Android Open Source - Android-Sessions Gravity2 D Activity

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License

The source code is released under:

MIT License

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Java Source Code

package uk.ac.icappsoc.appsocthree.accel;
/*  w ww .ja  va  2s . c om*/
import uk.ac.icappsoc.appsocthree.R;
import android.app.Activity;
import android.content.Context;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.os.Bundle;
import android.widget.Toast;

public class Gravity2DActivity extends Activity implements SensorEventListener {

  /**
   *  A reference to the system SensorManager, which we use to access all the sensors we'll want.
   *  In our case, we'll use it to start and stop listening for sensor events, as well as retrieve
   *  references to the sensors we will use.
   */
  private SensorManager sensorManager;

  private BouncyBallView gravityView;

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_gravity);

    // Retrieve the SensorManager and get a reference to the sensor we want.
    sensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);

    gravityView = (BouncyBallView) findViewById(R.id.gravity);
  }

  // Note that onResume() is called every time an Activity comes to the foreground, including the first time it starts up.
  @Override
  protected void onResume(){
    super.onResume();
    Sensor gravitySensor = sensorManager.getDefaultSensor(Sensor.TYPE_GRAVITY);
    // Register this Activity as the listener for our gravity sensor as soon as we resume running.
    // Note that we use SensorManager.SENSOR_DELAY_GAME to request faster sensor data than usual,
    // ca. 30fps or 35ms interval for SENSOR_DELAY_GAME vs 10fps or 100ms for SENSOR_DELAY_UI.
    sensorManager.registerListener(this, gravitySensor, SensorManager.SENSOR_DELAY_GAME);
    // On devices that may not have a GRAVITY sensor, we can fall back to ACCELEROMETER
    // Lucky for us, they return values that are almost equivalent.
    if(null == gravitySensor){
      Toast.makeText(this, "Device does not have GRAVITY sensor, using ACCELEROMETER instead.", Toast.LENGTH_SHORT).show();
      sensorManager.registerListener(this, sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER), SensorManager.SENSOR_DELAY_GAME);
    }
  }

  @Override
  protected void onPause(){
    super.onPause();
    // Unregister this Activity as soon as it's paused to prevent battery drain.
    sensorManager.unregisterListener(this);
  }

  @Override
  public void onAccuracyChanged(Sensor sensor, int accuracy) {
    // Typically we're not too interested in doing anything here.
  }

  @Override
  public void onSensorChanged(SensorEvent event) {
    // Here's where the meat lies!
    switch(event.sensor.getType()){
    case Sensor.TYPE_GRAVITY:
    case Sensor.TYPE_ACCELEROMETER:
      // We only want 2D gravity, so grab that.
      float gravityX = event.values[0];
      float gravityY = event.values[1];

      // Note - we flip gravityX
      gravityView.setGravity(-gravityX, gravityY);
      break;
    }
  }

}

Java Source Code List