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Practical-03

Problem Statement​

Create an application to draw a line on the screen as the user drags their finger.

Solution​

To solve this problem, follow the steps below:

  1. Create a new Android project in Android Studio.
  2. Open the MainActivity.java file.
  3. Implement the necessary logic to handle touch events on the screen.
  4. Override the onTouchEvent method and handle the ACTION_DOWN, ACTION_MOVE, and ACTION_UP events.
  5. In the ACTION_DOWN event, get the starting coordinates of the touch.
  6. In the ACTION_MOVE event, get the current coordinates of the touch and draw a line from the starting coordinates to the current coordinates.
  7. In the ACTION_UP event, stop drawing the line.
  8. Open the activity_main.xml layout file.
  9. Add a CustomView element to the layout with the following attributes:
    • android:id="@+id/customView"
    • android:layout_width="match_parent"
    • android:layout_height="match_parent"
  10. Create a new Java class called CustomView that extends View.
  11. Override the onDraw method in the CustomView class and implement the logic to draw the line on the screen.
  12. In the MainActivity class, find the CustomView element by its ID and set it as the content view using setContentView(R.layout.activity_main).
  13. Build and run the application on an Android device or emulator.

Explanation​

In this solution, we create an Android application that allows the user to draw a line on the screen by dragging their finger. We achieve this by implementing the necessary logic to handle touch events on the screen. When the user touches the screen, we get the starting coordinates of the touch. As the user moves their finger, we get the current coordinates and draw a line from the starting coordinates to the current coordinates. When the user releases their finger, we stop drawing the line.

By following the above steps, you will be able to create an Android program that meets the requirements of the problem statement.