Java tutorial
/* * Copyright (C) 2014 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.stasbar.knowyourself.timer; import android.animation.Animator; import android.animation.AnimatorListenerAdapter; import android.animation.AnimatorSet; import android.animation.ObjectAnimator; import android.content.Context; import android.content.Intent; import android.os.Bundle; import android.os.SystemClock; import android.support.annotation.NonNull; import android.support.annotation.VisibleForTesting; import android.support.v4.app.Fragment; import android.support.v4.content.ContextCompat; import android.support.v4.view.ViewPager; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.view.animation.AccelerateInterpolator; import android.view.animation.DecelerateInterpolator; import android.widget.Button; import android.widget.ImageButton; import android.widget.ImageView; import com.stasbar.knowyourself.DeskClock; import com.stasbar.knowyourself.LogUtils; import com.stasbar.knowyourself.MainActivity; import com.stasbar.knowyourself.R; import com.stasbar.knowyourself.data.ActivityItem; import com.stasbar.knowyourself.data.DataModel; import com.stasbar.knowyourself.data.Timer; import com.stasbar.knowyourself.data.TimerListener; import com.stasbar.knowyourself.databinding.TimerFragmentBinding; import com.stasbar.knowyourself.uidata.UiDataModel; import java.io.Serializable; import java.util.Arrays; import static android.view.View.ALPHA; import static android.view.View.GONE; import static android.view.View.INVISIBLE; import static android.view.View.SCALE_X; import static android.view.View.VISIBLE; /** * Displays a vertical list of timers in all states. */ public final class TimerFragment extends Fragment { private static final String EXTRA_TIMER_SETUP = "com.stasbar.lifetimetracker.action.TIMER_SETUP"; private static final String KEY_TIMER_SETUP_STATE = "timer_setup_input"; private static final String ACTIVITY_ITEM = "activity_item"; /** * Notified when the user swipes vertically to change the visible timer. */ private final TimerPageChangeListener mTimerPageChangeListener = new TimerPageChangeListener(); /** * Scheduled to update the timers while at least one is running. */ private final Runnable mTimeUpdateRunnable = new TimeUpdateRunnable(); /** * Updates the {@link #mPageIndicators} in response to timers being added or removed. */ private final TimerListener mTimerWatcher = new TimerWatcher(); ViewPager mViewPager; TimerSetupView mCreateTimerView; Button btnStartPause; Button btnStop; private TimerPagerAdapter mAdapter; private View mTimersView; private View mCurrentView; private ImageView[] mPageIndicators; private ActivityItem activityItem; private Serializable mTimerSetupState; /** * @return an Intent that selects the timers tab with the setup screen for a new timer in place. */ public static Intent createTimerSetupIntent(Context context) { return new Intent(context, DeskClock.class).putExtra(EXTRA_TIMER_SETUP, true); } /** * The public no-arg constructor required by all fragments. */ public TimerFragment() { } public static TimerFragment newInstance(ActivityItem activityItem) { TimerFragment fragment = new TimerFragment(); Bundle bundle = new Bundle(); bundle.putParcelable(ACTIVITY_ITEM, activityItem); fragment.setArguments(bundle); return fragment; } @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); if (getArguments() != null) { activityItem = getArguments().getParcelable(ACTIVITY_ITEM); } else { throw new IllegalArgumentException("Arguments can not be null"); } } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { TimerFragmentBinding bindiner = TimerFragmentBinding.inflate(inflater, container, false); View view = bindiner.getRoot(); mViewPager = bindiner.verticalViewPager; mCreateTimerView = bindiner.timerSetup; btnStartPause = bindiner.buttonStartPauseActivity; btnStop = bindiner.buttonStopActivity; mAdapter = new