Android NullPointerException in custom view access - android

I have created a custom view name StepView . Here is the code for StepView.
public class StepView extends LinearLayout {
private Context cont;
private LinearLayout stepHolder;
public StepView(Context context, AttributeSet attrs) {
super(context);
// TODO Auto-generated constructor stub
LayoutInflater.from(context).inflate(R.layout.stepview, this, true);
stepHolder = (LinearLayout) findViewById(R.id.stepHolder);
cont = context;
}
public void addStep(String title, int drawableId, View.OnClickListener stepAction){
View step = LayoutInflater.from(cont).inflate(R.layout.step, this, true);
TextView txtText = (TextView) step.findViewById(R.id.txtText);
ImageView imgStep = (ImageView) step.findViewById(R.id.imgStep);
txtText.setText(title);
imgStep.setImageResource(drawableId);
stepHolder.addView(step);
}
}
It is the code for stepview.xml.
<?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="match_parent"
android:orientation="vertical" >
<LinearLayout
android:id="#+id/stepHolder"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal" >
</LinearLayout>
</LinearLayout>
step.xml
<?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="match_parent"
android:orientation="vertical" >
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/imgStep"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/txtText">
</TextView>
</LinearLayout>
Now I used the XML in main layout.
<?xml version="1.0" encoding="utf-8"?>
<merge xmlns:android="http://schemas.android.com/apk/res/android" >
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="horizontal" >
..................
</LinearLayout>
<com.orthokeys.view.StepView
android:id="#+id/stepMenu"
android:layout_width="wrap_content"
android:layout_height="wrap_content" >
</com.orthokeys.view.StepView>
</merge>
I have cheched that it is appearing properly. But when I add the following code it is giving NullPointerException.
StepView stepMenu = (StepView) findViewById(R.id.stepMenu);
stepMenu.addStep("Picture", R.drawable.step01, null);
I have checked that stepMenu is giving null.
Whatis the problem in my code?

I solved the prob...change the code in constructor of StepView Class
public StepView(Context context, AttributeSet attrs) {
super(context, attrs);
....................
}

You are not showing the full code block where you get the error, but it looks like you may have forgotten to use setContentView(R.layout.main_layout); to set the layout in use.

Related

Replaced views in LinearLayout programmatically

I have layout:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="100dp"
android:background="#535353">
<TextView
android:id="#+id/promo"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_margin="5dp"
android:padding="5dp"
android:layout_weight="1"
/>
<TextView
android:id="#+id/title"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_margin="5dp"
android:padding="5dp"
android:layout_weight="1"
/>
</LinearLayout>
and I want to replace promo and title. Set first title, then promo.
I use this snippet.
public class AdView extends LinearLayout{
TextView promo;
public AdView(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
private void init() {
LayoutInflater.from(getContext()).inflate(R.layout.view, this);
promo = (TextView) findViewById(R.id.promo);
title = (TextView) findViewById(R.id.title);
}
private void changePosition() {
removeView(promo);
addView(promo);
}
But, I get error: java.lang.IllegalStateException: The specified child already has a parent. You must call removeView() on the child's parent first.
So, could you help me? How can I do this?

Android - Cannot get custom LinearLayout view to move with TranslateAnimation

I'm trying to do something simple - I have a custom LinearLayout view that I want to move across the screen using the TranslateAnimation. To test out the base case, I put the code in the constructor of my custom view to translate it as soon as it is created. But nothing happens, and the view stays put. Any idea why? I have pasted the relevant code below:
My custom LinearLayout View:
public MyView(Context context, AttributeSet attrs) {
super(context, attrs);
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
inflater.inflate(R.layout.my_view, this);
mText = (TextView) findViewById(R.id.my_text);
mImage = (ImageView) findViewById(R.id.my_picture);
//Test simple translate animation
TranslateAnimation translateMyView = new TranslateAnimation(10, 10, 5, 5);
translateMyView.setFillAfter(true);
translateMyView.setDuration(1000);
this.startAnimation(translateMyView);
}
The XML of this custom view:
<?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="match_parent"
android:orientation="vertical"
android:background="#drawable/border">
<TextView
android:id="#+id/my_text"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Example Text"/>
<ImageView
android:id="#+id/my_picture"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="#drawable/ic_launcher"/>
</LinearLayout>
And the way I have added this view in the main activity's view:
<RelativeLayout 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"
tools:context="${relativePackage}.${activityClass}"
android:id="#+id/main_view">
<com.pratikthaker.MyView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true"/>
</RelativeLayout>
What am I missing?

