Toast class

Toast class is used to show notification for a particular interval of time. After sometime it disappears. It doesn’t block the user interaction.

Constants of Toast class

There are only 2 constants of Toast class which are given below.

Constant	Description
public static final int LENGTH_LONG	displays view for the long duration of time.
public static final int LENGTH_SHORT	displays view for the short duration of time.

Methods of Toast class

The widely used methods of Toast class are given below.

Method	Description
public static Toast makeText(Context context, CharSequence text, int duration)	makes the toast containing text and duration.
public void show()	displays toast.
public void setMargin (float horizontalMargin, float verticalMargin)	changes the horizontal and vertical margin difference.

Android Toast Example

Toast.makeText(getApplicationContext(),”Hello Javatpoint”,Toast.LENGTH_SHORT).show();

Another code:

Toast toast=Toast.makeText(getApplicationContext(),”Hello Javatpoint”,Toast.LENGTH_SHORT);
toast.setMargin(50,50);
toast.show();

Here, getApplicationContext() method returns the instance of Context.

Full code of activity class displaying Toast

Let’s see the code to display the toast.File: MainActivity.java

package example.javatpoint.com.toast;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//Displaying Toast with Hello Javatpoint message
Toast.makeText(getApplicationContext(),”Hello Javatpoint”,Toast.LENGTH_SHORT).show();
}
}

Output:

Android CheckBox class

The android.widget.CheckBox class provides the facility of creating the CheckBoxes.

Methods of CheckBox class

There are many inherited methods of View, TextView, and Button classes in the CheckBox class. Some of them are as follows:

Method	Description
public boolean isChecked()	Returns true if it is checked otherwise false.
public void setChecked(boolean status)	Changes the state of the CheckBox.

Android CheckBox Example

activity_main.xml

Drag the three checkboxes and one button for the layout. Now the activity_main.xml file will look like this:File: 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=”example.javatpoint.com.checkbox.MainActivity”>
<CheckBox
android:id=”@+id/checkBox”
android:layout_width=”wrap_content”
android:layout_height=”wrap_content”
android:layout_marginLeft=”144dp”
android:layout_marginTop=”68dp”
android:text=”Pizza”
app:layout_constraintStart_toStartOf=”parent”
app:layout_constraintTop_toTopOf=”parent” />
<CheckBox
android:id=”@+id/checkBox2″
android:layout_width=”wrap_content”
android:layout_height=”wrap_content”
android:layout_marginLeft=”144dp”
android:layout_marginTop=”28dp”
android:text=”Coffee”
app:layout_constraintStart_toStartOf=”parent”
app:layout_constraintTop_toBottomOf=”@+id/checkBox” />
<CheckBox
android:id=”@+id/checkBox3″
android:layout_width=”wrap_content”
android:layout_height=”wrap_content”
android:layout_marginLeft=”144dp”
android:layout_marginTop=”28dp”
android:text=”Burger”
app:layout_constraintStart_toStartOf=”parent”
app:layout_constraintTop_toBottomOf=”@+id/checkBox2″ />
<Button
android:id=”@+id/button”
android:layout_width=”wrap_content”
android:layout_height=”wrap_content”
android:layout_marginLeft=”144dp”
android:layout_marginTop=”184dp”
android:text=”Order”
app:layout_constraintStart_toStartOf=”parent”
app:layout_constraintTop_toBottomOf=”@+id/checkBox3″ />
</android.support.constraint.ConstraintLayout>

Activity class

Let’s write the code to check which toggle button is ON/OFF.File: MainActivity.java

