android gridview always null - android

In my Activity i have:
DrawView which is a Custom Relative Layout.
This RelativeLayout should exist of a Custom Navigationbar and a Custom GridView
The Custom NavigationBar is added here to the DrawView:
final LayoutInflater factory = getLayoutInflater();
final View textEntryView = factory.inflate(R.layout.multiplechoice, null);
com.lernapp.src.Views.NavigationBarTest navigation = (com.lernapp.src.Views.NavigationBarTest)textEntryView.findViewById(R.id.navigationbar);
RelativeLayout parent = (RelativeLayout)navigation.getParent();
parent.removeAllViews();
drawView.addView(navigation);
i wanted to do something similar with the GridView..
I dont get it, my CustomGridView is always null, why is this!?
MyCustomGridView grid = (MyCustomGridView)findViewById(R.id.gridview);
xml:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<com.lernapp.src.Views.MyCustomGridView
android:id="#+id/gridview"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:cacheColorHint="#00000000"
android:listSelector="#android:color/transparent"
android:numColumns="auto_fit"
android:columnWidth="160dp"/>
</LinearLayout>
CustomGridView:
public class MyCustomGridView extends GridView implements OnItemClickListener{
private Listener mListener;
public MyCustomGridView(Context context, AttributeSet attrs) {
super(context, attrs);
setOnItemClickListener(this);
}
public void onItemClick(AdapterView parent, View v, int position, long id) {
if (mListener != null) {
mListener.onClick(position);
}
}
public void setListener(Listener l){
mListener = l;
}
public interface Listener{
void onClick(int position);
}
}
EDIT:
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
int height = this.getWindowManager().getDefaultDisplay().getHeight();
int width = this.getWindowManager().getDefaultDisplay().getWidth();
MyCustomGridView grid = (MyCustomGridView)findViewById(R.id.gridview);
DrawView drawView = new DrawView(this, dragFieldText, targetFieldText, height, width, grid);
final LayoutInflater factory = getLayoutInflater();
final View textEntryView = factory.inflate(R.layout.multiplechoice, null);
com.lernapp.src.Views.NavigationBarTest navigation = (com.lernapp.src.Views.NavigationBarTest)textEntryView.findViewById(R.id.navigationbar);
RelativeLayout parent = (RelativeLayout)navigation.getParent();
parent.removeAllViews();
drawView.addView(navigation);
setContentView(drawView);
}

Add this line to your onCreate and all will be good:
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.the_name_of_the_layout_for_this_activity);
And to be really clear, its
setContentView(R.layout.the_name_of_the_layout_for_this_activity);
You should add to the onCreate, and it must be added BEFORE you try and do findViewById().

You have 2 options
you use findViewById. The view you're looking for MUST be "on the screen" by having used setContentView(). THere's no other way around it, that's what the function findViewById is for.
If you cannot use setContentView() because you want to programatically set this view and it is not in an XML you want to set for some reason, you have to INFLATE the view and then do your magic with it, and then you can use setContentView() as you wish. Examples of how to do this are easy, but check out the manual and some random example

As Heinrisch said you need to call setContentView before using findViewById().
Why dont you add your custom Relative Layout to your layout xml? Usually you dont need to inflate Views by yourself.
<com.lernapp.src.Views.DrawView
android:layout_width="fill_parent"
android:layout_height="fill_parent" >
<com.lernapp.src.Views.MyCustomGridView
android:id="#+id/gridview"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:cacheColorHint="#00000000"
android:columnWidth="160dp"
android:listSelector="#android:color/transparent"
android:numColumns="auto_fit" />
</com.lernapp.src.Views.DrawView>

