/*
* Copyright (c) 2018 CoderLengary
*
* 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.example.lengary_l.wanandroid.component.banner;
import android.content.Context;
import android.content.res.TypedArray;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.util.AttributeSet;
import android.util.DisplayMetrics;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.widget.FrameLayout;
import android.widget.ImageView;
import android.widget.LinearLayout;
import com.example.lengary_l.wanandroid.component.banner.ViewPager.CustomBannerViewPager;
import com.example.lengary_l.wanandroid.component.banner.interfaze.ImageLoader;
import com.example.lengary_l.wanandroid.component.banner.interfaze.OnBannerListener;
import com.example.lengary_l.wanandroid.R;
import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.List;
/**
* Created by CoderLengary
*/
public class CustomBanner extends FrameLayout implements ViewPager.OnPageChangeListener {
//指示器
private int indicatorWidth;
private int indicatorHeight;
private int indicatorLeftMargin;
private int indicatorRightMargin;
private int defaultWidth;
private int selectIndicatorRes ;
private int unselectIndicatorRes ;
private List<ImageView> indicatorViews;
private int indicatorGravity ;
//指示器容器
private LinearLayout indicatorContainer;
//ViewPager
private CustomBannerViewPager viewPager;
//滑动时间
private int delayTime ;
private int scrollDuration ;
//自动滑动和手动滑动
private boolean isAutoPlay ;
private boolean isManuallyScrollable ;
//图片加载器
private ImageLoader imageLoader;
//图片
private List<String> imageUrls;
private List<View> imageViews;
private int count;
private int scaleType;
//点击监听器
private OnBannerListener listener;
//滑动监听器
private ViewPager.OnPageChangeListener onPageChangeListener;
private Context context;
private BannerPagerAdapter adapter;
private int currentItem;
private FrameLayout bannerDetailLayout;
private int screenHeight;
private WeakHandler handler = new WeakHandler();
private static final String TAG = "CustomBanner";
public CustomBanner(@NonNull Context context) {
this(context, null);
}
public CustomBanner(@NonNull Context context, @Nullable AttributeSet attrs) {
this(context, attrs, 0);
}
public CustomBanner(@NonNull Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
this.context = context;
imageUrls = new ArrayList<>();
imageViews = new ArrayList<>();
indicatorViews = new ArrayList<>();
DisplayMetrics dm = getResources().getDisplayMetrics();
defaultWidth = dm.widthPixels/80;
screenHeight = dm.heightPixels;
indicatorGravity = Gravity.CENTER;
initViews(context, attrs);
}
//数据和界面初始化
private void initViews(@NonNull Context context, @Nullable AttributeSet attrs) {
initAttr(context, attrs);
View view = LayoutInflater.from(context).inflate(R.layout.banner, this, true);
indicatorContainer = view.findViewById(R.id.circle_indicator_container);
viewPager = view.findViewById(R.id.custom_view_pager);
setViewPagerScrollDuration();
}
private void initAttr(@NonNull Context context, @Nullable AttributeSet attrs) {
TypedArray typedArray = context.obtainStyledAttributes(attrs, R.styleable.CustomBanner);
indicatorWidth = typedArray.getDimensionPixelOffset(R.styleable.CustomBanner_indicatorWidth, defaultWidth);
indicatorHeight = typedArray.getDimensionPixelOffset(R.styleable.CustomBanner_indicatorHeight, defaultWidth);
indicatorLeftMargin = typedArray.getDimensionPixelOffset(R.styleable.CustomBanner_indicatorLeftMargin, BannerConfig.MARGINING_SIZE);
indicatorRightMargin = typedArray.getDimensionPixelOffset(R.styleable.CustomBanner_indicatorRightMargin, BannerConfig.MARGINING_SIZE);
selectIndicatorRes = typedArray.getResourceId(R.styleable.CustomBanner_selectIndicatorRes, R.drawable.gray_radius);
unselectIndicatorRes = typedArray.getResourceId(R.styleable.CustomBanner_unselectIndicatorRes, R.drawable.white_radius);
delayTime = typedArray.getInt(R.styleable.CustomBanner_delayTime, BannerConfig.DELAY_TIME);
scrollDuration = typedArray.getInt(R.styleable.CustomBanner_scrollDuration, BannerConfig.SCROLL_DURATION);
