Files
app_Settings/src/com/android/settings/display/PreviewSeekBarPreferenceFragment.java
Tsung-Mao Fang f9ff6344e4 Fix the flickering on display/font size page
In framework design, framework needs to have a snapshot
when there's a config change event since redrawing window
takes some time.
Flickering problem is caused by the timing issue between the
snapshot mechinsm and local preview update.

User can observe the flickering problem if config commit()->
snapshot in framework(old screenshot) -> app update the preview
-> snapshot(old screen) fade out.

To prevent this problem, we make sure that we update the local preview
first and then we do the commit later. In this proposal, snapshot action
is able to get the new snaptshot for the new preview.

So, the core workaround is commitOnNextFrame, we ask a delay before
we submit the commit(). Note: It doesn't matter that we use
Choreographer or main thread handler since the delay time is longer
than 1 frame. Use Choreographer to let developer understand it's a
window update.

Fix: 148192402
Test: manual test
Change-Id: I9bfc5eb39e7a9ebce2fe1414d6f0a9dd470708e8
2021-07-09 14:02:34 +08:00

287 lines
10 KiB
Java

/*
* Copyright (C) 2018 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.settings.display;
import android.content.Context;
import android.content.res.Configuration;
import android.os.Bundle;
import android.os.SystemClock;
import android.view.Choreographer;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.accessibility.AccessibilityEvent;
import android.widget.SeekBar;
import android.widget.SeekBar.OnSeekBarChangeListener;
import android.widget.TextView;
import androidx.viewpager.widget.ViewPager;
import androidx.viewpager.widget.ViewPager.OnPageChangeListener;
import com.android.settings.R;
import com.android.settings.SettingsPreferenceFragment;
import com.android.settings.widget.DotsPageIndicator;
import com.android.settings.widget.LabeledSeekBar;
/**
* Preference fragment shows a preview and a seek bar to adjust a specific settings.
*/
public abstract class PreviewSeekBarPreferenceFragment extends SettingsPreferenceFragment {
/** List of entries corresponding the settings being set. */
protected String[] mEntries;
/** Index of the entry corresponding to initial value of the settings. */
protected int mInitialIndex;
/** Index of the entry corresponding to current value of the settings. */
protected int mCurrentIndex;
private ViewPager mPreviewPager;
private PreviewPagerAdapter mPreviewPagerAdapter;
private DotsPageIndicator mPageIndicator;
private TextView mLabel;
private LabeledSeekBar mSeekBar;
private View mLarger;
private View mSmaller;
private static final long MIN_COMMIT_INTERVAL_MS = 800;
private long mLastCommitTime;
private class onPreviewSeekBarChangeListener implements OnSeekBarChangeListener {
private static final long CHANGE_BY_SEEKBAR_DELAY_MS = 100;
private static final long CHANGE_BY_BUTTON_DELAY_MS = 300;
private boolean mSeekByTouch;
private boolean mIsChanged;
private long mCommitDelayMs;
private final Choreographer.FrameCallback mCommit = f -> {
commit();
mLastCommitTime = SystemClock.elapsedRealtime();
};
@Override
public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
if (mCurrentIndex == progress) {
mIsChanged = false;
return;
}
mIsChanged = true;
setPreviewLayer(progress, false);
if (mSeekByTouch) {
mCommitDelayMs = CHANGE_BY_SEEKBAR_DELAY_MS;
} else {
mCommitDelayMs = CHANGE_BY_BUTTON_DELAY_MS;
commitOnNextFrame();
}
}
@Override
public void onStartTrackingTouch(SeekBar seekBar) {
mSeekByTouch = true;
}
@Override
public void onStopTrackingTouch(SeekBar seekBar) {
mSeekByTouch = false;
if (!mIsChanged) {
return;
}
if (mPreviewPagerAdapter.isAnimating()) {
mPreviewPagerAdapter.setAnimationEndAction(this::commitOnNextFrame);
} else {
commitOnNextFrame();
}
}
private void commitOnNextFrame() {
if (SystemClock.elapsedRealtime() - mLastCommitTime < MIN_COMMIT_INTERVAL_MS) {
mCommitDelayMs += MIN_COMMIT_INTERVAL_MS;
}
final Choreographer choreographer = Choreographer.getInstance();
choreographer.removeFrameCallback(mCommit);
choreographer.postFrameCallbackDelayed(mCommit, mCommitDelayMs);
}
}
@Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
outState.putLong("mLastCommitTime", mLastCommitTime);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
if (savedInstanceState != null) {
mLastCommitTime = savedInstanceState.getLong("mLastCommitTime");
}
final View root = super.onCreateView(inflater, container, savedInstanceState);
