diff options
Diffstat (limited to 'library/main/src/com/android/setupwizardlib/template/RequireScrollMixin.java')
| -rw-r--r-- | library/main/src/com/android/setupwizardlib/template/RequireScrollMixin.java | 418 |
1 files changed, 198 insertions, 220 deletions
diff --git a/library/main/src/com/android/setupwizardlib/template/RequireScrollMixin.java b/library/main/src/com/android/setupwizardlib/template/RequireScrollMixin.java index fd3303b..02bcc1c 100644 --- a/library/main/src/com/android/setupwizardlib/template/RequireScrollMixin.java +++ b/library/main/src/com/android/setupwizardlib/template/RequireScrollMixin.java @@ -18,244 +18,222 @@ package com.android.setupwizardlib.template; import android.os.Handler; import android.os.Looper; -import android.view.View; -import android.view.View.OnClickListener; -import android.widget.Button; - import androidx.annotation.NonNull; import androidx.annotation.Nullable; import androidx.annotation.StringRes; - +import android.view.View; +import android.view.View.OnClickListener; +import android.widget.Button; import com.android.setupwizardlib.TemplateLayout; import com.android.setupwizardlib.view.NavigationBar; /** - * A mixin to require the a scrollable container (BottomScrollView, RecyclerView or ListView) to - * be scrolled to bottom, making sure that the user sees all content above and below the fold. + * A mixin to require the a scrollable container (BottomScrollView, RecyclerView or ListView) to be + * scrolled to bottom, making sure that the user sees all content above and below the fold. */ public class RequireScrollMixin implements Mixin { - /* static section */ - - /** - * Listener for when the require-scroll state changes. Note that this only requires the user to - * scroll to the bottom once - if the user scrolled to the bottom and back-up, scrolling to - * bottom is not required again. - */ - public interface OnRequireScrollStateChangedListener { + /* static section */ - /** - * Called when require-scroll state changed. - * - * @param scrollNeeded True if the user should be required to scroll to bottom. - */ - void onRequireScrollStateChanged(boolean scrollNeeded); - } + /** + * Listener for when the require-scroll state changes. Note that this only requires the user to + * scroll to the bottom once - if the user scrolled to the bottom and back-up, scrolling to bottom + * is not required again. + */ + public interface OnRequireScrollStateChangedListener { /** - * A delegate to detect scrollability changes and to scroll the page. This provides a layer - * of abstraction for BottomScrollView, RecyclerView and ListView. The delegate should call - * {@link #notifyScrollabilityChange(boolean)} when the view scrollability is changed. - */ - interface ScrollHandlingDelegate { - - /** - * Starts listening to scrollability changes at the target scrollable container. - */ - void startListening(); - - /** - * Scroll the page content down by one page. - */ - void pageScrollDown(); - } - - /* non-static section */ - - @NonNull - private final TemplateLayout mTemplateLayout; - - private final Handler mHandler = new Handler(Looper.getMainLooper()); - - private boolean mRequiringScrollToBottom = false; - - // Whether the user have seen the more button yet. - private boolean mEverScrolledToBottom = false; - - private ScrollHandlingDelegate mDelegate; - - @Nullable - private OnRequireScrollStateChangedListener mListener; - - /** - * @param templateLayout The template containing this mixin - */ - public RequireScrollMixin(@NonNull TemplateLayout templateLayout) { - mTemplateLayout = templateLayout; - } - - /** - * Sets the delegate to handle scrolling. The type of delegate should depend on whether the - * scrolling view is a BottomScrollView, RecyclerView or ListView. - */ - public void setScrollHandlingDelegate(@NonNull ScrollHandlingDelegate delegate) { - mDelegate = delegate; - } - - /** - * Listen to require scroll state changes. When scroll is required, - * {@link OnRequireScrollStateChangedListener#onRequireScrollStateChanged(boolean)} is called - * with {@code true}, and vice versa. - */ - public void setOnRequireScrollStateChangedListener( - @Nullable OnRequireScrollStateChangedListener listener) { - mListener = listener; - } - - /** - * @return The scroll state listener previously set, or {@code null} if none is registered. - */ - public OnRequireScrollStateChangedListener getOnRequireScrollStateChangedListener() { - return mListener; - } - - /** - * Creates an {@link OnClickListener} which if scrolling is required, will scroll the page down, - * and if scrolling is not required, delegates to the wrapped {@code listener}. Note that you - * should call {@link #requireScroll()} as well in order to start requiring scrolling. + * Called when require-scroll state changed. * - * @param listener The listener to be invoked when scrolling is not needed and the user taps on - * the button. If {@code null}, the click listener will be a no-op when scroll - * is not required. - * @return A new {@link OnClickListener} which will scroll the page down or delegate to the - * given listener depending on the current require-scroll state. - */ - public OnClickListener createOnClickListener(@Nullable final OnClickListener listener) { - return new OnClickListener() { - @Override - public void onClick(View view) { - if (mRequiringScrollToBottom) { - mDelegate.pageScrollDown(); - } else if (listener != null) { - listener.onClick(view); - } - } - }; - } - - /** - * Coordinate with the given navigation bar to require scrolling on the page. The more button - * will