I want to create a custom adapter for my list view. Is there any article that can walk me through how to create one and also explain how it works?
public class ListAdapter extends ArrayAdapter<Item> {
private int resourceLayout;
private Context mContext;
public ListAdapter(Context context, int resource, List<Item> items) {
super(context, resource, items);
this.resourceLayout = resource;
this.mContext = context;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
View v = convertView;
if (v == null) {
LayoutInflater vi;
vi = LayoutInflater.from(mContext);
v = vi.inflate(resourceLayout, null);
}
Item p = getItem(position);
if (p != null) {
TextView tt1 = (TextView) v.findViewById(R.id.id);
TextView tt2 = (TextView) v.findViewById(R.id.categoryId);
TextView tt3 = (TextView) v.findViewById(R.id.description);
if (tt1 != null) {
tt1.setText(p.getId());
}
if (tt2 != null) {
tt2.setText(p.getCategory().getId());
}
if (tt3 != null) {
tt3.setText(p.getDescription());
}
}
return v;
}
}
This is a class I had used for my project. You need to have a collection of your items which you want to display, in my case it's <Item>. You need to override View getView(int position, View convertView, ViewGroup parent) method.
R.layout.itemlistrow defines the row of the ListView.
<?xml version="1.0" encoding="utf-8"?>
<TableLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_height="wrap_content" android:orientation="vertical"
android:layout_width="fill_parent">
<TableRow android:layout_width="fill_parent"
android:id="#+id/TableRow01"
android:layout_height="wrap_content">
<TextView android:textColor="#FFFFFF"
android:id="#+id/id"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="id" android:textStyle="bold"
android:gravity="left"
android:layout_weight="1"
android:typeface="monospace"
android:height="40sp" />
</TableRow>
<TableRow android:layout_height="wrap_content"
android:layout_width="fill_parent">
<TextView android:textColor="#FFFFFF"
android:id="#+id/categoryId"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="categoryId"
android:layout_weight="1"
android:height="20sp" />
<TextView android:layout_height="wrap_content"
android:layout_width="fill_parent"
android:layout_weight="1"
android:textColor="#FFFFFF"
android:gravity="right"
android:id="#+id/description"
android:text="description"
android:height="20sp" />
</TableRow>
</TableLayout>
In the MainActivity define ListViewlike this,
ListView yourListView = (ListView) findViewById(R.id.itemListView);
// get data from the table by the ListAdapter
ListAdapter customAdapter = new ListAdapter(this, R.layout.itemlistrow, List<yourItem>);
yourListView .setAdapter(customAdapter);
I know this has already been answered... but I wanted to give a more complete example.
In my example, the ListActivity that will display our custom ListView is called OptionsActivity, because in my project this Activity is going to display the different options my user can set to control my app. There are two list item types, one list item type just has a TextView and the second list item type just has a Button. You can put any widgets you like inside each list item type, but I kept this example simple.
The getItemView() method checks to see which list items should be type 1 or type 2. According to my static ints I defined up top, the first 5 list items will be list item type 1, and the last 5 list items will be list item type 2. So if you compile and run this, you will have a ListView that has five items that just contain a Button, and then five items that just contain a TextView.
Below is the Activity code, the activity xml file, and an xml file for each list item type.