final ViewGroup listContainer = root.findViewById(android.R.id.list_container);
listContainer.removeAllViews();
final View content = inflater.inflate(getActivityLayoutResId(), listContainer, false);
listContainer.addView(content);
mLabel = content.findViewById(R.id.current_label);
// The maximum SeekBar value always needs to be non-zero. If there's
// only one available value, we'll handle this by disabling the
// seek bar.
final int max = Math.max(1, mEntries.length - 1);
mSeekBar = content.findViewById(R.id.seek_bar);
mSeekBar.setLabels(mEntries);
mSeekBar.setMax(max);
mSmaller = content.findViewById(R.id.smaller);
mSmaller.setOnClickListener(v -> {
final int progress = mSeekBar.getProgress();
if (progress > 0) {
mSeekBar.setProgress(progress - 1, true);
}
});
mLarger = content.findViewById(R.id.larger);
mLarger.setOnClickListener(v -> {
final int progress = mSeekBar.getProgress();
if (progress < mSeekBar.getMax()) {
mSeekBar.setProgress(progress + 1, true);
}
});
if (mEntries.length == 1) {
// The larger and smaller buttons will be disabled when we call
// setPreviewLayer() later in this method.
mSeekBar.setEnabled(false);
}
final Context context = getContext();
final Configuration origConfig = context.getResources().getConfiguration();
final boolean isLayoutRtl = origConfig.getLayoutDirection() == View.LAYOUT_DIRECTION_RTL;
Configuration[] configurations = new Configuration[mEntries.length];
for (int i = 0; i < mEntries.length; ++i) {
configurations[i] = createConfig(origConfig, i);
}
final int[] previews = getPreviewSampleResIds();
mPreviewPager = content.findViewById(R.id.preview_pager);
mPreviewPagerAdapter = new PreviewPagerAdapter(context, isLayoutRtl,
previews, configurations);
mPreviewPager.setAdapter(mPreviewPagerAdapter);
mPreviewPager.setCurrentItem(isLayoutRtl ? previews.length - 1 : 0);
mPreviewPager.addOnPageChangeListener(mPreviewPageChangeListener);
mPageIndicator = content.findViewById(R.id.page_indicator);
if (previews.length > 1) {
mPageIndicator.setViewPager(mPreviewPager);
mPageIndicator.setVisibility(View.VISIBLE);
mPageIndicator.setOnPageChangeListener(mPageIndicatorPageChangeListener);
} else {
mPageIndicator.setVisibility(View.GONE);
}
setPreviewLayer(mInitialIndex, false);
return root;
}
@Override
public void onStart() {
super.onStart();
// Set SeekBar listener here to avoid onProgressChanged() is called
// during onRestoreInstanceState().
mSeekBar.setProgress(mCurrentIndex);
mSeekBar.setOnSeekBarChangeListener(new onPreviewSeekBarChangeListener());
}
@Override
public void onStop() {
super.onStop();
mSeekBar.setOnSeekBarChangeListener(null);
}
/** Resource id of the layout for this preference fragment. */
protected abstract int getActivityLayoutResId();
/** Resource id of the layout that defines the contents inside preview screen. */
protected abstract int[] getPreviewSampleResIds();
/**
* Creates new configuration based on the current position of the SeekBar.
*/
protected abstract Configuration createConfig(Configuration origConfig, int index);
/**
* Persists the selected value and sends a configuration change.
*/
protected abstract void commit();
private void setPreviewLayer(int index, boolean animate) {
mLabel.setText(mEntries[index]);
mSmaller.setEnabled(index > 0);
mLarger.setEnabled(index < mEntries.length - 1);
setPagerIndicatorContentDescription(mPreviewPager.getCurrentItem());
mPreviewPagerAdapter.setPreviewLayer(index, mCurrentIndex,
mPreviewPager.getCurrentItem(), animate);
mCurrentIndex = index;
}
private void setPagerIndicatorContentDescription(int position) {
mPageIndicator.setContentDescription(
getString(R.string.preview_page_indicator_content_description,
position + 1, getPreviewSampleResIds().length));
}
private OnPageChangeListener mPreviewPageChangeListener = new OnPageChangeListener() {
@Override
public void onPageScrollStateChanged(int state) {
// Do nothing.
}
@Override
public void onPageScrolled(int position, float positionOffset,
int positionOffsetPixels) {
// Do nothing.
}
@Override
public void onPageSelected(int position) {
mPreviewPager.sendAccessibilityEvent(AccessibilityEvent.TYPE_ANNOUNCEMENT);
}
};
private OnPageChangeListener mPageIndicatorPageChangeListener = new OnPageChangeListener() {
@Override
public void onPageScrollStateChanged(int state) {
// Do nothing.
}
@Override
public void onPageScrolled(int position, float positionOffset,
int positionOffsetPixels) {
// Do nothing.
}
@Override
public void onPageSelected(int position) {
setPagerIndicatorContentDescription(position);
}
};
}