Related

scrollTo() for horizontalScrollView not working

I inflate another layout to appear below some view in my current layout.
This is done like this:
LayoutInflater vi = (LayoutInflater) getActivity().getApplicationContext()
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View rootView = vi.inflate(R.layout.horizontal_scroll_view, null);
horizontalScrollView = (HorizontalScrollView) rootView.findViewById(R.id.hsv_suggestions_scroll_view);
LinearLayout suggestionsContainer = (LinearLayout) horizontalScrollView.findViewById(R.id.ll_suggestions_container);
and I can confirm that it appears in the right place since I add some Views in it after a while and they all appear.
The layout I inflate is :
<HorizontalScrollView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/hsv_suggestions_scroll_view"
android:scrollbars="none" android:layout_gravity="center_horizontal"
android:paddingTop="16dp" android:fillViewport="true"
android:layout_width="match_parent" android:layout_height="wrap_content">
<LinearLayout
android:id="#+id/ll_suggestions_container"
android:gravity="center_horizontal" android:orientation="horizontal"
android:layout_width="wrap_content" android:layout_height="wrap_content">
</LinearLayout>
just a HorizontalScrollView with a LinearLayout as a child.
The Views I add later are all of them TextViews.
Now after a user action (write some text on an editText) I'm trying to scroll to that View and highlight it. Highlight works. What does not work is scroll.
I have tried :
horizontalScrollView.postDelayed(new Runnable() {
#Override
public void run() {
horizontalScrollView.smoothScrollTo(scrollTo, 0);
}
}, 300);
where variable scrollTo is what I get when I apply getLeft() to the View I wanna scroll to. I can confirm that it takes various values.
Anyone can help me with that ?
Got a similar issue.
I guess the root cause is that the UI was not yet rendered at that moment, causing the scroll not to work properly.
I just had to wrap my call to smoothScrollTo into .post as follows:
mScrollView.post(new Runnable() {
#Override
public void run() {
mScrollView.smoothScrollTo(xxx, yyy);
}
});
Notice that I do a post directly on the scrollView to make sure it is executed after it is being rendered. For example, doing a getActivity().runOnUIThread() would not work in my case.
Switch to using a RecyclerView with a LinearLayoutManager with orientation set to Horizontal. Like this:
scroll_view.xml
<android.support.v7.widget.RecyclerView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/scrollView"
android:scrollbars="none"
android:layout_gravity="center_horizontal"
android:paddingTop="16dp"
android:fillViewport="true"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layoutManager="android.support.v7.widget.LinearLayoutManager"
android:orientation="horizontal">
<LinearLayout
android:id="#+id/scrollContainer"
android:gravity="center_horizontal"
android:orientation="horizontal"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</android.support.v7.widget.RecyclerView>
Note: the layoutManager tag is required here for the layout to inflate. After it's inflated, we're going to set it programatically as well because otherwise we'll get an exception because the RecyclerView basically disposes of it before it's done with it.
OptionAdapter.java
public class OptionAdapter extends RecyclerView.Adapter<OptionAdapter.OptionHolder> {
private Context context;
private LayoutInflater inflater;
private ArrayList<String> options;
public OptionAdapter(Context context) {
this.context = context;
this.inflater = LayoutInflater.from(context);
options = new ArrayList<>();
}
#Override
public OptionHolder onCreateViewHolder(ViewGroup parent, int viewType) {
return new OptionHolder(inflater.inflate(R.layout.textview, parent, false));
}
#Override
public void onBindViewHolder(OptionHolder holder, int position) {
String option = options.get(position);
((TextView) holder.itemView).setText(option);
}
#Override
public int getItemCount() {
return options != null ? options.size() : 0;
}
public ArrayList<String> getOptions() {
return options;
}
public void addOption(String option, Integer index) {
if (index != null && index <= options.size()) {
options.add(index, option);
} else {
options.add(option);
}
notifyDataSetChanged();
}
public class OptionHolder extends RecyclerView.ViewHolder {
public OptionHolder(View itemView) {
super(itemView);
}
}
}
text_view.xml
<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_marginLeft="8dp"
android:layout_marginRight="8dp"
android:orientation="vertical"
android:layout_width="wrap_content"
android:layout_height="match_parent" />
Setting everything up
final LayoutInflater inflater = LayoutInflater.from(this);
final RecyclerView scrollView = (RecyclerView) inflater.inflate(R.layout.scroll_view, container, false);
scrollView.setLayoutManager(new LinearLayoutManager(this, LinearLayoutManager.HORIZONTAL, false));
final OptionAdapter adapter = new OptionAdapter(this);
scrollView.setAdapter(adapter);
container here is whatever view is going to be holding the RecyclerView. In my code, I've got it in a LinearLayout.
Adding a view to the list
adapter.addOption("The Added One", null);
Or if you want to add it to a specific position in the list.
adapter.addOption("The Added One", position);
Scrolling to a specific position
scrollView.smoothScrollToPosition(position);
Scrolling to a specific item in the list
scrollView.smoothScrollToPosition(adapter.getOptions().indexOf("ItemText"));
Hope it works for you!
Instead of smoothScrollTo(), try using scrollTo().
Make sure that your getLeft() is really returning a value > 0;