OptionsActivity.java:
public class OptionsActivity extends ListActivity {
private static final int LIST_ITEM_TYPE_1 = 0;
private static final int LIST_ITEM_TYPE_2 = 1;
private static final int LIST_ITEM_TYPE_COUNT = 2;
private static final int LIST_ITEM_COUNT = 10;
// The first five list items will be list item type 1
// and the last five will be list item type 2
private static final int LIST_ITEM_TYPE_1_COUNT = 5;
private MyCustomAdapter mAdapter;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mAdapter = new MyCustomAdapter();
for (int i = 0; i < LIST_ITEM_COUNT; i++) {
if (i < LIST_ITEM_TYPE_1_COUNT)
mAdapter.addItem("item type 1");
else
mAdapter.addItem("item type 2");
}
setListAdapter(mAdapter);
}
private class MyCustomAdapter extends BaseAdapter {
private ArrayList<String> mData = new ArrayList<String>();
private LayoutInflater mInflater;
public MyCustomAdapter() {
mInflater = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
public void addItem(final String item) {
mData.add(item);
notifyDataSetChanged();
}
#Override
public int getItemViewType(int position) {
if(position < LIST_ITEM_TYPE_1_COUNT)
return LIST_ITEM_TYPE_1;
else
return LIST_ITEM_TYPE_2;
}
#Override
public int getViewTypeCount() {
return LIST_ITEM_TYPE_COUNT;
}
#Override
public int getCount() {
return mData.size();
}
#Override
public String getItem(int position) {
return mData.get(position);
}
#Override
public long getItemId(int position) {
return position;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder = null;
int type = getItemViewType(position);
if (convertView == null) {
holder = new ViewHolder();
switch(type) {
case LIST_ITEM_TYPE_1:
convertView = mInflater.inflate(R.layout.list_item_type1, null);
holder.textView = (TextView)convertView.findViewById(R.id.list_item_type1_text_view);
break;
case LIST_ITEM_TYPE_2:
convertView = mInflater.inflate(R.layout.list_item_type2, null);
holder.textView = (TextView)convertView.findViewById(R.id.list_item_type2_button);
break;
}
convertView.setTag(holder);
} else {
holder = (ViewHolder)convertView.getTag();
}
holder.textView.setText(mData.get(position));
return convertView;
}
}
public static class ViewHolder {
public TextView textView;
}
}
activity_options.xml:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
>
<ListView
android:id="#+id/optionsList"
android:layout_width="match_parent"
android:layout_height="wrap_content" >
</ListView>
</LinearLayout>
list_item_type_1.xml:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/list_item_type1_layout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<TextView
android:id="#+id/list_item_type1_text_view"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Text goes here" />
</LinearLayout>
list_item_type2.xml:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/list_item_type2_layout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<Button
android:id="#+id/list_item_type2_button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Button text goes here" />
</LinearLayout>
This code is easy to understand.
three_horizontal_text_views_layout.xml
<?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="match_parent">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/leftTextView"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/centreTextView"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/rightTextView"/>
</LinearLayout>
ThreeStrings.java
public class ThreeStrings {
private String left;
private String right;
private String centre;
public ThreeStrings(String left, String right, String centre) {
this.left = left;
this.right = right;
this.centre = centre;
}
}
ThreeHorizontalTextViewsAdapter.java
public class ThreeHorizontalTextViewsAdapter extends ArrayAdapter<ThreeStrings> {
private int layoutResource;
public ThreeHorizontalTextViewsAdapter(Context context, int layoutResource, List<ThreeStrings> threeStringsList) {
super(context, layoutResource, threeStringsList);
this.layoutResource = layoutResource;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
View view = convertView;
if (view == null) {
LayoutInflater layoutInflater = LayoutInflater.from(getContext());
view = layoutInflater.inflate(layoutResource, null);
}
ThreeStrings threeStrings = getItem(position);
if (threeStrings != null) {
TextView leftTextView = (TextView) view.findViewById(R.id.leftTextView);
TextView rightTextView = (TextView) view.findViewById(R.id.rightTextView);
TextView centreTextView = (TextView) view.findViewById(R.id.centreTextView);
if (leftTextView != null) {
leftTextView.setText(threeStrings.getLeft());
}
if (rightTextView != null) {
rightTextView.setText(threeStrings.getRight());
}
if (centreTextView != null) {
centreTextView.setText(threeStrings.getCentre());
}
}
return view;
}
}
main_layout.xml
<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:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:paddingBottom="#dimen/activity_vertical_margin"
android:orientation="vertical"
tools:context="com.androidapplication.ListActivity">
<ListView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/listView"></ListView>
</LinearLayout>
MainActivity.java
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
List<ThreeStrings> threeStringsList = new ArrayList<>();
ThreeStrings threeStrings = new ThreeStrings("a", "b", "c");
threeStringsList.add(threeStrings);
ListView listView = (ListView)findViewById(R.id.listView);
ThreeHorizontalTextViewsAdapter threeHorizontalTextViewsAdapter = new ThreeHorizontalTextViewsAdapter(this, R.layout.three_horizontal_text_views_layout, threeStringsList);
listView.setAdapter(threeHorizontalTextViewsAdapter);
}
//......}
Google has an example called EfficientAdapter, which in my opinion is the best simple example of how to implement custom adapters. http://developer.android.com/resources/samples/ApiDemos/src/com/example/android/apis/view/List14.html
#CommonsWare has written a good explanation of the patterns used in the above example
http://commonsware.com/Android/excerpt.pdf
check this link, in very simple via the convertView, we can get the layout of a row which will be displayed in listview (which is the parentView).
