to look at are the setting of the LayoutParams which is sometimes a bit confussing.
The LayoutParams are set on the child view, but the class used depends on the parent view.
Also take in mind that to keep margins display independent you need to convert dp into pixels (for the sake of simplicity I haven't done that, but there are examples of how to do this here in SO).
It also uses View.generteViewId() go get an id for a view created dynamically.
To make it simple I included the reference View in the xml, but i could have also been created dynamically.
Layout
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/rlContainer"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="#+id/tvCenterText"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Texto estatico"
android:layout_centerInParent="true"/>
</RelativeLayout>
Main Activity
public class DynamicViewsActivity extends AppCompatActivity {
RelativeLayout rlContainer;
TextView centerText;
#Override
protected void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_dynamicviews);
rlContainer = findViewById(R.id.rlContainer);
centerText = findViewById(R.id.tvCenterText);
placeTextRelativeToBottomLeftOfViewAtXY(rlContainer, centerText, 100,10, "Hola");
}
public void placeTextRelativeToBottomLeftOfViewAtXY(final RelativeLayout layout, View component, int x, int y, String text) {
final TextView textView = new TextView(this);
textView.setId(View.generateViewId());
RelativeLayout.LayoutParams params = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.WRAP_CONTENT, RelativeLayout.LayoutParams.WRAP_CONTENT);
params.setMargins(x, y, x,y);
params.addRule(RelativeLayout.LEFT_OF, component.getId());
params.addRule(RelativeLayout.ALIGN_BASELINE, component.getId());
textView.setLayoutParams(params);
textView.setText(text);
layout.addView(textView);
}
}

Create Android subviews like iOS subviews

I'm trying to programmatically (not using XML files) create custom subviews in Android (that's what I call it in iOS) that is a basically a number of basic views (labels, buttons, text fields etc) put together into a reusable subview class so I can use it inside my UIViewControllers or Activity in Android.
I don't know what is the correct terminology in Android. There seems to be a million different terminologies.
Custom View, ViewGroups, Layouts, Widgets, Components, whatever you want to call it.
In iOS this is simply done like this:
CustomView.h
#interface CustomView : UIView
#property (nonatomic, strong) UILabel *message;
#property (nonatomic, strong) UIButton *button;
#end
CustomView.m
#implementation CustomView
-(id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if(self)
{
[self initViews];
[self initConstraints];
}
return self;
}
-(void)initViews
{
self.message = [[UILabel alloc] init];
self.button = [[UIButton alloc] init];
[self addSubview:self.message];
[self addSubview:self.button];
}
-(void)initConstraints
{
id views = #{
#"message": self.message,
#"button": self.button
};
[self addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:#"H:|[message]|" options:0 metrics:nil views:views]];
[self addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:#"H:|[button]|" options:0 metrics:nil views:views]];
[self addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:#"V:|[message][button]|" options:0 metrics:nil views:views]];
}
#end
Now I can reuse this custom view in any ViewController (Android Activity) I chose.
How does one achieve something like that in Android?
I've been looking around and from what I gather in Android, to add subviews, I add them to Layouts:
RelativeLayout relativeLayout = new RelativeLayout(...);
TextView textView = new TextView(...);
relativeLayout.addSubview(textView);
Does that mean I need extend RelativeLayout or ViewGroup?
Looking at this page: http://developer.android.com/reference/android/view/ViewGroup.html
It seems like we need to write some really complicated logic to layout the custom view such as:
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
int count = getChildCount();
// These keep track of the space we are using on the left and right for
// views positioned there; we need member variables so we can also use
// these for layout later.
mLeftWidth = 0;
mRightWidth = 0;
// Measurement will ultimately be computing these values.
int maxHeight = 0;
int maxWidth = 0;
int childState = 0;
// Iterate through all children, measuring them and computing our dimensions
// from their size.
for (int i = 0; i < count; i++) {
final View child = getChildAt(i);
if (child.getVisibility() != GONE) {
// Measure the child.
measureChildWithMargins(child, widthMeasureSpec, 0, heightMeasureSpec, 0);
// Update our size information based on the layout params. Children
// that asked to be positioned on the left or right go in those gutters.
final LayoutParams lp = (LayoutParams) child.getLayoutParams();
if (lp.position == LayoutParams.POSITION_LEFT) {
mLeftWidth += Math.max(maxWidth,
child.getMeasuredWidth() + lp.leftMargin + lp.rightMargin);
} else if (lp.position == LayoutParams.POSITION_RIGHT) {
mRightWidth += Math.max(maxWidth,
child.getMeasuredWidth() + lp.leftMargin + lp.rightMargin);
} else {
maxWidth = Math.max(maxWidth,
child.getMeasuredWidth() + lp.leftMargin + lp.rightMargin);
}
maxHeight = Math.max(maxHeight,
child.getMeasuredHeight() + lp.topMargin + lp.bottomMargin);
childState = combineMeasuredStates(childState, child.getMeasuredState());
}
}
// Total width is the maximum width of all inner children plus the gutters.
maxWidth += mLeftWidth + mRightWidth;
// Check against our minimum height and width
maxHeight = Math.max(maxHeight, getSuggestedMinimumHeight());
maxWidth = Math.max(maxWidth, getSuggestedMinimumWidth());
// Report our final dimensions.
setMeasuredDimension(resolveSizeAndState(maxWidth, widthMeasureSpec, childState),
resolveSizeAndState(maxHeight, heightMeasureSpec,
childState << MEASURED_HEIGHT_STATE_SHIFT));
}
All I'm trying to do is use multiple basic android labels, views, buttons in a custom view like the iOS example above, why is it so hard in Android ?
I was hoping for something simple like this:
public class CustomView extends View
{
public RelativeLayout mainLayout;
public TextView message;
public Button button;
// default constructor
public CustomView()
{
...
initViews();
initLayouts();
addViews();
}
public initViews()
{
mainLayout = new RelativeLayout(this);
message = new TextView(this);
button = new Button(this);
...
}
public initLayouts()
{
// --------------------------------------------------
// use Android layout params to position subviews
// within this custom view class
// --------------------------------------------------
}
public addViews()
{
mainLayout.addView(message);
mainLayout.addView(button);
setContentView(mainLayout);
}
}
I'm sorry I am sincerely trying to learn and build a basic Android application and not trying to bash Android's way of doing things.
I know how to add and layout subviews inside an Activity and have been doing so for the past two days but not inside a custom View/View Group/Layout. I don't want to end up constructing the exact same subview for each of my Activity in the Android app, that just goes against good coding practice right ? :D
Just need a bit of guidance here from others who have done both iOS and Android development.
Edit
It seems like what I'm looking for is called a Compound Control: http://developer.android.com/guide/topics/ui/custom-components.html
I'll keep digging and hopefully achieve the result I'm after :D
Just need to work out this Inflater business.

