I'm setting a TextView with the id #android:id/empty to display a message when there are no items in the ListView. However, this TextView gets displayed even if there are items in the ListView, right before the items show up.
How can I make it such that it only gets displayed when there are no elements in the ListView?
<?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" >
<ListView
android:id="#android:id/list"
android:layout_width="wrap_content"
android:layout_height="fill_parent"
android:dividerHeight="1dp" >
</ListView>
<TextView
android:id="#android:id/empty"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/empty_list" />
</LinearLayout>
PS: I'm using a Loader and a SimpleCursorAdapter with a ListFragment.
I'm guessing you are using a regular Fragment or Activity with a ListView inside of it. If you are, you must add the empty layout to the ListView manually.
E.g.
ListView lv = (ListView)findViewById(android.R.id.list);
TextView emptyText = (TextView)findViewById(android.R.id.empty);
lv.setEmptyView(emptyText);
Then your ListView will automatically use this view when its adapter is empty
If you are using a ListActivity you do not need to call setEmptyView() on the ListView since the ListActivity automatically manages that for you.
Set a TextView and assign to it whatever you want to display when the ListView is empty:
ProjectListAdapter projectListAdapter = new ProjectListAdapter();
TextView empty=(TextView)findViewById(R.id.empty);
projectsListView.setEmptyView(empty);
And in my xml file we write the below code
<TextView
android:id="#+id/empty"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:gravity="center"
android:text="Your text here"
android:textColor="#FFFFFF" />
I had this problem. You have to set the emptyView explicitly in your code.
Change your TextView:
<TextView
android:id="#+id/emptyResults"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/empty_list" />
Then in the onCreate():
listViewResults = (ListView) findViewById(R.id.list);
listViewResults.setEmptyView((LinearLayout) findViewById(R.id.emptyResults));
This code above assumes your ListView is in a LinearLayout.
I used ListFragment and had the same issue. I tried all variants from this answers, but the problem wasn't solved.
So I found my variant, to override setEmptyText():
public class NewsFragment extends ListFragment{
private TextView emptyText;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
//...
emptyText = (TextView)view.findViewById(android.R.id.empty);
//...
}
#Override
public void setEmptyText(CharSequence text) {
emptyText.setText(text);
}
}
Hope it will be helpful for somebody.
I know this is kind of late, but for it to work from XML, you need to put a weight on your ListView and have your TextView match_parent
<?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" >
<ListView
android:id="#android:id/list"
android:layout_width="wrap_content"
android:layout_height="0dp"
android:layout_weight="1"
android:dividerHeight="1dp" >
</ListView>
<TextView
android:id="#android:id/empty"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:text="#string/empty_list" />
</LinearLayout>
There's a good example of how to do it which works awesome:
When you want to show a message to the user when the ListView is
empty, you have to keep in mind the following 3 steps:
In the xml where the ListView is declared, create a TextView (the TextView can be inside a LinearLayout if you want) right
below the ListView
Set the TextView’s id as “emptyElement”
And inside the activity, set the setEmptyView() property to the ListView
1- Create an xml which will hold the ListView and name it
“my_activity”
and an activity called “MyActivity”.
Now, in the just created xml “my_activity”, you will have to set the ListView. And right below the ListView, you will have to add
a TextView. This will be used to display the empty message.
Important: The TextView must have as id the following name: “emptyElement”. This name is mandatory. The message won’t be displayed
if you use another name.
This is how “my_activity” xml should look like:
<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"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:paddingBottom="#dimen/activity_vertical_margin"
tools:context=".MyActivity">
<ListView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/listView"/>
<TextView android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/emptyElement"
android:text="The list is empty"
android:textStyle="bold"
android:textSize="15sp"
android:visibility="gone"
android:layout_centerInParent="true"
android:textColor="#android:color/darker_gray"/>
</RelativeLayout>
Create an xml for displaying items (when the list is not empty), and name it “list_item”.