View v = convertView;
if (v == null) {
LayoutInflater vi;
vi = LayoutInflater.from(getContext());
v = vi.inflate(R.layout.itemlistrow, null);
}
using the position, you can get the objects of the List<Item>.
Item p = items.get(position);
after that we'll have to set the desired details of the object to the identified form widgets.
if (p != null) {
TextView tt = (TextView) v.findViewById(R.id.id);
TextView tt1 = (TextView) v.findViewById(R.id.categoryId);
TextView tt3 = (TextView) v.findViewById(R.id.description);
if (tt != null) {
tt.setText(p.getId());
}
if (tt1 != null) {
tt1.setText(p.getCategory().getId());
}
if (tt3 != null) {
tt3.setText(p.getDescription());
}
}
then it will return the constructed view which will be attached to the parentView (which is a ListView/GridView).
Data Model
public class DataModel {
String name;
String type;
String version_number;
String feature;
public DataModel(String name, String type, String version_number, String feature ) {
this.name=name;
this.type=type;
this.version_number=version_number;
this.feature=feature;
}
public String getName() {
return name;
}
public String getType() {
return type;
}
public String getVersion_number() {
return version_number;
}
public String getFeature() {
return feature;
}
}
Array Adapter
public class CustomAdapter extends ArrayAdapter<DataModel> implements View.OnClickListener{
private ArrayList<DataModel> dataSet;
Context mContext;
// View lookup cache
private static class ViewHolder {
TextView txtName;
TextView txtType;
TextView txtVersion;
ImageView info;
}
public CustomAdapter(ArrayList<DataModel> data, Context context) {
super(context, R.layout.row_item, data);
this.dataSet = data;
this.mContext=context;
}
#Override
public void onClick(View v) {
int position=(Integer) v.getTag();
Object object= getItem(position);
DataModel dataModel=(DataModel)object;
switch (v.getId())
{
case R.id.item_info:
Snackbar.make(v, "Release date " +dataModel.getFeature(), Snackbar.LENGTH_LONG)
.setAction("No action", null).show();
break;
}
}
private int lastPosition = -1;
#Override
public View getView(int position, View convertView, ViewGroup parent) {
// Get the data item for this position
DataModel dataModel = getItem(position);
// Check if an existing view is being reused, otherwise inflate the view
ViewHolder viewHolder; // view lookup cache stored in tag
final View result;
if (convertView == null) {
viewHolder = new ViewHolder();
LayoutInflater inflater = LayoutInflater.from(getContext());
convertView = inflater.inflate(R.layout.row_item, parent, false);
viewHolder.txtName = (TextView) convertView.findViewById(R.id.name);
viewHolder.txtType = (TextView) convertView.findViewById(R.id.type);
viewHolder.txtVersion = (TextView) convertView.findViewById(R.id.version_number);
viewHolder.info = (ImageView) convertView.findViewById(R.id.item_info);
result=convertView;
convertView.setTag(viewHolder);
} else {
viewHolder = (ViewHolder) convertView.getTag();
result=convertView;
}
Animation animation = AnimationUtils.loadAnimation(mContext, (position > lastPosition) ? R.anim.up_from_bottom : R.anim.down_from_top);
result.startAnimation(animation);
lastPosition = position;
viewHolder.txtName.setText(dataModel.getName());
viewHolder.txtType.setText(dataModel.getType());
viewHolder.txtVersion.setText(dataModel.getVersion_number());
viewHolder.info.setOnClickListener(this);
viewHolder.info.setTag(position);
// Return the completed view to render on screen
return convertView;
}
}
Main Activity
public class MainActivity extends AppCompatActivity {
ArrayList<DataModel> dataModels;
ListView listView;
private static CustomAdapter adapter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
listView=(ListView)findViewById(R.id.list);
dataModels= new ArrayList<>();
dataModels.add(new DataModel("Apple Pie", "Android 1.0", "1","September 23, 2008"));
dataModels.add(new DataModel("Banana Bread", "Android 1.1", "2","February 9, 2009"));
dataModels.add(new DataModel("Cupcake", "Android 1.5", "3","April 27, 2009"));
dataModels.add(new DataModel("Donut","Android 1.6","4","September 15, 2009"));
dataModels.add(new DataModel("Eclair", "Android 2.0", "5","October 26, 2009"));
dataModels.add(new DataModel("Froyo", "Android 2.2", "8","May 20, 2010"));
dataModels.add(new DataModel("Gingerbread", "Android 2.3", "9","December 6, 2010"));
dataModels.add(new DataModel("Honeycomb","Android 3.0","11","February 22, 2011"));
dataModels.add(new DataModel("Ice Cream Sandwich", "Android 4.0", "14","October 18, 2011"));
