Develop Reference

Android Studio Toolbar With NO Layouts

I am extremely new to Android Studio, and as a learning exercise, I am trying to create an application without using any xml files other than manifest.
I want to make an activity, layout, toolbar, and drawer menu completely within Java. I know it is not how things are normally done, and I am likely causing myself a lot of unnecessary stress, but, as I said, this is a learning exercise.
Everything seems to execute, but the toolbar does not display. Also, getSupportActionBar().getHeight() returns zero.
Any help is appreciated!
Thanks,
John
Here is my Activity.java
package com.example.john.myblankapplication;
import android.graphics.Color;
import android.os.Bundle;
import android.support.v7.app.ActionBar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.support.design.widget.Snackbar;
import android.view.Gravity;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.LinearLayout;
import android.widget.RelativeLayout;
import android.widget.TextView;
/**
* Created by John on 7/3/2016.
*/
public class MyActivity extends AppCompatActivity {
private RelativeLayout myRelativeLayout;
private LinearLayout myLinearLayout;
private Toolbar myToolbar;
private TextView myTextView;
private ActionBar myActionBar;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Create the main layout programmatically
createRelativeLayout();
createLinearLayout();
// I have tried it with LinearLayout and RelativeLayout
setContentView(myLinearLayout);
// Create the toolbar layout programmatically
createToolbarLayout();
//myLinearLayout.addView(myToolbar); // that turned the whole screen red
setSupportActionBar(myToolbar);
myActionBar = getSupportActionBar();
myActionBar.setDisplayHomeAsUpEnabled(true); // new test - didn't help
// Create the text programmatically
myLinearLayout.addView(createTextView());
Snackbar.make(myTextView, "ActionBarHeight="+myActionBar.getHeight(),
Snackbar.LENGTH_LONG)
.setAction("Action", null).show(); // displays 0
}
private void createRelativeLayout() {
myRelativeLayout = new RelativeLayout(this);
// Specifies the layout properties
RelativeLayout.LayoutParams relativeParams = new RelativeLayout.LayoutParams(
RelativeLayout.LayoutParams.MATCH_PARENT,
RelativeLayout.LayoutParams.MATCH_PARENT
);
myRelativeLayout.setLayoutParams(relativeParams);
}
private void createLinearLayout() {
myLinearLayout = new LinearLayout(this);
// Specifies the layout properties
LinearLayout.LayoutParams linearParams = new LinearLayout.LayoutParams(
LinearLayout.LayoutParams.MATCH_PARENT,
LinearLayout.LayoutParams.MATCH_PARENT
);
myLinearLayout.setLayoutParams(linearParams);
}
private Toolbar createToolbarLayout() {
myToolbar = new Toolbar(this);
Toolbar.LayoutParams toolBarParams = new Toolbar.LayoutParams(
RelativeLayout.LayoutParams.MATCH_PARENT,
R.attr.actionBarSize, Gravity.TOP
);
myToolbar.setTitle("My Toolbar");
myToolbar.setLayoutParams(toolBarParams);
myToolbar.setBackgroundColor(Color.RED);
myToolbar.setVisibility(View.VISIBLE);
return myToolbar;
}
private TextView createTextView() {
myTextView = new TextView(this);
// Set initial layout parameters
RelativeLayout.LayoutParams textViewParams = new RelativeLayout.LayoutParams(
RelativeLayout.LayoutParams.WRAP_CONTENT,
RelativeLayout.LayoutParams.WRAP_CONTENT
);
// Set alignment parameters
//textViewParams.addRule(RelativeLayout.ALIGN_PARENT_TOP);
textViewParams.addRule(RelativeLayout.CENTER_HORIZONTAL);
myTextView.setText("Here is some text");
myTextView.setLayoutParams(textViewParams);
return myTextView;
}
}

You also need to add toolbar to linear layout.
// Create the toolbar layout programmatically
myLinearLayout.addView(// Create the toolbar layout programmatically
createToolbarLayout(););

I would recommend making the toolbar a custom view and just set the dimensions in the layout screen. You can declare the custom view as a toolbar if you import the toolbar package. Then you can use all the toolbar commands built in to add a title and items.
Hope this helps!