Activity with dynamicly added components freezes

My Application freezes and LogCat grows heap (frag case) to 14mb if add more then 3 own "components" to current activity/layout. It takes very long until the fourth "component" is added and Android asks to close my application.
I've written a Activity which has some components (EditTexts) and a own "component". I want to do something similar to the contacts app (Number adding) but with ingredients. So I've created a class IngredientsLayout which extends LinearLayout and a Layout xml file with a TextView and a "Add"-Button which I've placed on the Activity-Layout. Every time I press the Add Button, a single IngredientLayout with 3 EditTexts and a ImageButton will be added to the current IngredientsLayout which should "hold" all added ingredients.
What I'm doing wrong?
IngredientsLayout class:
public class IngredientsLayout extends LinearLayout {
ImageButton imageButtonAddIngredient;
ArrayList<IngredientLayout> arrayList;
public IngredientsLayout(Context context, AttributeSet attrs) {
super(context, attrs);
LayoutInflater inflater = (LayoutInflater) context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
inflater.inflate(R.layout.ingredients_list, this);
arrayList = new ArrayList<IngredientLayout>();
imageButtonAddIngredient = (ImageButton) findViewById(R.id.imageButtonAddIngredient);
imageButtonAddIngredient.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
LinearLayout layout = (LinearLayout) findViewById(R.id.linearLayoutIngredientsList);
IngredientLayout ingredientLayout = new IngredientLayout(getContext(), null);
ingredientLayout.setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT,
LayoutParams.WRAP_CONTENT));
arrayList.add(ingredientLayout);
layout.addView(ingredientLayout);
}
});
}
}
ingredients_layout.xml:
<?xml version="1.0" encoding="utf-8"?>
<merge xmlns:android="http://schemas.android.com/apk/res/android">
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/linearLayoutIngredientsList"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_margin="5dp"
android:orientation="horizontal" >
<TextView
android:id="#+id/textView1"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_gravity="left|center_vertical"
android:layout_weight="1"
android:text="#string/ingredients_list_name" />
<ImageButton
android:id="#+id/imageButtonAddIngredient"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="#android:color/transparent"
android:src="#drawable/ic_menu_add_ingredient" />
</LinearLayout>
</LinearLayout>
</merge>
IngredientLayout class:
public class IngredientLayout extends LinearLayout {
public IngredientLayout(Context context, AttributeSet attrs) {
super(context, attrs);
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
inflater.inflate(R.layout.ingredients_list_row, this);
}
}
ingredients_list_row.xml
<?xml version="1.0" encoding="utf-8"?>
<merge xmlns:android="http://schemas.android.com/apk/res/android">
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/linearLayoutIngredientRow"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<EditText
android:id="#+id/editTextAmount"
android:layout_width="45dp"
android:layout_height="fill_parent"
android:layout_weight="0.11"
android:ems="10"
android:hint="#string/ingredients_list_listrow_amount"
android:inputType="numberDecimal" >
<requestFocus />
</EditText>
<EditText
android:id="#+id/editTextUnit"
android:layout_width="60dp"
android:layout_height="fill_parent"
android:layout_weight="0.06"
android:ems="10"
android:hint="#string/ingredients_list_listrow_unit" /><EditText
android:id="#+id/editTextName"
android:layout_width="127dp"
android:layout_height="match_parent"
android:layout_gravity="left"
android:layout_weight="0.005"
android:ems="10"
android:hint="#string/ingredients_list_listrow_name" />
<ImageButton
android:id="#+id/imageButton1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="#android:color/transparent"
android:src="#drawable/ic_menu_cancel" />
</LinearLayout>
</merge>
LinearLayouts are not meant for this kind of dynamic accessing.
What you need to do is a ListView and a adapter.
And every time you add a new item into the adapter you call it's NottifyDataChanged to update the list view with the new item.

Android. How to adjust height and width of a custom component using XML attributes?