dataModels.add(new DataModel("Jelly Bean", "Android 4.2", "16","July 9, 2012"));
dataModels.add(new DataModel("Kitkat", "Android 4.4", "19","October 31, 2013"));
dataModels.add(new DataModel("Lollipop","Android 5.0","21","November 12, 2014"));
dataModels.add(new DataModel("Marshmallow", "Android 6.0", "23","October 5, 2015"));
adapter= new CustomAdapter(dataModels,getApplicationContext());
listView.setAdapter(adapter);
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
DataModel dataModel= dataModels.get(position);
Snackbar.make(view, dataModel.getName()+"\n"+dataModel.getType()+" API: "+dataModel.getVersion_number(), Snackbar.LENGTH_LONG)
.setAction("No action", null).show();
}
});
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
row_item.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:padding="10dp">
<TextView
android:id="#+id/name"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:text="Marshmallow"
android:textAppearance="?android:attr/textAppearanceSmall"
android:textColor="#android:color/black" />
<TextView
android:id="#+id/type"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#+id/name"
android:layout_marginTop="5dp"
android:text="Android 6.0"
android:textColor="#android:color/black" />
<ImageView
android:id="#+id/item_info"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentEnd="true"
android:layout_alignParentRight="true"
android:layout_centerVertical="true"
android:src="#android:drawable/ic_dialog_info" />
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true">
<TextView
android:id="#+id/version_heading"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="API: "
android:textColor="#android:color/black"
android:textStyle="bold" />
<TextView
android:id="#+id/version_number"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="23"
android:textAppearance="?android:attr/textAppearanceButton"
android:textColor="#android:color/black"
android:textStyle="bold" />
</LinearLayout>
</RelativeLayout>
You can take a look at this sample in the official ApiDemos. It shows how to extend BaseAdapter and apply it to a ListView. After that, just look at the reference for BaseAdapter and try to understand what each method does (including the inherited ones) and when/how to use it.
Also, Google is your friend :).
Here is the complete walk through to create a custom adapter for list view step by step -
https://www.caveofprogramming.com/guest-posts/custom-listview-with-imageview-and-textview-in-android.html
public class CustomAdapter extends BaseAdapter{
String [] result;
Context context;
int [] imageId;
private static LayoutInflater inflater=null;
public CustomAdapter(MainActivity mainActivity, String[] prgmNameList, int[] prgmImages) {
// TODO Auto-generated constructor stub
result=prgmNameList;
context=mainActivity;
imageId=prgmImages;
inflater = ( LayoutInflater )context.
getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
#Override
public int getCount() {
// TODO Auto-generated method stub
return result.length;
}
#Override
public Object getItem(int position) {
// TODO Auto-generated method stub
return position;
}
#Override
public long getItemId(int position) {
// TODO Auto-generated method stub
return position;
}
public class Holder
{
TextView tv;
ImageView img;
}
#Override
public View getView(final int position, View convertView, ViewGroup parent) {
// TODO Auto-generated method stub
Holder holder=new Holder();
View rowView;
rowView = inflater.inflate(R.layout.program_list, null);
holder.tv=(TextView) rowView.findViewById(R.id.textView1);
holder.img=(ImageView) rowView.findViewById(R.id.imageView1);
holder.tv.setText(result[position]);
holder.img.setImageResource(imageId[position]);
rowView.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
Toast.makeText(context, "You Clicked "+result[position], Toast.LENGTH_LONG).show();
}
});
return rowView;
}
}
A more compact example of a custom adapter (using list array as my data):
class MyAdapter extends ArrayAdapter<Object> {
public ArrayAdapter(Context context, List<MyObject> objectList) {
super(context, R.layout.my_list_item, R.id.textViewTitle, objectList.toArray());
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
View row = super.getView(position, convertView, parent);
TextView title = (TextView) row.findViewById(R.id.textViewTitle);
ImageView icon = (ImageView) row.findViewById(R.id.imageViewAccessory);
MyObject obj = (MyObject) getItem(position);
icon.setImageBitmap( ... );
title.setText(obj.name);
return row;
}
}
And this is how to use it:
List<MyObject> objectList = ...