isAutoPlay = typedArray.getBoolean(R.styleable.CustomBanner_isAutoPlay, BannerConfig.IS_AUTO_PLAY);
isManuallyScrollable = typedArray.getBoolean(R.styleable.CustomBanner_isManuallyScrollable, BannerConfig.IS_SCROLL);
scaleType = typedArray.getInteger(R.styleable.CustomBanner_scaleType, 1);
typedArray.recycle();
}
private CustomBanner setIndicatorGravity(int type) {
switch (type) {
case BannerConfig.LEFT:
indicatorGravity = Gravity.LEFT | Gravity.CENTER_VERTICAL;
break;
case BannerConfig.CENTER:
indicatorGravity = Gravity.CENTER;
break;
case BannerConfig.RIGHT:
indicatorGravity = Gravity.RIGHT | Gravity.CENTER_VERTICAL;
break;
default:
indicatorGravity = Gravity.CENTER;
}
return this;
}
//ViewPager滑动的时长是很短的，我们需要通过反射自定义时长
private void setViewPagerScrollDuration() {
try {
Field mField = ViewPager.class.getDeclaredField("mScroller");
//mScroller是私有的变量
mField.setAccessible(true);
BannerScroller scroller = new BannerScroller(viewPager.getContext());
scroller.setDuration(scrollDuration);
//设置当前的viewPager的Scroller是我们定义的scroller
mField.set(viewPager, scroller);
}catch (Exception e) {
e.printStackTrace();
}
}
public CustomBanner setDelayTime(int time) {
delayTime = time;
return this;
}
public CustomBanner setScrollDuration(int time) {
scrollDuration = time;
return this;
}
public CustomBanner isAutoPlay(boolean e) {
isAutoPlay = e;
return this;
}
public CustomBanner setImageLoader(ImageLoader imageLoader) {
this.imageLoader = imageLoader;
return this;
}
public CustomBanner setImages(List<String> imageUrls) {
this.imageUrls = imageUrls;
count = imageUrls.size();
return this;
}
private void displayImages(List<String> imageUrls) {
imageViews.clear();
if (!imageUrls.isEmpty()) {
for (int i = 0; i < count + 2; i++) {
ImageView view;
if (imageLoader != null) {
view = imageLoader.createImageView(context);
}else {
view = new ImageView(context);
}
setScaleType(view);
//由于普通循环会产生闪屏现象，所以用以下方法解决
//多生成两张图片，位置为0的图片是urls的最后一个，位置为最后的图片是urls的第一个
//中间的其它图片就是url里面的所有图片
//所以如果urls有3个【图片地址0，图片地址1，图片地址2】
//那么最终生成的图片有5个【图片地址2, 图片地址0，图片地址1，图片地址2, 图片地址0】
//当右滑动到最后一个图片的时候，currentItem立刻指向第二张图片(虽然位置不同，但是图片是相同的)
//当左滑动到第一张图片的时候，currentItem立刻指向倒数第二张图片(同理)
//这样就巧妙造成了“循环滑动”的假象
String url;
if (i == 0) {
url = imageUrls.get(count - 1);
} else if (i == count + 1){
url = imageUrls.get(0);
} else {
url = imageUrls.get(i - 1);
}
imageLoader.displayImage(context, url, view);
imageViews.add(view);
}
}
}
//特别注意：当urls有三个子项的时候
//当前viewPager的Position: 0 1 2 3 4
//应当返回的Url的Position : 2 0 1 2 0
private int getRealUrlPosition(int fakePosition) {
if (fakePosition == 0) {
return count - 1;
}else if (fakePosition == (count+1)) {
return 0;
}else {
return fakePosition - 1;
}
}
//特别注意：当urls有三个子项的时候
//当前viewPager的Position : 0 1 2 3 4
//应当返回的真正的页面Position : 3 1 2 3 1
private int getRealCurrentPosition(int fakePosition) {
if (fakePosition == 0) {
return count;
}else if (fakePosition == (count + 1)) {
return 1;
}else {
return fakePosition;
}
}
private void setScaleType(ImageView view) {
switch (scaleType) {
case 0:
view.setScaleType(ImageView.ScaleType.CENTER);
break;
case 1:
view.setScaleType(ImageView.ScaleType.CENTER_CROP);
break;
case 2:
view.setScaleType(ImageView.ScaleType.CENTER_INSIDE);
break;
case 3:
view.setScaleType(ImageView.ScaleType.FIT_CENTER);
break;
case 4:
view.setScaleType(ImageView.ScaleType.FIT_END);
break;
case 5:
view.setScaleType(ImageView.ScaleType.FIT_START);
break;
case 6:
view.setScaleType(ImageView.ScaleType.FIT_XY);
break;
case 7:
view.setScaleType(ImageView.ScaleType.MATRIX);
break;
}
}
private void displayIndicator() {
indicatorViews.clear();
indicatorContainer.removeAllViews();
for (int i = 0; i < count; i++) {
ImageView imageView = new ImageView(context);
imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(indicatorWidth, indicatorHeight);
params.leftMargin = indicatorLeftMargin;
params.rightMargin = indicatorRightMargin;
if (i == 0) {
imageView.setImageResource(R.drawable.gray_radius);
}else {
imageView.setImageResource(R.drawable.white_radius);
}
indicatorViews.add(imageView);