Android - removing layout programmatically

I have an activity that makes a layout programmatically from a Shared Preference using a for loop. The text views and buttons are enclosed in a linear layout. The user can input as many views as he wants. Now, the button will be a delete button. When pressed, I want to delete the linear layout the button and the other textviews are contained. How do I do this?
HERE IS MY CODE:
package com.dirkjan.myschools;
import android.app.Activity;
import android.content.Intent;
import android.content.SharedPreferences;
import android.content.res.Configuration;
import android.graphics.Typeface;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.TextView;
public class MainActivity extends Activity {
LinearLayout subjectLeft, subjectRight;
Button addSubj;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
subjectLeft = (LinearLayout) findViewById(R.id.llSubjectLeft);
subjectRight = (LinearLayout) findViewById(R.id.llSubjectRight);
//Load the saved subjects
SharedPreferences getSubjects = getSharedPreferences("SubjectInfo_Prefs", MODE_PRIVATE);
SharedPreferences.Editor editor = getSubjects.edit();
int subjectCount = getSubjects.getInt("count", 0);
if (subjectCount > 0 ){
for (int i = 1; i <= subjectCount; i++){
//Set the linear layout for each subject
LinearLayout ll = new LinearLayout(this);
ll.setOrientation(LinearLayout.VERTICAL);
LinearLayout.LayoutParams llParams = new LinearLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT);
float scale = getResources().getDisplayMetrics().density;
//SET BOTTOM MARGIN
float margin = 5; //RESIZE MARGIN HERE!
int margs = (int) (margin * scale + 0.5f);
//SET PADDING IN DP
float padding = 5; //RESIZE PADDING HERE!
int pads = (int) (padding * scale +0.5f);
llParams.setMargins(0,0,0,margs);
//SETTING THE LINEARLAYOUT PARAMS
ll.setLayoutParams(llParams);
ll.setPadding(pads, pads, pads, pads);
//SETTING THE BACKGROUND COLOR OF THE LINEAR LAYOUT
String chosenColor = getSubjects.getString("chosenColor" + i, "BLUE");
if (chosenColor.equals("Green")){
ll.setBackgroundResource(R.color.HoloGreen);
}else if (chosenColor.equals("Blue")){
ll.setBackgroundResource(R.color.HoloBlue);
}else if (chosenColor.equals("Gray")){
ll.setBackgroundResource(R.color.HoloGray);
}else if (chosenColor.equals("Orange")){
ll.setBackgroundResource(R.color.HoloOrange);
}else {
ll.setBackgroundResource(R.color.HoloYellow);
}
//ADDING THE LAYOUT TO THE APPROPRIATE CONTAINER (LEFT OR RIGHT)
if (i % 2 == 1){
subjectLeft.addView(ll);
} else {
subjectRight.addView(ll);
}
//SETTING THE SUBJECT NAME TEXTVIEW
TextView SubjectName = new TextView(this);
SubjectName.setText(getSubjects.getString("subjectName" + i, "Error"));
SubjectName.setLayoutParams(new ViewGroup.LayoutParams(
ViewGroup.LayoutParams.MATCH_PARENT,
ViewGroup.LayoutParams.WRAP_CONTENT));
SubjectName.setTextSize(22);
SubjectName.setTypeface(Typeface.DEFAULT_BOLD);
//SETTING THE SUBJECT NUMB TEXT VIEW
TextView SubjectNumber = new TextView(this);
SubjectNumber.setText(getSubjects.getString("subjectNumb" + i, "Error"));
SubjectNumber.setLayoutParams(new ViewGroup.LayoutParams(
ViewGroup.LayoutParams.MATCH_PARENT,
ViewGroup.LayoutParams.WRAP_CONTENT));
SubjectNumber.setTextSize(16);
//Creating the divider line
ImageView divider = new ImageView(this);
LinearLayout.LayoutParams dividerParams = new LinearLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, 2);
divider.setLayoutParams(dividerParams);
divider.setBackgroundResource(R.color.Black);
//Add Views into the Layout
ll.addView(SubjectNumber);
ll.addView(SubjectName);
ll.addView(divider);
}
}
addSubj = (Button) findViewById(R.id.buttonPlusSubject);
addSubj.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
Intent toAddSubj = new Intent(MainActivity.this,
AddSubjectActivity.class);
startActivity(toAddSubj);
finish();
}
});
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
Please do take note that no id is assigned for each layout. It would help if there is a code to identify the parent of the parent of the button (The button is in a relative layout, which is in a linear layout where the linear layout must be removed by clicking the button.