Put a button on a page from a ViewPager

I'm using ViewPager. I want to put a button on each page, but in doing so fills the entire page. I would like to determine the width and height of button but do not know how.
This is my code:
Pager Activity
public class PagerActivity extends Activity {
PagerContainer mContainer;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mContainer = (PagerContainer) findViewById(R.id.pager_container);
ViewPager pager = mContainer.getViewPager();
PagerAdapter adapter = new MyPagerAdapter();
pager.setAdapter(adapter);
//Necessary or the pager will only have one extra page to show
// make this at least however many pages you can see
pager.setOffscreenPageLimit(adapter.getCount());
//A little space between pages
pager.setPageMargin(15);
//If hardware acceleration is enabled, you should also remove
// clipping on the pager for its children.
pager.setClipChildren(false);
}
//Nothing special about this adapter, just throwing up colored views for demo
private class MyPagerAdapter extends PagerAdapter {
#Override
public Object instantiateItem(ViewGroup container, int position) {
TextView view = new TextView(PagerActivity.this);
view.setText("Item "+position);
view.setGravity(Gravity.CENTER);
view.setBackgroundColor(Color.argb(255, position * 50, position * 10, position * 50));
view.setTextColor(Color.parseColor("#CA2C68"));
Button buttonView = new Button(PagerActivity.this);
buttonView.setBackgroundResource(R.drawable.button_states_azul);
container.addView(buttonView);
return buttonView;
}
#Override
public void destroyItem(ViewGroup container, int position, Object object) {
container.removeView((View)object);
}
#Override
public int getCount() {
return 5;
}
#Override
public boolean isViewFromObject(View view, Object object) {
return (view == object);
}
}
}
activity_main.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/relativeLayout"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<LinearLayout
android:layout_width="match_parent"
android:layout_height="80dp"
android:background="#FF7CB8"
android:id="#+id/linear" >
<View
android:layout_width="match_parent"
android:layout_height="4dp"
android:background="#CA2C68"
android:layout_gravity="bottom"/>
</LinearLayout>
<com.example.slidee.PagerContainer
android:id="#+id/pager_container"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignBottom="#id/linear"
android:layout_alignParentBottom="true"
android:layout_below="#+id/linear"
android:background="#29C5FF" >
<android.support.v4.view.ViewPager
android:layout_width="234dp"
android:layout_height="match_parent"
android:layout_gravity="center_horizontal"
android:background="#29C5FF" />
</com.example.slidee.PagerContainer>
ViewPager expects the contained view to occupy the whole container.
Use some layout to contain a button:
LinearLayout lay = new LinearLayout(PagerActivity.this);
LayoutParams lp = new LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT);
buttonView.setLayoutParams(lp);
lay.addView(buttonView);
container.addView(lay);
an other way to do it is to make a new xml file and inflate it.
<?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:id="#+id/viewpager_button"
android:background="#drawable/button_states_azul"/>
</LinearLayout>
and in instantiateItem
LayoutInflater inflater = MainActivity.this.getLayoutInflater();
View pagerView = inflater.inflate(R.layout.viewpager_layout, null);
Button button = (Button) pagerView.findViewById(R.id.viewpager_button);
container.addView(button);
You are creating the button dynamically and hence by default it does a match_parent for width and height.
Add this line:
buttonView.setLayoutParams(new ViewGroup.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT));
This is how i do it, create a xml layout you want to inflate. Add all the view you are intending. Then inside your adapter class, inside instantiateItem override do something like this. remember to adjust your xml views to fit parents width and height as you wish.
#Override
public Object instantiateItem(ViewGroup container, final int position) {
LayoutInflater inflater = (LayoutInflater) mContext.getSystemService(Activity.LAYOUT_INFLATER_SERVICE);
View view = inflater.inflate(R.layout.your_view, container, false);
// get reference to your button over here if you have one
Button b = (Button) view.findViewById(R.id.enter_button);
container.addView(view);
return view;
}