indicatorContainer.addView(imageView, params);
}
}
public CustomBanner setOnBannerListener(OnBannerListener listener) {
this.listener = listener;
return this;
}
public CustomBanner setOnPageChangeListener(ViewPager.OnPageChangeListener onPageChangeListener) {
this.onPageChangeListener = onPageChangeListener;
return this;
}
public CustomBanner start() {
displayImages(imageUrls);
displayIndicator();
setIndicatorContainerGravity();
setViewPager();
if (isAutoPlay) {
startAutoPlay();
}
return this;
}
public void startAutoPlay() {
handler.removeCallbacks(task);
handler.postDelayed(task, delayTime);
}
public void stopAutoPlay() {
handler.removeCallbacks(task);
}
private final Runnable task = new Runnable() {
@Override
public void run() {
if (count > 1 && isAutoPlay) {
//手动左滑到0，会停止自动滑动，同时currentItem会被重置为3，手指离开
//开始自动滑动，currentItem+1=4 4%4+1=1 currentItem = 1 currentItem = 4 与 =1显示的图片是一样的。smoothScroll为false，无动画效果
//当是其他情况的时候，smoothScroll为true，动画效果显现出来
currentItem = currentItem % (count + 1) + 1;
if (currentItem == 1) {
viewPager.setCurrentItem(currentItem, false);
handler.post(task);
}else {
viewPager.setCurrentItem(currentItem);
handler.postDelayed(task, delayTime);
}
}
}
};
//处理手动触摸逻辑，手指按下就停止滑动，手指放开就开始滑动
@Override
public boolean dispatchTouchEvent(MotionEvent ev) {
if (isAutoPlay) {
int action = ev.getAction();
if (action == MotionEvent.ACTION_UP || action == MotionEvent.ACTION_CANCEL
|| action == MotionEvent.ACTION_OUTSIDE) {
startAutoPlay();
}else if (action == MotionEvent.ACTION_DOWN) {
stopAutoPlay();
}
}
return super.dispatchTouchEvent(ev);
}
private void setIndicatorContainerGravity() {
indicatorContainer.setGravity(indicatorGravity);
}
private void setViewPager() {
if (adapter == null) {
adapter = new BannerPagerAdapter();
viewPager.addOnPageChangeListener(this);
}
currentItem = 1;
viewPager.setAdapter(adapter);
viewPager.setFocusable(true);
viewPager.setCurrentItem(currentItem);
if (isManuallyScrollable && count > 1) {
viewPager.setScrollable(true);
} else {
viewPager.setScrollable(false);
}
}
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
if (onPageChangeListener != null) {
onPageChangeListener.onPageScrolled(getRealUrlPosition(position), positionOffset, positionOffsetPixels);
}
}
@Override
public void onPageSelected(int position) {
currentItem = position;
if (onPageChangeListener != null) {
onPageChangeListener.onPageSelected(position);
}
int realPosition = getRealUrlPosition(position);
for (int i =0; i < count; i++) {
indicatorViews.get(i).setImageResource(i == realPosition ? R.drawable.gray_radius : R.drawable.white_radius);
}
}
@Override
public void onPageScrollStateChanged(int state) {
if (onPageChangeListener != null) {
onPageChangeListener.onPageScrollStateChanged(state);
}
//当currentItem为0的时候，会被重置为3
//当currentItem为4的时候，会被重置为1
switch (state) {
case ViewPager.SCROLL_STATE_IDLE://无操作
viewPager.setCurrentItem(getRealCurrentPosition(currentItem), false);
break;
case ViewPager.SCROLL_STATE_DRAGGING://开始滑动
viewPager.setCurrentItem(getRealCurrentPosition(currentItem), false);
break;
case ViewPager.SCROLL_STATE_SETTLING://停止滑动
break;
}
}
/*
ViewPager里面对每个页面的管理是key-value形式的，
也就是说每个page都有个对应的id（id是object类型），
需要对page操作的时候都是通过id来完成的
*/
class BannerPagerAdapter extends PagerAdapter {
@Override
public int getCount() {
return imageViews.size();
}
//判断当前page的id是不是object
@Override
public boolean isViewFromObject(@NonNull View view, @NonNull Object object) {
return view == object;
}
//返回每个page的id，这里我们选择直接把view作为id
@NonNull
@Override
public Object instantiateItem(@NonNull ViewGroup container, final int position) {
View view = imageViews.get(position);
container.addView(view);
if (listener != null) {
view.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View view) {
listener.onBannerClick(getRealUrlPosition(position));
}
});
}
return view;
}
//超过limit需要执行删除页面逻辑，我们要移除view，只要把当前页面的ID object传入就好(Object 就是 view)
@Override
public void destroyItem(@NonNull ViewGroup container, int position, @NonNull Object object) {
container.removeView((View) object);
}
}
}
