Java tutorial
/* * Copyright (C) 2015 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.android.talkback; import android.content.BroadcastReceiver; import android.content.Intent; import android.content.IntentFilter; import android.content.Context; import android.content.SharedPreferences; import android.hardware.SensorManager; import android.support.v4.view.accessibility.AccessibilityEventCompat; import android.view.accessibility.AccessibilityEvent; import com.android.talkback.controller.FeedbackController; import com.android.talkback.controller.GestureController; import com.android.utils.AccessibilityEventListener; import com.android.utils.SharedPreferencesUtils; import com.android.utils.picidae.IntegratedTapDetector; import com.google.android.marvin.talkback.TalkBackService; /** * Manages detection of taps on the side of the device. Wraps IntegratedTapDetector. */ public class SideTapManager extends BroadcastReceiver implements IntegratedTapDetector.TapListener, FeedbackController.HapticFeedbackListener, AccessibilityEventListener { /* Ignore taps for this long after the screen is touched */ private static final long MIN_TIME_BETWEEN_TOUCH_AND_TAP_NANOS = 500 * 1000 * 1000; /* Ignore taps for this long after the screen is touched */ private static final long MIN_TIME_BETWEEN_HAPTIC_AND_TAP_NANOS = 500 * 1000 * 1000; /* Time interval for double taps */ private static final long DOUBLE_TAP_SPACING_NANOS = 500 * 1000 * 1000; private static final long MILIS_PER_NANO = 1000 * 1000; private Context mContext; /* Time of last touch of the screen */ private long mLastTouchTime = 0; /* Time of last haptic feedback */ private long mLastHapticTime = 0; /* Class that deals with the hardware and calls us back with taps */ private IntegratedTapDetector mIntegratedTapDetector; private final GestureController mGestureController; /** * @param context TalkBackService whose {@code performCustomGesture} * will be called when taps are detected */ public SideTapManager(TalkBackService context, GestureController gestureController) { if (gestureController == null) throw new IllegalStateException(); mContext = context; mIntegratedTapDetector = new IntegratedTapDetector( (SensorManager) mContext.getSystemService(Context.SENSOR_SERVICE)); mIntegratedTapDetector.addListener(this); mIntegratedTapDetector.setPostDelayTimeMillis(MIN_TIME_BETWEEN_TOUCH_AND_TAP_NANOS / MILIS_PER_NANO); mGestureController = gestureController; } /** * Stops tap detection. */ public void onSuspendInfrastructure() { mIntegratedTapDetector.stop(); } /** * Enables tap detection if appropriate based on preferences. */ public void onReloadPreferences() { SharedPreferences settings = SharedPreferencesUtils.getSharedPreferences(mContext); boolean enableTapDetection = false; if (!settings .getString(mContext.getString(R.string.pref_shortcut_single_tap_key), mContext.getString(R.string.pref_shortcut_single_tap_default)) .equals(mContext.getString(R.string.shortcut_value_unassigned))) { /* Single tap is assigned */ enableTapDetection = true; } if (!settings .getString(mContext.getString(R.string.pref_shortcut_double_tap_key), mContext.getString(R.string.pref_shortcut_double_tap_default)) .equals(mContext.getString(R.string.shortcut_value_unassigned))) { /* Double tap is assigned */ enableTapDetection = true; mIntegratedTapDetector.setMaxDoubleTapSpacingNanos(DOUBLE_TAP_SPACING_NANOS); } else { mIntegratedTapDetector.setMaxDoubleTapSpacingNanos(0); } /* The setting is 'sensitivity', which is the opposite of the detector's 'quality' */ if (settings .getString(mContext.getString(R.string.pref_tap_sensitivity_key), mContext.getString(R.string.pref_tap_sensitivity_default)) .equals(mContext.getString(R.string.tap_sensitivity_value_lowest))) { mIntegratedTapDetector.setTapDetectionQuality(IntegratedTapDetector.TAP_QUALITY_HIGHEST); } if (settings .getString(mContext.getString(R.string.pref_tap_sensitivity_key), mContext.getString(R.string.pref_tap_sensitivity_default)) .equals(mContext.getString(R.string.tap_sensitivity_value_low))) { mIntegratedTapDetector.setTapDetectionQuality(IntegratedTapDetector.TAP_QUALITY_HIGH); } if (settings .getString(mContext.getString(R.string.pref_tap_sensitivity_key), mContext.getString(R.string.pref_tap_sensitivity_default)) .equals(mContext.getString(R.string.tap_sensitivity_value_medium))) { mIntegratedTapDetector.setTapDetectionQuality(IntegratedTapDetector.TAP_QUALITY_MEDIUM); } if (settings .getString(mContext.getString(R.string.pref_tap_sensitivity_key), mContext.getString(R.string.pref_tap_sensitivity_default)) .equals(mContext.getString(R.string.tap_sensitivity_value_high))) { mIntegratedTapDetector.setTapDetectionQuality(IntegratedTapDetector.TAP_QUALITY_LOW); } /* Second tap of double taps can be low quality */ mIntegratedTapDetector.setDoubleTapDetectionQuality(IntegratedTapDetector.TAP_QUALITY_LOW); if (enableTapDetection) { mIntegratedTapDetector.start(); } else { mIntegratedTapDetector.stop(); } } /** * Called so we can avoid detecting screen touches as side taps. */ public void onAccessibilityEvent(AccessibilityEvent event) { if (event.getEventType() == AccessibilityEventCompat.TYPE_TOUCH_INTERACTION_START) { mLastTouchTime = System.nanoTime(); } } /* Handle a single tap on the side of the device */ @Override public void onSingleTap(long timeStamp) { boolean talkBackActive = TalkBackService.isServiceActive(); boolean tapIsntFromScreenTouch = (Math .abs(timeStamp - mLastTouchTime) > MIN_TIME_BETWEEN_TOUCH_AND_TAP_NANOS); boolean tapIsntFromHaptic = (Math.abs(timeStamp - mLastHapticTime) > MIN_TIME_BETWEEN_HAPTIC_AND_TAP_NANOS); if (talkBackActive && tapIsntFromScreenTouch && tapIsntFromHaptic) { SharedPreferences prefs = SharedPreferencesUtils.getSharedPreferences(mContext); mGestureController .performAction(prefs.getString(mContext.getString(R.string.pref_shortcut_single_tap_key), mContext.getString(R.string.pref_shortcut_single_tap_default))); } } /* Handle a double tap on the side of the device */ @Override public void onDoubleTap(long timeStamp) { boolean talkBackActive = TalkBackService.isServiceActive(); boolean tapIsntFromScreenTouch = (Math .abs(timeStamp - mLastTouchTime) > MIN_TIME_BETWEEN_TOUCH_AND_TAP_NANOS); boolean tapIsntFromHaptic = (Math.abs(timeStamp - mLastHapticTime) > MIN_TIME_BETWEEN_HAPTIC_AND_TAP_NANOS); if (talkBackActive && tapIsntFromScreenTouch && tapIsntFromHaptic) { SharedPreferences prefs = SharedPreferencesUtils.getSharedPreferences(mContext); mGestureController .performAction(prefs.getString(mContext.getString(R.string.pref_shortcut_double_tap_key), mContext.getString(R.string.pref_shortcut_double_tap_default))); } } /* * Haptic feedback can be interpreted as a tap, similarly to a screen tap. */ @Override public void onHapticFeedbackStarting(long currentNanoTime) { mLastHapticTime = currentNanoTime; } @Override public void onReceive(Context context, Intent intent) { if (!TalkBackService.isServiceActive()) { return; } String action = intent.getAction(); if (action.equals(Intent.ACTION_SCREEN_ON)) { onReloadPreferences(); } if (action.equals(Intent.ACTION_SCREEN_OFF)) { mIntegratedTapDetector.stop(); } } public static IntentFilter getFilter() { IntentFilter filter = new IntentFilter(); filter.addAction(Intent.ACTION_SCREEN_ON); filter.addAction(Intent.ACTION_SCREEN_OFF); return filter; } /** * Permit tests to replace the tap detector to verify calls to it * @param itd new IntegratedTapDetector */ // Visible for testing /* package */ void setIntegratedTapDetector(IntegratedTapDetector itd) { mIntegratedTapDetector = itd; } }