Let’s assume you want to display a list in your Android app. For this you will use the ListView provided by Android. ListViews don’t actually contain any data themselves. It’s just a UI element without data in it. You can populate your ListViews by using an Android adapter.
Adapter is an interface whose implementations provide data and control the display of that data. ListViews own adapters that completely control the ListView’s display. So adapters control the content displayed in the list as well as how to display it.
The Adapter interface includes various methods to communicate data to the ListView. You can create your own adapter from scratch by implementing BaseAdapter.
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MainActivity[MainActivity.class]
package com.androidfeeders.baseadapersample;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Gravity;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ListView;
import android.widget.Toast;
import java.util.ArrayList;
import java.util.List;
/**
* Created by Ramasamy on 01-07-2018.
*/
public class MainActivity extends AppCompatActivity implements
AdapterView.OnItemClickListener {
public static final String[] titles = new String[] { "logo",
"symbol", "auto", "beach" };
public static final String[] descriptions = new String[] {
"android logo",
"dollar symbol", "refresh",
"umbrella" };
public static final Integer[] images = { R.mipmap.logo,
R.mipmap.symbol, R.mipmap.auto, R.mipmap.beach };
ListView listView;
List rowItems;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
rowItems = new ArrayList();
for (int i = 0; i < titles.length; i++) {
ModelClass item = new ModelClass(images[i], titles[i], descriptions[i]);
rowItems.add(item);
}
listView = (ListView) findViewById(R.id.list);
CustomBaseAdapter adapter = new CustomBaseAdapter(this, rowItems);
listView.setAdapter(adapter);
listView.setOnItemClickListener(this);
}
@Override
public void onItemClick(AdapterView parent, View view, int position,
long id) {
Toast toast = Toast.makeText(getApplicationContext(),
"Item " + (position + 1) + ": " + rowItems.get(position),
Toast.LENGTH_SHORT);
toast.setGravity(Gravity.CENTER|Gravity.CENTER_HORIZONTAL, 0, 0);
toast.show();
}
}
CustomBaseAdapter[CustomBaseAdapter.class]
package com.androidfeeders. CustomBaseAdapter;
import android.app.Activity;
import android.content.Context;
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 java.util.List;
/**
* Created by Ramasamy on 01-07-2018.
*/
public class CustomBaseAdapter extends BaseAdapter {
Context context;
List modelClassList;
public CustomBaseAdapter(Context context, List modelClassList) {
this.context = context;
this.modelClassList = modelClassList;
}
/*private view holder class*/
private class ViewHolder {
ImageView imageView;
TextView txtTitle;
TextView txtDesc;
}
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder = null;
LayoutInflater mInflater = (LayoutInflater)
context.getSystemService(Activity.LAYOUT_INFLATER_SERVICE);
if (convertView == null) {
convertView = mInflater.inflate(R.layout.row_item, null);
holder = new ViewHolder();
holder.txtDesc = (TextView) convertView.findViewById(R.id.desc);
holder.txtTitle = (TextView) convertView.findViewById(R.id.title);
holder.imageView = (ImageView) convertView.findViewById(R.id.icon);
convertView.setTag(holder);
}
else {
holder = (ViewHolder) convertView.getTag();
}
ModelClass rowItem = (ModelClass) getItem(position);
holder.txtDesc.setText(rowItem.getDesc());
holder.txtTitle.setText(rowItem.getTitle());
holder.imageView.setImageResource(rowItem.getImageId());
return convertView;
}
@Override
public int getCount() {
return modelClassList.size();
}
@Override
public Object getItem(int position) {
return modelClassList.get(position);
}
@Override
public long getItemId(int position) {
return modelClassList.indexOf(getItem(position));
}
}
ModelClass[ModelClass.class]
package com.androidfeeders.ModelClass;
/**
* Created by Ramasamy on 01-07-2018.
*/
public class ModelClass {
private int imageId;
private String title;
private String desc;
public ModelClass(int imageId, String title, String desc) {
this.imageId = imageId;
this.title = title;
this.desc = desc;
}
public int getImageId()
{
return imageId;
}
public void setImageId(int imageId)
{
this.imageId = imageId;
}
public String getDesc()
{
return desc;
}
public void setDesc(String desc)
{
this.desc = desc;
}
public String getTitle()
{
return title;
}
public void setTitle(String title)
{
this.title = title;
}
@Override
public String toString()
{
return title + "\n" + desc;
}
}
Layout Resource[activity_main.xml]
<?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"
tools:context=".MainActivity">
<ListView
android:id="@+id/list"
android:layout_width="match_parent"
android:layout_height="wrap_content"
/>
</android.support.constraint.ConstraintLayout/>
Layout Resource[row_item.xml]
<?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="fill_parent" >
<ImageView
android:id="@+id/icon"
android:layout_width="80dp"
android:layout_height="80dp"
android:contentDescription="@string/image"
android:paddingLeft="10dp"
android:paddingRight="10dp" />
<TextView
android:id="@+id/title"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_toRightOf="@+id/icon"
android:paddingBottom="10dp"
android:textColor="#CC0033"
android:textSize="16dp" />
<TextView
android:id="@+id/desc"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/title"
android:layout_toRightOf="@+id/icon"
android:paddingLeft="10dp"
android:textColor="#3399FF"
android:textSize="14dp" />
</RelativeLayout>
Gradle Scripts~build.gradle[Module:app]
apply plugin: 'com.android.application'
android {
compileSdkVersion 26
buildToolsVersion '27.0.3'
defaultConfig {
applicationId "com.androidfeeders.baseadapersample"
minSdkVersion 15
targetSdkVersion 26
versionCode 1
versionName "1.0"
testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
}
dependencies {
compile fileTree(dir: 'libs', include: ['*.jar'])
androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
exclude group: 'com.android.support', module: 'support-annotations'
})
compile 'com.android.support:appcompat-v7:26.+'
compile 'com.android.support.constraint:constraint-layout:1.0.2'
testCompile 'junit:junit:4.12'
}
Gradle Scripts~build.gradle[Project:BaseAdapterSample]
// Top-level build file where you can add configuration options common to all sub-projects/modules.
buildscript {
repositories {
jcenter()
google()
}
dependencies {
classpath 'com.android.tools.build:gradle:3.1.1'
// NOTE: Do not place your application dependencies here; they belong
// in the individual module build.gradle files
}
}
allprojects {
repositories {
jcenter()
google()
}
}
task clean(type: Delete) {
delete rootProject.buildDir
}
Resource[strings.xml]
<resources>
<string name="app_name">BaseAdapterSample</string>
</resources>
manifests
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.androidfeeders.baseadaptersample">
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:roundIcon="@mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
I started to learn android and Kotlin and iOS and Hybrid application and i cant code IOS very well. But i love more interesting to code and finding new developer minds who are join to me You're welcome to keep on using my website.Instead, you can join our FB page for developer comments and post there: https://www.facebook.com/ramasamy.m.779 Best wishes :) Ramasamy(Software Developer)
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Ramasamy
5 min agoKotlin and React native example too
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5 min agoKotlin and React native example too
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5 min agoKotlin and React native example too
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