First find your parent layout using
ll = (LinearLayout) findViewById(R.id.main_linearlayout);
get the child layout using
final LinearLayout child = (LinearLayout) ll.findViewById(count);
now to remove the whole layout you can use removeview() method as below
ll.removeView(child);
to only remove all views from the particular layout(here for eg. child) you can use
child.removeAllViews();

You can call view.setVisiblility(View.GONE) if you want to remove it from the layout, or view.setVisibility(View.INVISIBLE) if you just want to hide it.

You can remove a Child View from a parent by calling removeView(View view), for example like this :
parent.removeView(child);

Supposing that your LinearLayout ID is my_linear_layout, just do this in your onClickListener:
findViewById(R.id.my_linear_layout).setVisibility(View.GONE);
In your XML, be sure to put the ID:
<LinearLayout
android:id="#+id/my_linear_layout"
...>
</LinearLayout>

you can do this like get the id of the currently clicked item
and assigned in root layout
LinearLayout layout = (LinearLayout) v.getParent();
And remove using this code given below:
linearLayout.removeView(layout);

how to draw a ImageView in the middle of the screen? (programatically)

I want to draw a simple ImageView in the middle of the screen, horizontally and vertically. But i want to do it without using XML files, i need to do it programatically.
I tryed with the next code, but it doesn't works fine, it draws the image a little to the right and a little to the bottom. How to solve it?
ARImage = new ImageView(getApplicationContext());
ARImage.setImageResource(R.drawable.x);
rl.addView(ARImage); //rl is the relative layout that it's inserted into a frame layout
Display display = ((WindowManager) getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay();
int w = display.getWidth();
int h = display.getHeight();
RelativeLayout.LayoutParams position = new RelativeLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
position.leftMargin = (int)(w/2);
position.topMargin = (int)(h/2);
ARImage.setLayoutParams(position);

It works for me like this:
package pete.android.study;
import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.view.Display;
import android.view.WindowManager;
import android.widget.ImageView;
import android.widget.RelativeLayout;
import android.widget.RelativeLayout.LayoutParams;
public class Main extends Activity {
/*
* (non-Javadoc)
* #see android.app.Activity#onCreate(android.os.Bundle)
*/
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
ImageView ARImage = new ImageView(getApplicationContext());
ARImage.setImageResource(R.drawable.icon);
RelativeLayout rl = new RelativeLayout(this);
Display display = ((WindowManager) getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay();
int w = display.getWidth();
int h = display.getHeight();
RelativeLayout.LayoutParams position = new RelativeLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
ARImage.setLayoutParams(position);
position.addRule(RelativeLayout.CENTER_IN_PARENT);
rl.addView(ARImage, position);
setContentView(rl);
}
}

Try to use
position.leftMargin = (int)(w/2 - whalf);
position.topMargin = (int)(h/2 - hhalf);
where whalf and hhalf are halfs of your image parameters.

