/**
* Copyright 2015 bingoogolapple
* <p/>
* 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
* <p/>
* http://www.apache.org/licenses/LICENSE-2.0
* <p/>
* 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.lcodecore.tkrefreshlayout.utils;
import android.content.Context;
import android.graphics.Rect;
import android.os.Build;
import android.support.v4.view.ViewCompat;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.StaggeredGridLayoutManager;
import android.util.DisplayMetrics;
import android.view.View;
import android.view.ViewGroup;
import android.view.WindowManager;
import android.webkit.WebView;
import android.widget.AbsListView;
import android.widget.ScrollView;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
public class ScrollingUtil {
private ScrollingUtil() {
}
/**
* 用来判断是否可以下拉
* 手指在屏幕上该方法才有效
*/
public static boolean canChildScrollUp(View mChildView) {
if (mChildView == null) {
return false;
}
if (Build.VERSION.SDK_INT < 14) {
if (mChildView instanceof AbsListView) {
final AbsListView absListView = (AbsListView) mChildView;
return absListView.getChildCount() > 0
&& (absListView.getFirstVisiblePosition() > 0 || absListView.getChildAt(0)
.getTop() < absListView.getPaddingTop());
} else {
return ViewCompat.canScrollVertically(mChildView, -1) || mChildView.getScrollY() > 0;
}
} else {
return ViewCompat.canScrollVertically(mChildView, -1);
}
}
/**
* Whether it is possible for the child view of this layout to scroll down. Override this if the child view is a custom view.
* 判断是否可以上拉
*/
public static boolean canChildScrollDown(View mChildView) {
if (Build.VERSION.SDK_INT < 14) {
if (mChildView instanceof AbsListView) {
final AbsListView absListView = (AbsListView) mChildView;
return absListView.getChildCount() > 0
&& (absListView.getLastVisiblePosition() < absListView.getChildCount() - 1
|| absListView.getChildAt(absListView.getChildCount() - 1).getBottom() > absListView.getPaddingBottom());
} else {
return ViewCompat.canScrollVertically(mChildView, 1) || mChildView.getScrollY() < 0;
}
} else {
return ViewCompat.canScrollVertically(mChildView, 1);
}
}
public static boolean isScrollViewOrWebViewToTop(View view) {
return view != null && view.getScrollY() == 0;
}
public static boolean isViewToTop(View view, int mTouchSlop) {
if (view instanceof AbsListView) return isAbsListViewToTop((AbsListView) view);
if (view instanceof RecyclerView) return isRecyclerViewToTop((RecyclerView) view);
return (view != null && Math.abs(view.getScrollY()) <= 2 * mTouchSlop);
}
public static boolean isViewToBottom(View view, int mTouchSlop) {
if (view instanceof AbsListView) return isAbsListViewToBottom((AbsListView) view);
if (view instanceof RecyclerView) return isRecyclerViewToBottom((RecyclerView) view);
if (view instanceof WebView) return isWebViewToBottom((WebView) view, mTouchSlop);
if (view instanceof ViewGroup) return isViewGroupToBottom((ViewGroup) view);
return false;
}
public static boolean isAbsListViewToTop(AbsListView absListView) {
if (absListView != null) {
int firstChildTop = 0;
if (absListView.getChildCount() > 0) {
// 如果AdapterView的子控件数量不为0，获取第一个子控件的top
firstChildTop = absListView.getChildAt(0).getTop() - absListView.getPaddingTop();
}
if (absListView.getFirstVisiblePosition() == 0 && firstChildTop == 0) {
return true;
}
}
return false;
}
public static boolean isRecyclerViewToTop(RecyclerView recyclerView) {
if (recyclerView != null) {
RecyclerView.LayoutManager manager = recyclerView.getLayoutManager();
if (manager == null) {
return true;
}
if (manager.getItemCount() == 0) {
return true;
}
int firstChildTop = 0;
if (recyclerView.getChildCount() > 0) {
// 处理item高度超过一屏幕时的情况
View firstVisibleChild = recyclerView.getChildAt(0);
if (firstVisibleChild != null && firstVisibleChild.getMeasuredHeight() >= recyclerView.getMeasuredHeight()) {
if (android.os.Build.VERSION.SDK_INT < 14) {
return !(ViewCompat.canScrollVertically(recyclerView, -1) || recyclerView.getScrollY() > 0);
} else {
return !ViewCompat.canScrollVertically(recyclerView, -1);
}
}
// 如果RecyclerView的子控件数量不为0，获取第一个子控件的top
// 解决item的topMargin不为0时不能触发下拉刷新
View firstChild = recyclerView.getChildAt(0);
RecyclerView.LayoutParams layoutParams = (RecyclerView.LayoutParams) firstChild.getLayoutParams();
firstChildTop = firstChild.getTop() - layoutParams.topMargin - getRecyclerViewItemTopInset(layoutParams) - recyclerView.getPaddingTop();
}
if (manager instanceof LinearLayoutManager) {
LinearLayoutManager layoutManager = (LinearLayoutManager) manager;
if (layoutManager.findFirstCompletelyVisibleItemPosition() < 1 && firstChildTop == 0) {
return true;
}
} else if (manager instanceof StaggeredGridLayoutManager) {
StaggeredGridLayoutManager layoutManager = (StaggeredGridLayoutManager) manager;
int[] out = layoutManager.findFirstCompletelyVisibleItemPositions(null);
if (out[0] < 1 && firstChildTop == 0) {