MyAdapter adapter = new MyAdapter(this.getActivity(), objectList);
listView.setAdapter(adapter);
BaseAdapter is best custom adapter for listview.
Class MyAdapter extends BaseAdapter{}
and it has many functions such as getCount(), getView() etc.
It is very simple.
import android.content.Context;
import android.content.DialogInterface;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v7.app.AlertDialog;
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;
/**
* Created by Belal on 9/14/2017.
*/
//we need to extend the ArrayAdapter class as we are building an adapter
public class MyListAdapter extends ArrayAdapter<Hero> {
//the list values in the List of type hero
List<Hero> heroList;
//activity context
Context context;
//the layout resource file for the list items
int resource;
//constructor initializing the values
public MyListAdapter(Context context, int resource, List<Hero> heroList) {
super(context, resource, heroList);
this.context = context;
this.resource = resource;
this.heroList = heroList;
}
//this will return the ListView Item as a View
#NonNull
#Override
public View getView(final int position, #Nullable View convertView, #NonNull ViewGroup parent) {
//we need to get the view of the xml for our list item
//And for this we need a layoutinflater
LayoutInflater layoutInflater = LayoutInflater.from(context);
//getting the view
View view = layoutInflater.inflate(resource, null, false);
//getting the view elements of the list from the view
ImageView imageView = view.findViewById(R.id.imageView);
TextView textViewName = view.findViewById(R.id.textViewName);
TextView textViewTeam = view.findViewById(R.id.textViewTeam);
Button buttonDelete = view.findViewById(R.id.buttonDelete);
//getting the hero of the specified position
Hero hero = heroList.get(position);
//adding values to the list item
imageView.setImageDrawable(context.getResources().getDrawable(hero.getImage()));
textViewName.setText(hero.getName());
textViewTeam.setText(hero.getTeam());
//adding a click listener to the button to remove item from the list
buttonDelete.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
//we will call this method to remove the selected value from the list
//we are passing the position which is to be removed in the method
removeHero(position);
}
});
//finally returning the view
return view;
}
//this method will remove the item from the list
private void removeHero(final int position) {
//Creating an alert dialog to confirm the deletion
AlertDialog.Builder builder = new AlertDialog.Builder(context);
builder.setTitle("Are you sure you want to delete this?");
//if the response is positive in the alert
builder.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialogInterface, int i) {
//removing the item
heroList.remove(position);
//reloading the list
notifyDataSetChanged();
}
});
//if response is negative nothing is being done
builder.setNegativeButton("No", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialogInterface, int i) {
}
});
//creating and displaying the alert dialog
AlertDialog alertDialog = builder.create();
alertDialog.show();
}
}
Source: Custom ListView Android Tutorial
public class CustomAdapter extends BaseAdapter{
ArrayList<BookPojo> data;
Context ctx;
int index=0;
public CustomAdapter(ArrayList<BookPojo> data, Context ctx) {
super();
this.data = data;
this.ctx = ctx;
}
#Override
public int getCount() {
// TODO Auto-generated method stub
return data.size();
}
#Override
public Object getItem(int position) {
// TODO Auto-generated method stub
return data.get(position);
}
#Override
public long getItemId(int position) {
// TODO Auto-generated method stub
return position;
}
#Override
public View getView(int position, View convertview, ViewGroup parent) {
// TODO Auto-generated method stub
View v=convertview;
if(v==null){
LayoutInflater vi=LayoutInflater.from(ctx);
v=vi.inflate(R.layout.messgeview,null);
}
RelativeLayout rlmessage=(RelativeLayout)v.findViewById(R.id.rlmessgeview);
TextView tvisdn=(TextView)v.findViewById(R.id.tvisdn);
TextView tvtitle=(TextView)v.findViewById(R.id.tvtitle);
TextView tvauthor=(TextView)v.findViewById(R.id.tvauthor);
TextView tvprice=(TextView)v.findViewById(R.id.tvprice);
BookPojo bpj=data.get(position);
tvisdn.setText(bpj.isdn+"");
tvtitle.setText(bpj.title);
tvauthor.setText(bpj.author);
tvprice.setText(bpj.price+"");
if(index%2==0)
{
rlmessage.setBackgroundColor(Color.BLUE);
}
else
{
rlmessage.setBackgroundColor(Color.YELLOW);
}
index++;
return v;
}
}
import android.app.Activity;
import android.content.Context;
import android.text.Html;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.TextView;
import org.json.JSONObject;
import java.util.ArrayList;