TimerPagerAdapter(getChildFragmentManager()); mViewPager.setAdapter(mAdapter); mViewPager.addOnPageChangeListener(mTimerPageChangeListener); mTimersView = view.findViewById(R.id.timer_view); mPageIndicators = new ImageView[] { (ImageView) view.findViewById(R.id.page_indicator0), (ImageView) view.findViewById(R.id.page_indicator1), (ImageView) view.findViewById(R.id.page_indicator2), (ImageView) view.findViewById(R.id.page_indicator3) }; DataModel.getDataModel().addTimerListener(mAdapter); DataModel.getDataModel().addTimerListener(mTimerWatcher); // If timer setup state is present, retrieve it to be later honored. if (savedInstanceState != null) { mTimerSetupState = savedInstanceState.getSerializable(KEY_TIMER_SETUP_STATE); } return view; } @Override public void onStart() { super.onStart(); // Initialize the page indicators. updatePageIndicators(); boolean createTimer = false; int showTimerId = -1; // Examine the intent of the parent activity to determine which view to display. final Intent intent = getActivity().getIntent(); if (intent != null) { // These extras are single-use; remove them after honoring them. createTimer = intent.getBooleanExtra(EXTRA_TIMER_SETUP, false); intent.removeExtra(EXTRA_TIMER_SETUP); showTimerId = intent.getIntExtra(TimerService.EXTRA_TIMER_ID, -1); intent.removeExtra(TimerService.EXTRA_TIMER_ID); } // Choose the view to display in this fragment. if (showTimerId != -1) { // A specific timer must be shown; show the list of timers. showTimersView(); } else if (!hasTimers() || createTimer || mTimerSetupState != null) { // No timers exist, a timer is being created, or the last view was timer setup; // show the timer setup view. showCreateTimerView(); if (mTimerSetupState != null) { mCreateTimerView.setState(mTimerSetupState); mTimerSetupState = null; } } else { // Otherwise, default to showing the list of timers. showTimersView(); } // If the intent did not specify a timer to show, show the last timer that expired. if (showTimerId == -1) { final Timer timer = DataModel.getDataModel().getMostRecentExpiredTimer(); showTimerId = timer == null ? -1 : timer.getId(); } // If a specific timer should be displayed, display the corresponding timer tab. if (showTimerId != -1) { final Timer timer = DataModel.getDataModel().getTimer(showTimerId); if (timer != null) { final int index = DataModel.getDataModel().getTimers().indexOf(timer); mViewPager.setCurrentItem(index); } } } @Override public void onResume() { super.onResume(); // We may have received a new intent while paused. final Intent intent = getActivity().getIntent(); if (intent != null && intent.hasExtra(TimerService.EXTRA_TIMER_ID)) { // This extra is single-use; remove after honoring it. final int showTimerId = intent.getIntExtra(TimerService.EXTRA_TIMER_ID, -1); intent.removeExtra(TimerService.EXTRA_TIMER_ID); final Timer timer = DataModel.getDataModel().getTimer(showTimerId); if (timer != null) { // A specific timer must be shown; show the list of timers. final int index = DataModel.getDataModel().getTimers().indexOf(timer); mViewPager.setCurrentItem(index); animateToView(mTimersView, null); } } } @Override public void onStop() { super.onStop(); // Stop updating the timers when this fragment is no longer visible. stopUpdatingTime(); } @Override public void onDestroyView() { super.onDestroyView(); DataModel.getDataModel().removeTimerListener(mAdapter); DataModel.getDataModel().removeTimerListener(mTimerWatcher); } @Override public void onSaveInstanceState(Bundle outState) { super.onSaveInstanceState(outState); // If the timer creation view is visible, store the input for later restoration. if (mCurrentView == mCreateTimerView) { mTimerSetupState = mCreateTimerView.getState(); outState.putSerializable(KEY_TIMER_SETUP_STATE, mTimerSetupState); } } public void onUpdateFab(@NonNull ImageView fab) { if (mCurrentView == mTimersView) { final Timer timer = getTimer(); if (timer == null) { fab.setVisibility(INVISIBLE); return; } fab.setVisibility(VISIBLE); switch (timer.getState()) { case