be shown instead of the next button while scrolling is required. + * @param scrollNeeded True if the user should be required to scroll to bottom. */ - public void requireScrollWithNavigationBar(@NonNull final NavigationBar navigationBar) { - setOnRequireScrollStateChangedListener( - new OnRequireScrollStateChangedListener() { - @Override - public void onRequireScrollStateChanged(boolean scrollNeeded) { - navigationBar.getMoreButton() - .setVisibility(scrollNeeded ? View.VISIBLE : View.GONE); - navigationBar.getNextButton() - .setVisibility(scrollNeeded ? View.GONE : View.VISIBLE); - } - }); - navigationBar.getMoreButton().setOnClickListener(createOnClickListener(null)); - requireScroll(); - } - - /** - * @see #requireScrollWithButton(Button, CharSequence, OnClickListener) - */ - public void requireScrollWithButton( - @NonNull Button button, - @StringRes int moreText, - @Nullable OnClickListener onClickListener) { - requireScrollWithButton(button, button.getContext().getText(moreText), onClickListener); - } - - /** - * Use the given {@code button} to require scrolling. When scrolling is required, the button - * label will change to {@code moreText}, and tapping the button will cause the page to scroll - * down. - * - * <p>Note: Calling {@link View#setOnClickListener} on the button after this method will remove - * its link to the require-scroll mechanism. If you need to do that, obtain the click listener - * from {@link #createOnClickListener(OnClickListener)}. - * - * <p>Note: The normal button label is taken from the button's text at the time of calling this - * method. Calling {@link android.widget.TextView#setText} after calling this method causes - * undefined behavior. - * - * @param button The button to use for require scroll. The button's "normal" label is taken from - * the text at the time of calling this method, and the click listener of it will - * be replaced. - * @param moreText The button label when scroll is required. - * @param onClickListener The listener for clicks when scrolling is not required. - */ - public void requireScrollWithButton( - @NonNull final Button button, - final CharSequence moreText, - @Nullable OnClickListener onClickListener) { - final CharSequence nextText = button.getText(); - button.setOnClickListener(createOnClickListener(onClickListener)); - setOnRequireScrollStateChangedListener(new OnRequireScrollStateChangedListener() { - @Override - public void onRequireScrollStateChanged(boolean scrollNeeded) { - button.setText(scrollNeeded ? moreText : nextText); - } + void onRequireScrollStateChanged(boolean scrollNeeded); + } + + /** + * A delegate to detect scrollability changes and to scroll the page. This provides a layer of + * abstraction for BottomScrollView, RecyclerView and ListView. The delegate should call {@link + * #notifyScrollabilityChange(boolean)} when the view scrollability is changed. + */ + interface ScrollHandlingDelegate { + + /** Starts listening to scrollability changes at the target scrollable container. */ + void startListening(); + + /** Scroll the page content down by one page. */ + void pageScrollDown(); + } + + /* non-static section */ + + private final Handler handler = new Handler(Looper.getMainLooper()); + + private boolean requiringScrollToBottom = false; + + // Whether the user have seen the more button yet. + private boolean everScrolledToBottom = false; + + private ScrollHandlingDelegate delegate; + + @Nullable private OnRequireScrollStateChangedListener listener; + + /** @param templateLayout The template containing this mixin */ + public RequireScrollMixin(@NonNull TemplateLayout templateLayout) { + } + + /** + * Sets the delegate to handle scrolling. The type of delegate should depend on whether the + * scrolling view is a BottomScrollView, RecyclerView or ListView. + */ + public void setScrollHandlingDelegate(@NonNull ScrollHandlingDelegate delegate) { + this.delegate = delegate; + } + + /** + * Listen to require scroll state changes. When scroll is required, {@link + * OnRequireScrollStateChangedListener#onRequireScrollStateChanged(boolean)} is called with {@code + * true}, and vice versa. + */ + public void setOnRequireScrollStateChangedListener( + @Nullable OnRequireScrollStateChangedListener listener) { + this.listener = listener; + } + + /** @return The scroll state listener previously set, or {@code null} if none is registered. */ + public OnRequireScrollStateChangedListener getOnRequireScrollStateChangedListener() { + return listener; + } + + /** + * Creates an {@link OnClickListener} which if scrolling is required, will scroll the page down, + * and if scrolling is not required, delegates to the wrapped {@code listener}. Note that you + * should call {@link #requireScroll()} as well in order to start requiring scrolling. + * + * @param listener The listener to be invoked when scrolling is not needed and the user taps on + * the button. If {@code null}, the click listener will be a no-op when scroll is not + * required. + * @return A new {@link OnClickListener} which will scroll the page down or delegate to the given + * listener depending on the current require-scroll state. + */ + public OnClickListener createOnClickListener(@Nullable final OnClickListener listener) { + return new OnClickListener() { + @Override + public void onClick(View view) { + if (requiringScrollToBottom) { + delegate.pageScrollDown(); + } else if (listener != null) { + listener.onClick(view); + } + } + }; + } + + /** + * Coordinate with the given navigation bar to require scrolling on the page. The more button will + * be shown instead of the next button while scrolling is required. + */ + public void requireScrollWithNavigationBar(@NonNull final NavigationBar navigationBar) { + setOnRequireScrollStateChangedListener( + new OnRequireScrollStateChangedListener() { + @Override + public void onRequireScrollStateChanged(boolean scrollNeeded) { + navigationBar.getMoreButton().setVisibility(scrollNeeded ? View.VISIBLE : View.GONE); + navigationBar.getNextButton().setVisibility(scrollNeeded ? View.GONE : View.VISIBLE); + } }); - requireScroll(); - } - - /** - * @return True if scrolling is required. Note that this mixin only requires the user to - * scroll to the bottom once - if the user scrolled to the bottom and back-up, scrolling to - * bottom is not required again. - */ - public boolean isScrollingRequired() { - return mRequiringScrollToBottom; + navigationBar.getMoreButton().setOnClickListener(createOnClickListener(null)); + requireScroll(); + } + + /** @see #requireScrollWithButton(Button, CharSequence, OnClickListener) */ + public void requireScrollWithButton( + @NonNull Button button, @StringRes int moreText, @Nullable OnClickListener onClickListener) { + requireScrollWithButton(button, button.getContext().getText(moreText), onClickListener); + } + + /** + * Use the given {@code button} to require scrolling. When scrolling is required, the button label + * will change to {@code moreText}, and tapping the button will cause the page to scroll down. + * + * <p>Note: Calling {@link View#setOnClickListener} on the button after this method will remove + * its link to the require-scroll mechanism. If you need to do that, obtain the click listener + * from {@link #createOnClickListener(OnClickListener)}. + * + * <p>Note: The normal button label is taken from the button's text at the time of calling this + * method. Calling {@link android.widget.TextView#setText} after calling this method causes + * undefined behavior. + * + * @param button The button to use for require scroll. The button's "normal" label is taken from + * the text at the time of calling this method, and the click listener of it will be replaced. + * @param moreText The button label when scroll is required. + * @param onClickListener The listener for clicks when scrolling is not required. + */ + public void requireScrollWithButton( + @NonNull final Button button, + final CharSequence moreText, + @Nullable OnClickListener onClickListener) { + final CharSequence nextText = button.getText(); + button.setOnClickListener(createOnClickListener(onClickListener)); + setOnRequireScrollStateChangedListener( + new OnRequireScrollStateChangedListener() { + @Override + public void onRequireScrollStateChanged(boolean scrollNeeded) { + button.setText(scrollNeeded ? moreText : nextText); + } + }); + requireScroll(); + } + + /** + * @return True if scrolling is required. Note that this mixin only requires the user to scroll to + * the bottom once - if the user scrolled to the bottom and back-up, scrolling to bottom is + * not required again. + */ + public boolean isScrollingRequired() { + return requiringScrollToBottom; + } + + /** + * Start requiring scrolling on the layout. After calling this method, this mixin will start + * listening to scroll events from the scrolling container, and call {@link + * OnRequireScrollStateChangedListener} when the scroll state changes. + */ + public void requireScroll() { + delegate.startListening(); + } + + /** + * {@link ScrollHandlingDelegate} should call this method when the scrollability of the scrolling + * container changed, so this mixin can recompute whether scrolling should be required. + * + * @param canScrollDown True if the view can scroll down further. + */ + void notifyScrollabilityChange(boolean canScrollDown) { + if (canScrollDown == requiringScrollToBottom) { + // Already at the desired require-scroll state + return; } - - /** - * Start requiring scrolling on the layout. After calling this method, this mixin will start - * listening to scroll events from the scrolling container, and call - * {@link OnRequireScrollStateChangedListener} when the scroll state changes. - */ - public void requireScroll() { - mDelegate.startListening(); + if (canScrollDown) { + if (!everScrolledToBottom) { + postScrollStateChange(true); + requiringScrollToBottom = true; + } + } else { + postScrollStateChange(false); + requiringScrollToBottom = false; + everScrolledToBottom = true; } - - /** - * {@link ScrollHandlingDelegate} should call this method when the scrollability of the - * scrolling container changed, so this mixin can recompute whether scrolling should be - * required. - * - * @param canScrollDown True if the view can scroll down further. - */ - void notifyScrollabilityChange(boolean canScrollDown) { - if (canScrollDown == mRequiringScrollToBottom) { - // Already at the desired require-scroll state - return; - } - if (canScrollDown) { - if (!mEverScrolledToBottom) { - postScrollStateChange(true); - mRequiringScrollToBottom = true; - } - } else { - postScrollStateChange(false); - mRequiringScrollToBottom = false; - mEverScrolledToBottom = true; - } - } - - private void postScrollStateChange(final boolean scrollNeeded) { - mHandler.post(new Runnable() { - @Override - public void run() { - if (mListener != null) { - mListener.onRequireScrollStateChanged(scrollNeeded); - } + } + + private void postScrollStateChange(final boolean scrollNeeded) { + handler.post( + new Runnable() { + @Override + public void run() { + if (listener != null) { + listener.onRequireScrollStateChanged(scrollNeeded); } + } }); - } + } } |