<TextView android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/list_item_text_view"
android:textSize="20sp"
android:padding="10dp"
android:layout_marginLeft="5dp"/>
Create a new Java class for the custom adapter which will be used by the ListView and name “MyCustomAdapter”. The code for the adapter
is written below:
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.TextView;
import java.util.ArrayList;
public class MyCustomAdapter extends BaseAdapter {
private ArrayList<String> mListItems;
private LayoutInflater mLayoutInflater;
public MyCustomAdapter(Context context, ArrayList<String> arrayList){
mListItems = arrayList;
//get the layout inflater
mLayoutInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
#Override
public int getCount() {
//getCount() represents how many items are in the list
return mListItems.size();
}
#Override
//get the data of an item from a specific position
//i represents the position of the item in the list
public Object getItem(int i) {
return null;
}
#Override
//get the position id of the item from the list
public long getItemId(int i) {
return 0;
}
#Override
public View getView(int position, View view, ViewGroup viewGroup) {
// create a ViewHolder reference
ViewHolder holder;
//check to see if the reused view is null or not, if is not null then reuse it
if (view == null) {
holder = new ViewHolder();
view = mLayoutInflater.inflate(R.layout.list_item, null);
holder.itemName = (TextView) view.findViewById(R.id.list_item_text_view);
// the setTag is used to store the data within this view
view.setTag(holder);
} else {
// the getTag returns the viewHolder object set as a tag to the view
holder = (ViewHolder)view.getTag();
}
//get the string item from the position "position" from array list to put it on the TextView
String stringItem = mListItems.get(position);
if (stringItem != null) {
if (holder.itemName != null) {
//set the item name on the TextView
holder.itemName.setText(stringItem);
}
}
//this method must return the view corresponding to the data at the specified position.
return view;
}
/**
* Static class used to avoid the calling of "findViewById" every time the getView() method is called,
* because this can impact to your application performance when your list is too big. The class is static so it
* cache all the things inside once it's created.
*/
private static class ViewHolder {
protected TextView itemName;
}
}
Now go to MyActivity class and add the code below:
import android.app.Activity;
import android.os.Bundle;
import android.widget.ListView;
import java.util.ArrayList;
import java.util.List;
public class MyActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.my_activity);
ListView listView = (ListView) findViewById(R.id.listView);
// Create an empty array list of strings
List<String> items = new ArrayList<String>();
// Set the adapter
MyCustomAdapter adapter = new MyCustomAdapter(items);
listView.setAdapter(adapter);
// Set the emptyView to the ListView
listView.setEmptyView(findViewById(R.id.emptyElement));
}
}
TextView tv=(TextView) view.findViewById(R.id.empty);
tv.setVisibiliy(View.GONE);
Related
I've tried creating a RecyclerView which displays the songs I have on my phone from a pre-populated ArrayList. Here is my code for my activity:
public class HomeActivity extends AppCompatActivity
implements NavigationView.OnNavigationItemSelectedListener {
private RecyclerView songRecyclerView;
private RecyclerView.Adapter songRecyclerAdapter;
private RecyclerView.LayoutManager recyclerLayoutManager;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_home);
//get the songs list for the adapter
ArrayList<Audio> songList;
StorageUtils storageUtils = new StorageUtils(getApplicationContext());
songList = storageUtils.loadAudio();
//Recycler view setup for songs display
songRecyclerView = (RecyclerView) findViewById(R.id.recycler_view);
songRecyclerView.setHasFixedSize(true);
recyclerLayoutManager = new LinearLayoutManager(this);
songRecyclerView.setLayoutManager(recyclerLayoutManager);
songRecyclerAdapter = new SongAdapter(songList);
songRecyclerView.setAdapter(songRecyclerAdapter);
}
The Audio class has the getTitle() and getArtist() methods, which do work. The loud audio() also works so Songlist definitely has elements in it.
Here is the xml of the recyclerview item:
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/recycler_item"
android:layout_width="match_parent"
android:layout_height="72dp"
android:visibility="visible">
<TextView
android:id="#+id/recycler_item_songName"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginEnd="16dp"
android:layout_marginStart="16dp"
android:layout_marginTop="8dp"
android:text="song name"
android:textColor="#color/textPrimary"
android:textSize="16sp"
android:textStyle="normal"
android:visibility="visible"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<TextView
android:id="#+id/recycler_item_artistName"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginEnd="16dp"
android:layout_marginStart="16dp"
android:text="song artist"
android:textColor="#color/textSecondary"
android:textSize="16sp"
android:textStyle="normal"
android:visibility="visible"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/recycler_item_songName" />
</android.support.constraint.ConstraintLayout>
Here is my implementation of the Adapter:
package com.ecebuc.gesmediaplayer;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import java.util.ArrayList;
public class SongAdapter extends RecyclerView.Adapter<SongAdapter.ViewHolder> {
// The dataset
private ArrayList<Audio> songList;
public static class ViewHolder extends RecyclerView.ViewHolder {
public TextView recyclerTitleView, recyclerArtistView;
public ViewHolder(View itemView) {
super(itemView);
this.recyclerTitleView = (TextView) itemView.findViewById(R.id.recycler_item_songName);
this.recyclerArtistView = (TextView) itemView.findViewById(R.id.recycler_item_artistName);
}
}
// Constructor
public SongAdapter(ArrayList<Audio> songList){
this.songList = songList;
}
#Override
public SongAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
// create a new view
LayoutInflater layoutInflater = LayoutInflater.from(parent.getContext());
View listItemView = layoutInflater.inflate(R.layout.song_list_item, parent, false);
ViewHolder viewHolder = new ViewHolder(listItemView);
return viewHolder;
}
#Override
public void onBindViewHolder(ViewHolder holder, int position) {
Audio currentSong = songList.get(position);
holder.recyclerTitleView.setText(currentSong.getTitle());
holder.recyclerArtistView.setText(currentSong.getArtist());
Log.d("onBind: ", (String)holder.recyclerTitleView.getText() + (String)holder.recyclerArtistView.getText());
}
#Override
public int getItemCount() {
return songList.size();
}
}
The frustrating thing is that at my very first attempt at creating the whole recycleView, it did work and displayed the text. I tried adding an imageView as the cover of the songs to the layout of each item in the list, and the code to display that as well, and it wasn't working anymore. When tried to revert and have only the code for text, it stopped working altogether.