RUNNING: fab.setImageResource(R.drawable.ic_pause_white_24dp); fab.setContentDescription(fab.getResources().getString(R.string.timer_stop)); break; case RESET: case PAUSED: fab.setImageResource(R.drawable.ic_start_white_24dp); fab.setContentDescription(fab.getResources().getString(R.string.timer_start)); break; case MISSED: case EXPIRED: fab.setImageResource(R.drawable.ic_stop_white_24dp); fab.setContentDescription(fab.getResources().getString(R.string.timer_stop)); break; } } else if (mCurrentView == mCreateTimerView) { if (mCreateTimerView.hasValidInput()) { fab.setImageResource(R.drawable.ic_start_white_24dp); fab.setContentDescription(fab.getResources().getString(R.string.timer_start)); fab.setVisibility(VISIBLE); } else { fab.setVisibility(INVISIBLE); } } } public void onUpdateFabButtons(@NonNull ImageButton left, @NonNull ImageButton right) { if (mCurrentView == mTimersView) { left.setEnabled(true); left.setImageResource(R.drawable.ic_delete); left.setContentDescription(left.getResources().getString(R.string.timer_delete)); left.setVisibility(mCurrentView != mTimersView ? GONE : VISIBLE); right.setEnabled(true); right.setImageResource(R.drawable.ic_add_timer); right.setContentDescription(right.getResources().getString(R.string.timer_add_timer)); right.setVisibility(mCurrentView != mTimersView ? GONE : VISIBLE); } else if (mCurrentView == mCreateTimerView) { left.setEnabled(true); left.setImageResource(R.drawable.ic_close); left.setContentDescription(left.getResources().getString(R.string.timer_cancel)); // If no timers yet exist, the user is forced to create the first one. left.setVisibility(hasTimers() ? VISIBLE : INVISIBLE); right.setVisibility(GONE); } } public void onStartPauseClick(View view) { if (!(view instanceof Button)) return; Button button = (Button) view; if (mCurrentView == mTimersView) { final Timer timer = getTimer(); // If no timer is currently showing a fab action is meaningless. if (timer == null) { return; } switch (timer.getState()) { case RUNNING: DataModel.getDataModel().pauseTimer(timer); button.setCompoundDrawables( ContextCompat.getDrawable(getActivity(), R.drawable.ic_pause_white_24dp), null, null, null); button.setText(getString(R.string.start)); break; case PAUSED: case RESET: DataModel.getDataModel().startTimer(timer); button.setCompoundDrawables( ContextCompat.getDrawable(getActivity(), R.drawable.ic_start_white_24dp), null, null, null); button.setText(getString(R.string.pause)); break; case EXPIRED: case MISSED: DataModel.getDataModel().resetOrDeleteTimer(timer, R.string.label_deskclock); break; } } else if (mCurrentView == mCreateTimerView) { btnStop.setVisibility(VISIBLE); button.setText(getString(R.string.pause)); // Create the new timer. final long length = mCreateTimerView.getTimeInMillis(); final Timer timer = DataModel.getDataModel().addTimer(length, "", false); // Start the new timer. DataModel.getDataModel().startTimer(timer); // Reset the state of the create view. mCreateTimerView.reset(); // Display the freshly created timer view. mViewPager.setCurrentItem(0); // Return to the list of timers. animateToView(mTimersView, null); } } public void onStopActivity(View left) { if (mCurrentView == mTimersView) { final Timer timer = getTimer(); if (timer == null) { return; } if (mAdapter.getCount() > 1) { animateTimerRemove(timer); } else { animateToView(mCreateTimerView, timer); } left.announceForAccessibility(getActivity().getString(R.string.timer_deleted)); } else if (mCurrentView == mCreateTimerView) { // Clicking the X icon on the timer creation page returns to the timers list. mCreateTimerView.reset(); animateToView(mTimersView, null); left.announceForAccessibility(getActivity().getString(R.string.timer_canceled)); } } public void onRightButtonClick(@NonNull ImageButton right) { if (mCurrentView != mCreateTimerView) { animateToView(mCreateTimerView, null); } } /** * Updates the state of the page indicators so they reflect the selected page