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效果
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Android
AppBar作为Android5.0的重要动画效果, 非常绚丽的UI, 通过内容驱动, 可以减少页面的访问, 更加便捷的传递主题思想. 那么我们看看如何使用.
本文源码的GitHub下载地址
1. 准备
创建一个Navigation Drawer的工程, 修改主题颜色.
#FF1493
#FF1493
#FF4081
修改抽屉的渐变颜色side_nav_bar.xml
2. ViewPager
修改app_bar_main.xml, 在CoordinatorLayout中添加ViewPager.
设置ViewPager的Fragment内容
/**
* 简单的Fragment
*
* Created by wangchenlong on 15/11/9.
*/
public class SimpleFragment extends Fragment {
private static final String ARG_SELECTION_NUM = "arg_selection_num";
@Bind(R.id.main_tv_text) TextView mTvText;
public SimpleFragment() {
}
public static SimpleFragment newInstance(int selectionNum) {
SimpleFragment simpleFragment = new SimpleFragment();
Bundle args = new Bundle();
args.putInt(ARG_SELECTION_NUM, selectionNum);
simpleFragment.setArguments(args);
return simpleFragment;
}
@Nullable @Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_main, container, false);
ButterKnife.bind(this, view);
return view;
}
@Override public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
mTvText.setText("Page " + String.valueOf(getArguments().getInt(ARG_SELECTION_NUM)));
}
@Override public void onDestroyView() {
super.onDestroyView();
ButterKnife.unbind(this);
}
}
设置ViewPager的适配器
/**
* ViewPager的适配器
*
* Created by wangchenlong on 15/11/9.
*/
public class SimpleAdapter extends FragmentPagerAdapter {
private static final String[] TITLE = {"SELECTION 1", "SELECTION 2", "SELECTION 3"};
public SimpleAdapter(FragmentManager fm) {
super(fm);
}
@Override public Fragment getItem(int position) {
return SimpleFragment.newInstance(position + 1);
}
@Override public int getCount() {
return TITLE.length;
}
@Override public CharSequence getPageTitle(int position) {
if (position >= 0 && position < TITLE.length) {
return TITLE[position];
}
return null;
}
}
在MainActivity中添加ViewPager逻辑
mVpContainer.setAdapter(new SimpleAdapter(getSupportFragmentManager()));
3. AppBarLayout
修改AppBarLayout, 添加CollapsingToolbarLayout.
删除Toolbar的background颜色, 避免Toolbar挡住图片;
AppBarLayout设置fitsSystemWindows覆盖StatusBar背景;
CollapsingToolbarLayout包含图片和Toolbar.
4. TabLayout
在AppBarLayout中, 添加TabLayout
TabLayout添加
layout_scrollFlags确保滑动.
把ViewPager加入TabLayout
mTlTab.setupWithViewPager(mVpContainer);
基本功能已经完成, 再添加随着页面切换AppBarLayout的图片视图.
5. 渐变效果
在图片视图中, 再添加一层图片, 模拟渐变动画.
修改Adapter, 为每个页面添加一个图片
/**
* ViewPager的适配器
*
* Created by wangchenlong on 15/11/9.
*/
public class SimpleAdapter extends FragmentPagerAdapter {
private static final Section[] SECTIONS = {
new Section("Tiffany", R.drawable.tiffany),
new Section("Taeyeon", R.drawable.taeyeon),
new Section("Yoona", R.drawable.yoona)
};
public SimpleAdapter(FragmentManager fm) {
super(fm);
}
@Override public Fragment getItem(int position) {
return SimpleFragment.newInstance(position + 1);
}
@Override public int getCount() {
return SECTIONS.length;
}
@Override public CharSequence getPageTitle(int position) {
if (position >= 0 && position < SECTIONS.length) {
return SECTIONS[position].getTitle();
}
return null;
}
@DrawableRes
public int getDrawable(int position) {
if (position >= 0 && position < SECTIONS.length) {
return SECTIONS[position].getDrawable();
}
return -1;
}
private static final class Section {
private final String mTitle; // 标题
@DrawableRes private final int mDrawable; // 图片
public Section(String title, int drawable) {
mTitle = title;
mDrawable = drawable;
}
public String getTitle() {
return mTitle;
}
public int getDrawable() {
return mDrawable;
}
}
}
两个图像页面的渐变动画
/**
* 渐变的动画效果
*
* Created by wangchenlong on 15/11/9.