I am bashing my head over this because if I did make some small change somewhere, I don't know where it might be any more now. But I did try to recreate the class for the adapter and the layout file for the whole recycler functionality from scratch, and still not showing. The layout items have to be there because I see the shadow of the scroll.
Also, in the adapter's onBindViewHolder, that Log.d displays correctly each song title and artist. And it calls the newly created views' getText(). It's like the text was white. And no, the values of #color/text primary and textSecondary in the XML are #212121 and #424242 and were always like that (again, it did display the values the first time, and I haven't touched the colours).
I've looked for similar problems on StackOverflow and online, but I don't seem to have that kind of mistakes. I don't know what to do anymore. Heck, I'll even include the XML of the screen that has the actual recyclerView in it. At this point I don't know what could make those views invisible:
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
tools:context=".HomeActivity"
tools:showIn="#layout/app_bar_home">
<android.support.v7.widget.RecyclerView
android:id="#+id/recycler_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:scrollbars="vertical"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</android.support.constraint.ConstraintLayout>
Finally, I thought of looking at the developer options on my phone and display layout outlines, and this is what I had...as if the two textViews are not being created, yet I was able to get their text content after I've set it, so how is that even possible? Thank you to whoever can help me, I'm just trying to learn here...
For future reference in case anyone has a similar problem, I managed to solve it by simply changing my constraint layout in the recycler view item XML, to linear layout (or I'd guess whatever type of layout other than constraint) and compiled.
It worked well, displaying everything correctly. Then changing the XML back to constraint layout like before, and everything was still working fine. At this point I'd say it will forever remain a mystery.
make some change in adapter constructor like below code..
public Context context;
// Constructor
public SongAdapter(Context context,ArrayList<Audio> songList){
this.context=context;
this.songList = songList;
}
then after main activity make adapter object like below ..
SongAdapter adapter;
and remove this line of code ..
private RecyclerView.Adapter songRecyclerAdapter;
and used set adapter like below code..
RecyclerView recyclerView;
SongAdapter songRecyclerAdapter;
private void setAdapter(){
recyclerView.setLayoutManager(new LinearLayoutManager(this));
if (songRecyclerAdapter==null) {
songRecyclerAdapter = new SongAdapter(this,songList);
recyclerView.setAdapter(songRecyclerAdapter);
songRecyclerAdapter.notifyDataSetChanged();
}
else{
songRecyclerAdapter.notifyDataSetChanged();
}
}
UPDATE WITH CODE (Sorry for crappy formatting of my code, some reason it had problems allowing me to post it so I had to mess with the lines for a whole to get it to allow me to save thisedit)
Here is the idea. I have an app that works with Clarifia's image recognition. I generated the app using Google's pre built navegation bar, so there is extra xml files and code for that, but it can be ignored the two needed for this is activity_main.xml and content_main.xml. anyways in content_main.xml it is a linear layout that has an imageview and a listview. My goal is to dynamically generate the listview with a list of BUTTONS. each button will have setText() done to it to give it a tag, so for example if a image selected is a dog, and the tags are dog, animal, etc, then that many buttons will be generated, with a setText() of one button being dog, the other button being animal, etc . now Since I have to do a network call, the network call is done in asynctask. After it is done, the method onPostExecute() is called and from there I get the tags. NOW since i got the tags, I want to call set an adapter that will hold an array of buttons, and loop geting the ID for each button and doing settext() on each button with the tags. from there i want to set the adapter to the list view..
Problems:
way to many to count, but I THINK i narrowed it down to me not knowing how to get the "views" from the second xml file to have the elements be used on the first xml file, because everything comes out NULL. I tried googling it but i just keep running into road blocks. I just want to name each button with a tag and put them into listview, but like i said, since these elements are in a different xml file than main_activity, I think this is the problem. so here is the code per request.