public class OurteamAdapter extends BaseAdapter {
Context cont;
ArrayList<OurteamModel> llist;
OurteamAdapter madap;
LayoutInflater inflater;
JsonHelper Jobj;
String Id;
JSONObject obj = null;
int position = 0;
public OurteamAdapter(Context c,ArrayList<OurteamModel> Mi)
{
this.cont = c;
this.llist = Mi;
}
#Override
public int getCount()
{
// TODO Auto-generated method stub
return llist.size();
}
#Override
public Object getItem(int position) {
// TODO Auto-generated method stub
return llist.get(position);
}
#Override
public long getItemId(int position) {
// TODO Auto-generated method stub
return position;
}
#Override
public View getView(final int position, View convertView, ViewGroup parent)
{
// TODO Auto-generated method stub
if(convertView == null)
{
LayoutInflater in = (LayoutInflater) cont.getSystemService(Activity.LAYOUT_INFLATER_SERVICE);
convertView = in.inflate(R.layout.doctorlist, null);
}
TextView category = (TextView) convertView.findViewById(R.id.button1);
TextView title = (TextView) convertView.findViewById(R.id.button2);
ImageView i1=(ImageView) convertView.findViewById(R.id.imageView1);
category.setText(Html.fromHtml(llist.get(position).getGalleryName()));
title.setText(Html.fromHtml(llist.get(position).getGalleryDetail()));
if(llist.get(position).getImagesrc()!=null)
{
i1.setImageBitmap(llist.get(position).getImagesrc());
}
else
{
i1.setImageResource(R.drawable.anandlogo);
}
return convertView;
}
}
I'm basically trying to display multiple views via the same ListView adapter. However, the adapter ends up generating multiple duplicates and crashes sometimes as well with a NullPointer. My guess is that I have implemented the adapter all wrong. Here's my complete code:
The item could either be a photo or a text.
Adapter:
public class FeedAdapter extends BaseAdapter {
static private Activity activity;
private static LayoutInflater inflater = null;
ArrayList<ActivityTable> actList = new ArrayList<ActivityTable>();
Holder holder;
public FeedAdapter(Activity a, ArrayList<ActivityTable> actList) {
activity = a;
this.actList = actList;
}
public View getView(int position, View convertView, ViewGroup parent) {
Holder holder;
final ActivityTable act = actList.get(position);
inflater = (LayoutInflater) activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
if (convertView == null) {
if (act.getType().equals("text")) {
convertView = inflater.inflate(R.layout.feed_single_text, null);
holder = new Holder();
//More code that Set the caption to the holder
convertView.setTag(holder);
}
if (act.getType().equals("photo")) {
convertView = inflater.inflate(R.layout.feed_single_picture, parent, false);
holder = new Holder();
holder.media = (ImageView) convertView.findViewById(R.id.postphoto);
//More code that Set the photo to the holder
convertView.setTag(holder);
}
} else {
holder = (Holder) convertView.getTag();
}
return convertView;
}
public static class Holder {
ImageView media;
TextView caption;
}
}
Am I inflating multiple views in the same adapter the wrong way? Can anyone point out the error?
You have 2 diffrent layout for each row so I think you should add
#Override
public int getViewTypeCount() {
return 2;
}
to your listview adapter
In your code, try to initial your LayoutInflater inside the constructor of your adapter
public FeedAdapter(Activity a, ArrayList<ActivityTable> actList) {
...
inflater = (LayoutInflater) activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
And also you should optimize your ListView performance
Here is my experience
It is good to have these 3 in place.
#Override
public int getCount() {
return actList().size();
}
#Override
public Object getItem(int position) {
return actList().get(position);
}
#Override
public long getItemId(int position) {
return position;
}
Here is the important part,
first you have to tell the adapter how many type,
and then you have to tell the adapter how to determine the type.
Here I tell type View Type = 2
#Override
public int getViewTypeCount() {
return 2;
}
and Here I tell the adapter How I put the type number into the array
I use setType = 0 || set Type = 1
personal preference here: I like to use int instead of String
#Override
public int getItemViewType(int position) {
return act.get(position).getType();
}
and then later at the getView
#Override
public View getView(int position, View convertView, ViewGroup parent) {
View v = convertView;
int listViewItemType = getItemViewType(position);
if (v == null) {
..whatevever you doing to make v not null
}
if (listViewItemType == 0) {
//Do something
}else if(listViewItemType == 1){
// Do something different
}
return v;
}
Yes you will get duplicate Item, Because Convertview is reusing. Once convertview is created that view using if you scroll.
