优化合并的进度展示。

app/src/main/java/com/all/pdfreader/pro/app/util/PdfUtils.kt

@@ -15,6 +15,7 @@ import kotlinx.coroutines.delay
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.flow
 import kotlinx.coroutines.flow.flowOn
+import kotlinx.coroutines.launch
 import kotlinx.coroutines.withContext
 import java.io.File
 import java.io.FileOutputStream
@@ -173,16 +174,34 @@ object PdfUtils {
 
         try {
             val merger = PDFMergerUtility()
+            val total = 100
+
+            // 加载文件 0~30%
             inputFiles.forEachIndexed { index, file ->
                 merger.addSource(file)
-                onProgress?.invoke(index + 1, inputFiles.size)
-                delay(100)
+                val progress = ((index + 1).toFloat() / inputFiles.size * 30).toInt()
+                onProgress?.invoke(progress, total)
+                delay(50)
             }
 
             merger.destinationFileName = outputFile.absolutePath
 
+            // 伪进度（30%~95%）
+            var fakeProgress = 30
+            val fakeJob = launch {
+                while (fakeProgress < 95) {
+                    fakeProgress += (1..3).random() // 每次前进一点点
+                    if (fakeProgress > 95) fakeProgress = 95
+                    onProgress?.invoke(fakeProgress, total)
+                    delay((100L..300L).random()) // 模拟不均匀的进度
+                }
+            }
+
             merger.mergeDocuments(MemoryUsageSetting.setupTempFileOnly())
 
+            fakeJob.cancel()
+            onProgress?.invoke(100, total)
+
             outputFile
         } catch (e: Exception) {
             e.printStackTrace()