MainActivity.java
public class MainActivity extends AppCompatActivity implements NavigationView.OnNavigationItemSelectedListener
{
private static final String CLASS = MainActivity.class.getSimpleName();
private Button selectButton;
private Toolbar toolbar;
private NavigationView navigationView;
private Clari
faiData cdata = null;
private ImageView imageview;
private ListView listview;
private TagAdapter adapter;
private List<Button> data;
protected Context context;
private GoogleApiClient client;
protected LinearLayout main;
#Override
protected void onCreate(Bundle savedInstanceState)
{
// THIS IS MY ATTEMPT TO DO THIS
// http://www.java2s.com/Code/Android/UI/UsingtwolayoutxmlfileforoneActivity.htm
super.onCreate(savedInstanceState);
context = MainActivity.this;
main = new LinearLayout (this);
setContentView(R.layout.activity_main);
// AUTO GENERATED stuff left out for nav bar, just showing this line*********
selectButton = (Button) findViewById(R.id.select_button);
selectButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
final Intent media_intent = new Intent(Intent.ACTION_PICK, MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
// START API OVER NET
startActivityForResult(media_intent, cdata.getOKCode());
}
});
// MY STUFF********************************************************
cdata = new ClarifaiData(this);
imageview = (ImageView) findViewById(R.id.image_view);
client = new GoogleApiClient.Builder(this).addApi(AppIndex.API).build();
}
#Override
protected void onActivityResult(int requestCode, int resultCode, Intent intent)
{
super.onActivityResult(requestCode, resultCode, intent);
if (requestCode == cdata.getOKCode() && resultCode == RESULT_OK)
{
Uri image = intent.getData();
if (image != null) {
// LEFT OUT STUFF FOR IMAGE RESIZING***************************
//************************************************** START LOOKING HERE***************************************
new AsyncTask<Uri, Void, RecognitionResult>()
{
#Override
protected RecognitionResult doInBackground(Uri... image)
{
// SO API CALL OVER INTERNET, SO NEEDED ASYNC
return cdata.recognizeBitmap(image[0]);
}
#Override
protected void onPostExecute(RecognitionResult result)
{
super.onPostExecute(result);
if (cdata.getTags(result))
{
selectButton.setEnabled(true);
selectButton.setText("Select a photo");
// MY ATTEMPT TO GET THE
// http://www.java2s.com/Code/Android/UI/UsingtwolayoutxmlfileforoneActivity.htm
LayoutInflater inflate = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
LinearLayout taglayout = (LinearLayout) inflate.inflate(R.layout.tag_list_item_trio_item, null);
LinearLayout.LayoutParams parm = new LinearLayout.LayoutParams(
LinearLayout.LayoutParams.WRAP_CONTENT,
LinearLayout.LayoutParams.WRAP_CONTENT);
listview = (ListView) main.findViewById(R.id.tagview);
main.addView(taglayout, parm);
// this is a arraylist of tags that hold strings
List tags = cdata.getMapTags();
// data is a array of buttons, each button will be labled by each value in tags
data = new ArrayList<Button>();
for (int i = 0; i < tags.size(); i++)
{
// GET ID FOR EACH BUTTON AND PUT IT INTO ARRAY THEN SETTEXT
String loc = "button_item_" + i;
int ID = getResources().getIdentifier(loc, "id", getPackageName());
Button temp = (Button) main.findViewById(R.id.button_item_0);
temp.setText("TEST " + i);
}
// HERE IS THE PROBLEM, I NEED A WAY TO GET THE LAYOUT STUFF FROM MAIN ACTIVITY
adapter = new TagAdapter(MainActivity.this, getResources().getIdentifier("tag_list_item_trio_item", "id", getPackageName()), data);
listview.setAdapter(adapter);
}
else
bottomToast(cdata.getRecError());
}
}.execute(image);
} else {
bottomToast(cdata.getLoadError());
}
}
}
tagAdapter.java
import android.content.Context;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;
import java.util.List;
public class TagAdapter extends ArrayAdapter<Button> {
private Context context;
private List<Button> taglist;
public TagAdapter(Context context, int resource, List<Button> objects) {
super(context, resource, objects);
Log.i("Test", "constructor " );
this.context = context;
this.taglist = objects;
}
#Override
public int getCount()
{
return taglist.size();
}
getView(int, android.view.View, android.view.ViewGroup)
#Override
public View getView(final int position, View convertView, ViewGroup parent)
{
LayoutInflater layoutInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
layoutInflater.inflate(R.layout.tag_list_item_dual_item, parent, false);
final Button tag = taglist.get(position);
View view = null;
view = layoutInflater.inflate(R.layout.tag_list_item_trio_item, parent, false);
else
{
view = layoutInflater.inflate(R.layout.tag_list_item_dual_item, parent, false);
Button nameTextView = (Button) view.findViewById(R.id.first_button_dual_item);
