[SOLVED] zib4j zipfile throws ZipException for zip file size less than minimum when adding files or folders

zib4j zipfile throws ZipException for zip file size less than minimum when adding files or folders

I try to add a folder to a zip file but I always get a ZipException that the zip file is less than the expected size.

val file = File.createTempFile("export_", ".zip")
val zipfile = ZipFile(file)

val tmpFolder = context.cacheDir.absolutePath + "/test"
File(tmpFolder).mkdir()
File(tmpFolder + "/test1.txt").createNewFile()
File(tmpFolder + "/test2.txt").createNewFile()

zipfile.addFolder(File(tmpFolder))

On the last line the ZipException is raised

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: xxxx, PID: 20023
    java.lang.RuntimeException: java.lang.reflect.InvocationTargetException
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:612)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1130)
     Caused by: java.lang.reflect.InvocationTargetException
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:602)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1130) 
     Caused by: net.lingala.zip4j.exception.ZipException: Zip file size less than minimum expected zip file size. Probably not a zip file or a corrupted zip file
        at net.lingala.zip4j.headers.HeaderReader.readAllHeaders(HeaderReader.java:69)
        at net.lingala.zip4j.ZipFile.readZipInfo(ZipFile.java:1142)
        at net.lingala.zip4j.ZipFile.addFolder(ZipFile.java:378)
        at net.lingala.zip4j.ZipFile.addFolder(ZipFile.java:365)
        at net.lingala.zip4j.ZipFile.addFolder(ZipFile.java:331)
        at android.view.View.performClick(View.java:8160)
        at android.widget.TextView.performClick(TextView.java:16222)
        at com.google.android.material.button.MaterialButton.performClick(MaterialButton.java:1119)
        at android.view.View.performClickInternal(View.java:8137)
        at android.view.View.access$3700(View.java:888)
        at android.view.View$PerformClick.run(View.java:30236)
        at android.os.Handler.handleCallback(Handler.java:938)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:246)

The files and folders all exist, so why is there an exception?

Solution

File.createTempFile("export_", ".zip") creates a file on disk while File("somefile.zip") only points to a file but does not create it. zip4j seems to check if the file exists and if it exists it expects the file to be a valid zip file. That's why using ZipFile(file) fails if file was created with createTempFile().