implement own EventDetailsDescriptionPresenter

app/src/main/java/de/nicidienase/chaosflix/EventDetailsDescriptionPresenter.java

@@ -1,7 +1,14 @@
 package de.nicidienase.chaosflix;
 
+import android.graphics.Paint;
 import android.support.v17.leanback.widget.AbstractDetailsDescriptionPresenter;
+import android.support.v17.leanback.widget.Presenter;
 import android.text.TextUtils;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.view.ViewTreeObserver;
+import android.widget.TextView;
 
 import de.nicidienase.chaosflix.entities.Event;
 
@@ -9,12 +16,14 @@ import de.nicidienase.chaosflix.entities.Event;
  * Created by felix on 18.03.17.
  */
 
-public class EventDetailsDescriptionPresenter extends AbstractDetailsDescriptionPresenter {
+public class EventDetailsDescriptionPresenter extends Presenter {
-	@Override
+
 	protected void onBindDescription(ViewHolder vh, Object item) {
 		Event event = (Event) item;
 
+		vh.getTitle().setMaxLines(3);
 		vh.getTitle().setText(event.getTitle());
+		vh.getSubtitle().setMaxLines(3);
 		vh.getSubtitle().setText(event.getSubtitle());
 		StringBuilder sb = new StringBuilder();
 		String speaker = TextUtils.join(", ", event.getPersons());
@@ -28,6 +37,200 @@ public class EventDetailsDescriptionPresenter extends AbstractDetailsDescription
 				.append(event.getUpdatedAt())
 				.append("\nTags: ")
 				.append(event.getTags());
+		vh.getBody().setEllipsize(null);
+		vh.getBody().setMaxLines(30);
 		vh.getBody().setText(sb.toString());
 	}
+
+	public static class ViewHolder extends Presenter.ViewHolder {
+		public TextView mTitle;
+		public TextView mSubtitle;
+		public TextView mBody;
+		public int mTitleMargin;
+		public int mUnderTitleBaselineMargin;
+		public int mUnderSubtitleBaselineMargin;
+		public int mTitleLineSpacing;
+		public int mBodyLineSpacing;
+		public int mBodyMaxLines;
+		public int mBodyMinLines;
+		public Paint.FontMetricsInt mTitleFontMetricsInt;
+		public Paint.FontMetricsInt mSubtitleFontMetricsInt;
+		public Paint.FontMetricsInt mBodyFontMetricsInt;
+		public int mTitleMaxLines;
+		private ViewTreeObserver.OnPreDrawListener mPreDrawListener;
+
+		public ViewHolder(final View view) {
+			super(view);
+			mTitle = (TextView) view.findViewById(android.support.v17.leanback.R.id.lb_details_description_title);
+			mSubtitle = (TextView) view.findViewById(android.support.v17.leanback.R.id.lb_details_description_subtitle);
+			mBody = (TextView) view.findViewById(android.support.v17.leanback.R.id.lb_details_description_body);
+
+			Paint.FontMetricsInt titleFontMetricsInt = getFontMetricsInt(mTitle);
+			final int titleAscent = view.getResources().getDimensionPixelSize(
+					android.support.v17.leanback.R.dimen.lb_details_description_title_baseline);
+			// Ascent is negative
+			mTitleMargin = titleAscent + titleFontMetricsInt.ascent;
+
+			mUnderTitleBaselineMargin = view.getResources().getDimensionPixelSize(
+					android.support.v17.leanback.R.dimen.lb_details_description_under_title_baseline_margin);
+			mUnderSubtitleBaselineMargin = view.getResources().getDimensionPixelSize(
+					android.support.v17.leanback.R.dimen.lb_details_description_under_subtitle_baseline_margin);
+
+			mTitleLineSpacing = view.getResources().getDimensionPixelSize(
+					android.support.v17.leanback.R.dimen.lb_details_description_title_line_spacing);
+			mBodyLineSpacing = view.getResources().getDimensionPixelSize(
+					android.support.v17.leanback.R.dimen.lb_details_description_body_line_spacing);
+
+			mBodyMaxLines = 15;
+			mBodyMinLines = view.getResources().getInteger(
+					android.support.v17.leanback.R.integer.lb_details_description_body_min_lines);
+			mTitleMaxLines = mTitle.getMaxLines();
+
+			mTitleFontMetricsInt = getFontMetricsInt(mTitle);
+			mSubtitleFontMetricsInt = getFontMetricsInt(mSubtitle);
+			mBodyFontMetricsInt = getFontMetricsInt(mBody);
+
+			mTitle.addOnLayoutChangeListener(new View.OnLayoutChangeListener() {
+				@Override
+				public void onLayoutChange(View v, int left, int top, int right, int bottom,
+										   int oldLeft, int oldTop, int oldRight, int oldBottom) {
+					addPreDrawListener();
+				}
+			});
+		}
+
+		void addPreDrawListener() {
+			if (mPreDrawListener != null) {
+				return;
+			}