nameTextView.setText("test");
Button nameTextView2 = (Button) view.findViewById(R.id.second_button_dual_item);
nameTextView2.setText("test2");
}
return view;
}
}
content_main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/main_content"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:paddingBottom="#dimen/activity_vertical_margin"
android:gravity="center|bottom"
android:orientation="vertical"
app:layout_behavior="#string/appbar_scrolling_view_behavior">
<ImageView
android:layout_width="match_parent"
android:layout_height="0dp"
android:adjustViewBounds="true"
android:id="#+id/image_view"
android:background="#653fff"
android:layout_weight="0.5"
android:padding="1dp" />
<ListView
android:id="#+id/tagview"
android:layout_width="match_parent"
android:layout_weight="0.35"
android:layout_height="0dp"
android:padding="5dp"
android:background="#68343f"
android:layout_marginTop="10dp"
android:layout_gravity="center_horizontal"
android:textAlignment="center" />
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/imageView"
android:layout_gravity="center_horizontal"
android:textAlignment="center"
/>
<Button
android:id="#+id/select_button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/sel_image"
android:layout_marginTop="8dp"
android:layout_marginBottom="16dp"
android:paddingLeft="24dp"
android:paddingRight="24dp"
android:background="#3d88ec" />
</LinearLayout>
tag_list_item_trio.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_centerHorizontal="true"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:textAlignment="center"
android:layout_centerInParent="true"
android:orientation="horizontal">
<Button
android:id="#+id/button_item_0"
android:layout_width="0dp"
android:layout_weight="1"
android:layout_height="wrap_content"
android:layout_margin="5dp"
android:paddingLeft="10dp"
android:paddingRight="10dp"
android:background="#000000"
android:layout_gravity="center"
android:adjustViewBounds="true"
android:text="TEST 1"
android:textColor="#ffffff"
/>
<Button
android:id="#+id/button_item_1"
android:layout_width="0dp"
android:layout_weight="1"
android:layout_height="wrap_content"
android:layout_margin="5dp"
android:paddingLeft="10dp"
android:paddingRight="10dp"
android:background="#000000"
android:layout_gravity="center"
android:adjustViewBounds="true"
android:text="TEST 2"
android:textColor="#ffffff"
/>
<Button
android:id="#+id/button_item_2"
android:layout_width="0dp"
android:layout_weight="1"
android:layout_height="wrap_content"
android:layout_margin="5dp"
android:paddingLeft="10dp"
android:paddingRight="10dp"
android:background="#000000"
android:layout_gravity="center"
android:adjustViewBounds="true"
android:text="TEST 3"
android:textColor="#ffffff"
/>
</LinearLayout>
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_centerHorizontal="true"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:textAlignment="center"
android:layout_centerInParent="true"
android:orientation="horizontal">
<Button
android:id="#+id/button_item_0"
android:layout_width="0dp"
android:layout_weight="1"
android:layout_height="wrap_content"
android:layout_margin="5dp"
android:paddingLeft="10dp"
android:paddingRight="10dp"
android:background="#000000"
android:layout_gravity="center"
android:adjustViewBounds="true"
android:text="TEST 1"
android:textColor="#ffffff"
/>
<Button
android:id="#+id/button_item_1"
android:layout_width="0dp"
android:layout_weight="1"
android:layout_height="wrap_content"
android:layout_margin="5dp"
android:paddingLeft="10dp"
android:paddingRight="10dp"
android:background="#000000"
android:layout_gravity="center"
android:adjustViewBounds="true"
android:text="TEST 2"
android:textColor="#ffffff"
/>
<Button
android:id="#+id/button_item_2"
android:layout_width="0dp"
android:layout_weight="1"
android:layout_height="wrap_content"
android:layout_margin="5dp"
android:paddingLeft="10dp"
android:paddingRight="10dp"
android:background="#000000"
android:layout_gravity="center"
android:adjustViewBounds="true"
android:text="TEST 3"
android:textColor="#ffffff"
/>
</LinearLayout>
One thing you should know is a Listview and its items are virtualized or recycled/reused or duplicated if i should say. so from how i see it i think your approach is off.
This is how i suggest you rectify it, before i get to that i want to clarify the way i understood a portion of your requirement
My goal is to dynamically generate the listview with a list of BUTTONS. each button will have setText() done to it to give it a tag, so for example if a image selected is a dog, and the tags are dog, animal, etc, then that many buttons will be generated, with a setText() of one button being dog
so you are saying you want a listView with 4 buttons on each row.
