优化代码

app/src/main/java/io/legado/app/ui/book/read/page/ContentTextView.kt

@@ -159,13 +159,14 @@ class ContentTextView(context: Context, attrs: AttributeSet?) : View(context, at
         lineBottom: Float,
     ) {
         textLine.textChars.forEach { textChar ->
-            val rectF = RectF(textChar.start, lineTop, textChar.end, lineBottom)
-            ImageProvider.getImage(ReadBook.book!!,
-                textPage.chapterIndex,
-                textChar.charData,
-                true)?.let {
-                canvas.drawBitmap(it, null, rectF, null)
+            ReadBook.book?.let { book ->
+                val rectF = RectF(textChar.start, lineTop, textChar.end, lineBottom)
+                ImageProvider.getImage(book, textPage.chapterIndex, textChar.charData, true)
+                    ?.let {
+                        canvas.drawBitmap(it, null, rectF, null)
+                    }
             }
+
         }
     }