Alertdialog inflating RecyclerView android

Im trying to add a view to my Material dialog using setView(...), I want to have my inflated view look like this
That is the recycler view will always take up roughly 2/3 of the screen. That includes when it is empty, where it will be an empty space and when it has many lines of data, where it can become scroll able.
This is my aim. However when I try to inflate this View inside my dialog I get the following..
That screen represents an empty recyclerview taking up most of the screen.
Here is the code
//Adding to dialog
mMaterialDialog = new MaterialDialog(mContext)
.setView(new ISEQDialog(mContext))
//.setBackgroundResource(R.drawable.dublin_watchlist)
.setPositiveButton("OK", new View.OnClickListener() {
#Override
public void onClick(View v) {
mMaterialDialog.dismiss();
}
});
mMaterialDialog.show();
}
});
//View
public class ISEQDialog extends FrameLayout{
SeekBar mBuySeekBar;
TextView mStockHeading;
Context mContext;
View mView;
RecyclerView mStockDataList;
public ISEQDialog(Context context) {
super(context);
this.mContext = context;
LayoutInflater inflater = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
if(inflater != null){
mView = inflater.inflate(R.layout.stock_dialog, null);
}
mStockDataList = (RecyclerView) mView.findViewById(R.id.rv_stock_data_list);
//
mStockDataList.setAdapter(new ISEQDialofRecyclerViewAdapter());
LinearLayoutManager layoutManager = new LinearLayoutManager(mContext);
layoutManager.setOrientation(LinearLayoutManager.VERTICAL);
layoutManager.scrollToPosition(0);
mStockDataList.setLayoutManager(layoutManager);
//mStockDataList.addItemDecoration(new DividerItemDecoration(mContext.getDrawable(R.drawable.divider)));
addView(mView);
}
}
//RecyclerViewAdapter
public class ISEQDialofRecyclerViewAdapter extends RecyclerView.Adapter<ISEQDialofRecyclerViewAdapter.ViewHolder>{
#Override
public ISEQDialofRecyclerViewAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
return null;
}
#Override
public void onBindViewHolder(ISEQDialofRecyclerViewAdapter.ViewHolder holder, int position) {
}
#Override
public int getItemCount() {
return 0;
}
public static class ViewHolder extends RecyclerView.ViewHolder {
public ViewHolder(View itemView) {
super(itemView);
}
}
}
//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">
<TextView
android:id="#+id/tv_stock_dialog_heading"
android:layout_weight="0.2"
android:layout_width="match_parent"
android:layout_height="0dp"
android:gravity="center"
android:textColor="#color/list_divider_pressed"
android:layout_gravity="top"
android:background="#null"
android:textSize="35dp"
android:text="Portfolio Value"
/>
<android.support.v7.widget.RecyclerView
android:id="#+id/rv_stock_data_list"
android:layout_weight="0.7"
android:layout_height="0dp"
android:divider="#drawable/list_selector"
android:dividerHeight="1dip"
android:layout_width="match_parent">
</android.support.v7.widget.RecyclerView>
<SeekBar
android:id="#+id/sb_buy_stocks"
android:layout_weight="0.1"
android:layout_width="match_parent"
android:layout_height="0dp"
android:gravity="center"
android:indeterminate="false" />
</LinearLayout>
I had the same issue trying to add the recycler view to the dialog.
When i tried troubleshooting i realized that only the constrcutor of the recycler view adapter gets called and stops. The remaining methods as getItemCount(), onCreateViewHolder() and onBindViewHolder() doesn't gets called.
So i did the following
1) i replaced the recyclerview with the linear layout.
2) referenced the linear layout as view holder in code.
3) Then i manually iterated through the list i was to pass to the recycler view and on so i inflated the single row xml file, referenced the views and set text on it.
4) I added the view to the view holder and displayed the dialog. It works
5) This operation inflates the view as we are not recycling anything so if the items to display is below 10-15 you can use this as well or else hits the performance of the app a slight.
In Activity
Dialog myTestDialog = new Dialog(getActivity());
myTestDialog.setContentView(R.layout.order_details_orders_to_deliver);
//get the layout group
ViewGroup layout = (ViewGroup) myTestDialog.findViewById(R.id.order_details_recycler_view);
List<OrderItemDetails> orderItemDetailsList = mDatabaseOperationsAdapter.getOrderDetail(ordersToDeliver.getOrderId());
for (int x = 0; x < orderItemDetailsList.size(); x++) {
OrderItemDetails orderItemDetails = orderItemDetailsList.get(x);
View view = inflater.inflate(R.layout.order_details_row, null);
TextView itemName = (TextView) view.findViewById(R.id.order_details_item_name);
TextView quantity = (TextView) view.findViewById(R.id.order_details_item_quantity);
TextView itemTotal = (TextView) view.findViewById(R.id.order_details_item_total);
itemName.setText(orderItemDetails.getProductName());
quantity.setText(String.valueOf(orderItemDetails.getProductQuantity()));
itemTotal.setText(String.valueOf(orderItemDetails.getTotalPrice()));
layout.addView(view);
}
myTestDialog.show();
Note : order_details_recycler_view is the linear layout not recycler view as i changed it to linear layout keeping the id same.
List orderItemDetailsList is the list that was to be passed to the adapter.
This problem is related to RecyclerView as i know, when it is empty it fills layout, unless you give fixed layout_height.
There is trick, which is you check list of items before you create alertDialog. If empty, create alertDialog without RecyclerView, just with warning text. Otherwise create your custom alertDialog.

