[FIXED] How do I send a image bitmap trough socket Android Socket

Issue

My teacher gave me an assignment, a mini project in android studio.
I want to get a good grade so Im trying to create an app that allows to transfer photos,
between 2 phones connected to the same WIFI network.(with sockets)

I have created an App that let you send a string to the server, But I cant figure out how to send a photo. (The photo choose section is done)

There is My Code of the client:

void client() throws IOException{
        ipAddr = ipAddrEditText.getText().toString();
        InputStream imageStream = getContentResolver().openInputStream(imageUri);
        final Bitmap imageBitMap = BitmapFactory.decodeStream(imageStream);

        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        imageBitMap.compress(Bitmap.CompressFormat.PNG,0, bos);
        byte[] array = bos.toByteArray();

        Socket s = new Socket(ipAddr,7800);
        OutputStream out = s.getOutputStream();
        DataOutputStream dos = new DataOutputStream(out);
        dos.writeInt(array.length);
        dos.write(array,0,array.length);
        dos.flush();


        dos.close();
        out.close();
        s.close();
    } 

There is the Server's code:

void server() {
        ServerSocket ss = null;
        try {
            ss = new ServerSocket(7800);
            DataInputStream dis;
            int len;
            byte[] data;
            Socket s;
            while(true) {
                s = ss.accept();
                InputStream is = s.getInputStream();
                dis = new DataInputStream(is);
                len = dis.readInt();
                data = new byte[len];
                dis.readFully(data,0,data.length);

                photoBitmap = BitmapFactory.decodeByteArray(data,0,data.length);
                img.setImageBitmap(photoBitmap);

                dis.close();
                s.close();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }

The Server is crashing every time Im trying to transfer the photo.
------------------------------------------------
the log cat erors:

    Process: com.example.theminiproject, PID: 15123
    android.view.ViewRootImpl$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views.
        at android.view.ViewRootImpl.checkThread(ViewRootImpl.java:10554)
        at android.view.ViewRootImpl.requestLayout(ViewRootImpl.java:2113)
        at android.view.View.requestLayout(View.java:27069)
        at android.view.View.requestLayout(View.java:27069)
        at android.view.View.requestLayout(View.java:27069)
        at android.view.View.requestLayout(View.java:27069)
        at android.view.View.requestLayout(View.java:27069)
        at android.view.View.requestLayout(View.java:27069)
        at androidx.constraintlayout.widget.ConstraintLayout.requestLayout(ConstraintLayout.java:3239)
        at android.view.View.requestLayout(View.java:27069)
        at android.widget.ImageView.setImageDrawable(ImageView.java:600)
        at androidx.appcompat.widget.AppCompatImageView.setImageDrawable(AppCompatImageView.java:104)
        at android.widget.ImageView.setImageBitmap(ImageView.java:764)
        at androidx.appcompat.widget.AppCompatImageView.setImageBitmap(AppCompatImageView.java:112)
        at com.example.theminiproject.MainActivity2.server(MainActivity2.java:70)
        at com.example.theminiproject.-$$Lambda$jVrGEiH1Ep-S9RdZnfrW_UVFTWs.run(Unknown Source:2)
        at java.lang.Thread.run(Thread.java:923)
2021-03-08 12:24:31.431 15123-15123/? I/ViewRootImpl@867b75a[MainActivity]: stopped(false) old=true
2021-03-08 12:24:31.434 15123-15123/? I/ViewRootImpl@867b75a[MainActivity]: stopped(false) old=false
2021-03-08 12:24:31.441 15123-26157/? I/Process: Sending signal. PID: 15123 SIG: 9

Because Im a beginner i can not understand any of it.
Thank you.

Solution

I found the error in my code thanks to the helpers in the comments section.

a Thread can not change an ImageView, you must create a separate function to change it.

in my case Ive created a Button that change the image.

    public void changePhoto(View v) {
            img.setImageBitmap(photoBitmap);
    }

• if you call the function trough the Thread the photo will change but the app will crush 0.1 second later.

Thanks for everyone who helped.

Answered By - GeverAL

Answer Checked By - Mildred Charles (PHPFixing Admin)