So better use single layout and with both Image and text. Based type hide any one.
xml file
<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:id="#+id/ImgFeed"
android:layout_width="fill_parent"
android:layout_height="wrap_content" />
<TextView
android:id="#+id/txtCaption"
android:layout_width="fill_parent"
android:layout_height="wrap_content" />
</LinearLayout>
try this you are using ImageView insted of TextView
public View getView(int position, View convertView, ViewGroup parent) {
Holder holder;
final ActivityTable act = actList.get(position);
inflater = (LayoutInflater) activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
if (convertView == null) {
convertView = inflater.inflate(R.layout.feed_layout, null);
holder = new Holder();
holder.caption = (TextView) convertView.findViewById(R.id.txtCaption);
holder.media = (ImageView) convertView.findViewById(R.id.ImgFeed);
if (act.getType().equals("text")) {
holder.media.setVisibility(View.GONE)
}
else if (act.getType().equals("photo")) {
holder.caption.setVisibility(View.GONE)
}
convertView.setTag(holder);
} else {
holder = (Holder) convertView.getTag();
}
return convertView;
}
I have made my custom adapter and am adapting an array of "persons". In my list item xml i have put a checkbox, but this is where i get confused. I want my list to only be able to have one check box checked at a time. And i also want to implement an OnCheckBox click listener of some sort to preform an action each time a different check box is selected.
this is my custom adapter
public class PersonAdapter extends BaseAdapter {
Context mContext;
Person[] mPersonArray;
public PersonAdapter(Context context , Person[] persons) {
mContext = context;
mPersonArray = persons;
}
#Override
public int getCount() {
return mPersonArray.length;
}
#Override
public Object getItem(int position) {
return mPersonArray[position];
}
#Override
public long getItemId(int position) {
return 0; // we wont use
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder;
if (convertView == null) {
// brand new
convertView = LayoutInflater.from(mContext).inflate(R.layout.person_list_item , null);
holder = new ViewHolder();
holder.nameText = (TextView) convertView.findViewById(R.id.nameTextView);
holder.birthDateText = (TextView) convertView.findViewById(R.id.birthDateTextView);
holder.checkBoxList = (CheckBox) convertView.findViewById(R.id.checkBox);
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}
Person personForList = mPersonArray[position];
holder.nameText.setText(personForList.getName());
holder.birthDateText.setText(personForList.getBirthDate());
return convertView;
}
public static class ViewHolder {
TextView nameText;
TextView birthDateText;
CheckBox checkBoxList;
}
Here is my list item xml
<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="wrap_content"
tools:background="#ff53">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Evan Dix"
android:id="#+id/nameTextView"
android:textColor="#ff323232"
android:textSize="30sp"
android:layout_marginLeft="50dp"
android:layout_marginStart="86dp"
android:layout_alignParentTop="true"
android:layout_alignParentStart="true"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceMedium"
android:text="11-12-12"
android:id="#+id/birthDateTextView"
android:textColor="#ff323232"
android:layout_marginStart="23dp"
android:layout_centerVertical="true"
android:layout_toEndOf="#+id/imageView"/>
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/imageView"
android:src="#android:drawable/presence_invisible"
android:layout_centerVertical="true"
android:layout_toEndOf="#+id/nameTextView"
android:layout_marginStart="12dp"/>
<CheckBox
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/checkBox"
android:layout_centerVertical="true"
android:layout_alignParentEnd="true"
android:layout_marginEnd="29dp"
android:checked="false"
android:clickable="true"
android:choiceMode = "singleChoice"/>
And inside my class where i am populating the listview.... it extends ListAdapter
Person[] personArray = new Person[mPersonArrayList.size()];
personArray = mPersonArrayList.toArray(personArray);
PersonAdapter adapter = new PersonAdapter(this , personArray);
setListAdapter(adapter);
I had used this in my project and you can also try, but if you have to check one checkbox at one time then why are you using checkbox you have to use radiobutton.
