4860e4ee48
Test: make setup-wizard-lib Bug: 76692459 Change-Id: I40171e973d442b1a1815e9e7d7c2cc984cb38bac
105 lines
3.2 KiB
Java
105 lines
3.2 KiB
Java
/*
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* Copyright (C) 2015 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.android.setupwizardlib.view;
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import android.content.Context;
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import android.util.AttributeSet;
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import android.view.View;
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import android.widget.ScrollView;
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import androidx.annotation.VisibleForTesting;
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/**
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* An extension of ScrollView that will invoke a listener callback when the ScrollView needs
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* scrolling, and when the ScrollView is being scrolled to the bottom. This is often used in Setup
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* Wizard as a way to ensure that users see all the content before proceeding.
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*/
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public class BottomScrollView extends ScrollView {
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public interface BottomScrollListener {
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void onScrolledToBottom();
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void onRequiresScroll();
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}
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private BottomScrollListener mListener;
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private int mScrollThreshold;
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private boolean mRequiringScroll = false;
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private final Runnable mCheckScrollRunnable = new Runnable() {
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@Override
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public void run() {
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checkScroll();
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}
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};
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public BottomScrollView(Context context) {
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super(context);
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}
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public BottomScrollView(Context context, AttributeSet attrs) {
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super(context, attrs);
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}
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public BottomScrollView(Context context, AttributeSet attrs, int defStyle) {
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super(context, attrs, defStyle);
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}
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public void setBottomScrollListener(BottomScrollListener l) {
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mListener = l;
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}
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@VisibleForTesting
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public int getScrollThreshold() {
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return mScrollThreshold;
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}
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@Override
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protected void onLayout(boolean changed, int l, int t, int r, int b) {
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super.onLayout(changed, l, t, r, b);
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final View child = getChildAt(0);
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if (child != null) {
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mScrollThreshold = Math.max(0, child.getMeasuredHeight() - b + t - getPaddingBottom());
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}
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if (b - t > 0) {
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// Post check scroll in the next run loop, so that the callback methods will be invoked
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// after the layout pass. This way a new layout pass will be scheduled if view
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// properties are changed in the callbacks.
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post(mCheckScrollRunnable);
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}
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}
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@Override
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protected void onScrollChanged(int l, int t, int oldl, int oldt) {
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super.onScrollChanged(l, t, oldl, oldt);
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if (oldt != t) {
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checkScroll();
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}
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}
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private void checkScroll() {
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if (mListener != null) {
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if (getScrollY() >= mScrollThreshold) {
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mListener.onScrolledToBottom();
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} else if (!mRequiringScroll) {
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mRequiringScroll = true;
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mListener.onRequiresScroll();
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}
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}
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}
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}
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