Android: button showing up multiple times in list view

I trying to write code to highlight the selected value of the list with "Next" button at the bottom of the layout. But for some reason, after every list item, "next" button also shows up. Can someone please help me resolve this problem?
Here is the layout file:
<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:orientation="vertical"
android:id="#+id/questionLayout"
>
<TextView android:id="#+id/txtExample"
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:textSize="25sp"
android:textColor="#000000"
android:background="#FF0000"
/>
<ListView
android:id="#+id/listExample"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#CCCCCC"
android:choiceMode="singleChoice"
/>
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="horizontal">
<Button
android:id = "#+id/next"
android:text="Next"
android:layout_width = "wrap_content"
android:layout_height = "wrap_content"
android:layout_gravity="center"
android:layout_weight="50"
/>
<Button
android:id = "#+id/submit"
android:text="Submit"
android:layout_width = "0dp"
android:layout_height = "wrap_content"
android:layout_weight="50"
android:layout_gravity="center"
/>
</LinearLayout>
</LinearLayout>
Java Code:
public class updateList extends Activity {
private SelectedAdapter selectedAdapter;
private ArrayList<String> list;
int correct_answer;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
list = new ArrayList<String>();
list.add("Choice One");
list.add("Choice Two");
list.add("Choice Three");
selectedAdapter = new SelectedAdapter(this,0,list);
selectedAdapter.setNotifyOnChange(true);
ListView listview = (ListView) findViewById(R.id.listExample);
listview.setAdapter(selectedAdapter);
listview.setOnItemClickListener(new OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> arg0, View view,
int position, long id) {
// user clicked a list item, make it "selected"
selectedAdapter.setSelectedPosition(position);
}
});
}
}
Thanks in advance
SSP
Selected Adaptor class:
public class SelectedAdapter extends ArrayAdapter{
// used to keep selected position in ListView
private int selectedPos = -1; // init value for not-selected
public SelectedAdapter(Context context, int textViewResourceId,
List objects) {
super(context, textViewResourceId, objects);
}
public void setSelectedPosition(int pos){
selectedPos = pos;
// inform the view of this change
notifyDataSetChanged();
}
public int getSelectedPosition(){
return selectedPos;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
View v = convertView;
// only inflate the view if it's null
if (v == null) {
LayoutInflater vi = (LayoutInflater)this.getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
v = vi.inflate(R.layout.activity_main, null);
}
// get text view
TextView label = (TextView)v.findViewById(R.id.txtExample);
// change the row color based on selected state
if(selectedPos == position){
label.setBackgroundColor(Color.CYAN);
}else{
label.setBackgroundColor(Color.WHITE);
}
label.setText(this.getItem(position).toString());
/*
// to use something other than .toString()
MyClass myobj = (MyClass)this.getItem(position);
label.setText(myobj.myReturnsString());
*/
return(v);
}
}
change your listview in xml as like this
<ListView
android:id="#+id/listExample"
android:layout_width="fill_parent"
android:layout_height="0dp"
android:layout_weight="1"//===== set maximum heighthere
android:layout_marginBottom="50dp"// === give some space at bottom so that buttons will appear
android:background="#CCCCCC"
android:choiceMode="singleChoice"
/>
But for some reason, after every list item, "next" button also shows up.
The ListView's row layout is determined by the layout you inflate in getView() or pass to your Adapter's super class if you haven't overridden getView(). Double check this layout and remove the unwanted code.
Addition
The layout for your ListView's items only needs to be one TextView since you only want to display a phrase in each. However you are currently passing your entire main layout, this creates the Buttons, an unused ListView, and everthing else in every row...
Instead use android.R.layout.simple_list_item_1 in getView(), of course you'll need to change the id you pass to findViewById() as well:
if (v == null) {
LayoutInflater vi = (LayoutInflater)this.getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
v = vi.inflate(android.R.layout.simple_list_item_1, null);
}
// get text view
TextView label = (TextView)v.findViewById(android.R.id.text1);
Please watch Android's Romain Guy discuss writing an efficient adapter to speed things up.