// initialize selectPosition in your base adapter
int selectedPosition = -1;
#Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder;
if (convertView == null) {
// brand new
convertView = LayoutInflater.from(mContext).inflate(R.layout.person_list_item , null);
holder = new ViewHolder();
holder.nameText = (TextView) convertView.findViewById(R.id.nameTextView);
holder.birthDateText = (TextView) convertView.findViewById(R.id.birthDateTextView);
holder.checkBoxList = (CheckBox) convertView.findViewById(R.id.checkBox);
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}
Person personForList = mPersonArray[position];
holder.nameText.setText(personForList.getName());
holder.birthDateText.setText(personForList.getBirthDate());
holder.checkBoxList.setChecked(position == selectedPosition);
holder.checkBoxList.setTag(position);
holder.checkBoxList.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
selectedPosition = (Integer) view.getTag();
notifyDataSetInvalidated();
notifyDataSetChanged();
}
});
return convertView;
}
It sounds like what your are looking for is a radio button rather than a check box.
Check boxes are made so that you are able to select multiple items of one category, where radio buttons are made so that you are able to only click one of the category.
I've searched a lot this but I really did not find what I need exactly.
What I want is :
I have a listview and load it on my main class. I load it like this:
ArrayAdapter<String> adapter = new ArrayAdapter<String>(Main.this,
R.layout.myrow,R.id.text );
if (friends != null) {
for (ParseObject friend : friends) {
adapter.add((String) friend.get("name"));
}
}
setListAdapter(adapter);
and myrow layout xml is here:
< RelativeLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:gravity="center" >
<ProgressBar
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:id="#+id/my_prog"
></ProgressBar>
<TextView
android:id="#+id/text"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:textSize="25sp" >
</TextView>
</RelativeLayout >
You can see I have progress bar on textview so I need to reach it and set it's visible. I mean sometimes I set it invisible sometimes visible
What I did is:
On my MainActivity on create method the code is here :
ProgressBar my_prog;
my_prog=(ProgressBar)findViewById(R.id.my_prog);
my_prog.setVisibility(View.INVISIBLE);
The error is:
07-16 13:35:39.219: E/AndroidRuntime(29096): java.lang.RuntimeException: Unable to start activity ComponentInfo{....MainActivity}: java.lang.NullPointerException
I think I cant reach my_prog on my main activity but I need it.
How can I do that.
thanks in adnvace...
You need to implement a custom Adapter to do this. I have written this ExampleAdapter to show you how it works, I commented all the important parts:
public class ExampleAdapter extends BaseAdapter {
private final LayoutInflater inflater;
private final List<ParseObject> objects;
private final boolean[] activated;
public ExampleAdapter(Context context, List<ParseObject> objects) {
this.inflater = LayoutInflater.from(context);
this.objects = objects;
this.activated = new boolean[objects.size()];
}
public void showProgressBar(int position, boolean visible) {
this.activated[position] = visible;
notifyDataSetChanged();
}
#Override
public int getCount() {
return this.objects.size();
}
#Override
public ParseObject getItem(int position) {
return this.objects.get(position);
}
#Override
public long getItemId(int position) {
return 0;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
// If the convertView is null, we need to inflate a new one
if(convertView == null) {
// We inflate the view with your layout
convertView = inflater.inflate(R.layout.myrow, parent, false);
// Here we create a view holder object which keeps a
// reference to the Views in this row so we have to
// perform the expensive findViewById() only once
ViewHolder holder = new ViewHolder();
holder.text = (TextView) convertView.findViewById(R.id.text);
holder.my_prog = (ProgressBar) convertView.findViewById(R.id.my_prog);
// The view holder is set as tag to the view so we can access it later
convertView.setTag(holder);
}
// We retrieve the ParseObject for the current position
ParseObject parseObject = getItem(position);
// And get the view holder from the View
ViewHolder holder = (ViewHolder) convertView.getTag();
// We read the data we need from the ParseObject
String name = parseObject.get("name");
// And here is the visibility logic
int progressBarVisibility = this.activated[position] ? View.VISIBLE : View.GONE;
int textViewVisibility = this.activated[position] ? View.GONE : View.VISIBLE;
// Now we set the data to the Views through the view holder
holder.text.setText(name);
holder.text.setVisibility(textViewVisibility);
holder.my_prog.setVisibility(progressBarVisibility);
return convertView;
}
// This is our view holder class. It keeps a reference to the Views
// inside each row so we have to perform the expensive
// findViewById() only once
private class ViewHolder {
public TextView text;
public ProgressBar my_prog;
}
}
You can use the ExampleAdapter like this:
if(friends != null) {
ExampleAdapter adapter = new ExampleAdapter(Main.this, friends);
setListAdapter(adapter);
}
If you want to show a ProgressBar at a specific position you just do this:
// Shows the ProgressBar in the first row
adapter.showProgressBar(0, true)