feat(activity): 优化图片加载为协程并新增大图左右切换功能

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/src/main/java/com/sw/inbound/activity/LocalImagePreviewActivity.kt

@@ -8,6 +8,7 @@ import android.view.LayoutInflater
 import android.view.ViewGroup
 import android.view.WindowManager
 import androidx.core.graphics.drawable.toDrawable
+import androidx.lifecycle.lifecycleScope
 import com.sw.inbound.base.BaseActivity
 import androidx.recyclerview.widget.GridLayoutManager
 import coil.load
@@ -17,6 +18,10 @@ import com.sw.inbound.databinding.ActivityLocalImagePreviewBinding
 import com.sw.inbound.databinding.DialogImageFullPreviewBinding
 import com.sw.inbound.databinding.ListItemImagePreviewBinding
 import com.sw.inbound.dialog.Loading
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.withContext
 import java.io.File
 
 class LocalImagePreviewActivity : BaseActivity() {
@@ -38,36 +43,41 @@ class LocalImagePreviewActivity : BaseActivity() {
 
     /** 从缓存 crop 目录加载所有图片文件 */
     fun loadData() {
-        Thread {
-            runOnUiThread {
-                Loading.show(this)
-            }
-            val cropFile = File(this.cacheDir, "crop")
-            cropFile.listFiles()?.forEach {
-                // 跳过子目录，只处理文件
-                if (it.isDirectory) return@forEach
-                // 跳过非 jpg 图片
-                if (!it.name.endsWith(".jpg", ignoreCase = true)) return@forEach
-                val nameWithoutExt = it.nameWithoutExtension
-                // 兼容 IMG_CROP_{时间戳} 和其他命名格式
-                val displayName = if (nameWithoutExt.startsWith("IMG_CROP_")) {
-                    nameWithoutExt.removePrefix("IMG_CROP_")
-                } else {
-                    nameWithoutExt
+        lifecycleScope.launch {
+            // 主线程显示加载框
+            Loading.show(this@LocalImagePreviewActivity)
+            // 切换到 IO 线程执行文件读取
+            withContext(Dispatchers.IO) {
+                val cropFile = File(this@LocalImagePreviewActivity.cacheDir, "crop")
+                cropFile.listFiles()?.forEach {
+                    // 跳过子目录，只处理文件
+                    if (it.isDirectory) return@forEach
+                    // 跳过非 jpg 图片
+                    if (!it.name.endsWith(".jpg", ignoreCase = true)) return@forEach
+                    val nameWithoutExt = it.nameWithoutExtension
+                    // 兼容 IMG_CROP_{时间戳} 和其他命名格式
+                    val displayName = if (nameWithoutExt.startsWith("IMG_CROP_")) {
+                        nameWithoutExt.removePrefix("IMG_CROP_")
+                    } else {
+                        nameWithoutExt
+                    }
+                    imageList.add(ImageBean(file = it, name = displayName))
                 }
-                imageList.add(ImageBean(file = it, name = displayName))
+                // 按文件名升序排列
+                imageList.sortBy { it.name }
             }
-            // 按文件名升序排列
-            imageList.sortBy { it.name }
-            runOnUiThread {
-                imageAdapter.notifyDataSetChanged()
-                Loading.dismiss()
-            }
-        }.start()
+            // 回到主线程刷新列表
+            imageAdapter.notifyDataSetChanged()
+            // 延迟 500ms 后关闭加载框
+            delay(500)
+            Loading.dismiss()
+        }
     }
 
-    /** 弹出全屏大图预览 Dialog */
-    private fun showFullImagePreview(item: ImageBean) {
+    /** 弹出全屏大图预览 Dialog，支持左右切换 */
+    private fun showFullImagePreview(startPosition: Int) {
+        var currentIndex = startPosition
+
         val dialogBinding = DialogImageFullPreviewBinding.inflate(layoutInflater)
         val dialog = Dialog(this, android.R.style.Theme_Black_NoTitleBar_Fullscreen)
         dialog.setContentView(dialogBinding.root)
@@ -81,15 +91,37 @@ class LocalImagePreviewActivity : BaseActivity() {
             )
         }
 
