Fix inline code and code blocks formatting messages.

Author: Sam1301

app/src/main/java/com/zulip/android/activities/RecyclerMessageAdapter.java

@@ -8,7 +8,6 @@
 import android.graphics.Bitmap;
 import android.graphics.Color;
 import android.graphics.drawable.GradientDrawable;
-import android.net.Uri;
 import android.support.annotation.ColorInt;
 import android.support.v4.content.ContextCompat;
 import android.support.v4.view.ViewCompat;
@@ -34,6 +33,7 @@
 import com.zulip.android.models.MessageType;
 import com.zulip.android.models.Person;
 import com.zulip.android.models.Stream;
+import com.zulip.android.util.ConvertDpPx;
 import com.zulip.android.util.MutedTopics;
 import com.zulip.android.util.OnItemClickListener;
 import com.zulip.android.util.UrlHelper;
@@ -380,6 +380,9 @@ public void onBindViewHolder(final RecyclerView.ViewHolder holder, final int pos
                 messageHolder.contentView.setText(message.getFormattedContent(zulipApp));
                 messageHolder.contentView.setMovementMethod(LinkMovementMethod.getInstance());
 
+                int padding = ConvertDpPx.convertDpToPixel(4);
+                messageHolder.contentView.setShadowLayer(padding, 0, 0, 0);
+
                 final String url = message.extractImageUrl(zulipApp);
                 if (url != null) {
                     messageHolder.contentImageContainer.setVisibility(View.VISIBLE);

app/src/main/java/com/zulip/android/util/ConvertDpPx.java

@@ -0,0 +1,35 @@
+package com.zulip.android.util;
+
+import android.content.res.Resources;
+import android.util.DisplayMetrics;
+
+/**
+ * This class is used during conversions between dp and px.
+ */
+
+public class ConvertDpPx {
+
+    /**
+     * This method converts dp unit to equivalent pixels, depending on device density.
+     *
+     * @param dp A value in dp (density independent pixels) unit. Which we need to convert into pixels
+     * @return A float value to represent px equivalent to dp depending on device density
+     */
+    public static int convertDpToPixel(float dp){
+        DisplayMetrics metrics = Resources.getSystem().getDisplayMetrics();
+        float px = dp * ((float)metrics.densityDpi / DisplayMetrics.DENSITY_DEFAULT);
+        return Math.round(px);
+    }
+
+    /**
+     * This method converts device specific pixels to density independent pixels.
+     *
+     * @param px A value in px (pixels) unit. Which we need to convert into db
+     * @return A float value to represent dp equivalent to px value
+     */
+    public static float convertPixelsToDp(float px){
+        DisplayMetrics metrics = Resources.getSystem().getDisplayMetrics();
+        float dp = px / ((float)metrics.densityDpi / DisplayMetrics.DENSITY_DEFAULT);
+        return dp;
+    }
+}

app/src/main/java/com/zulip/android/util/CustomHtmlToSpannedConverter.java

@@ -21,6 +21,7 @@
 import android.content.res.Resources;
 import android.graphics.Canvas;
 import android.graphics.Paint;
+import android.graphics.Rect;
 import android.graphics.Typeface;
 import android.graphics.drawable.Drawable;
 import android.support.annotation.NonNull;
@@ -31,8 +32,10 @@
 import android.text.SpannableStringBuilder;
 import android.text.Spanned;
 import android.text.TextUtils;
+import android.text.style.BackgroundColorSpan;
 import android.text.style.ForegroundColorSpan;
 import android.text.style.ImageSpan;
+import android.text.style.LineBackgroundSpan;
 import android.text.style.ParagraphStyle;
 import android.text.style.QuoteSpan;
 import android.text.style.RelativeSizeSpan;
@@ -45,6 +48,7 @@
 import android.text.style.URLSpan;
 import android.text.style.UnderlineSpan;
 import android.text.util.Linkify;
+import android.util.DisplayMetrics;
 import android.util.Pair;
 
 import com.zulip.android.R;
@@ -66,8 +70,6 @@
 import java.util.List;
 import java.util.Locale;
 
