The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2008 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | package android.view; |
| 18 | |
| 19 | import android.content.Context; |
| 20 | import android.hardware.Sensor; |
| 21 | import android.hardware.SensorEvent; |
| 22 | import android.hardware.SensorEventListener; |
| 23 | import android.hardware.SensorManager; |
| 24 | import android.util.Config; |
| 25 | import android.util.Log; |
| 26 | |
| 27 | /** |
| 28 | * Helper class for receiving notifications from the SensorManager when |
| 29 | * the orientation of the device has changed. |
| 30 | */ |
| 31 | public abstract class OrientationEventListener { |
| 32 | private static final String TAG = "OrientationEventListener"; |
| 33 | private static final boolean DEBUG = false; |
| 34 | private static final boolean localLOGV = DEBUG ? Config.LOGD : Config.LOGV; |
| 35 | private int mOrientation = ORIENTATION_UNKNOWN; |
| 36 | private SensorManager mSensorManager; |
| 37 | private boolean mEnabled = false; |
| 38 | private int mRate; |
| 39 | private Sensor mSensor; |
| 40 | private SensorEventListener mSensorEventListener; |
| 41 | private OrientationListener mOldListener; |
| 42 | |
| 43 | /** |
| 44 | * Returned from onOrientationChanged when the device orientation cannot be determined |
| 45 | * (typically when the device is in a close to flat position). |
| 46 | * |
| 47 | * @see #onOrientationChanged |
| 48 | */ |
| 49 | public static final int ORIENTATION_UNKNOWN = -1; |
| 50 | |
| 51 | /** |
| 52 | * Creates a new OrientationEventListener. |
| 53 | * |
| 54 | * @param context for the OrientationEventListener. |
| 55 | */ |
| 56 | public OrientationEventListener(Context context) { |
| 57 | this(context, SensorManager.SENSOR_DELAY_NORMAL); |
| 58 | } |
| 59 | |
| 60 | /** |
| 61 | * Creates a new OrientationEventListener. |
| 62 | * |
| 63 | * @param context for the OrientationEventListener. |
| 64 | * @param rate at which sensor events are processed (see also |
| 65 | * {@link android.hardware.SensorManager SensorManager}). Use the default |
| 66 | * value of {@link android.hardware.SensorManager#SENSOR_DELAY_NORMAL |
| 67 | * SENSOR_DELAY_NORMAL} for simple screen orientation change detection. |
| 68 | */ |
| 69 | public OrientationEventListener(Context context, int rate) { |
| 70 | mSensorManager = (SensorManager)context.getSystemService(Context.SENSOR_SERVICE); |
| 71 | mRate = rate; |
| 72 | mSensor = mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER); |
| 73 | if (mSensor != null) { |
| 74 | // Create listener only if sensors do exist |
| 75 | mSensorEventListener = new SensorEventListenerImpl(); |
| 76 | } |
| 77 | } |
| 78 | |
| 79 | void registerListener(OrientationListener lis) { |
| 80 | mOldListener = lis; |
| 81 | } |
| 82 | |
| 83 | /** |
| 84 | * Enables the OrientationEventListener so it will monitor the sensor and call |
| 85 | * {@link #onOrientationChanged} when the device orientation changes. |
| 86 | */ |
| 87 | public void enable() { |
| 88 | if (mSensor == null) { |
| 89 | Log.w(TAG, "Cannot detect sensors. Not enabled"); |
| 90 | return; |
| 91 | } |
| 92 | if (mEnabled == false) { |
| 93 | if (localLOGV) Log.d(TAG, "OrientationEventListener enabled"); |
| 94 | mSensorManager.registerListener(mSensorEventListener, mSensor, mRate); |
| 95 | mEnabled = true; |
| 96 | } |
| 97 | } |
| 98 | |
| 99 | /** |
| 100 | * Disables the OrientationEventListener. |
| 101 | */ |
| 102 | public void disable() { |
| 103 | if (mSensor == null) { |
| 104 | Log.w(TAG, "Cannot detect sensors. Invalid disable"); |
| 105 | return; |
| 106 | } |
| 107 | if (mEnabled == true) { |
| 108 | if (localLOGV) Log.d(TAG, "OrientationEventListener disabled"); |
| 109 | mSensorManager.unregisterListener(mSensorEventListener); |
| 110 | mEnabled = false; |
| 111 | } |
| 112 | } |
| 113 | |
| 114 | class SensorEventListenerImpl implements SensorEventListener { |
| 115 | private static final int _DATA_X = 0; |
| 116 | private static final int _DATA_Y = 1; |
| 117 | private static final int _DATA_Z = 2; |
| 118 | |
| 119 | public void onSensorChanged(SensorEvent event) { |
| 120 | float[] values = event.values; |
| 121 | int orientation = ORIENTATION_UNKNOWN; |
| 122 | float X = -values[_DATA_X]; |
| 123 | float Y = -values[_DATA_Y]; |
| 124 | float Z = -values[_DATA_Z]; |
| 125 | float magnitude = X*X + Y*Y; |
| 126 | // Don't trust the angle if the magnitude is small compared to the y value |
| 127 | if (magnitude * 4 >= Z*Z) { |
| 128 | float OneEightyOverPi = 57.29577957855f; |
| 129 | float angle = (float)Math.atan2(-Y, X) * OneEightyOverPi; |
| 130 | orientation = 90 - (int)Math.round(angle); |
| 131 | // normalize to 0 - 359 range |
| 132 | while (orientation >= 360) { |
| 133 | orientation -= 360; |
| 134 | } |
| 135 | while (orientation < 0) { |
| 136 | orientation += 360; |
| 137 | } |
| 138 | } |
| 139 | if (mOldListener != null) { |
| 140 | mOldListener.onSensorChanged(Sensor.TYPE_ACCELEROMETER, event.values); |
| 141 | } |
| 142 | if (orientation != mOrientation) { |
| 143 | mOrientation = orientation; |
| 144 | onOrientationChanged(orientation); |
| 145 | } |
| 146 | } |
| 147 | |
| 148 | public void onAccuracyChanged(Sensor sensor, int accuracy) { |
| 149 | |
| 150 | } |
| 151 | } |
| 152 | |
| 153 | /* |
| 154 | * Returns true if sensor is enabled and false otherwise |
| 155 | */ |
| 156 | public boolean canDetectOrientation() { |
| 157 | return mSensor != null; |
| 158 | } |
| 159 | |
| 160 | /** |
| 161 | * Called when the orientation of the device has changed. |
| 162 | * orientation parameter is in degrees, ranging from 0 to 359. |
| 163 | * orientation is 0 degrees when the device is oriented in its natural position, |
| 164 | * 90 degrees when its left side is at the top, 180 degrees when it is upside down, |
| 165 | * and 270 degrees when its right side is to the top. |
| 166 | * {@link #ORIENTATION_UNKNOWN} is returned when the device is close to flat |
| 167 | * and the orientation cannot be determined. |
| 168 | * |
| 169 | * @param orientation The new orientation of the device. |
| 170 | * |
| 171 | * @see #ORIENTATION_UNKNOWN |
| 172 | */ |
| 173 | abstract public void onOrientationChanged(int orientation); |
| 174 | } |