package example.javatpoint.com.checkbox;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {
CheckBox pizza,coffe,burger;
Button buttonOrder;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
addListenerOnButtonClick();
}
public void addListenerOnButtonClick(){
//Getting instance of CheckBoxes and Button from the activty_main.xml file
pizza=(CheckBox)findViewById(R.id.checkBox);
coffe=(CheckBox)findViewById(R.id.checkBox2);
burger=(CheckBox)findViewById(R.id.checkBox3);
buttonOrder=(Button)findViewById(R.id.button);
//Applying the Listener on the Button click
buttonOrder.setOnClickListener(new View.OnClickListener(){
@Override
public void onClick(View view) {
int totalamount=0;
StringBuilder result=new StringBuilder();
result.append(“Selected Items:”);
if(pizza.isChecked()){
result.append(“\nPizza 100Rs”);
totalamount+=100;
}
if(coffe.isChecked()){
result.append(“\nCoffe 50Rs”);
totalamount+=50;
}
if(burger.isChecked()){
result.append(“\nBurger 120Rs”);
totalamount+=120;
}
result.append(“\nTotal: “+totalamount+”Rs”);
//Displaying the message on the toast
Toast.makeText(getApplicationContext(), result.toString(), Toast.LENGTH_LONG).show();
}
});
}
}

Output:

Android RadioButton

RadioButton is a two states button which is either checked or unchecked. If a single radio button is unchecked, we can click it to make checked radio button. Once a radio button is checked, it cannot be marked as unchecked by user.

RadioButton is generally used with RadioGroup. RadioGroup contains several radio buttons, marking one radio button as checked makes all other radio buttons as unchecked.

Example of Radio Button

In this example, we are going to implement single radio button separately as well as radio button in RadioGroup.

activity_main.xml

File: activity_main.xml

<?xml version=”1.0″ encoding=”utf-8″?>
<LinearLayout
xmlns:android=”http://schemas.android.com/apk/res/android”
xmlns:tools=”http://schemas.android.com/tools”
android:layout_width=”match_parent”
android:layout_height=”match_parent”
android:orientation=”vertical”
tools:context=”example.javatpoint.com.radiobutton.MainActivity”>
<TextView
android:id=”@+id/textView1″
android:layout_width=”fill_parent”
android:layout_height=”wrap_content”
android:layout_marginTop=”30dp”
android:gravity=”center_horizontal”
android:textSize=”22dp”
android:text=”Single Radio Buttons” />
<!– Default RadioButtons –>
<RadioButton
android:id=”@+id/radioButton1″
android:layout_width=”fill_parent”
android:layout_height=”wrap_content”
android:layout_gravity=”center_horizontal”
android:text=”Radio Button 1″
android:layout_marginTop=”20dp”
android:textSize=”20dp” />
<RadioButton
android:id=”@+id/radioButton2″
android:layout_width=”fill_parent”
android:layout_height=”wrap_content”
android:text=”Radio Button 2″
android:layout_marginTop=”10dp”
android:textSize=”20dp” />
<View
android:layout_width=”fill_parent”
android:layout_height=”1dp”
android:layout_marginTop=”20dp”
android:background=”#B8B894″ />
<TextView
android:id=”@+id/textView2″
android:layout_width=”fill_parent”
android:layout_height=”wrap_content”
android:layout_marginTop=”30dp”
android:gravity=”center_horizontal”
android:textSize=”22dp”
android:text=”Radio button inside RadioGroup” />
<!– Customized RadioButtons –>
<RadioGroup
android:layout_width=”wrap_content”
android:layout_height=”wrap_content”
android:id=”@+id/radioGroup”>
<RadioButton
android:id=”@+id/radioMale”
android:layout_width=”fill_parent”
android:layout_height=”wrap_content”
android:text=” Male”
android:layout_marginTop=”10dp”
android:checked=”false”
android:textSize=”20dp” />
<RadioButton
android:id=”@+id/radioFemale”
android:layout_width=”fill_parent”
android:layout_height=”wrap_content”
android:text=” Female”
android:layout_marginTop=”20dp”
android:checked=”false”
android:textSize=”20dp” />
</RadioGroup>
<Button
android:layout_width=”wrap_content”
android:layout_height=”wrap_content”
android:text=”Show Selected”
android:id=”@+id/button”
android:onClick=”onclickbuttonMethod”
android:layout_gravity=”center_horizontal” />
</LinearLayout>

Activity class

File: MainActivity.java

package example.javatpoint.com.radiobutton;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {
Button button;
RadioButton genderradioButton;
RadioGroup radioGroup;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
radioGroup=(RadioGroup)findViewById(R.id.radioGroup);
}
public void onclickbuttonMethod(View v){
int selectedId = radioGroup.getCheckedRadioButtonId();
genderradioButton = (RadioButton) findViewById(selectedId);
if(selectedId==-1){
Toast.makeText(MainActivity.this,”Nothing selected”, Toast.LENGTH_SHORT).show();
}
else{
Toast.makeText(MainActivity.this,genderradioButton.getText(), Toast.LENGTH_SHORT).show();
}
}
}

Output

Android AlertDialog Example

Android AlertDialog can be used to display the dialog message with OK and Cancel buttons. It can be used to interrupt and ask the user about his/her choice to continue or discontinue.