Do this, _i am taking relevant portions.
private ListView listview; //your listview
private TagAdapter adapter; // your adapter
//we are in oncreate
//i have no knowledge on cdata so bare with me here
//now remove List<Button> data; from your code
we have jumped to the TagAdapter class
private Context context;
//private List<Button> taglist; remove this also
private ArrayList<TheClassThatContainsTags> myTags;//i am assuming this will be cdata or?
//but this list should contain what setText() for a button will get its text
public TagAdapter(Context context) { //this is how your constructor will look
super(context);
Log.i("Test", "constructor " );
this.context = context;
//here you start your async task and put your async task logic here
//if the async task requires some objects or items which is not in this class
// since this is a separate class, you can inject them, when i say inject
// put them in the constructor of TagAdapter like you inject the Context
//object instance, so it might change to
// public TagAdapter(Context context,OneMoreClassIfIWant omciiw) {
// here you aysnc task will execute, now when onPostExecute is triggered/
//called you will do the following, but so remove all the code lines
// you currently have under onPostExecute
// onPostExecute has triggered
myTags = // the tag items result from onpostExecute
//now your myTags Arraylist of type TheClassThatContainsTags has been
//instantiated
}
we are now moving to getCount still in your custom adapter
#Override
public int getCount() {
return (myTags == null) ? 0 : myTags.size();
}
we are now moving to getView still in your custom adapter
#Override
public View getView(final int position, View convertView, ViewGroup parent) {
//in your posted getview, did you edit that too? if not does it give you errors?
//nevermind
// what you do here is check if convertView is null and instantiate it
// the position here in your method parameter is the index in your myTags
// list
if(convertView == null){
//guess you know how to do this. it should be the same as your old
//getview minus this final Button tag = taglist.get(position);
// and the line below it.
}
//here we are still in the getview - what you do is ,
you find what particular button you want by convertView.findViewById()
//my understanding as i pointer out is you want to have 4 buttons in a row
//it should be something like this
Button b = convertView.findViewById(R.id.button1);
b.setText(getItem(position));//getItem() is an instance method for the
//class you are extending, and it returns an Object of Type T, which in my
//example is TheClassThatContainsTags.class;
// and you can do the same for the next 3 buttons
}
we are out of your getview and custom adapter class , and we are in your oncreate .
here set when you need your tags then you do
tagAdapter = new TagAdapter(context,anyIfDesired_OtherInjections);
listview.setAdatper(tagAdapter);
now you are done. Hope it helps, also please read listview and Arraylist Adapter so you get a foresight of what you are doing and what i have posted here. it will help you trim down the hours you waste, if you spend 12 hours on the docs your will spend 5 minutes writing this and the next time you want to replicate it will be the same 5 minutes.
Be good sir and wish you success.
Alright, so I'm using a ListView with a custom adapter. Everything works fine and dandy...until the user selects a ListView row and tries to scroll.
When the user selects a row, the background color of that row changes to blue (which is good).
But, problems occur when we begin scrolling: When we scroll past the selected row, the blue fixes itself to either the bottom or the top of the ListView, depending on which way we were scrolling.
Selected row changes color on touch (good)
Part of the background of selected row is fixed to top when scrolling down (not good)
Part of the background of selected row is fixed to bottom when scrolling up (not good)
Here is my source code:
List View that I'm populating dynamically
<ListView
android:id="#+id/tallyDataListView"
android:layout_height="wrap_content"
android:layout_width="fill_parent"
android:divider="#000000"
android:dividerHeight="1dp"
android:fadeScrollbars="false"
android:listSelector="#0099FF" >
layout_list_view_row.xml
<?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="wrap_content"
