Java tutorial
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We also recommend that a * file or class name and description of purpose be included on the * same "printed page" as the copyright notice for easier * identification within third-party archives. * * Copyright 2016 Alibaba Group * * 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.taobao.weex.ui.view; import android.annotation.SuppressLint; import android.content.Context; import android.support.v4.view.PagerAdapter; import android.support.v4.view.ViewPager; import android.util.AttributeSet; import android.view.MotionEvent; import android.view.View; import android.view.animation.Interpolator; import com.taobao.weex.ui.view.gesture.WXGesture; import com.taobao.weex.ui.view.gesture.WXGestureObservable; import com.taobao.weex.utils.WXLogUtils; import java.lang.ref.WeakReference; import java.lang.reflect.Field; /** */ @SuppressLint("HandlerLeak") public class WXCircleViewPager extends ViewPager implements WXGestureObservable { private WXGesture wxGesture; private boolean isAutoScroll; private long intervalTime = 3 * 1000; private WXSmoothScroller mScroller; private boolean needLoop = true; private boolean scrollable = true; private int mState = ViewPager.SCROLL_STATE_IDLE; private Runnable scrollAction = new ScrollAction(this, intervalTime); @SuppressLint("NewApi") public WXCircleViewPager(Context context) { super(context); init(); } private void init() { setOverScrollMode(View.OVER_SCROLL_NEVER); addOnPageChangeListener(new OnPageChangeListener() { @Override public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) { } @Override public void onPageSelected(int position) { } @Override public void onPageScrollStateChanged(int state) { mState = state; WXCirclePageAdapter adapter = getCirclePageAdapter(); int currentItemInternal = WXCircleViewPager.super.getCurrentItem(); if (needLoop && state == ViewPager.SCROLL_STATE_IDLE && adapter.getCount() > 1) { if (currentItemInternal == adapter.getCount() - 1) { superSetCurrentItem(1, false); } else if (currentItemInternal == 0) { superSetCurrentItem(adapter.getCount() - 2, false); } } } }); postInitViewPager(); } /** * Override the Scroller instance with our own class so we can change the * duration */ private void postInitViewPager() { if (isInEditMode()) { return; } try { Field scroller = ViewPager.class.getDeclaredField("mScroller"); scroller.setAccessible(true); Field interpolator = ViewPager.class.getDeclaredField("sInterpolator"); interpolator.setAccessible(true); mScroller = new WXSmoothScroller(getContext(), (Interpolator) interpolator.get(null)); scroller.set(this, mScroller); } catch (Exception e) { WXLogUtils.e("[CircleViewPager] postInitViewPager: ", e); } } @SuppressLint("NewApi") public WXCircleViewPager(Context context, AttributeSet attrs) { super(context, attrs); init(); } @Override public int getCurrentItem() { return getRealCurrentItem(); } public int superGetCurrentItem() { return super.getCurrentItem(); } @Override public boolean onTouchEvent(MotionEvent ev) { if (!scrollable) { return true; } boolean result = super.onTouchEvent(ev); if (wxGesture != null) { result |= wxGesture.onTouch(this, ev); } return result; } @Override public void scrollTo(int x, int y) { if (scrollable || mState != ViewPager.SCROLL_STATE_DRAGGING) { super.scrollTo(x, y); } } /** * Start auto scroll. Must be called after {@link #setAdapter(PagerAdapter)} */ public void startAutoScroll() { isAutoScroll = true; removeCallbacks(scrollAction); postDelayed(scrollAction, intervalTime); } public void pauseAutoScroll() { removeCallbacks(scrollAction); } /** * Stop auto scroll. */ public void stopAutoScroll() { isAutoScroll = false; removeCallbacks(scrollAction); } public boolean isAutoScroll() { return isAutoScroll; } @Override public void setCurrentItem(int item) { setRealCurrentItem(item); } /** * @return the circlePageAdapter */ public WXCirclePageAdapter getCirclePageAdapter() { return (WXCirclePageAdapter) getAdapter(); } /** * @param circlePageAdapter the circlePageAdapter to set */ public void setCirclePageAdapter(WXCirclePageAdapter circlePageAdapter) { this.setAdapter(circlePageAdapter); } /** * Get auto scroll interval. The time unit is micro second. * The default time interval is 3000 micro second * @return the intervalTime */ public long getIntervalTime() { return intervalTime; } /** * Set auto scroll interval. The time unit is micro second. * The default time interval is 3000 micro second * @param intervalTime the intervalTime to set */ public void setIntervalTime(long intervalTime) { this.intervalTime = intervalTime; } public void setCircle(boolean circle) { needLoop = circle; } @Override public boolean dispatchTouchEvent(MotionEvent ev) { switch (ev.getAction()) { case MotionEvent.ACTION_DOWN: case MotionEvent.ACTION_MOVE: removeCallbacks(scrollAction); break; case MotionEvent.ACTION_UP: case MotionEvent.ACTION_CANCEL: if (isAutoScroll()) { postDelayed(scrollAction, intervalTime); } break; } return super.dispatchTouchEvent(ev); } public void destory() { } @Override public void registerGestureListener(WXGesture wxGesture) { this.wxGesture = wxGesture; } public int getRealCurrentItem() { int i = super.getCurrentItem(); return ((WXCirclePageAdapter) getAdapter()).getRealPosition(i); } private void setRealCurrentItem(int item) { superSetCurrentItem(((WXCirclePageAdapter) getAdapter()).getFirst() + item, false); } private void superSetCurrentItem(int item, boolean smooth) { try { super.setCurrentItem(item, smooth); } catch (IllegalStateException e) { WXLogUtils.e(e.toString()); if (getAdapter() != null) { getAdapter().notifyDataSetChanged(); super.setCurrentItem(item, smooth); } } } public int getRealCount() { return ((WXCirclePageAdapter) getAdapter()).getRealCount(); } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { try { super.onMeasure(widthMeasureSpec, heightMeasureSpec); } catch (IllegalStateException e) { WXLogUtils.e(e.toString()); if (getAdapter() != null) { getAdapter().notifyDataSetChanged(); super.onMeasure(widthMeasureSpec, heightMeasureSpec); } } } public boolean isScrollable() { return scrollable; } public void setScrollable(boolean scrollable) { this.scrollable = scrollable; } @Override protected void onDetachedFromWindow() { super.onDetachedFromWindow(); removeCallbacks(scrollAction); } private static final class ScrollAction implements Runnable { private WeakReference<WXCircleViewPager> targetRef; private long intervalTime; private ScrollAction(WXCircleViewPager target, long intervalTime) { this.targetRef = new WeakReference<>(target); this.intervalTime = intervalTime; } @Override public void run() { WXLogUtils.d("[CircleViewPager] trigger auto play action"); WXCircleViewPager target; if ((target = targetRef.get()) != null) { target.superSetCurrentItem(target.superGetCurrentItem() + 1, true); target.removeCallbacks(this); target.postDelayed(this, intervalTime); } } } }