I don't think you can set the left and top margin like that:
position.leftMargin = (int)(w/2);
position.topMargin = (int)(h/2);
Try setting the margins like this:
position.setMargins((int)(w/2), (int)(h/2), 0, 0); // left, top, right, bottom

Knowing that it is inside of RelativeLayout, you can place it in center of this layout:
RelativeLayout.LayoutParams lp = new RelativeLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
lp.addRule(RelativeLayout.CENTER_IN_PARENT);
rl.addView(ARImage, lp);

Android Runtime Layout Tutorial

Does anyone know how to perform or have a good reference for doing an activity layout at runtime in android?
Here is the code for my activity. I'm sure I'm just neglecting to do something here:
package com.isi.sa;
import android.app.Activity;
import android.os.Bundle;
import android.widget.LinearLayout;
import android.widget.TextView;
public class SimpleAssessmentTest extends Activity {
LinearLayout layout;
TextView question;
#Override
public void onCreate(Bundle icicle) {
super.onCreate(icicle);
layout = new LinearLayout(this);
question = new TextView(this);
layout.setLayoutParams(new ViewGroup.LayoutParams(-1,-1));
layout.setBackgroundColor(R.color.blue);
question.setLayoutParams(new ViewGroup.LayoutParams(-1,-2));
question.setTextColor(R.color.green);
question.setTextSize(1,14);
question.setText("This is question1");
layout.addView(question);
setContentView(layout);
}
}
As you can see I'm just trying to add a linear layout with a single text view (just for testing purposes) however, when the activity starts I just get a black screen with a title bar of my app name.
Thanks

You forgot to set your contentView. You should add
setContentView(layout);
At the end of the onCreate method

You can check out this URL: http://www.linux-mag.com/cache/7705/1.html . It has both library widgets and custom widgets.
EDIT:
setBackgroundColor requires input in proper ARGB format: 0xAARRGGBB. Each AA, RR, GG and BB range from 00 (minimum) to ff (maximum).
The bare minimum example goes here and it works flawlessly. Here are the screenshot and code (modified a bit):
http://picturepush.com/public/3313522 (old)
package us.simpleit;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.EditText;
import android.widget.LinearLayout;
import android.widget.TextView;
public class SimpleGUI extends Activity {
TextView tv;
EditText et;
LinearLayout ll;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//LinearLayout ll = new LinearLayout(this);
ll = new LinearLayout(this);
ll.setOrientation(android.widget.LinearLayout.VERTICAL);
ll.setLayoutParams(new ViewGroup.LayoutParams(-1,-1));
// ARGB: Opaque Red
ll.setBackgroundColor(0x88ff0000);
tv = new TextView(this);
tv.setLayoutParams(new ViewGroup.LayoutParams(-1,-2));
tv.setText("sample text goes here");
// ARGB: Opaque Green
tv.setBackgroundColor(0x5500ff00);
ll.addView(tv);
et = new EditText(this);
et.setLayoutParams(new ViewGroup.LayoutParams(-1,-2));
et.setText("edit me please");
// ARGB: Solid Blue
et.setBackgroundColor(0xff0000ff);
ll.addView(et);
Button btn = new Button(this);
btn.setText("Go!");
btn.setOnClickListener(new Button.OnClickListener() {
public void onClick(View v) {
tv.setText(et.getText().toString());
}
});
ll.addView(btn);
setContentView(ll);
//setContentView(R.layout.main);
}
}