android:orientation="horizontal" >
<View
android:focusable="false"
android:focusableInTouchMode="false"
style="#style/tableSideBorderLine" />
<TextView
android:id="#+id/COLUMN_PIPE_NUMBER"
android:layout_height="wrap_content"
android:layout_width="0dp"
android:layout_weight="1"
style="#style/tableColumn"
xmlns:android="http://schemas.android.com/apk/res/android" />
<View
android:focusable="false"
android:focusableInTouchMode="false"
style="#style/tableColumnDivider" />
<TextView
android:id="#+id/COLUMN_TOTAL_LENGTH"
android:layout_height="wrap_content"
android:layout_width="0dp"
android:layout_weight="1"
style="#style/tableColumn"
xmlns:android="http://schemas.android.com/apk/res/android" />
<View
android:focusable="false"
android:focusableInTouchMode="false"
style="#style/tableColumnDivider" />
<TextView
android:id="#+id/COLUMN_ADJUSTED"
android:layout_height="wrap_content"
android:layout_width="0dp"
android:layout_weight="1"
style="#style/tableColumn"
xmlns:android="http://schemas.android.com/apk/res/android" />
<View
android:focusable="false"
android:focusableInTouchMode="false"
style="#style/tableSideBorderLine" />
</LinearLayout>
My Custom Adapter
import android.app.Activity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.TextView;
import java.util.ArrayList;
public class ListViewAdapter extends ArrayAdapter<String>{
LayoutInflater inflater;
private final ArrayList<String> adjustedValues;
private final ArrayList<String> pipeNumbers;
private final ArrayList<String> totalLengthValues;
public ListViewAdapter(Activity pContext, ArrayList<String> pPipeNumbers,
ArrayList<String> pTotalLengthValues, ArrayList<String> pAdjustedValues)
{
super(pContext, R.layout.layout_list_view_row, pAdjustedValues);
adjustedValues = pAdjustedValues;
pipeNumbers = pPipeNumbers;
totalLengthValues = pTotalLengthValues;
inflater = pContext.getLayoutInflater();
}
#Override
public View getView(int pPosition, View pView, ViewGroup pParent)
{
View view = inflater.inflate(R.layout.layout_list_view_row, pParent, false);
TextView col1 = (TextView)view.findViewById(R.id.COLUMN_PIPE_NUMBER);
col1.setText(pipeNumbers.get(pPosition));
TextView col2 = (TextView)view.findViewById(R.id.COLUMN_TOTAL_LENGTH);
col2.setText(totalLengthValues.get(pPosition));
TextView col3 = (TextView)view.findViewById(R.id.COLUMN_ADJUSTED);
col3.setText(adjustedValues.get(pPosition));
return view;
}
}
This is the common problem about the listview. When you scroll down it creates the new view every time. That is why the selected element from the top gets out of the focus and another element is selected.
For this problem you have to extend the BaseAdapter class and
#Override
public View getView(int position, View convertView, ViewGroup parent) {
Vehical vehical = vehicals.get(position);
ViewHolder viewHolder = null;
if(convertView==null)
{
viewHolder = new ViewHolder();
convertViewactivity.getLayoutInflater().inflate(R.layout.list_item,null);
convertView.setTag(viewHolder);
}
else
{
viewHolder = (ViewHolder) convertView.getTag();
}
viewHolder.tvVehicalName = (TextView) convertView.findViewById(R.id.vehicle_name);
viewHolder.tvVehicalName.setText(vehical.getVehicalName());
if(vehical.isSelected()){
viewHolder.tvVehicalName.setTextColor(Color.RED);
}
else
{
viewHolder.tvVehicalName.setTextColor(Color.BLACK);
}
return convertView;
}
//On listener of the listview
searchList.setOnItemClickListener(
new OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> arg0, View view, int position, long arg3) {
if(searchAdapter.isItemSelected(position))
{
searchAdapter.setSelectedItem(position,false);
selectedList.remove(((Vehical)searchAdapter.getItem(position)).getVehicalName());
}
else
{
if(selectedList.size()<new_vehiclelimit){
searchAdapter.setSelectedItem(position,true);
selectedList.add(((Vehical)searchAdapter.getItem(position)).getVehicalName());
}
else
{
Toast.makeText(getApplicationContext(), "Vechicle Limit is Over", Toast.LENGTH_SHORT).show();
}
}
Keep a reference for selected row position in your Adapter, say
int selectedPos = -1;
The value will be -1 when no row is selected. And in the OnItemClickListener of the listview,update selectedPos with the clicked position and call notifyDatasetChanged() on the adapter. In the getView method of the adapter, check for the selectedPos value and highlight the row accordingly.