-        // 加载大图
-        dialogBinding.ivFullImage.load(item.file)
-        // 显示文件名
-        dialogBinding.tvFileName.text = item.file.name
-        // 点击关闭按钮关闭弹窗
-        dialogBinding.btnClose.setOnClickListener { dialog.dismiss() }
-        // 点击图片本身也关闭弹窗
-        dialogBinding.ivFullImage.setOnClickListener { dialog.dismiss() }
+        /** 根据 currentIndex 刷新图片、文件名、页码及按钮状态 */
+        fun updateContent() {
+            val item = imageList[currentIndex]
+            dialogBinding.ivFullImage.load(item.file)
+            dialogBinding.tvFileName.text = item.file.name
+            dialogBinding.tvPageIndicator.text = "${currentIndex + 1} / ${imageList.size}"
+            // 到达边界时隐藏对应方向的按钮
+            dialogBinding.btnPrev.alpha = if (currentIndex > 0) 1f else 0.2f
+            dialogBinding.btnNext.alpha = if (currentIndex < imageList.size - 1) 1f else 0.2f
+        }
 
+        // 点击图片本身关闭弹窗
+        dialogBinding.ivFullImage.setOnClickListener { dialog.dismiss() }
+        // 关闭按钮
+        dialogBinding.btnClose.setOnClickListener { dialog.dismiss() }
+        // 上一张
+        dialogBinding.btnPrev.setOnClickListener {
+            if (currentIndex > 0) {
+                currentIndex--
+                updateContent()
+            }
+        }
+        // 下一张
+        dialogBinding.btnNext.setOnClickListener {
+            if (currentIndex < imageList.size - 1) {
+                currentIndex++
+                updateContent()
+            }
+        }
+
+        updateContent()
         dialog.show()
     }
 
@@ -97,8 +129,8 @@ class LocalImagePreviewActivity : BaseActivity() {
     private val imageAdapter: ImageAdapter by lazy {
         ImageAdapter(imageList).apply {
             setOnItemClickListener { _, _, position ->
-                // 点击缩略图，弹出大图预览
-                showFullImagePreview(imageList[position])
+                // 点击缩略图，弹出大图预览，传入当前索引以支持左右切换
+                showFullImagePreview(position)
             }
         }
     }

app/src/main/res/layout/dialog_image_full_preview.xml

@@ -12,7 +12,32 @@
         android:layout_marginBottom="120dp"
         android:scaleType="fitCenter" />
 
-    <!-- 底部工具栏：显示文件名 + 关闭按钮 -->
+    <!-- 左侧翻页按钮 -->
+    <ImageView
+        android:id="@+id/btnPrev"
+        android:layout_width="80dp"
+        android:layout_height="80dp"
+        android:layout_gravity="center_vertical|start"
+        android:layout_marginBottom="120dp"
+        android:layout_marginStart="20dp"
+        android:padding="16dp"
+        android:src="@mipmap/ic_back_white2"
+        android:background="#55000000" />
+
+    <!-- 右侧翻页按钮 -->
+    <ImageView
+        android:id="@+id/btnNext"
+        android:layout_width="80dp"
+        android:layout_height="80dp"
+        android:layout_gravity="center_vertical|end"
+        android:layout_marginBottom="120dp"
+        android:layout_marginEnd="20dp"
+        android:padding="16dp"
+        android:src="@mipmap/ic_back_white2"
+        android:rotation="180"
+        android:background="#55000000" />
+
+    <!-- 底部工具栏：文件名 + 页码指示器 + 关闭按钮 -->
     <LinearLayout
         android:layout_width="match_parent"
         android:layout_height="120dp"
@@ -32,6 +57,14 @@
             android:textColor="#FFFFFFFF"
             android:textSize="26sp" />
 
+        <TextView
+            android:id="@+id/tvPageIndicator"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_marginHorizontal="30dp"
+            android:textColor="#CCFFFFFF"
+            android:textSize="26sp" />
+
         <FrameLayout
             android:id="@+id/btnClose"
             android:layout_width="200dp"