*/
public class ImageAnimator {
private final SimpleAdapter mAdapter; // 适配器
private final ImageView mTargetImage; // 原始图片
private final ImageView mOutgoingImage; // 渐变图片
private int mActualStart; // 实际起始位置
public ImageAnimator(SimpleAdapter adapter, ImageView targetImage, ImageView outgoingImage) {
mAdapter = adapter;
mTargetImage = targetImage;
mOutgoingImage = outgoingImage;
}
/**
* 启动动画, 之后选择向前或向后滑动
*
* @param startPosition 起始位置
* @param endPosition 终止位置
*/
public void start(int startPosition, int endPosition) {
mActualStart = startPosition;
// 终止位置的图片
@DrawableRes int incomeId = mAdapter.getDrawable(endPosition);
// 原始图片
mOutgoingImage.setImageDrawable(mTargetImage.getDrawable()); // 原始的图片
mOutgoingImage.setVisibility(View.VISIBLE);
mOutgoingImage.setAlpha(1.0f);
// 目标图片
mTargetImage.setImageResource(incomeId);
}
/**
* 滑动结束的动画效果
*
* @param endPosition 滑动位置
*/
public void end(int endPosition) {
@DrawableRes int incomeId = mAdapter.getDrawable(endPosition);
mTargetImage.setTranslationX(0f);
// 设置原始图片
if (endPosition == mActualStart) {
mTargetImage.setImageDrawable(mOutgoingImage.getDrawable());
} else {
mTargetImage.setImageResource(incomeId);
mTargetImage.setAlpha(1f);
mOutgoingImage.setVisibility(View.GONE);
}
}
// 向后滚动, 比如0->1, offset滚动的距离(0->1), 目标渐渐淡出
public void forward(float positionOffset) {
mTargetImage.setAlpha(positionOffset);
}
// 向前滚动, 比如1->0, offset滚动的距离(1->0), 目标渐渐淡出
public void backwards(float positionOffset) {
mTargetImage.setAlpha(1 - positionOffset);
}
}
注释已经写的很详细了, 注意的是向前向后滑动, position的值不同. 向前滑动, position的值是当前值减一; 向后滑动, position的值不变. 也就是说, position总是较小值. 偏移量, 向后滑动时, 从0至1; 向前滑动时, 从1至0.
ViewPager的监听, 使用动画效果
/**
* ViewPager滑动页面监听
*
* Created by wangchenlong on 15/11/9.
*/
public class PagerChangeListener implements ViewPager.OnPageChangeListener {
private ImageAnimator mImageAnimator;
private int mCurrentPosition;
private int mFinalPosition;
private boolean mIsScrolling = false;
public PagerChangeListener(ImageAnimator imageAnimator) {
mImageAnimator = imageAnimator;
}
public static PagerChangeListener newInstance(SimpleAdapter adapter, ImageView originImage, ImageView outgoingImage) {
ImageAnimator imageAnimator = new ImageAnimator(adapter, originImage, outgoingImage);
return new PagerChangeListener(imageAnimator);
}
/**
* 滑动监听
*
* @param position 当前位置
* @param positionOffset 偏移[当前值+-1]
* @param positionOffsetPixels 偏移像素
*/
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
Log.e("DEBUG-WCL", "position: " + position + ", positionOffset: " + positionOffset);
// 以前滑动, 现在终止
if (isFinishedScrolling(position, positionOffset)) {
finishScroll(position);
}
// 判断前后滑动
if (isStartingScrollToPrevious(position, positionOffset)) {
startScroll(position);
} else if (isStartingScrollToNext(position, positionOffset)) {
startScroll(position + 1); // 向后滚动需要加1
}
// 向后滚动
if (isScrollingToNext(position, positionOffset)) {
mImageAnimator.forward(positionOffset);
} else if (isScrollingToPrevious(position, positionOffset)) { // 向前滚动
mImageAnimator.backwards(positionOffset);
}
}
/**
* 终止滑动
* 滑动 && [偏移是0&&滑动终点] || 动画之中
*
* @param position 位置
* @param positionOffset 偏移量
* @return 终止滑动
*/
public boolean isFinishedScrolling(int position, float positionOffset) {
return mIsScrolling && (positionOffset == 0f && position == mFinalPosition);
}
/**
* 从静止到开始滑动, 下一个
* 未滑动 && 位置是当前位置 && 偏移量不是0
*
* @param position 位置
* @param positionOffset 偏移量
* @return 是否
*/
private boolean isStartingScrollToNext(int position, float positionOffset) {
return !mIsScrolling && position == mCurrentPosition && positionOffset != 0f;
}
/**
* 从静止到开始滑动, 前一个[position会-1]
*
* @param position 位置
* @param positionOffset 偏移量
* @return 是否
*/
private boolean isStartingScrollToPrevious(int position, float positionOffset) {
return !mIsScrolling && position != mCurrentPosition && positionOffset != 0f;
}
/**
* 开始滚动, 向后
*
* @param position 位置
* @param positionOffset 偏移
* @return 是否
*/
private boolean isScrollingToNext(int position, float positionOffset) {
return mIsScrolling && position == mCurrentPosition && positionOffset != 0f;
}
/**
* 开始滚动, 向前
*
* @param position 位置
* @param positionOffset 偏移
* @return 是否
*/
private boolean isScrollingToPrevious(int position, float positionOffset) {
return mIsScrolling && position != mCurrentPosition && positionOffset != 0f;
}
/**
* 开始滑动
* 滚动开始, 结束位置是position[前滚时position会自动减一], 动画从当前位置到结束位置.