Is there a site where I can find the inner workings of the BaseExpandableListAdapter? I read the API and I still don't understand how it loops through the whole array that is supplied to provide the view. I'm having problems with my own implementation. I can't create a whole list of expandable lists without using ExpandableListActivity, even though both are the same. It's supposed to retrieve strings from the database and create an expandablelistview out of each one, and add all the created expandablelists to a linearlayout inside main.xml. What happens is that only the expandablelistview for the first string is shown. Here's the snippet
Main Class:
public class MainActivity extends Activity implements OnClickListener {
DBAdapter groupTable = new DBAdapter(this);
ExpandableListView groupLabel;
GroupAdapter adapter;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
groupTable.open();
adapter = new GroupAdapter(groupTable.getAllGroups());
retrieveExpandables(adapter);
groupTable.close();
Button addGroupButton = (Button)findViewById(R.id.addGroup);
addGroupButton.setOnClickListener(this);
}
public void retrieveExpandables(GroupAdapter adapter) {
LinearLayout layout = (LinearLayout)findViewById(R.id.grouplist);
LinearLayout groupLayout =
(LinearLayout)getLayoutInflater().inflate(R.layout.grouplistview, null);
ExpandableListView groupExpandableList =
(ExpandableListView)groupLayout.findViewById(R.id.groupLabel);
groupExpandableList.setAdapter(adapter);
layout.addView(groupLayout);
}
BaseExpandableListAdapter class:
#Override
public View getGroupView(int groupPosition, boolean isExpanded,
View convertView, ViewGroup parent) {
if (convertView instanceof ViewGroup)
return (ViewGroup) convertView;
Context context = parent.getContext();
LayoutInflater inflater = LayoutInflater.from(context);
ViewGroup item = (ViewGroup)inflater.inflate(R.layout.grouplisttext, null);
TextView groupLabel = (TextView)item.findViewById(R.id.groupLabel);
groupLabel.setText(groups[groupPosition].name);
groupLabel.setVisibility(View.VISIBLE);
Log.d("A1", "This part repeating");
return item;
}
XML file for the TextView that will be the expandable list title
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:id="#+id/groups"
android:layout_height="wrap_content">
<TextView android:id="#+id/groupLabel"
android:textSize="24sp"
android:text="asdf"
android:textStyle="bold"
android:layout_width="fill_parent"
android:layout_weight="1"
android:layout_height="40dip"
android:layout_marginLeft="45dip"
android:gravity="center_vertical" />
</LinearLayout>
XML file for the ExpandableListView
<?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:id="#+id/groups"
android:layout_height="wrap_content">
<ExpandableListView android:id="#+id/groupLabel"
android:textSize="24sp"
android:textStyle="bold"
android:layout_width="fill_parent"
android:layout_weight="1"
android:layout_height="40dip" />
</LinearLayout>
Sorry if I posted too much code, I tried removing as much unnecessary information as possible.
I found out where the problem went wrong. Apparently I got the LinearLayout and the ScrollView inside the main.xml interchanged, and the method for getViewGroup class was wrong. It's all good now
i have to make a listview that haves a list of names, and also, aligned to the left, but in the same field, the sex of the person, male or female
is possible to do it? how?
code examples welcome
EDIT
I try with the first user answer, and i got this exception: 12-14 22:39:56.191: ERROR/AndroidRuntime(917): java.lang.IllegalStateException: ArrayAdapter requires the resource ID to be a TextView
this is the code of the XML item i make:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content" >
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Left side"
android:layout_alignParentLeft="true"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Right side"
android:layout_alignParentRight="true"/>
</RelativeLayout>
and this is the code where i have my list:
public class PendingInvitations extends ListActivity {
......
.....
....
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
private List<String> usernames=new ArrayList<String>();
for (int i=0;i<friends.size();i++)
{
usernames.add(i,friends.get(i).getFullName());
}
setListAdapter(new ArrayAdapter<String>(this, R.layout.list_item2, usernames));
this would be the view that is used for each cell
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="wrap_content" >
<TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Left side" android:layout_alignParentLeft="true"/>
<TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Right side" android:layout_alignParentRight="true"/>
</RelativeLayout>
this is an example since i have no idea where your knowledge is at with lists, if the above xml was called "temp.xml" you would use this in the setlistadapter function
import android.app.ListActivity;
import android.os.Bundle;
import android.widget.ArrayAdapter;
public class FooList extends ListActivity extends BaseAdapter {
String[] listItems = {"item 1", "item 2 ", "list", "android", "item 3", "foobar", "bar", };
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.layout_with_listview);
// implement your own adapter
}
}
public View getView(int position, View convertView, ViewGroup parent) {
// A ViewHolder keeps references to children views to avoid unneccessary calls
// to findViewById() on each row.
ViewHolder holder;
// When convertView is not null, we can reuse it directly, there is no need
// to reinflate it. We only inflate a new View when the convertView supplied
// by ListView is null.
if (convertView == null) {
convertView = mInflater.inflate(R.layout.temp, null);
// Creates a ViewHolder and store references to the two children views
// we want to bind data to.
holder = new ViewHolder();
holder.left = (TextView) convertView.findViewById(R.id.left);
holder.right = (TextView) convertView.findViewById(R.id.right);
convertView.setTag(holder);
} else {
// Get the ViewHolder back to get fast access to the TextView
// and the ImageView.
holder = (ViewHolder) convertView.getTag();
}
// Bind the data efficiently with the holder.
holder.left.setText("left text");
holder.right.setText("right text");
return convertView;
}
class ViewHolder
{
public TextView left;
public TextView right;
}
Each item of a ListView has to be a View. This includes ViewGroups. So you can use any Layout to arrange several Views inside a ListView item.