An orthographic camera controller that handles inputs and gestures, for libGDX.

OrthographicCameraController.java

package com.jamesrskemp.libgdx.utils;

import com.badlogic.gdx.Gdx;
import com.badlogic.gdx.Input;
import com.badlogic.gdx.InputProcessor;
import com.badlogic.gdx.graphics.OrthographicCamera;
import com.badlogic.gdx.input.GestureDetector;
import com.badlogic.gdx.math.Vector2;

/**
 * Author: James Skemp ( jamesrskemp.com / strivinglife.com / github.com/JamesSkemp ), based upon libGDX 1.6.2.
 * 
 * This orthographic camera controller will handle both inputs and gestures, and can log when it's triggered.
 * 
 * Usage example:

	camera = new OrthographicCamera();
	camera.setToOrtho(false, Constants.VIEWPORT_GUI_WIDTH, Constants.VIEWPORT_GUI_HEIGHT);
	camera.update();

	cameraController = new OrthographicCameraController(camera);

	// Handle inputs.
	InputMultiplexer inputMultiplexer = new InputMultiplexer();
	// TODO add any game-related actions you want to handle before the camera.
	inputMultiplexer.addProcessor(new GestureDetector(cameraController));
	inputMultiplexer.addProcessor(cameraController);

	Gdx.input.setInputProcessor(inputMultiplexer);
 */
public class OrthographicCameraController implements InputProcessor, GestureDetector.GestureListener {
	private static final String TAG = OrthographicCameraController.class.getName();

	final OrthographicCamera camera;

	/**
	 * Enables logging. Setting this to false will override all options below.
	 */
	boolean logActivity = true;
	/**
	 * Log verbose activities, such as moving the mouse. These tend to generate a lot of log entries.
	 */
	boolean logVerboseActivity = false;
	/**
	 * Log all activity, overriding all options below.
	 */
	boolean logAllActivity = true;
	/**
	 * Log activity from InputProcessor
	 */
	boolean logInputProcessorActivity = false;
	/**
	 * Log activity from GestureListener.
	 */
	boolean logGestureListenerActivity = true;

	public OrthographicCameraController(OrthographicCamera camera) {
		this.camera = camera;
	}

	@Override
	public boolean fling(float velocityX, float velocityY, int button) {
		if (logActivity && (logAllActivity || logGestureListenerActivity)) {
			Gdx.app.log(TAG, "fling triggered. velocityX " + velocityX + " velocityY " + velocityY + " button " + button);
		}
		return false;
	}

	@Override
	public boolean keyDown(int keycode) {
		if (logActivity && (logAllActivity || logInputProcessorActivity)) {
			Gdx.app.log(TAG, "keyDown triggered. keycode " + keycode + " (" + Input.Keys.toString(keycode) + ")");
		}
		return false;
	}

	@Override
	public boolean keyTyped(char character) {
		if (logActivity && (logAllActivity || logInputProcessorActivity)) {
			Gdx.app.log(TAG, "keyTyped triggered. keycode " + character);
		}
		return false;
	}

	@Override
	public boolean keyUp(int keycode) {
		if (logActivity && (logAllActivity || logInputProcessorActivity)) {
			Gdx.app.log(TAG, "keyUp triggered. keycode " + keycode + " (" + Input.Keys.toString(keycode) + ")");
		}
		return false;
	}

	@Override
	public boolean longPress(float x, float y) {
		if (logActivity && (logAllActivity || logGestureListenerActivity)) {
			Gdx.app.log(TAG, "longPress triggered. x " + x + " y " + y);
		}
		return false;
	}

	@Override
	public boolean mouseMoved(int screenX, int screenY) {
		if (logActivity && (logAllActivity || logInputProcessorActivity) && logVerboseActivity) {
			Gdx.app.log(TAG, "mouseMoved triggered. screenX " + screenX + " screenY " + screenY);
		}
		return false;
	}

	@Override
	public boolean pan(float x, float y, float deltaX, float deltaY) {
		if (logActivity && (logAllActivity || logGestureListenerActivity)) {
			Gdx.app.log(TAG, "pan triggered. x " + x + " y " + y + " deltaX " + deltaX + " deltaY " + deltaY);
		}
		return false;
	}

	@Override
	public boolean panStop(float x, float y, int pointer, int button) {
		if (logActivity && (logAllActivity || logGestureListenerActivity)) {
			Gdx.app.log(TAG, "panStop triggered. x " + x + " y " + y + " pointer " + pointer + " button " + button);
		}
		return false;
	}

	@Override
	public boolean pinch(Vector2 initialPointer1, Vector2 initialPointer2, Vector2 pointer1, Vector2 pointer2) {
		if (logActivity && (logAllActivity || logGestureListenerActivity)) {
			Gdx.app.log(TAG, "pinch triggered. initialPointer1 " + initialPointer1 + " initialPointer2 " + initialPointer2 + " pointer1 " + pointer1 + " pointer2 " + pointer2);
		}
		return false;
	}

	@Override
	public boolean scrolled(int amount) {
		if (logActivity && (logAllActivity || logInputProcessorActivity)) {
			Gdx.app.log(TAG, "scrolled triggered. amount " + amount);
		}
		return false;
	}
	@Override
	public boolean tap(float x, float y, int count, int button) {
		if (logActivity && (logAllActivity || logGestureListenerActivity)) {
			Gdx.app.log(TAG, "tap triggered. x " + x + " y " + y + " count " + count + " button " + button);
		}
		return false;
	}

	@Override
	public boolean touchDown(float x, float y, int pointer, int button) {
		if (logActivity && (logAllActivity || logGestureListenerActivity)) {
			Gdx.app.log(TAG, "touchDown (Gesture) triggered. x " + x + " y " + y + " pointer " + pointer + " button " + button);
		}
		return false;
	}

	@Override
	public boolean touchDown(int screenX, int screenY, int pointer, int button) {
		if (logActivity && (logAllActivity || logInputProcessorActivity)) {
			Gdx.app.log(TAG, "touchDown (Input) triggered. screenX " + screenX + " screenY " + screenY + " pointer " + pointer + " button " + button);
		}
		return false;
	}

	@Override
	public boolean touchDragged(int screenX, int screenY, int pointer) {
		if (logActivity && (logAllActivity || logInputProcessorActivity)) {
			Gdx.app.log(TAG, "touchDragged triggered. screenX " + screenX + " screenY " + screenY + " pointer " + pointer);
		}
		return false;
	}

	@Override
	public boolean touchUp(int screenX, int screenY, int pointer, int button) {
		if (logActivity && (logAllActivity || logInputProcessorActivity)) {
			Gdx.app.log(TAG, "touchUp triggered. screenX " + screenX + " screenY " + screenY + " pointer " + pointer + " button " + button);
		}
		return false;
	}

	@Override
	public boolean zoom(float initialDistance, float distance) {
		if (logActivity && (logAllActivity || logGestureListenerActivity)) {
			Gdx.app.log(TAG, "zoom triggered. initialDistance " + initialDistance + " distance " + distance);
		}
		return false;
	}
}

Note that you still need to add the necessary logic to actually handle the inputs.