Don't crash if links on descriptions cannot be handled

Basically the same safety net for ActivityNotFoundException that we had for
links in the menus, but for links in the descriptions too now.

CHANGELOG.md

@@ -16,6 +16,8 @@
 
 * Normalize and check URLs of repos being added
 
+* Don't crash if links on descriptions cannot be handled by any application
+
 * Support building as part of a ROM via an Android.mk using gradle
 
 ### 0.88 (2015-04-28)

F-Droid/src/org/fdroid/fdroid/AppDetails.java

@@ -23,6 +23,7 @@ import android.app.Activity;
 import android.app.AlertDialog;
 import android.app.ProgressDialog;
 import android.bluetooth.BluetoothAdapter;
+import android.content.ActivityNotFoundException;
 import android.content.ContentValues;
 import android.content.Context;
 import android.content.DialogInterface;
@@ -41,13 +42,18 @@ import android.support.v4.app.NavUtils;
 import android.support.v4.view.MenuItemCompat;
 import android.support.v7.app.ActionBarActivity;
 import android.text.Html;
+import android.text.Layout;
+import android.text.Selection;
+import android.text.Spannable;
 import android.text.Spanned;
 import android.text.format.DateFormat;
 import android.text.method.LinkMovementMethod;
+import android.text.style.ClickableSpan;
 import android.util.Log;
 import android.view.LayoutInflater;
 import android.view.Menu;
 import android.view.MenuItem;
+import android.view.MotionEvent;
 import android.view.SubMenu;
 import android.view.View;
 import android.view.ViewGroup;
@@ -717,7 +723,7 @@ public class AppDetails extends ActionBarActivity implements ProgressListener, A
     }
 
 
-    public void tryOpenUri(String s) {
+    private void tryOpenUri(String s) {
         Intent intent = new Intent(Intent.ACTION_VIEW, Uri.parse(s));
         if (intent.resolveActivity(getPackageManager()) == null) {
             Toast.makeText(this,
@@ -728,6 +734,62 @@ public class AppDetails extends ActionBarActivity implements ProgressListener, A
         startActivity(intent);
     }
 
+    private static class SafeLinkMovementMethod extends LinkMovementMethod {
+
+        private static SafeLinkMovementMethod instance;
+
+        private final Context ctx;
+
+        private SafeLinkMovementMethod(Context ctx) {
+            this.ctx = ctx;
+        }
+
+        public static SafeLinkMovementMethod getInstance(Context ctx) {
+            if (instance == null) {
+                instance = new SafeLinkMovementMethod(ctx);
+            }
+            return instance;
+        }
+
+        private static CharSequence getLink(TextView widget, Spannable buffer,
+                MotionEvent event) {
+            int x = (int) event.getX();
+            int y = (int) event.getY();
+            x -= widget.getTotalPaddingLeft();
+            y -= widget.getTotalPaddingTop();
+            x += widget.getScrollX();
+            y += widget.getScrollY();
+
+            Layout layout = widget.getLayout();
+            final int line = layout.getLineForVertical(y);
+            final int off = layout.getOffsetForHorizontal(line, x);
+            final ClickableSpan[] links = buffer.getSpans(off, off, ClickableSpan.class);
+
+            if (links.length > 0) {
+                final ClickableSpan link = links[0];
+                final Spanned s = (Spanned) widget.getText();
+                return s.subSequence(s.getSpanStart(link), s.getSpanEnd(link));
+            }
+            return "null";
+        }
+
+        @Override
+        public boolean onTouchEvent(TextView widget, Spannable buffer,
+                MotionEvent event) {
+            try {
+                return super.onTouchEvent(widget, buffer, event);
+            } catch (ActivityNotFoundException ex) {
+                Selection.removeSelection(buffer);
+                final CharSequence link = getLink(widget, buffer, event);
+                Toast.makeText(ctx,
+                        ctx.getString(R.string.no_handler_app, link),
+                        Toast.LENGTH_LONG).show();
+                return true;
+            }
+        }
+
+    }
+
     protected void navigateUp() {
         NavUtils.navigateUpFromSameTask(this);
     }
@@ -1142,7 +1204,7 @@ public class AppDetails extends ActionBarActivity implements ProgressListener, A
 
             TextView description = (TextView) view.findViewById(R.id.description);
             Spanned desc = Html.fromHtml(getApp().description, null, new Utils.HtmlTagHandler());
-            description.setMovementMethod(LinkMovementMethod.getInstance());
+            description.setMovementMethod(SafeLinkMovementMethod.getInstance(getActivity()));
             description.setText(desc.subSequence(0, desc.length() - 2));
 
             TextView appIdView = (TextView) view.findViewById(R.id.appid);