The following demonstrates how to create views and layouts programmatically without using the layout xml files. It also creates a rounded rectangle layout object that draws a rounded rectangle around any child objects that are placed in it.
package android.example;
import android.app.Activity;
import android.graphics.Color;
import android.os.Bundle;
import android.util.DisplayMetrics;
import android.util.TypedValue;
import android.view.ViewGroup.LayoutParams;
import android.widget.LinearLayout;
import android.widget.TextView;
public class MessageScreen extends Activity {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
int mainBackgroundColor = Color.parseColor("#2E8B57");
int labelTextColor = Color.parseColor("#FF4500");
int messageBackgroundColor = Color.parseColor("#3300FF");
int messageTextColor = Color.parseColor("#FFFF00");
DisplayMetrics metrics = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(metrics);
float density = metrics.density;
int minMarginSize = Math.round(density * 8);
int paddingSize = minMarginSize * 2;
int maxMarginSize = minMarginSize * 4;
TextView label = new TextView(this);
/*
* The LayoutParams are instructions to the Layout that will contain the
* View for laying out the View, so you need to use the LayoutParams of
* the Layout that will contain the View.
*/
LinearLayout.LayoutParams labelLayoutParams = new LinearLayout.LayoutParams(
LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
label.setLayoutParams(labelLayoutParams);
label.setTextSize(TypedValue.COMPLEX_UNIT_SP, 18);
label.setPadding(paddingSize, paddingSize, paddingSize, paddingSize);
label.setText(R.string.title);
label.setTextColor(labelTextColor);
TextView message = new TextView(this);
RoundedRectangle.LayoutParams messageLayoutParams = new RoundedRectangle.LayoutParams(
LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT);
/*
* This is one of the calls must made to force a ViewGroup to call its
* draw method instead of just calling the draw method of its children.
* This tells the RoundedRectangle to put some extra space around the
* View.
*/
messageLayoutParams.setMargins(minMarginSize, paddingSize,
minMarginSize, maxMarginSize);
message.setLayoutParams(messageLayoutParams);
message.setTextSize(TypedValue.COMPLEX_UNIT_SP, paddingSize);
message.setText(R.string.message);
message.setTextColor(messageTextColor);
message.setBackgroundColor(messageBackgroundColor);
RoundedRectangle messageContainer = new RoundedRectangle(this);
LinearLayout.LayoutParams messageContainerLayoutParams = new LinearLayout.LayoutParams(
LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT);
messageContainerLayoutParams.setMargins(paddingSize, 0, paddingSize, 0);
messageContainer.setLayoutParams(messageContainerLayoutParams);
messageContainer.setOrientation(LinearLayout.VERTICAL);
/*
* This is one of the calls must made to force a ViewGroup to call its
* draw method instead of just calling the draw method of its children.
* This tells the RoundedRectangle to color the the exta space that was
* put around the View as well as the View. This is exterior color of
* the RoundedRectangle.
*/
messageContainer.setBackgroundColor(mainBackgroundColor);
/*
* This is one of the calls must made to force a ViewGroup to call its
* draw method instead of just calling the draw method of its children.
* This is the interior color of the RoundedRectangle. It must be
* different than the exterior color of the RoundedRectangle or the
* RoundedRectangle will not call its draw method.
*/
messageContainer.setInteriorColor(messageBackgroundColor);
// Add the message to the RoundedRectangle.
messageContainer.addView(message);
//
LinearLayout main = new LinearLayout(this);
LinearLayout.LayoutParams mainLayoutParams = new LinearLayout.LayoutParams(
LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT);
main.setLayoutParams(mainLayoutParams);
main.setOrientation(LinearLayout.VERTICAL);
main.setBackgroundColor(mainBackgroundColor);
main.addView(label);
main.addView(messageContainer);
setContentView(main);
}
}
The class for RoundedRectangle layout object is as defined here:
/**
* A LinearLayout that draws a rounded rectangle around the child View that was added to it.
*/
package android.example;
import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Rect;
import android.graphics.RectF;
import android.util.AttributeSet;
import android.util.DisplayMetrics;
import android.widget.LinearLayout;
/**
* A LinearLayout that has rounded corners instead of square corners.
*
* #author Danny Remington
*
* #see LinearLayout
*
*/
public class RoundedRectangle extends LinearLayout {
private int mInteriorColor;
public RoundedRectangle(Context p_context) {
super(p_context);
}
public RoundedRectangle(Context p_context, AttributeSet attributeSet) {
super(p_context, attributeSet);
}
// Listener for the onDraw event that occurs when the Layout is drawn.
protected void onDraw(Canvas canvas) {
Rect rect = new Rect(0, 0, getWidth(), getHeight());
RectF rectF = new RectF(rect);
DisplayMetrics metrics = new DisplayMetrics();
Activity activity = (Activity) getContext();
activity.getWindowManager().getDefaultDisplay().getMetrics(metrics);
float density = metrics.density;
int arcSize = Math.round(density * 10);
Paint paint = new Paint();
paint.setColor(mInteriorColor);
canvas.drawRoundRect(rectF, arcSize, arcSize, paint);
}
/**
* Set the background color to use inside the RoundedRectangle.
*
* #param Primitive int - The color inside the rounded rectangle.
*/
public void setInteriorColor(int interiorColor) {
mInteriorColor = interiorColor;
}
/**
* Get the background color used inside the RoundedRectangle.
*
* #return Primitive int - The color inside the rounded rectangle.
*/
public int getInteriorColor() {
return mInteriorColor;
}
}