+			mPreDrawListener = new ViewTreeObserver.OnPreDrawListener() {
+				@Override
+				public boolean onPreDraw() {
+					if (mSubtitle.getVisibility() == View.VISIBLE
+							&& mSubtitle.getTop() > view.getHeight()
+							&& mTitle.getLineCount() > 1) {
+						mTitle.setMaxLines(mTitle.getLineCount() - 1);
+						return false;
+					}
+					final int titleLines = mTitle.getLineCount();
+					final int maxLines = titleLines > 1 ? mBodyMinLines : mBodyMaxLines;
+					if (mBody.getMaxLines() != maxLines) {
+						mBody.setMaxLines(maxLines);
+						return false;
+					} else {
+						removePreDrawListener();
+						return true;
+					}
+				}
+			};
+			view.getViewTreeObserver().addOnPreDrawListener(mPreDrawListener);
+		}
+
+		void removePreDrawListener() {
+			if (mPreDrawListener != null) {
+				view.getViewTreeObserver().removeOnPreDrawListener(mPreDrawListener);
+				mPreDrawListener = null;
+			}
+		}
+
+		public TextView getTitle() {
+			return mTitle;
+		}
+
+		public TextView getSubtitle() {
+			return mSubtitle;
+		}
+
+		public TextView getBody() {
+			return mBody;
+		}
+
+		private Paint.FontMetricsInt getFontMetricsInt(TextView textView) {
+			Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
+			paint.setTextSize(textView.getTextSize());
+			paint.setTypeface(textView.getTypeface());
+			return paint.getFontMetricsInt();
+		}
+	}
+
+	@Override
+	public final AbstractDetailsDescriptionPresenter.ViewHolder onCreateViewHolder(ViewGroup parent) {
+		View v = LayoutInflater.from(parent.getContext())
+				.inflate(android.support.v17.leanback.R.layout.lb_details_description, parent, false);
+		return new AbstractDetailsDescriptionPresenter.ViewHolder(v);
+	}
+
+	@Override
+	public void onBindViewHolder(Presenter.ViewHolder viewHolder, Object item) {
+		ViewHolder vh = (ViewHolder) viewHolder;
+		onBindDescription(vh, item);
+
+		boolean hasTitle = true;
+		if (TextUtils.isEmpty(vh.mTitle.getText())) {
+			vh.mTitle.setVisibility(View.GONE);
+			hasTitle = false;
+		} else {
+			vh.mTitle.setVisibility(View.VISIBLE);
+			vh.mTitle.setLineSpacing(vh.mTitleLineSpacing - vh.mTitle.getLineHeight()
+					+ vh.mTitle.getLineSpacingExtra(), vh.mTitle.getLineSpacingMultiplier());
+			vh.mTitle.setMaxLines(vh.mTitleMaxLines);
+		}
+		setTopMargin(vh.mTitle, vh.mTitleMargin);
+
+		boolean hasSubtitle = true;
+		if (TextUtils.isEmpty(vh.mSubtitle.getText())) {
+			vh.mSubtitle.setVisibility(View.GONE);
+			hasSubtitle = false;
+		} else {
+			vh.mSubtitle.setVisibility(View.VISIBLE);
+			if (hasTitle) {
+				setTopMargin(vh.mSubtitle, vh.mUnderTitleBaselineMargin
+						+ vh.mSubtitleFontMetricsInt.ascent - vh.mTitleFontMetricsInt.descent);
+			} else {
+				setTopMargin(vh.mSubtitle, 0);
+			}
+		}
+
+		if (TextUtils.isEmpty(vh.mBody.getText())) {
+			vh.mBody.setVisibility(View.GONE);
+		} else {
+			vh.mBody.setVisibility(View.VISIBLE);
+			vh.mBody.setLineSpacing(vh.mBodyLineSpacing - vh.mBody.getLineHeight()
+					+ vh.mBody.getLineSpacingExtra(), vh.mBody.getLineSpacingMultiplier());
+
+			if (hasSubtitle) {
+				setTopMargin(vh.mBody, vh.mUnderSubtitleBaselineMargin
+						+ vh.mBodyFontMetricsInt.ascent - vh.mSubtitleFontMetricsInt.descent);
+			} else if (hasTitle) {
+				setTopMargin(vh.mBody, vh.mUnderTitleBaselineMargin
+						+ vh.mBodyFontMetricsInt.ascent - vh.mTitleFontMetricsInt.descent);
+			} else {
+				setTopMargin(vh.mBody, 0);
+			}
+		}
+	}
+
+	@Override
+	public void onUnbindViewHolder(Presenter.ViewHolder viewHolder) {}
+
+	public void onViewAttachedToWindow(EventDetailsDescriptionPresenter.ViewHolder holder) {
+		// In case predraw listener was removed in detach, make sure
+		// we have the proper layout.
+		ViewHolder vh = (EventDetailsDescriptionPresenter.ViewHolder) holder;
+		vh.addPreDrawListener();
+		super.onViewAttachedToWindow(holder);
+	}
+
+	@Override
+	public void onViewDetachedFromWindow(Presenter.ViewHolder holder) {
+		ViewHolder vh = (EventDetailsDescriptionPresenter.ViewHolder) holder;
+		vh.removePreDrawListener();
+		super.onViewDetachedFromWindow(holder);
+	}
+
+	private void setTopMargin(TextView textView, int topMargin) {
+		ViewGroup.MarginLayoutParams lp = (ViewGroup.MarginLayoutParams) textView.getLayoutParams();
+		lp.topMargin = topMargin;
+		textView.setLayoutParams(lp);
+	}
 }