-import static android.R.attr.id;
-
 public class CustomHtmlToSpannedConverter implements ContentHandler {
 
     private static final float[] HEADER_SIZES = {1.5f, 1.4f, 1.3f, 1.2f, 1.1f,
@@ -84,6 +86,7 @@ public class CustomHtmlToSpannedConverter implements ContentHandler {
     private Html.TagHandler mTagHandler;
     private Html.ImageGetter mEmojiGetter;
     private String mBaseUri;
+    private boolean isCode;
 
     public CustomHtmlToSpannedConverter(String source,
                                         Html.ImageGetter imageGetter, Html.TagHandler tagHandler,
@@ -523,8 +526,10 @@ private void handleStartTag(String tag, Attributes attributes) {
         } else if (tag.equalsIgnoreCase("sub")) {
             start(mSpannableStringBuilder, new Sub());
         } else if (tag.equalsIgnoreCase("code")) {
+            isCode = true;
             start(mSpannableStringBuilder, new InlineCode());
         } else if (tag.equalsIgnoreCase("pre")) {
+            isCode = true;
             start(mSpannableStringBuilder, new CodeBlock());
         } else if (tag.equalsIgnoreCase("del")) {
             start(mSpannableStringBuilder, new StrikeThrough());
@@ -601,11 +606,17 @@ private void handleEndTag(String tag) {
         } else if (tag.equalsIgnoreCase("code")) {
             endMultiple(mSpannableStringBuilder, InlineCode.class,
                     new Object[]{new TypefaceSpan(MONOSPACE),
-                            new ForegroundColorSpan(0xffdd1144) // pink
+                            new ForegroundColorSpan(0xffdd1144),
+                            new BackgroundColorSpan(0xfff7f7f9)
                     });
+            isCode = false;
         } else if (tag.equalsIgnoreCase("pre")) {
-            end(mSpannableStringBuilder, CodeBlock.class, new TypefaceSpan(
-                    MONOSPACE));
+            endMultiple(mSpannableStringBuilder, CodeBlock.class, new Object[]{
+                    new TypefaceSpan(MONOSPACE),
+                    new ForegroundColorSpan(0xff000000),
+                    new CodeBlockLine(0xfff5f5f5)
+            });
+            isCode = false;
         } else if (tag.equalsIgnoreCase("del")) {
             end(mSpannableStringBuilder, StrikeThrough.class, new StrikethroughSpan());
         } else if (tag.equalsIgnoreCase("s")) {
@@ -676,8 +687,14 @@ public void characters(char ch[], int start, int length)
                     pred = sb.charAt(len - 1);
                 }
 
-                if (pred != ' ' && pred != '\n') {
-                    sb.append(' ');
+                if (!isCode) {
+                    if (pred != ' ' && pred != '\n') {
+                        sb.append(' ');
+                    }
+                } else {
+                    if ((pred != ' ' && c == ' ') || (pred != '\n' && c == '\n')) {
+                        sb.append(c);
+                    }
                 }
             } else {
                 sb.append(c);
@@ -760,6 +777,26 @@ public Header(int level) {
         }
     }
 
+    private static class CodeBlockLine implements LineBackgroundSpan {
+        private int fillColor;
+
+        public CodeBlockLine(int fillColor) {
+            this.fillColor = fillColor;
+        }
+
+        @Override
+        public void drawBackground(Canvas c, Paint p, int left, int right, int top, int baseline,
+                                   int bottom, CharSequence text, int start, int end, int lnum) {
+            int paddingInPx = ConvertDpPx.convertDpToPixel(12);
+            Rect rect = new Rect(left - paddingInPx, top - paddingInPx,
+                    right + paddingInPx, bottom + paddingInPx);
+            final int paintColor = p.getColor();
+            p.setColor(this.fillColor);
+            c.drawRect(rect, p);
+            p.setColor(paintColor);
+        }
+    }
+
     private class CustomQuoteSpan extends QuoteSpan {
         private static final int STRIPE_WIDTH = 10;
         private static final int GAP_WIDTH = 20;