OK, I think I got it, not sure if it's the best solution but it does what I want.
So it goes something like this:
public class CustomView extends RelativeLayout
{
private Context context;
public TextView message;
public Button button;
public CustomView(Context context)
{
super(context);
// ---------------------------------------------------------
// store context as I like to create the views inside
// initViews() method rather than in the constructor
// ---------------------------------------------------------
this.context = context;
initViews();
initLayouts();
addViews();
}
public CustomView(Context context, AttributeSet attrs)
{
super(context, attrs);
// ---------------------------------------------------------
// store context as I like to create the views inside
// initViews() method rather than in the constructor
// ---------------------------------------------------------
this.context = context;
initViews();
initLayouts();
addViews();
}
public initViews()
{
// ----------------------------------------
// note "context" refers to this.context
// that we stored above.
// ----------------------------------------
message = new TextView(context);
...
button = new Button(context);
...
}
public initLayouts()
{
// --------------------------------------------------
// use Android layout params to position subviews
// within this custom view class
// --------------------------------------------------
message.setId(View.generateViewId());
button.setId(View.generateViewId());
RelativeLayout.LayoutParams messageLayoutParams = new RelativeLayout.LayoutParams(
LayoutParams.MATCH_PARENT,
LayoutParams.MATCH_PARENT
);
message.setLayoutParams(messageLayoutParams);
RelativeLayout.LayoutParams buttonLayoutParams = new RelativeLayout.LayoutParams(
LayoutParams.MATCH_PARENT,
LayoutParams.WRAP_CONTENT
);
button.setLayoutParams(buttonLayoutParams);
}
public addViews()
{
// adding subviews to layout
addView(message);
addView(button);
}
}
Now I can use this custom view in any of my Activity:
public class MainActivity extends ActionBarActivity {
// custom view instance
protected CustomView approvalView;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
...
initViews();
}
public initViews()
{
...
approvalView = new CustomView(this);
approvalView.message.setText("1 + 1 = 2");
approvalView.button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Log.d("Logger", "Math formula approved! :D");
}
});
}
}
Inflater is used if we create our layout using XML which isn't something I like to do, so I generated my view's layout programmatically :D
The above "RelativeLayout" in "extends RelativeLayout" can be replace with "LinearLayout" or other layouts of course.

