fix(App): saveImage use writer

src/platforms/app-plus/helpers/save-image.js

 let index = 0
 
-export default function saveImage (base64, dirname, callback) {
+export default function saveImage (dataURL, dirname, callback) {
   const id = `${Date.now()}${index++}`
-  const bitmap = new plus.nativeObj.Bitmap(`bitmap${id}`)
-  bitmap.loadBase64Data(base64, function () {
-    const format = (base64.match(/data:image\/(\S+?);/) || [null, 'png'])[1].replace('jpeg', 'jpg')
-    const tempFilePath = `${dirname}/${id}.${format}`
-    bitmap.save(tempFilePath, {
-      overwrite: true,
-      quality: 100,
-      format
-    }, function () {
-      clear()
-      callback(null, tempFilePath)
-    }, function (error) {
-      clear()
-      callback(error)
-    })
-  }, function (error) {
-    clear()
-    callback(error)
-  })
+  const array = dataURL.split(',')
+  const scheme = array[0]
+  const base64 = array[1]
+  const format = (scheme.match(/data:image\/(\S+?);/) || [null, 'png'])[1].replace('jpeg', 'jpg')
+  const fileName = `${id}.${format}`
+  const tempFilePath = `${dirname}/${fileName}`
 
-  function clear () {
-    bitmap.clear()
-  }
+  const i = dirname.indexOf('/')
+  const basePath = dirname.substring(0, i)
+  const dirPath = dirname.substring(i + 1)
+  plus.io.resolveLocalFileSystemURL(basePath, function (entry) {
+    entry.getDirectory(dirPath, {
+      create: true,
+      exclusive: false
+    }, function (entry) {
+      entry.getFile(fileName, {
+        create: true,
+        exclusive: false
+      }, function (entry) {
+        entry.createWriter(function (writer) {
+          writer.onwrite = function () {
+            callback(null, tempFilePath)
+          }
+          writer.onerror = callback
+          writer.seek(0)
+          writer.writeAsBinary(base64)
+        }, callback)
+      }, callback)
+    }, callback)
+  }, callback)
 }