in the context of * all pages. */ private void updatePageIndicators() { final int page = mViewPager.getCurrentItem(); final int pageIndicatorCount = mPageIndicators.length; final int pageCount = mAdapter.getCount(); final int[] states = computePageIndicatorStates(page, pageIndicatorCount, pageCount); for (int i = 0; i < states.length; i++) { final int state = states[i]; final ImageView pageIndicator = mPageIndicators[i]; if (state == 0) { pageIndicator.setVisibility(GONE); } else { pageIndicator.setVisibility(VISIBLE); pageIndicator.setImageResource(state); } } } /** * @param page the selected page; value between 0 and {@code pageCount} * @param pageIndicatorCount the number of indicators displaying the {@code page} location * @param pageCount the number of pages that exist * @return an array of length {@code pageIndicatorCount} specifying which image to display for * each page indicator or 0 if the page indicator should be hidden */ @VisibleForTesting static int[] computePageIndicatorStates(int page, int pageIndicatorCount, int pageCount) { // Compute the number of page indicators that will be visible. final int rangeSize = Math.min(pageIndicatorCount, pageCount); // Compute the inclusive range of pages to indicate centered around the selected page. int rangeStart = page - (rangeSize / 2); int rangeEnd = rangeStart + rangeSize - 1; // Clamp the range of pages if they extend beyond the last page. if (rangeEnd >= pageCount) { rangeEnd = pageCount - 1; rangeStart = rangeEnd - rangeSize + 1; } // Clamp the range of pages if they extend beyond the first page. if (rangeStart < 0) { rangeStart = 0; rangeEnd = rangeSize - 1; } // Build the result with all page indicators initially hidden. final int[] states = new int[pageIndicatorCount]; Arrays.fill(states, 0); // If 0 or 1 total pages exist, all page indicators must remain hidden. if (rangeSize < 2) { return states; } // Initialize the visible page indicators to be dark. Arrays.fill(states, 0, rangeSize, R.drawable.ic_swipe_circle_dark); // If more pages exist before the first page indicator, make it a fade-in gradient. if (rangeStart > 0) { states[0] = R.drawable.ic_swipe_circle_top; } // If more pages exist after the last page indicator, make it a fade-out gradient. if (rangeEnd < pageCount - 1) { states[rangeSize - 1] = R.drawable.ic_swipe_circle_bottom; } // Set the indicator of the selected page to be light. states[page - rangeStart] = R.drawable.ic_swipe_circle_light; return states; } /** * Display the view that creates a new timer. */ private void showCreateTimerView() { // Stop animating the timers. stopUpdatingTime(); // Show the creation view; hide the timer view. mTimersView.setVisibility(GONE); mCreateTimerView.setVisibility(VISIBLE); // Record the fact that the create view is visible. mCurrentView = mCreateTimerView; } /** * Display the view that lists all existing timers. */ private void showTimersView() { // Clear any defunct timer creation state; the next timer creation starts fresh. mTimerSetupState = null; // Show the timer view; hide the creation view. mTimersView.setVisibility(VISIBLE); mCreateTimerView.setVisibility(GONE); // Record the fact that the create view is visible. mCurrentView = mTimersView; // Start animating the timers. startUpdatingTime(); } /** * @param timerToRemove the timer to be removed during the animation */ private void animateTimerRemove(final Timer timerToRemove) { final long duration = UiDataModel.getUiDataModel().getShortAnimationDuration(); final Animator fadeOut = ObjectAnimator.ofFloat(mViewPager, ALPHA, 1, 0); fadeOut.setDuration(duration); fadeOut.setInterpolator(new DecelerateInterpolator()); fadeOut.addListener(new AnimatorListenerAdapter() { @Override public void onAnimationEnd(Animator animation) { LogUtils.d("animateTimerRemove"); DataModel.getDataModel().removeTimer(timerToRemove); } }); final Animator fadeIn = ObjectAnimator.ofFloat(mViewPager, ALPHA, 0, 