I'm not sure if this question has been answered or not, but I just overcame this same issue today. Viet touched on the issue above but did not explicitly point out to check your color values. If you're coming from J2ME background like myself, you might be defining your color int values as 0xRRGGBB, so for full red J2ME would define it as 0xFF0000. However, doing so on Android will result in an int value of 0x00FF0000. Because Android uses the format of 0xAARRGGBB, a value of 0xFF0000 (J2ME) is actually (0x00FF0000) in Android this is full Red color that is COMPLETLY TRANSPARENT, so it's not seen on screen.
I Noticed above in your code you're using question.setTextColor(R.color.green); This statement will assign the id value created in the R file, so it's probably a high number with some value as 0x7f050000 where the Alpha is set lower than FULL OPAQUE. Try your example with:
question.setTextColor( getResources().getColor( R.color.green ) );
This should set the text color to the value in R.color.green not the ID of R.color.green.

Refreshing a LinearLayout after adding a view

I'm trying to add views dynamically to a linearlayout.
I see through getChildCount() that the views are added to the layout, but even calling invalidate() on the layout doesn't give me the childs showed up.
Am I missing something?

A couple of things you can check in your code:
On the View that is being added, check that you call its setLayoutParameter method with an appropriate ViewGroup.LayoutParameter.
When you adding the new Views, make sure you are doing it on the UI thread. To do this, you can use the parent View's post method.
This self contained example adds a TextView after a short delay when it starts:
import java.util.Timer;
import java.util.TimerTask;
import android.app.Activity;
import android.os.Bundle;
import android.view.ViewGroup;
import android.widget.LinearLayout;
import android.widget.TextView;
public class ProgrammticView extends Activity {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
final LinearLayout layout = new LinearLayout(this);
layout.setLayoutParams(new ViewGroup.LayoutParams(
ViewGroup.LayoutParams.FILL_PARENT,
ViewGroup.LayoutParams.FILL_PARENT));
setContentView(layout);
// This is just going to programatically add a view after a short delay.
Timer timing = new Timer();
timing.schedule(new TimerTask() {
#Override
public void run() {
final TextView child = new TextView(ProgrammticView.this);
child.setText("Hello World!");
child.setLayoutParams(new ViewGroup.LayoutParams(
ViewGroup.LayoutParams.FILL_PARENT,
ViewGroup.LayoutParams.WRAP_CONTENT));
// When adding another view, make sure you do it on the UI
// thread.
layout.post(new Runnable() {
public void run() {
layout.addView(child);
}
});
}
}, 5000);
}
}

I had the same problem and noticed that my overriden onMeasure() method wasn't called after the invalidate. So I created my own subroutine in the LinearLayout and called it before the invalidate() method.
Here is the code for an vertical LinearLayout:
private void measure() {
if (this.getOrientation() == LinearLayout.VERTICAL) {
int h = 0;
int w = 0;
this.measureChildren(0, 0);
for (int i = 0; i < this.getChildCount(); i++) {
View v = this.getChildAt(i);
h += v.getMeasuredHeight();
w = (w < v.getMeasuredWidth()) ? v.getMeasuredWidth() : w;
}
height = (h < height) ? height : h;
width = (w < width) ? width : w;
}
this.setMeasuredDimension(width, height);
}

I spent a lot of time to solve this problem too. And I found a simple method of refresh LinearLayout in 3 lines of code
You must set transperent color in style.xml
<color name="transparent">#00000000</color>
And in the code just call to set background
LinearLayout ll = (LinearLayout) findViewById(R.id.noteList);
ll.setBackgroundColor(getResources().getColor(R.color.transparent));
ll.invalidate();
If you has drawable background call
ll.setBackgroundResource(R.drawable.your_drawable);