ProgressBars

In Android, ProgressBar is used to display the status of work being done like analyzing status of work or downloading a file etc. In Android, by default a progress bar will be displayed as a spinning wheel but If we want it to be displayed as a horizontal bar then we need to use style attribute as horizontal. It mainly use the “android.widget.ProgressBar” class. 

Important Note: A progress bar can also be made indeterminate. In this mode a progress bar shows a cyclic animation without an indication of progress. This mode is used in application when we don’t know the amount of work to be done.

To add a progress bar to a layout (xml) file, you can use the <ProgressBar> element. By default, a progress bar is a spinning wheel (an indeterminate indicator). To change to a horizontal progress bar, apply the progress bar’s horizontal style.

ProgressBar Example In Android Studio:

In the example of ProgressBar we displayed a default spinning wheel progress bar and a start button whenever a user click on the button the progress bar is displayed. Below is the final output, download code and step by step explanation:

Step 1: Create a new project and name it ProgressBarExample. 

Step 2: Open res  -> layout -> activity_main.xml (or) main.xml and add following code:

In this step we open an xml file and add the code for displaying a progress bar  and set its visibility to invisible and one start button.

<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:paddingBottom="@dimen/activity_vertical_margin"

    android:paddingLeft="@dimen/activity_horizontal_margin"

    android:paddingRight="@dimen/activity_horizontal_margin"

    android:paddingTop="@dimen/activity_vertical_margin"

    tools:context=".MainActivity">

    <ProgressBar

        android:id="@+id/simpleProgressBar"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:visibility="invisible"

        android:layout_centerHorizontal="true"/>

    <Button

        android:id="@+id/startButton"

        android:layout_width="200dp"

        android:layout_height="wrap_content"

        android:text="Start"

        android:textSize="20sp"

        android:textStyle="bold"

        android:layout_centerHorizontal="true"

        android:layout_marginTop="100dp"

        android:padding="10dp"

        android:background="#0f0"

        android:textColor="#fff"/>

</RelativeLayout>

Step 3: Now Open src -> package -> MainActivity.java

In this step we open MainActivity where we add the code to initiate the progress bar & button and then perform click event on button which display the progress bar.

package example.gb.progressbarexample;

import ...

public class MainActivity extends AppCompatActivity {

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        // initiate progress bar and start button

        final ProgressBar simpleProgressBar = (ProgressBar) findViewById(R.id.simpleProgressBar);

        Button startButton = (Button) findViewById(R.id.startButton);

        // perform click event on button

        startButton.setOnClickListener(new View.OnClickListener() {

            @Override

            public void onClick(View v) {

                // visible the progress bar

                simpleProgressBar.setVisibility(View.VISIBLE);

            }

        });

    }

}

Output:

Now start the AVD in Emulator and run the App. Click on the start button and Progress Bar will be displayed on screen