SensorTest.java

← Back

The file containing the source code shown below is located in the corresponding directory in <sdk>/samples/android-<version>/...

/*
 * Copyright (C) 2007 The Android Open Source Project
 *
 * 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.
 */

package com.example.android.apis.graphics;

import android.content.Context;
import android.graphics.*;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.os.Bundle;
import android.util.Log;
import android.view.View;

public class SensorTest extends GraphicsActivity {
    private final String TAG = "SensorTest";

    private SensorManager mSensorManager;
    private Sensor mSensor;
    private SampleView mView;
    private float[] mValues;

    private static class RunAve {
        private final float[] mWeights;
        private final float mWeightScale;
        private final float[] mSamples;
        private final int mDepth;
        private int mCurr;

        public RunAve(float[] weights) {
            mWeights = weights;

            float sum = 0;
            for (int i = 0; i < weights.length; i++) {
                sum += weights[i];
            }
            mWeightScale = 1 / sum;

            mDepth = weights.length;
            mSamples = new float[mDepth];
            mCurr = 0;
        }

        public void addSample(float value) {
            mSamples[mCurr] = value;
            mCurr = (mCurr + 1) % mDepth;
        }

        public float computeAve() {
            final int depth = mDepth;
            int index = mCurr;
            float sum = 0;
            for (int i = 0; i < depth; i++) {
                sum += mWeights[i] * mSamples[index];
                index -= 1;
                if (index < 0) {
                    index = depth - 1;
                }
            }
            return sum * mWeightScale;
        }
    };

    private final SensorEventListener mListener = new SensorEventListener() {

        private final float[] mScale = new float[] { 2, 2.5f, 0.5f };   // accel
        private float[] mPrev = new float[3];
        private long mLastGestureTime;

        public void onSensorChanged(SensorEvent event) {
            boolean show = false;
            float[] diff = new float[3];

            for (int i = 0; i < 3; i++) {
                diff[i] = Math.round(mScale[i] * (event.values[i] - mPrev[i]) * 0.45f);
                if (Math.abs(diff[i]) > 0) {
                    show = true;
                }
                mPrev[i] = event.values[i];
            }

            if (show) {
                // only shows if we think the delta is big enough, in an attempt
                // to detect "serious" moves left/right or up/down
                Log.e(TAG, "sensorChanged " + event.sensor.getName() +
                        " (" + event.values[0] + ", " + event.values[1] + ", " +
                        event.values[2] + ")" + " diff(" + diff[0] +
                        " " + diff[1] + " " + diff[2] + ")");
            }

            long now = android.os.SystemClock.uptimeMillis();
            if (now - mLastGestureTime > 1000) {
                mLastGestureTime = 0;

                float x = diff[0];
                float y = diff[1];
                boolean gestX = Math.abs(x) > 3;
                boolean gestY = Math.abs(y) > 3;

                if ((gestX || gestY) && !(gestX && gestY)) {
                    if (gestX) {
                        if (x < 0) {
                            Log.e("test", "<<<<<<<< LEFT <<<<<<<<<<<<");
                        } else {
                            Log.e("test", ">>>>>>>>> RITE >>>>>>>>>>>");
                        }
                    } else {
                        if (y < -2) {
                            Log.e("test", "<<<<<<<< UP <<<<<<<<<<<<");
                        } else {
                            Log.e("test", ">>>>>>>>> DOWN >>>>>>>>>>>");
                        }
                    }
                    mLastGestureTime = now;
                }
            }
        }

        public void onAccuracyChanged(Sensor sensor, int accuracy) {
        }
    };

    @Override
    protected void onCreate(Bundle icicle) {
        super.onCreate(icicle);
        mSensorManager = (SensorManager)getSystemService(Context.SENSOR_SERVICE);
        mSensor = mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
        mView = new SampleView(this);
        setContentView(mView);
        if (false) Log.d(TAG, "create " + mSensorManager);
    }

    @Override
    protected void onResume() {
        super.onResume();
        mSensorManager.registerListener(mListener, mSensor, SensorManager.SENSOR_DELAY_FASTEST);
        if (false) Log.d(TAG, "resume " + mSensorManager);
    }

    @Override
    protected void onStop() {
        mSensorManager.unregisterListener(mListener);
        super.onStop();
        if (false) Log.d(TAG, "stop " + mSensorManager);
    }

    private class SampleView extends View {
        private Paint   mPaint = new Paint();
        private Path    mPath = new Path();
        private boolean mAnimate;

        public SampleView(Context context) {
            super(context);

            // Construct a wedge-shaped path
            mPath.moveTo(0, -50);
            mPath.lineTo(-20, 60);
            mPath.lineTo(0, 50);
            mPath.lineTo(20, 60);
            mPath.close();
        }

        @Override
        protected void onDraw(Canvas canvas) {
            Paint paint = mPaint;

            canvas.drawColor(Color.WHITE);

            paint.setAntiAlias(true);
            paint.setColor(Color.BLACK);
            paint.setStyle(Paint.Style.FILL);

            int w = canvas.getWidth();
            int h = canvas.getHeight();
            int cx = w / 2;
            int cy = h / 2;

            canvas.translate(cx, cy);
            if (mValues != null) {
                canvas.rotate(-mValues[0]);
            }
            canvas.drawPath(mPath, mPaint);
        }

        @Override
        protected void onAttachedToWindow() {
            mAnimate = true;
            if (false) Log.d(TAG, "onAttachedToWindow. mAnimate="+mAnimate);
            super.onAttachedToWindow();
        }

        @Override
        protected void onDetachedFromWindow() {
            mAnimate = false;
            if (false) Log.d(TAG, "onAttachedToWindow. mAnimate="+mAnimate);
            super.onDetachedFromWindow();
        }
    }
}