fix ImageSpan删除卡顿

app/src/main/java/com/drake/spannable/sample/RichInputActivity.kt

@@ -20,6 +20,7 @@ import android.graphics.Typeface
 import android.os.Bundle
 import android.text.Editable
 import com.drake.engine.utils.dp
+import com.drake.spannable.factory.ImageEditableFactory
 import com.drake.spannable.listener.ModifyTextWatcher
 import com.drake.spannable.replaceSpan
 import com.drake.spannable.sample.base.BaseMenuActivity
@@ -34,23 +35,41 @@ class RichInputActivity : BaseMenuActivity() {
     // 匹配规则, 因为同一个Span对象重复设置仅最后一个有效故每次都得创建新的对象
     private val matchRules = mapOf<Regex, (MatchResult) -> Any?>(
         "@[^@]+?(?=\\s|\$)".toRegex() to { HighlightSpan("#ed6a2c") },
-        "#[^@]+?(?=\\s|\$)".toRegex() to { HighlightSpan("#4a70d2", Typeface.defaultFromStyle(Typeface.BOLD)) },
+        "#[^@]+?(?=\\s|\$)".toRegex() to {
+            HighlightSpan(
+                "#4a70d2",
+                Typeface.defaultFromStyle(Typeface.BOLD)
+            )
+        },
         "蚂蚁".toRegex() to { CenterImageSpan(this, R.drawable.ic_ant).setDrawableSize(50.dp) },
-        "生气|angry".toRegex() to { CenterImageSpan(this, R.drawable.ic_angry).setDrawableSize(50.dp) },
-        "开心|happy".toRegex() to { CenterImageSpan(this, R.drawable.ic_happy).setDrawableSize(50.dp) }
+        "生气|angry".toRegex() to {
+            CenterImageSpan(
+                this,
+                R.drawable.ic_angry
+            ).setDrawableSize(50.dp)
+        },
+        "开心|happy".toRegex() to {
+            CenterImageSpan(
+                this,
+                R.drawable.ic_happy
+            ).setDrawableSize(50.dp)
+        }
     )
 
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         setContentView(binding.root)
 
         // 包含 @用户 #标签 表情包 等自动替换规则
-        binding.etInput.addTextChangedListener(object : ModifyTextWatcher() {
-            override fun onModify(s: Editable) {
-                matchRules.forEach { rule ->
-                    s.replaceSpan(rule.key, replacement = rule.value)
+        with(binding) {
+            etInput.setEditableFactory(ImageEditableFactory.instance)
+            etInput.addTextChangedListener(object : ModifyTextWatcher() {
+                override fun onModify(s: Editable) {
+                    matchRules.forEach { rule ->
+                        s.replaceSpan(rule.key, replacement = rule.value)
+                    }
                 }
-            }
-        })
+            })
+        }
     }
 }

spannable/src/main/java/com/drake/spannable/SpanUtils.kt

@@ -250,7 +250,7 @@ fun CharSequence.replaceSpan(
                     (spanBuilder as SpannableStringBuilder).replace(range.first + offset, range.first + offset + matchLength, adjustReplacement)
                     offset += adjustReplacement.length - matchLength
                 }
-                else -> spanBuilder[range.first, range.last + 1] = spanned
+                else -> spanBuilder.setSpan(spanned,range.first, range.last + 1)
             }
         }
     }

spannable/src/main/java/com/drake/spannable/factory/ImageEditableFactory.kt

@@ -0,0 +1,82 @@
+package com.drake.spannable.factory
+
+import android.annotation.SuppressLint
+import android.text.Editable
+import androidx.annotation.GuardedBy
+import com.drake.spannable.factory.SpannableBuilder.Companion.create
+
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */ /**
+ * EditableFactory used to improve editing operations on an EditText.
+ *
+ *
+ * EditText uses DynamicLayout, which attaches to the Spannable instance that is being edited using
+ * ChangeWatcher. ChangeWatcher implements SpanWatcher and Textwatcher. Currently every delete/add
+ * operation is reported to DynamicLayout, for every span that has changed. For each change,
+ * DynamicLayout performs some expensive computations. i.e. if there is 100 EmojiSpans and the first
+ * span is deleted, DynamicLayout gets 99 calls about the change of position occurred in the
+ * remaining spans. This causes a huge delay in response time.
+ *
+ *
+ * Since "android.text.DynamicLayout$ChangeWatcher" class is not a public class,
+ * ImageEditableFactory checks if the watcher is in the classpath, and if so uses the modified
+ * Spannable which reduces the total number of calls to DynamicLayout for operations that affect
+ * EmojiSpans.
+ *
+ * @see SpannableBuilder
+ */
+class ImageEditableFactory @SuppressLint("PrivateApi") private constructor() :
+    Editable.Factory() {
+    init {
+        try {
+            val className = "android.text.DynamicLayout\$ChangeWatcher"
+            sWatcherClass = Class.forName(className, false, javaClass.classLoader)
+        } catch (t: Throwable) {
+            // ignore
+        }
+    }
+
+    override fun newEditable(source: CharSequence): Editable {
+        return if (sWatcherClass != null) {
+            create(
+                sWatcherClass!!,
+                source
+            )
+        } else super.newEditable(
+            source
+        )
+    }
+
+    companion object {
+        private val INSTANCE_LOCK = Any()
+
+        @GuardedBy("INSTANCE_LOCK")
+        @Volatile
+        private var sInstance: Editable.Factory? = null
+        private var sWatcherClass: Class<*>? = null
+        val instance: Editable.Factory?
+            get() {
+                if (sInstance == null) {
+                    synchronized(INSTANCE_LOCK) {
+                        if (sInstance == null) {
+                            sInstance = ImageEditableFactory()
+                        }
+                    }
+                }
+                return sInstance
+            }
+    }
+}