findViewById usage in View

I'm struggling with a problem for a few days already and couldn't find solution to my problem so far.
I have two classes:
- StartActivity extends Activity
- TimeGraphView extends SurfaceView
What I want to achieve is to add dynamically buttons from within TimeGraphView to another view (LinearLayout).
To do so wanted to get that LinearLayout inside TimeGraphView with findViewById() but it returns null, and it should because I call it in TimeGraphView not in root element where I used setContentView();
So my question is how can I add button dynamically from custom view level to another view.
And my code:
public class StartActivity extends Activity {
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.time_graph);
LinearLayout layout = (LinearLayout) this.findViewById(R.id.TimeGraphLayout);
//here I can add button but it's not what I want
}
}
and ...
public class TimeGraphView extends SurfaceView implements SurfaceHolder.Callback, Runnable {
public TimeGraphView(Context context) {
super(context);
}
public TimeGraphView(Context context, AttributeSet set) {
super(context, set);
}
public TimeGraphView(Context context, AttributeSet set, int arg) {
super(context, set, arg);
}
public void run() {
while (run) {
if (something) {
LinearLayout layout = (LinearLayout) findViewById(R.id.TimeGraphLayout);
if (layout != null) {
Button button = new Button(context);
button.setText(text);
layout.addView(button);
} else {
Log.e("TimeGraphView", "TimeGraphLayout is null");
//and "layout" is always null and that's the problem ;(
}
}
}
}
}
... and my XML
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/TimeGraphRootLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<HorizontalScrollViewa
android:id="#+id/TimeGraphPanel"
android:layout_width="match_parent"
android:layout_height="wrap_content" >
<LinearLayout
android:id="#+id/TimeGraphLayout"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal" />
</HorizontalScrollView>
<my.package.TimeGraphView
android:id="#+id/TimeGraphChart"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</LinearLayout>
You cannot use it in that way. If you add a root element Linearlayout and reference that in addition it might work. If you want to get the TimeGraphLayout class though:
TimeGraphView layout = (TimeGraphView) findViewById(R.id.TimeGraphLayout);
setContentView(layout);
The original way you did it will not work because TimeGraphView is not a LinearLayout

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