return true;
}
}
}
return false;
}
/**
* 通过反射获取RecyclerView的item的topInset
*
* @param layoutParams
* @return
*/
private static int getRecyclerViewItemTopInset(RecyclerView.LayoutParams layoutParams) {
try {
Field field = RecyclerView.LayoutParams.class.getDeclaredField("mDecorInsets");
field.setAccessible(true);
// 开发者自定义的滚动监听器
Rect decorInsets = (Rect) field.get(layoutParams);
return decorInsets.top;
} catch (Exception e) {
e.printStackTrace();
}
return 0;
}
public static boolean isWebViewToBottom(WebView webview, int mTouchSlop) {
return webview != null && ((webview.getContentHeight() * webview.getScale() - (webview.getHeight() + webview.getScrollY())) <= 2 * mTouchSlop);
}
public static boolean isViewGroupToBottom(ViewGroup viewGroup) {
View subChildView = viewGroup.getChildAt(0);
return (subChildView != null && subChildView.getMeasuredHeight() <= viewGroup.getScrollY() + viewGroup.getHeight());
}
public static boolean isScrollViewToBottom(ScrollView scrollView) {
if (scrollView != null) {
int scrollContentHeight = scrollView.getScrollY() + scrollView.getMeasuredHeight() - scrollView.getPaddingTop() - scrollView.getPaddingBottom();
int realContentHeight = scrollView.getChildAt(0).getMeasuredHeight();
if (scrollContentHeight == realContentHeight) {
return true;
}
}
return false;
}
public static boolean isAbsListViewToBottom(AbsListView absListView) {
if (absListView != null && absListView.getAdapter() != null && absListView.getChildCount() > 0 && absListView.getLastVisiblePosition() == absListView.getAdapter().getCount() - 1) {
View lastChild = absListView.getChildAt(absListView.getChildCount() - 1);
return lastChild.getBottom() <= absListView.getMeasuredHeight();
}
return false;
}
public static boolean isRecyclerViewToBottom(RecyclerView recyclerView) {
if (recyclerView != null) {
RecyclerView.LayoutManager manager = recyclerView.getLayoutManager();
if (manager == null || manager.getItemCount() == 0) {
return false;
}
if (manager instanceof LinearLayoutManager) {
// 处理item高度超过一屏幕时的情况
View lastVisibleChild = recyclerView.getChildAt(recyclerView.getChildCount() - 1);
if (lastVisibleChild != null && lastVisibleChild.getMeasuredHeight() >= recyclerView.getMeasuredHeight()) {
if (android.os.Build.VERSION.SDK_INT < 14) {
return !(ViewCompat.canScrollVertically(recyclerView, 1) || recyclerView.getScrollY() < 0);
} else {
return !ViewCompat.canScrollVertically(recyclerView, 1);
}
}
LinearLayoutManager layoutManager = (LinearLayoutManager) manager;
if (layoutManager.findLastCompletelyVisibleItemPosition() == layoutManager.getItemCount() - 1) {
return true;
}
} else if (manager instanceof StaggeredGridLayoutManager) {
StaggeredGridLayoutManager layoutManager = (StaggeredGridLayoutManager) manager;
int[] out = layoutManager.findLastCompletelyVisibleItemPositions(null);
int lastPosition = layoutManager.getItemCount() - 1;
for (int position : out) {
if (position == lastPosition) {
return true;
}
}
}
}
return false;
}
public static void scrollAViewBy(View view, int height) {
if (view instanceof RecyclerView) ((RecyclerView) view).scrollBy(0, height);
else if (view instanceof ScrollView) ((ScrollView) view).smoothScrollBy(0, height);
else if (view instanceof AbsListView) ((AbsListView) view).smoothScrollBy(height, 0);
else {
try {
Method method = view.getClass().getDeclaredMethod("smoothScrollBy", Integer.class, Integer.class);
method.invoke(view, 0, height);
} catch (Exception e) {
view.scrollBy(0, height);
}
}
}
public static void scrollToBottom(final ScrollView scrollView) {
if (scrollView != null) {
scrollView.post(new Runnable() {
@Override
public void run() {
scrollView.fullScroll(ScrollView.FOCUS_DOWN);
}
});
}
}
public static void scrollToBottom(final AbsListView absListView) {
if (absListView != null) {
if (absListView.getAdapter() != null && absListView.getAdapter().getCount() > 0) {
absListView.post(new Runnable() {
@Override
public void run() {
absListView.setSelection(absListView.getAdapter().getCount() - 1);
}
});
}
}
}
public static void scrollToBottom(final RecyclerView recyclerView) {
if (recyclerView != null) {
if (recyclerView.getAdapter() != null && recyclerView.getAdapter().getItemCount() > 0) {
recyclerView.post(new Runnable() {
@Override
public void run() {
recyclerView.smoothScrollToPosition(recyclerView.getAdapter().getItemCount() - 1);
}
});
}
}
}
public static void scrollToBottom(View view) {
if (view instanceof RecyclerView) scrollToBottom((RecyclerView) view);
if (view instanceof AbsListView) scrollToBottom((AbsListView) view);
if (view instanceof ScrollView) scrollToBottom((ScrollView) view);
}
public static int getScreenHeight(Context context) {
WindowManager windowManager = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
DisplayMetrics dm = new DisplayMetrics();
windowManager.getDefaultDisplay().getMetrics(dm);
return dm.heightPixels;
}
}