*
* @param position 滚动结束之后的位置
*/
private void startScroll(int position) {
mIsScrolling = true;
mFinalPosition = position;
// 开始滚动动画
mImageAnimator.start(mCurrentPosition, position);
}
/**
* 如果正在滚动, 结束时, 固定position位置, 停止滚动, 调动截止动画
*
* @param position 位置
*/
private void finishScroll(int position) {
if (mIsScrolling) {
mCurrentPosition = position;
mIsScrolling = false;
mImageAnimator.end(position);
}
}
@Override
public void onPageScrollStateChanged(int state) {
//NO-OP
}
@Override
public void onPageSelected(int position) {
if (!mIsScrolling) {
mIsScrolling = true;
mFinalPosition = position;
mImageAnimator.start(mCurrentPosition, position);
}
}
}
详细内容参见注释
ViewPager添加滚动监听.
SimpleAdapter adapter = new SimpleAdapter(getSupportFragmentManager());
mVpContainer.setAdapter(adapter);
mVpContainer.addOnPageChangeListener(PagerChangeListener.newInstance(adapter, mIvTarget, mIvOutgoing));
6. 页面滚动
在ViewPager上, 嵌套NestedScrollView.
android:fillViewport允许ScrollView内的组件填充, 否则ViewPager显示.
设置标题, MainActivity.
setTitle("Girls' Generation");
动画效果
AppBar
7. 偏移滚动
额, 与其说是AppBar, 不如说是ViewPager, 再添加一些动画效果, 和修复Bug.
把图片的左右10%, 隐藏起来, 滑动时, 一边渐变一边侧移.
在app_bar_main中, 替换FrameLayout为PercentFrameLayout, 宽度设置为120%.
修改滑动动画(Image), 在向前向后滑动时, setTranslationXX轴平移.
/**
* 渐变的动画效果
*
* Created by wangchenlong on 15/11/9.
*/
public class ImageAnimator {
private static final float FACTOR = 0.1f;
private final SimpleAdapter mAdapter; // 适配器
private final ImageView mTargetImage; // 原始图片
private final ImageView mOutgoingImage; // 渐变图片
private int mActualStart; // 实际起始位置
private int mStart;
private int mEnd;
public ImageAnimator(SimpleAdapter adapter, ImageView targetImage, ImageView outgoingImage) {
mAdapter = adapter;
mTargetImage = targetImage;
mOutgoingImage = outgoingImage;
}
/**
* 启动动画, 之后选择向前或向后滑动
*
* @param startPosition 起始位置
* @param endPosition 终止位置
*/
public void start(int startPosition, int endPosition) {
mActualStart = startPosition;
// 终止位置的图片
@DrawableRes int incomeId = mAdapter.getDrawable(endPosition);
// 原始图片
mOutgoingImage.setImageDrawable(mTargetImage.getDrawable()); // 原始的图片
// 起始图片
mOutgoingImage.setTranslationX(0f);
mOutgoingImage.setVisibility(View.VISIBLE);
mOutgoingImage.setAlpha(1.0f);
// 目标图片
mTargetImage.setImageResource(incomeId);
mStart = Math.min(startPosition, endPosition);
mEnd = Math.max(startPosition, endPosition);
}
/**
* 滑动结束的动画效果
*
* @param endPosition 滑动位置
*/
public void end(int endPosition) {
@DrawableRes int incomeId = mAdapter.getDrawable(endPosition);
mTargetImage.setTranslationX(0f);
// 设置原始图片
if (endPosition == mActualStart) {
mTargetImage.setImageDrawable(mOutgoingImage.getDrawable());
} else {
mTargetImage.setImageResource(incomeId);
mTargetImage.setAlpha(1f);
mOutgoingImage.setVisibility(View.GONE);
}
}
// 向前滚动, 比如0->1, offset滚动的距离(0->1), 目标渐渐淡出
public void forward(float positionOffset) {
Log.e("DEBUG-WCL", "forward-positionOffset: " + positionOffset);
int width = mTargetImage.getWidth();
mOutgoingImage.setTranslationX(-positionOffset * (FACTOR * width));
mTargetImage.setTranslationX((1 - positionOffset) * (FACTOR * width));
mTargetImage.setAlpha(positionOffset);
}
// 向后滚动, 比如1->0, offset滚动的距离(1->0), 目标渐渐淡入
public void backwards(float positionOffset) {
Log.e("DEBUG-WCL", "backwards-positionOffset: " + positionOffset);
int width = mTargetImage.getWidth();
mOutgoingImage.setTranslationX((1 - positionOffset) * (FACTOR * width));
mTargetImage.setTranslationX(-(positionOffset) * (FACTOR * width));
mTargetImage.setAlpha(1 - positionOffset);
}
// 判断停止
public boolean isWithin(int position) {
return position >= mStart && position < mEnd;
}
}
修复滚动Bug, 连续滚动时, 及时更新当前图片, 否则图片异常.
/**
* 终止滑动
* 滑动 && [偏移是0&&滑动终点] || 动画之中 || 未在区间即连续滚动
*
* @param position 位置
* @param positionOffset 偏移量
* @return 终止滑动
*/
public boolean isFinishedScrolling(int position, float positionOffset) {
return mIsScrolling && (positionOffset == 0f && position == mFinalPosition) || !mImageAnimator.isWithin(position);
}
全部功能都已经完成了. AppBar的知识就这些了.
OK, that's all! Enjoy it!