To add a simple answer for the general visitor to this question...
You can't add subviews to an Android View like you can with an iOS UIView.
If you need to add subviews in Android, then use one of the ViewGroup subclasses (like LinearLayout, RelativeLayout, or even your own custom subclass).
myViewGroup.addView(myView);

Android and ios app development are two different concepts, each have its own way to perform your task. Sometimes its difficult to develop a piece of code in android and sometimes in ios.
To create your view screen/design/GUI in android you can create XML file (recommended) or by code (which is somehow difficult to maintain w.r.t XML).
For your question you don't need to create your own ViewGroup or RelativeLayout or LinearLayout e.g. if you want to use RelativeLayout as a parent for your view than by using XML you can use.
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Some Text"/>
</RelativeLayout>
If you want to create your view pragmatically than use
RelativeLayout parentRelativeLayout = new RelativeLayout(context);
RelativeLayout.LayoutParams parentParams = new RelativeLayout.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);
parentRelativeLayout.setLayoutParams(parentParams);
TextView childTextView = new TextView(context);
childTextView.setText("Some Text");
mRelativeLayout.addView(childTextView);
Its just a sample code both have identical output but with programmatic approach it will be difficult as your view grows.
Looking your code you are creating custom view (why?) in android we only need custom views if default views not are providing some functionally which we need to use/implement in our code.
As far as i understand you want to use custom views for reuse. Its good approach but if android is providing some functionality than why you are trying to invent wheel again, just use different layouts, use only custom views if you want something extra.

Android TextView baseline related margin

I need to position a TextView the way its baseline is 20dp from the bottom of the container.
How can I achieve this?
The layout with bottom margin or padding produces the same result.
I would like to make the text 'sit' on the purple line.
When I write 'sit' I mean, the 'wert' should touch the line, not 'q...y'.
The padding / margin is equal to the purple square size:

If you still need it, I wrote custom method, to not create lots of custom views. It works for me with TextView:
public static void applyExistingBotMarginFromBaseline(View view) {
final int baseline = view.getBaseline();
final int height = view.getHeight();
final ViewGroup.MarginLayoutParams marginLayoutParams;
try {
marginLayoutParams = ((ViewGroup.MarginLayoutParams) view.getLayoutParams());
} catch (ClassCastException e) {
throw new IllegalArgumentException("Applying margins on a view with wrong layout params.");
}
final int baselineMarginValue = baseline + marginLayoutParams.bottomMargin;
marginLayoutParams.bottomMargin = baselineMarginValue - height;
view.setLayoutParams(marginLayoutParams);
}
You can apply it when view is measured already, so like this:
final TextView title = (TextView) findViewById(R.id.title);
title.post(new Runnable() {
#Override public void run() {
Utils.applyExistingBotMarginFromBaseline(title);
}
});
Also you can use databinding framework and write your own custom BindingAdapter with a bit customized method, to use it from xml.

Your problem is not the padding/margin referenced to the parent, I think is about your font, I recommend you to change the fontFamily:"yourStyle"
even worst you have to re-difine your own font style which is explained here Custom fonts and XML layouts (Android) or Set specific font in a styles.xml

Android - How to add a View programmatically to an Activity's Absolute Layout setting its position?

I have a form with several Views on it, the last one is a Spinner that is bound to an adapter to get it's data from a Web Server via a POST request, at the end I append an additional entry for "Other...". If this option is selected on the spinner, a new EditText View at the bottom where the user enters a custom value, I've managed to get the EditText View to show on the screen, but it's positioned at the very top, over my other Views and I can't seem to find the way to make it appear at the bottom, below the Spinner as I want it to, here is the code I have so far:
EditText suggestCarrierField = new EditText(getBaseContext());
suggestCarrierField.setLayoutParams(new ViewGroup.LayoutParams(
ViewGroup.LayoutParams.FILL_PARENT,
ViewGroup.LayoutParams.WRAP_CONTENT));
suggestCarrierField.setHint("Suggest your carrier");
((AbsoluteLayout) findViewById(R.id.createAccountView)).addView(suggestCarrierField);
((AbsoluteLayout) findViewById(R.id.createAccountView)).invalidate();

Using an AbsoluteLayout, you need to use AbsoluteLayout.LayoutParams, rather than ViewGroup.LayoutParams.
int width = 100, height = 25, x = 0, y = 200;
AbsoluteLayout.LayoutParams lp = new AbsoluteLayout.LayoutParams(width, height, x, y);
suggestCarrierField.setLayoutParams(lp);
Having said that, I strongly urge you to consider implementing this with a RelativeLayout (or LinearLayout) instead... AbsoluteLayout is deprecated, and for very good reason. There are so many different Android devices with different sized screens now, AbsoluteLayout just won't work across them all.