Android AlertDialog is composed of three regions: title, content area and action buttons.

Android AlertDialog is the subclass of Dialog class.

Methods of AlertDialog class

Method	Description
public AlertDialog.Builder setTitle(CharSequence)	This method is used to set the title of AlertDialog.
public AlertDialog.Builder setMessage(CharSequence)	This method is used to set the message for AlertDialog.
public AlertDialog.Builder setIcon(int)	This method is used to set the icon over AlertDialog.

Android AlertDialog Example

Let’s see a simple example of android alert dialog.

activity_main.xml

You can have multiple components, here we are having only a textview.File: 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=”example.javatpoint.com.alertdialog.MainActivity”>
<Button
android:layout_width=”wrap_content”
android:layout_height=”wrap_content”
android:id=”@+id/button”
android:text=”Close app”
app:layout_constraintBottom_toBottomOf=”parent”
app:layout_constraintLeft_toLeftOf=”parent”
app:layout_constraintRight_toRightOf=”parent”
app:layout_constraintTop_toTopOf=”parent” />
</android.support.constraint.ConstraintLayout>

strings.xml

Optionally, you can store the dialog message and title in the strings.xml file.File: strings.xml

<resources>
<string name=”app_name”>AlertDialog</string>
<string name=”dialog_message”>Welcome to Alert Dialog</string>
<string name=”dialog_title”>Javatpoint Alert Dialog</string>
</resources>

Activity class

Let’s write the code to create and show the AlertDialog.File: MainActivity.java

package example.javatpoint.com.alertdialog;
import android.content.DialogInterface;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.app.AlertDialog;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {
Button closeButton;
AlertDialog.Builder builder;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
closeButton = (Button) findViewById(R.id.button);
builder = new AlertDialog.Builder(this);
closeButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
//Uncomment the below code to Set the message and title from the strings.xml file
builder.setMessage(R.string.dialog_message) .setTitle(R.string.dialog_title);
//Setting message manually and performing action on button click
builder.setMessage(“Do you want to close this application ?”)
.setCancelable(false)
.setPositiveButton(“Yes”, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
finish();
Toast.makeText(getApplicationContext(),”you choose yes action for alertbox”,
Toast.LENGTH_SHORT).show();
}
})
.setNegativeButton(“No”, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
// Action for ‘NO’ Button
dialog.cancel();
Toast.makeText(getApplicationContext(),”you choose no action for alertbox”,
Toast.LENGTH_SHORT).show();
}
});
//Creating dialog box
AlertDialog alert = builder.create();
//Setting the title manually
alert.setTitle(“AlertDialogExample”);
alert.show();
}
});
}
}

Output:

Android Image Switcher

Android image switcher provides an animation over images to transition from one image to another. In order to use image switcher, we need to implement ImageSwitcher component in .xml file.

The setFactory() method of ImageSwitcher provide implementation of ViewFactory interface. ViewFactory interface implements its unimplemented method and returns an ImageView.

Example of Image Switcher

Let’s implement an image switcher.

Create activity_main.xml and content_main.xml file in layout folder.

