Android JavaMail，无法使用 IMAP 获取 email

Question

I am trying to write email app on Android. I have found this question and tried to use check method on my application, but I always get

W/System: ClassLoader referenced unknown path: /data/app/com.example.mailappjava-2/lib/x86
W/art: Before Android 4.1, method android.graphics.PorterDuffColorFilter androidx.vectordrawable.graphics.drawable.VectorDrawableCompat.updateTintFilter(android.graphics.PorterDuffColorFilter, android.content.res.ColorStateList, android.graphics.PorterDuff$Mode) would have incorrectly overridden the package-private method in android.graphics.drawable.Drawable
D/OpenGLRenderer: Use EGL_SWAP_BEHAVIOR_PRESERVED: true
D/: HostConnection::get() New Host Connection established 0xaa3611c0, tid 7129
D/: HostConnection::get() New Host Connection established 0xaa361740, tid 7160
I/OpenGLRenderer: Initialized EGL, version 1.4
W/OpenGLRenderer: Failed to choose config with EGL_SWAP_BEHAVIOR_PRESERVED, retrying without...
D/EGL_emulation: eglCreateContext: 0xae594600: maj 3 min 1 rcv 4
D/EGL_emulation: eglMakeCurrent: 0xae594600: ver 3 1 (tinfo 0xae592b50)
E/eglCodecCommon: glUtilsParamSize: unknow param 0x000082da
    glUtilsParamSize: unknow param 0x00008cdf
E/eglCodecCommon: glUtilsParamSize: unknow param 0x00008824
D/EGL_emulation: eglMakeCurrent: 0xae594600: ver 3 1 (tinfo 0xae592b50)
W/System.err: android.os.NetworkOnMainThreadException
        at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1273)
        at java.net.InetAddress.lookupHostByName(InetAddress.java:431)
        at java.net.InetAddress.getAllByNameImpl(InetAddress.java:252)
        at java.net.InetAddress.getByName(InetAddress.java:305)
        at java.net.InetSocketAddress.<init>(InetSocketAddress.java:100)
        at java.net.InetSocketAddress.<init>(InetSocketAddress.java:85)
        at com.sun.mail.util.SocketFetcher.createSocket(SocketFetcher.java:233)
        at com.sun.mail.util.SocketFetcher.getSocket(SocketFetcher.java:189)
        at com.sun.mail.iap.Protocol.<init>(Protocol.java:107)
        at com.sun.mail.imap.protocol.IMAPProtocol.<init>(IMAPProtocol.java:104)
        at com.sun.mail.imap.IMAPStore.protocolConnect(IMAPStore.java:538)
        at javax.mail.Service.connect(Service.java:288)
        at javax.mail.Service.connect(Service.java:169)
        at com.example.mailappjava.JavaMailAPIretrevial.check(JavaMailAPIretrevial.java:47)
        at com.example.mailappjava.ui.home.HomeFragment.onClick(HomeFragment.java:55)
        at android.view.View.performClick(View.java:5198)
        at android.view.View$PerformClick.run(View.java:21147)
        at android.os.Handler.handleCallback(Handler.java:739)
        at android.os.Handler.dispatchMessage(Handler.java:95)
        at android.os.Looper.loop(Looper.java:148)
        at android.app.ActivityThread.main(ActivityThread.java:5417)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)

I would be very grateful for your help

Answer 1

Pass your exception log: android.os.NetworkOnMainThreadException

You cannot go to the network request in the main thread.

Can you provide the code of the place where the mail is requested?

    public void onClick(View v){
        new Thread(new Runnable() {
            @Override
            public void run() {
                JavaMailAPIretrevial recieve = new JavaMailAPIretrevial(fragment_context);
            }
        }).start();

    }

Answer 2

To anyone that may be in the same situation as I was. I couldn't find any tutorial about how to implement an Inbox on Android, but after some research on Github, I found a nice repository for both sending and getting emails. If you are stuck as I was, check this repo for reference: https://github.com/Sunghee2/Email-android