Is there any way to adjust height and width of a custom component using XML attributes?
For example, I created a component and its layout.
Here is XML layout of the component:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="horizontal" >
<TextView
android:id="#+id/textView1"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_weight="1"
android:text="TextView" />
<TextView
android:id="#+id/textView2"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_weight="1"
android:text="TextView" />
<TextView
android:id="#+id/textView3"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_weight="1"
android:text="TextView" />
</LinearLayout>
And here is a simple class that inflates this layout:
public class CustomComponent extends LinearLayout
{
public CustomComponent(Context context, AttributeSet attrs)
{
super(context, attrs);
LayoutInflater inflater = (LayoutInflater)context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
ViewGroup view = (ViewGroup)inflater.inflate(
R.layout.custom_component, null);
addView(view);
}
}
The custom component is used in layout of some activity that looks something like this:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<view
class = "com.tests.CustomComponent"
android:layout_width="fill_parent"
android:layout_height="fill_parent" />
</LinearLayout>
The component is meant to be stretched to full size of a screen (that's why its layout parameters set to "fill_parent") but that is never happen.
Can anyone help me with this?
Seeing as your CustomComponent extends LinearLayout, you just need to inflate the layout directly into it (parsing this as the ViewGroup, as your CustomComponent will be the holding view):
public class CustomComponent extends LinearLayout
{
public CustomComponent(Context context, AttributeSet attrs)
{
super(context, attrs);
inflate( context, R.layout.custom_component, this );
}
}
If that doens't work, try supplying only the constructor that takes a context:
public class CustomComponent extends LinearLayout
{
public CustomComponent(Context context)
{
super(context);
inflate( context, R.layout.custom_component, this );
}
}

Android: Same xml acts differently depending on where I inflate it and I don't know why