1); fadeIn.setDuration(duration); fadeIn.setInterpolator(new AccelerateInterpolator()); final AnimatorSet animatorSet = new AnimatorSet(); animatorSet.play(fadeOut).before(fadeIn); animatorSet.start(); } /** * @param toView one of {@link #mTimersView} or {@link #mCreateTimerView} * @param timerToRemove the timer to be removed during the animation; {@code null} if no timer * should be removed */ private void animateToView(View toView, final Timer timerToRemove) { if (mCurrentView == toView) { return; } final boolean toTimers = toView == mTimersView; final long duration = UiDataModel.getUiDataModel().getShortAnimationDuration(); final Animator rotateFrom = ObjectAnimator.ofFloat(mCurrentView, SCALE_X, 1, 0); rotateFrom.setDuration(duration); rotateFrom.setInterpolator(new DecelerateInterpolator()); rotateFrom.addListener(new AnimatorListenerAdapter() { @Override public void onAnimationEnd(Animator animation) { if (timerToRemove != null) { DataModel.getDataModel().removeTimer(timerToRemove); ((MainActivity) getActivity()).stopActivity(activityItem, timerToRemove); } mCurrentView.setScaleX(1); if (toTimers) { showTimersView(); } else { showCreateTimerView(); } } }); final Animator rotateTo = ObjectAnimator.ofFloat(toView, SCALE_X, 0, 1); rotateTo.setDuration(duration); rotateTo.setInterpolator(new AccelerateInterpolator()); final AnimatorSet animatorSet = new AnimatorSet(); animatorSet.play(rotateFrom).before(rotateTo); animatorSet.start(); } private boolean hasTimers() { return mAdapter.getCount() > 0; } private Timer getTimer() { if (mViewPager == null) { return null; } return mAdapter.getCount() == 0 ? null : mAdapter.getTimer(mViewPager.getCurrentItem()); } private void startUpdatingTime() { // Ensure only one copy of the runnable is ever scheduled by first stopping updates. stopUpdatingTime(); mViewPager.post(mTimeUpdateRunnable); } private void stopUpdatingTime() { mViewPager.removeCallbacks(mTimeUpdateRunnable); } /** * Periodically refreshes the state of each timer. */ private class TimeUpdateRunnable implements Runnable { @Override public void run() { final long startTime = SystemClock.elapsedRealtime(); // If no timers require continuous updates, avoid scheduling the next update. if (!mAdapter.updateTime()) { return; } final long endTime = SystemClock.elapsedRealtime(); // Try to maintain a consistent period of time between redraws. final long delay = Math.max(0, startTime + 20 - endTime); mTimersView.postDelayed(this, delay); } } /** * Update the page indicators and fab in response to a new timer becoming visible. */ private class TimerPageChangeListener extends ViewPager.SimpleOnPageChangeListener { @Override public void onPageSelected(int position) { updatePageIndicators(); // Showing a new timer page may introduce a timer requiring continuous updates. startUpdatingTime(); } @Override public void onPageScrollStateChanged(int state) { // Teasing a neighboring timer may introduce a timer requiring continuous updates. if (state == ViewPager.SCROLL_STATE_DRAGGING) { startUpdatingTime(); } } } /** * Update the page indicators in response to timers being added or removed. * Update the fab in response to the visible timer changing. */ private class TimerWatcher implements TimerListener { @Override public void timerAdded(Timer timer) { updatePageIndicators(); } @Override public void timerUpdated(Timer before, Timer after) { // If the timer started, animate the timers. if (before.isReset() && !after.isReset()) { startUpdatingTime(); } // Fetch the index of the change. final int index = DataModel.getDataModel().getTimers().indexOf(after); // If the timer just expired but is not displayed, display it now. if (!before.isExpired() && after.isExpired() && index != mViewPager.getCurrentItem()) { mViewPager.setCurrentItem(index, true); } } @Override public void timerRemoved(Timer timer) { updatePageIndicators(); if (mCurrentView == mTimersView) { if (mAdapter.getCount() == 0) animateToView(mCreateTimerView, null); } } } }