Place some images in drawable folder which are to be switch.

activity_main.xml

File: activity_main.xml

<?xml version=”1.0″ encoding=”utf-8″?>
<android.support.design.widget.CoordinatorLayout 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”
android:fitsSystemWindows=”true”
tools:context=”com.example.test.imageswitcher.MainActivity”>
<android.support.design.widget.AppBarLayout
android:layout_width=”match_parent”
android:layout_height=”wrap_content”
android:theme=”@style/AppTheme.AppBarOverlay”>
<android.support.v7.widget.Toolbar
android:id=”@+id/toolbar”
android:layout_width=”match_parent”
android:layout_height=”?attr/actionBarSize”
android:background=”?attr/colorPrimary”
app:popupTheme=”@style/AppTheme.PopupOverlay” />
</android.support.design.widget.AppBarLayout>
<include layout=”@layout/content_main” />
</android.support.design.widget.CoordinatorLayout>

content_main.xml

File: content_main.xml

<?xml version=”1.0″ encoding=”utf-8″?>
<RelativeLayout 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”
android:paddingBottom=”@dimen/activity_vertical_margin”
android:paddingLeft=”@dimen/activity_horizontal_margin”
android:paddingRight=”@dimen/activity_horizontal_margin”
android:paddingTop=”@dimen/activity_vertical_margin”
app:layout_behavior=”@string/appbar_scrolling_view_behavior”
tools:context=”com.example.test.imageswitcher.MainActivity”
tools:showIn=”@layout/activity_main”>
<TextView
android:layout_width=”wrap_content”
android:layout_height=”wrap_content”
android:text=”Image Switcher Example”
android:id=”@+id/textView”
android:layout_alignParentTop=”true”
android:layout_centerHorizontal=”true” />
<ImageSwitcher
android:id=”@+id/imageSwitcher”
android:layout_width=”match_parent”
android:layout_height=”250dp”
android:layout_marginBottom=”28dp”
android:layout_marginTop=”40dp” />
<Button
android:layout_width=”wrap_content”
android:layout_height=”wrap_content”
android:text=”Next”
android:id=”@+id/button”
android:layout_marginBottom=”47dp”
android:layout_alignParentBottom=”true”
android:layout_centerHorizontal=”true” />
</RelativeLayout>

Activity class

File: MainActivity.java

package com.example.test.imageswitcher;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.widget.Button;
import android.widget.ImageSwitcher;
import android.widget.ImageView;
import android.widget.ViewSwitcher;
import android.app.ActionBar;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
public class MainActivity extends AppCompatActivity {
ImageSwitcher imageSwitcher;
Button nextButton;
int imageSwitcherImages[] =
{R.drawable.cpp, R.drawable.c_sarp, R.drawable.jsp, R.drawable.mysql, R.drawable.hadoop};
int switcherImageLength = imageSwitcherImages.length;
int counter = -1;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
imageSwitcher = (ImageSwitcher) findViewById(R.id.imageSwitcher);
nextButton = (Button) findViewById(R.id.button);
imageSwitcher.setFactory(new ViewSwitcher.ViewFactory() {
@Override
public View makeView() {
ImageView switcherImageView = new ImageView(getApplicationContext());
switcherImageView.setLayoutParams(new ImageSwitcher.LayoutParams(
ActionBar.LayoutParams.FILL_PARENT, ActionBar.LayoutParams.FILL_PARENT
));
switcherImageView.setScaleType(ImageView.ScaleType.FIT_CENTER);
switcherImageView.setImageResource(R.drawable.hadoop);
//switcherImageView.setMaxHeight(100);
return switcherImageView;
}
});
Animation aniOut = AnimationUtils.loadAnimation(this, android.R.anim.slide_out_right);
Animation aniIn = AnimationUtils.loadAnimation(this, android.R.anim.slide_in_left);
imageSwitcher.setOutAnimation(aniOut);
imageSwitcher.setInAnimation(aniIn);
nextButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
counter++;
if (counter == switcherImageLength){
counter = 0;
imageSwitcher.setImageResource(imageSwitcherImages[counter]);
}
else{
imageSwitcher.setImageResource(imageSwitcherImages[counter]);
}
}
});
}
}

Output

Android

สัปดาห์ที่ 7

Toast class

Constants of Toast class

Methods of Toast class

Android Toast Example

Full code of activity class displaying Toast

Output:

Android CheckBox class

Methods of CheckBox class

Android CheckBox Example

activity_main.xml

Activity class

Output:

Android RadioButton

Example of Radio Button

activity_main.xml

Activity class

Android AlertDialog Example

Methods of AlertDialog class

Android AlertDialog Example

activity_main.xml

strings.xml

Activity class

Output:

Android Image Switcher

Example of Image Switcher

activity_main.xml

content_main.xml

Activity class