Why do some views in a linearlayout within a scrollview fill the parent when fill_parent is set when inflated from xml directly but don't when added via a custom component that inflates the same xml?
The result of inflating the same xml in two different places:
The top item of the two is as a result of inflating the xml in a class that extends linearLayout and then adding that class to the linearLayout inside the scroll view. This view isn't filling the parent and I can't work out why.
The bottom item is the result of inflating the xml directly in the activity that this is all contained within. It appears as I expected.
This is the code that adds the two views in the activity:
scrollList.addView(new CommunityTaskListItem(this, null));
scrollList.addView(View.inflate(getBaseContext(), R.layout.communitytask, null));
This is the code that inflates the activity within a custom component class "CommunityTaskListItem":
View communityTask = View.inflate(context, R.layout.communitytask, null);
addView(communityTask);
I assume the xml is okay because it works fine when inflated directly in the activity. My question is why the fill_parent property seems to be lost when the xml is inflated in a custom component's class?
For good measure, here is the xml being inflated: EDIT: I gave you the wrong one before!!! Here's the right one:
<?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="wrap_content">
<LinearLayout android:layout_width="fill_parent" android:layout_height="wrap_content" android:id="#+id/linearLayout1" android:background="#drawable/plainbutton" android:layout_marginBottom="5px" android:layout_marginTop="5px" android:layout_weight="1">
<TextView android:layout_height="wrap_content" style="#style/CommunityTaskText" android:layout_width="fill_parent" android:layout_weight="1" android:id="#+id/textViewCommunityTaskTimes" android:text="xx:xx - xx:xx"></TextView>
<TextView android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_weight="1" style="#style/CommunityTaskText" android:id="#+id/textViewCommunityTaskDescription" android:text="Task"></TextView>
</LinearLayout>
</LinearLayout>
I'd like to keep the custom component and not inflate the xml within my activity if I could.
EDIT: Code where CommunityTaskListItem is inflated:
import android.content.Context;
import android.util.AttributeSet;
import android.view.View;
import android.widget.LinearLayout;
import android.widget.TextView;
public class CommunityTaskListItem extends LinearLayout {
TextView textViewCommunityTaskTimes;
TextView textViewCommunityTaskDescription;
public CommunityTaskListItem(Context context, AttributeSet attrs) {
super(context, attrs);
View communityTask = View.inflate(context, R.layout.communitytask, null);
addView(communityTask);
textViewCommunityTaskTimes = (TextView)findViewById(R.id.textViewCommunityTaskTimes);
textViewCommunityTaskDescription = (TextView)findViewById(R.id.textViewCommunityTaskDescription);
}
...
EDIT: All working now! Here's the final code for anyone else incase they have a similar issue:
Contructor for the custom object:
public CommunityTaskListItem(Context context, AttributeSet attrs) {
super(context, attrs);
setOrientation(VERTICAL);
addView(inflate(context, R.layout.communitytask, null));
textViewCommunityTaskTimes = (TextView)findViewById(R.id.textViewCommunityTaskTimes);
textViewCommunityTaskDescription = (TextView)findViewById(R.id.textViewCommunityTaskDescription);
}
Custom object xml:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android">
<LinearLayout android:layout_width="fill_parent" android:layout_height="wrap_content" android:id="#+id/linearLayout1" android:background="#drawable/plainbutton" android:layout_marginBottom="5px" android:layout_marginTop="5px" android:layout_weight="1">
<TextView android:layout_height="wrap_content" style="#style/CommunityTaskText" android:layout_width="fill_parent" android:layout_weight="1" android:id="#+id/textViewCommunityTaskTimes" android:text="xx:xx - xx:xx"></TextView>
<TextView android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_weight="1" style="#style/CommunityTaskText" android:id="#+id/textViewCommunityTaskDescription" android:text="Task"></TextView>
</LinearLayout>
</LinearLayout>
To be honest I don't know exactly what the mistake I was making was so if someone could make that clear I'd be very grateful.
The first line should be:
scrollList.addView(new CommunityTaskListItem(this, null)
new LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT));
You call inflate() inside CommunityTaskListItem class and inflated view becomes a child view of the CommunityTaskListItem view. But you don't set width and height for this view so it doesn't match its parent's width.
EDIT: I think your XML should look like this:
<?xml version="1.0" encoding="utf-8"?>
<packagename.CommunityTaskListItem
xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent" android:layout_height="wrap_content">
<LinearLayout android:layout_width="fill_parent" android:layout_height="wrap_content" android:id="#+id/linearLayout1" android:background="#drawable/plainbutton" android:layout_marginBottom="5px" android:layout_marginTop="5px" android:layout_weight="1">
<TextView android:layout_height="wrap_content" style="#style/CommunityTaskText" android:layout_width="fill_parent" android:layout_weight="1" android:id="#+id/textViewCommunityTaskTimes" android:text="xx:xx - xx:xx"></TextView>
<TextView android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_weight="1" style="#style/CommunityTaskText" android:id="#+id/textViewCommunityTaskDescription" android:text="Task"></TextView>
</LinearLayout>
</packagename.CommunityTaskListItem>
where packagename is the name of the package of the CommunityTaskListItem class.
In this case you should change the CommunityTaskListItem:
public class CommunityTaskListItem extends LinearLayout {
TextView textViewCommunityTaskTimes;
TextView textViewCommunityTaskDescription;
public CommunityTaskListItem(Context context, AttributeSet attrs) {
super(context, attrs);
}
#Override
protected void onFinishInflate() {
textViewCommunityTaskTimes = (TextView)findViewById(R.id.textViewCommunityTaskTimes);
textViewCommunityTaskDescription = (TextView)findViewById(R.id.textViewCommunityTaskDescription);
}
// ....
}
This class cannot be created using its constructor. It can be only inflated.
The second way is to inflate children in the constructor like you do. But the XML should differ:
<?xml version="1.0" encoding="utf-8"?>
<merge
xmlns:android="http://schemas.android.com/apk/res/android">
<LinearLayout android:layout_width="fill_parent" android:layout_height="wrap_content" android:id="#+id/linearLayout1" android:background="#drawable/plainbutton" android:layout_marginBottom="5px" android:layout_marginTop="5px" android:layout_weight="1">
<TextView android:layout_height="wrap_content" style="#style/CommunityTaskText" android:layout_width="fill_parent" android:layout_weight="1" android:id="#+id/textViewCommunityTaskTimes" android:text="xx:xx - xx:xx"></TextView>
<TextView android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_weight="1" style="#style/CommunityTaskText" android:id="#+id/textViewCommunityTaskDescription" android:text="Task"></TextView>
</LinearLayout>
</merge>
The CommunityTaskListItem will be:
public class CommunityTaskListItem extends LinearLayout {
TextView textViewCommunityTaskTimes;
TextView textViewCommunityTaskDescription;
public CommunityTaskListItem(Context context) {
this(context, null);
}
public CommunityTaskListItem(Context context, AttributeSet attrs) {
super(context, attrs);
setOrientation(VERTICAL);
inflate(context, R.layout.communitytask);
textViewCommunityTaskTimes = (TextView)findViewById(R.id.textViewCommunityTaskTimes);
textViewCommunityTaskDescription = (TextView)findViewById(R.id.textViewCommunityTaskDescription);
}
// ....
}
This class can be created using its contructor and inflated from an XML. But if you want to inflate it, you should create a separate XML file. Let's call it task.xml.
<?xml version="1.0" encoding="utf-8"?>
<packagename.CommunityTaskListItem
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent" android:layout_height="wrap_content"/>
And that's how you can use it:
scrollList.addView(new CommunityTaskListItem(this),
new LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT));
scrollList.addView(View.inflate(getBaseContext(), R.layout.task, null));

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