字符串替换的时候增加检查:替换规则不能为空,替换规则为正则表达式的时候，需要合法

(cherry picked from commit ad01a5518a2f36d4f0573ec59563296b88ad37b8)

app/src/main/java/io/legado/app/data/entities/ReplaceRule.kt

@@ -1,11 +1,14 @@
 package io.legado.app.data.entities
 
 import android.os.Parcelable
+import android.text.TextUtils
 import androidx.room.ColumnInfo
 import androidx.room.Entity
 import androidx.room.Index
 import androidx.room.PrimaryKey
 import kotlinx.android.parcel.Parcelize
+import java.util.regex.Pattern
+import java.util.regex.PatternSyntaxException
 
 @Parcelize
 @Entity(
@@ -37,4 +40,20 @@ data class ReplaceRule(
     override fun hashCode(): Int {
         return id.hashCode()
     }
+
+    fun isValid(): Boolean{
+        if (TextUtils.isEmpty(pattern)){
+            return false;
+        }
+        //判断正则表达式是否正确
+        if (isRegex){
+            try {
+                Pattern.compile(pattern);
+            }
+            catch (ex: PatternSyntaxException){
+                return false;
+            }
+        }
+        return true;
+    }
 }

app/src/main/java/io/legado/app/help/storage/ImportOldData.kt

@@ -136,15 +136,19 @@ object ImportOldData {
         return bookSources.size
     }
 
+
+
     fun importOldReplaceRule(json: String): Int {
         val replaceRules = mutableListOf<ReplaceRule>()
         val items: List<Map<String, Any>> = Restore.jsonPath.parse(json).read("$")
         for (item in items) {
             val jsonItem = Restore.jsonPath.parse(item)
             OldRule.jsonToReplaceRule(jsonItem.jsonString())?.let {
+                if (it.isValid()){
                     replaceRules.add(it)
                 }
             }
+        }
         App.db.replaceRuleDao().insert(*replaceRules.toTypedArray())
         return replaceRules.size
     }

app/src/main/java/io/legado/app/ui/replacerule/edit/ReplaceEditDialog.kt

@@ -16,6 +16,7 @@ import io.legado.app.constant.Theme
 import io.legado.app.data.entities.ReplaceRule
 import io.legado.app.utils.applyTint
 import io.legado.app.utils.getViewModel
+import io.legado.app.utils.toast
 import kotlinx.android.synthetic.main.dialog_replace_edit.*
 
 class ReplaceEditDialog : DialogFragment(),
@@ -73,12 +74,18 @@ class ReplaceEditDialog : DialogFragment(),
     override fun onMenuItemClick(item: MenuItem?): Boolean {
         when (item?.itemId) {
             R.id.menu_save -> {
-                viewModel.save(getReplaceRule()) {
+                val rule = getReplaceRule();
+                if (!rule.isValid()){
+                    toast(R.string.replace_rule_invalid)
+                }
+                else{
+                    viewModel.save(rule) {
                         callBack?.onReplaceRuleSave()
                         dismiss()
                     }
                 }
             }
+        }
         return true
     }
 

app/src/main/res/values/strings.xml

@@ -204,6 +204,7 @@
     <string name="clear_all_content">清除缓存会删除所有已保存章节,是否确认删除?</string>
     <string name="book_source_share_url">书源共享</string>
     <string name="replace_rule_summary">替换规则名称</string>
+    <string name="replace_rule_invalid">替换规则为空或者不满足正则表达式要求</string>
     <string name="select_action">选择操作</string>
     <string name="select_all">全选</string>
     <string name="select_all_count">全选(%d/%d)</string>