swipe

detects swipe events on Android with listener and RxJava Observable

Check out an exemplary animation!

JavaDoc is available at: http://pwittchen.github.io/swipe/RxJava2.x

Current Branch	Branch	Artifact Id	Build Status	Maven Central
	RxJava1.x	swipe
☑️	RxJava2.x	swipe-rx2

Contents

• Usage
  • Imperative way - Listener
  • Reactive way - RxJava
• Configuring swipe threshold
• Listening to several events
• Example
• Download
• Tests
• Code style
• Static code analysis
• References
• License

Usage

Imperative way - Listener

Step 1: Create Swipe attribute in the Activity:

private Swipe swipe;

Step 2: Initialize Swipe object and set listener:

@Override protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);

  setContentView(R.layout.activity_main);
  info = (TextView) findViewById(R.id.info);

  swipe = new Swipe();
  swipe.setListener(new SwipeListener() {
    @Override public void onSwipingLeft(final MotionEvent event) {
      info.setText("SWIPING_LEFT");
    }

    @Override public void onSwipedLeft(final MotionEvent event) {
      info.setText("SWIPED_LEFT");
    }

    @Override public void onSwipingRight(final MotionEvent event) {
      info.setText("SWIPING_RIGHT");
    }

    @Override public void onSwipedRight(final MotionEvent event) {
      info.setText("SWIPED_RIGHT");
    }

    @Override public void onSwipingUp(final MotionEvent event) {
      info.setText("SWIPING_UP");
    }

    @Override public void onSwipedUp(final MotionEvent event) {
      info.setText("SWIPED_UP");
    }

    @Override public void onSwipingDown(final MotionEvent event) {
      info.setText("SWIPING_DOWN");
    }

    @Override public void onSwipedDown(final MotionEvent event) {
      info.setText("SWIPED_DOWN");
    }
  });
}

Step 3: override dispatchTouchEvent(MotionEvent event):

@Override public boolean dispatchTouchEvent(MotionEvent event) {
  swipe.dispatchTouchEvent(event);
  return super.dispatchTouchEvent(event);
}

Reactive way - RxJava

Step 1: Create Swipe attribute and Subscription in the Activity:

private Swipe swipe;
private Disposable disposable;

Step 2: Initialize Swipe object and subscribe Observable:

@Override protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  info = (TextView) findViewById(R.id.info);

  swipe = new Swipe();

  disposable = swipe.observe()
      .subscribeOn(Schedulers.computation())
      .observeOn(AndroidSchedulers.mainThread())
      .subscribe(swipeEvent -> info.setText(swipeEvent.toString()));
}

SwipeEvent is an enum with the following values:

public enum SwipeEvent {
  SWIPING_LEFT,
  SWIPED_LEFT,
  SWIPING_RIGHT,
  SWIPED_RIGHT,
  SWIPING_UP,
  SWIPED_UP,
  SWIPING_DOWN,
  SWIPED_DOWN
}

Step 3: override dispatchTouchEvent(MotionEvent event):

@Override public boolean dispatchTouchEvent(MotionEvent event) {
  swipe.dispatchTouchEvent(event);
  return super.dispatchTouchEvent(event);
}

Step 4: dispose previously created Disposable when it's no longer needed:

@Override protected void onPause() {
  super.onPause();
  if (disposable != null && !disposable.isDisposed()) {
    disposable.dispose();
  }
}

Configuring swipe threshold

If you want to configure swipe threshold to adjust swipe sensitivity, you can use the following constructor:

Swipe(int swipingThreshold, int swipedThreshold)

Default swipingThreshold is equal to 20 and default swipedThreshold is equal to 100. In the case of using Swipe() constructor, these values are set. Decreasing these values will increase swiping and swiped events sensitivity. We can adjust them manually for our needs.

Listening to several events

If you want to react only on one event or several events in imperative way, use abstract class SimpleSwipeListener instead of SwipeListener interface and implement methods, which you need.

Example

Exemplary application is located in app directory of this repository.

If you would like to know, how to use this library with Kotlin, check app-kotlin directory in this repository.

Below, you can see an animation presenting how sample application works.

Download

You can depend on the library through Maven:

<dependency>
    <groupId>com.github.pwittchen</groupId>
    <artifactId>swipe-rx2</artifactId>
    <version>0.3.0</version>
</dependency>

or through Gradle:

dependencies {
  compile 'com.github.pwittchen:swipe-rx2:0.3.0'
}

Tests

To execute unit tests run:

./gradlew test

Code style

Code style used in the project is called SquareAndroid from Java Code Styles repository by Square available at: https://github.com/square/java-code-styles.

Static code analysis

Static code analysis runs Checkstyle, PMD and Lint. It can be executed with command:

./gradlew check

Reports from analysis are generated in library/build/reports/ directory.

References

• better gesture detector project
• detecting swipe gesture in mobile application
• dispatchTouchEvent(event) method in documentation
• MotionEvent class in documentation

License

Copyright 2016 Piotr Wittchen

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

   http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.