When setting the LayoutParams for suggestCarrierField, don't use ViewGroup but instead use AbsoluteLayout.LayoutParams. It has a constructor which takes a height, width AND x and y coordinates. See the AbsoluteLayout.LayoutParams doc . Here is a quick app I whipped which demos this:
public class AbsoluteLayoutTest extends Activity {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
AbsoluteLayout as = new AbsoluteLayout(this);
TextView tvTop = new TextView(this);
tvTop.setText("top");
tvTop.setLayoutParams(new AbsoluteLayout.LayoutParams(AbsoluteLayout.LayoutParams.FILL_PARENT, AbsoluteLayout.LayoutParams.WRAP_CONTENT, 0, 0));
TextView tvMid = new TextView(this);
tvMid.setText("middle");
tvMid.setLayoutParams(new AbsoluteLayout.LayoutParams(AbsoluteLayout.LayoutParams.FILL_PARENT, AbsoluteLayout.LayoutParams.WRAP_CONTENT, 0, 80));
TextView tvBot = new TextView(this);
tvBot.setText("bottom");
tvBot.setLayoutParams(new AbsoluteLayout.LayoutParams(AbsoluteLayout.LayoutParams.FILL_PARENT, AbsoluteLayout.LayoutParams.WRAP_CONTENT, 0, 180));
as.addView(tvTop);
as.addView(tvMid);
as.addView(tvBot);
setContentView(as);
}
}
This will result in three text views. One at the top (y-coord = 0), one in the middle (y-coord = 80) and one at the bottom (y-coord = 180).

Place view inside FrameLayout in Android

I want to add a view inside a FrameLayout programmatically and to place it in a specific point within the layout with a specific width and height. Does FrameLayout support this? If not, should I use an intermediate ViewGroup to achieve this?
int x; // Can be negative?
int y; // Can be negative?
int width;
int height;
View v = new View(context);
// v.setLayoutParams(?); // What do I put here?
frameLayout.addView(v);
My initial idea was to add an AbsoluteLayout to the FrameLayout and place the view inside the AbsoluteLayout. Unfortunately I just found out that AbsoluteLayout is deprecated.
Any pointers will be much appreciated. Thanks.

The following example (working code) shows how to place a view (EditText) inside of a FrameLayout. Also it shows how to set the position of the EditText using the setPadding setter of the FrameLayout (everytime the user clicks on the FrameLayout, the position of the EditText is set to the position of the click):
public class TextToolTestActivity extends Activity{
FrameLayout frmLayout;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
frmLayout = (FrameLayout)findViewById(R.id.frameLayout1);
frmLayout.setFocusable(true);
EditText et = new EditText(this);
frmLayout.addView(et,100,100);
frmLayout.setOnTouchListener(new OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
Log.i("TESTING","touch x,y == " + event.getX() + "," + event.getY() );
frmLayout.setPadding(Math.round(event.getX()),Math.round(event.getY()) , 0, 0);
return true;
}
});
}
}
main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="fill_parent"
android:layout_height="fill_parent">
<FrameLayout
android:id="#+id/frameLayout1"
android:layout_height="fill_parent" android:layout_width="fill_parent">
</FrameLayout>
</LinearLayout>

You can also add a margin around the newly added view to position it inside the FrameLayout.
FrameLayout frameLayout = (FrameLayout) findViewById(R.id.main); // or some other R.id.xxx
DisplayMetrics metrics = context.getResources().getDisplayMetrics();
LayoutParams params = new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
params.setMargins(0, metrics.heightPixels - 20, 0, 0);
View v = new View(context);
v.setLayoutParams(params);
frameLayout.addView(v);
This will position the FrameLayout 20 pixels from the bottom of the screen.
Edit: completed the example so it stands by itself. And oh, yes it does work.

It's true that with FrameLayout all children are pegged to the top left of the screen, but you still have some control with setting their padding. If you set different padding values to different children, they will show up at different places in the FrameLayout.

From the link Quinn1000 provided:
You can add multiple children to a FrameLayout, but all children are pegged to the top left of the screen.
This means you can't put your View at a specific point inside the FrameLayout (except you want it to be at the top left corner :-)).
If you need the absolute positioning of the View, try the AbsoluteLayout:
A layout that lets you specify exact locations (x/y coordinates) of its children. Absolute layouts are less flexible and harder to maintain than other types of layouts without absolute positioning.
As for setting the width and height of the View, also like Quinn1000 said, you supply the v.setLayoutParams() method a LayoutParams object, depending on the container you chose (AbsoluteLayout, LinearLayout, etc.)

The thread here on stackOverflow at
How do you setLayoutParams() for an ImageView?
covers it somewhat.
For instance:
LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(30, 30);
yourImageView.setLayoutParams(layoutParams);
implies that you need to be defining a LinearLayout.LayoutParams (or in your case a FrameLayout.layoutParams) object to pass to the setLayoutParams method of your v object.
At
http://developer.android.com/reference/android/widget/FrameLayout.html
it almost makes it looks like you could ask your v to:
generateDefaultLayoutParams () via this method if you have not defined the parameters specifically.
But it's late, and those links are making my eyes bleed a little. Let me know if they nhelp any :-)