python - 从 Android Studio 通过 Flask 服务器发送文件的问题

Question

所以我在这里遵循了这个教程：https ://heartbeat.fritz.ai/uploading-images-from-android-to-a-python-based-flask-server-691e4092a95e

并设置我的 android studio 和 flask 服务器。

我面临的问题是将图像发送到烧瓶服务器。当我单击连接到服务器时，我在发送时收到此错误。

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.flaskserver, PID: 28524
    java.lang.IllegalStateException: Could not find method connectServer(View) in a parent or ancestor Context for android:onClick attribute defined on view class com.google.android.material.button.MaterialButton
        at androidx.appcompat.app.AppCompatViewInflater$DeclaredOnClickListener.resolveMethod(AppCompatViewInflater.java:447)
        at androidx.appcompat.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:405)
        at android.view.View.performClick(View.java:7448)
        at com.google.android.material.button.MaterialButton.performClick(MaterialButton.java:1119)
        at android.view.View.performClickInternal(View.java:7425)
        at android.view.View.access$3600(View.java:810)
        at android.view.View$PerformClick.run(View.java:28305)
        at android.os.Handler.handleCallback(Handler.java:938)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:223)
        at android.app.ActivityThread.main(ActivityThread.java:7656)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)
I/Process: Sending signal. PID: 28524 SIG: 9

这是我的 Android Studio 代码：

package com.example.flaskserver;

import androidx.annotation.RequiresApi;
import androidx.appcompat.app.AppCompatActivity;

import android.annotation.SuppressLint;
import android.content.ContentUris;
import android.content.Context;
import android.content.Intent;
import android.database.Cursor;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.net.Uri;
import android.os.Build;
import android.os.Environment;
import android.provider.DocumentsContract;
import android.provider.MediaStore;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import okhttp3.Call;
import okhttp3.Callback;
import okhttp3.MediaType;
import okhttp3.MultipartBody;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.RequestBody;
import okhttp3.Response;




public class MainActivity extends AppCompatActivity {
    String selectedImagePath;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        connectServer(findViewById(R.id.connectServer));
    }

    @SuppressLint("SetTextI18n")
    void connectServer(View v){
        EditText ipv4AddressView = findViewById(R.id.IPAddress);
        String ipv4Address = ipv4AddressView.getText().toString();
        EditText portNumberView = findViewById(R.id.portNumber);
        String portNumber = portNumberView.getText().toString();

        String postUrl= "http://"+ipv4Address+":"+portNumber+"/";

        ByteArrayOutputStream stream = new ByteArrayOutputStream();
        BitmapFactory.Options options = new BitmapFactory.Options();
        options.inPreferredConfig = Bitmap.Config.RGB_565;
        // Read BitMap by file path
        Bitmap bitmap = BitmapFactory.decodeFile(selectedImagePath, options);
        bitmap.compress(Bitmap.CompressFormat.JPEG, 100, stream);
        byte[] byteArray = stream.toByteArray();

        RequestBody postBodyImage = new MultipartBody.Builder()
                .setType(MultipartBody.FORM)
                .addFormDataPart("image", "androidFlask.jpg", RequestBody.create(MediaType.parse("image/*jpg"), byteArray))
                .build();

        TextView responseText = findViewById(R.id.responseText);
        responseText.setText("Please wait ...");

        postRequest(postUrl, postBodyImage);
    }

    void postRequest(String postUrl, RequestBody postBody) {

        OkHttpClient client = new OkHttpClient();

        Request request = new Request.Builder()
                .url(postUrl)
                .post(postBody)
                .build();

        client.newCall(request).enqueue(new Callback() {
            @SuppressLint("SetTextI18n")
            @Override
            public void onFailure(Call call, IOException e) {
                // Cancel the post on failure.
                call.cancel();

                // In order to access the TextView inside the UI thread, the code is executed inside runOnUiThread()
                runOnUiThread(() -> {
                    TextView responseText = findViewById(R.id.responseText);
                    responseText.setText("Failed to Connect to Server");
                });
            }

            @Override
            public void onResponse(Call call, final Response response) {
                // In order to access the TextView inside the UI thread, the code is executed inside runOnUiThread()
                runOnUiThread(() -> {
                    TextView responseText = findViewById(R.id.responseText);
                    try {
                        responseText.setText(response.body().string());
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                });
            }
        });
    }

    public void selectImage(View v) {
        Intent intent = new Intent();
        intent.setType("*/*");
        intent.setAction(Intent.ACTION_GET_CONTENT);
        startActivityForResult(intent, 0);
    }

    @RequiresApi(api = Build.VERSION_CODES.KITKAT)
    @Override
    protected void onActivityResult(int reqCode, int resCode, Intent data) {
        super.onActivityResult(reqCode, resCode, data);
        if (resCode == RESULT_OK && data != null) {
            Uri uri = data.getData();

            selectedImagePath = getPath(getApplicationContext(), uri);
            EditText imgPath = findViewById(R.id.imgPath);
            imgPath.setText(selectedImagePath);
            Toast.makeText(getApplicationContext(), selectedImagePath, Toast.LENGTH_LONG).show();
        }
    }

    // Implementation of the getPath() method and all its requirements is taken from the StackOverflow Paul Burke's answer: https://stackoverflow.com/a/20559175/5426539
    @RequiresApi(api = Build.VERSION_CODES.KITKAT)
    public static String getPath(final Context context, final Uri uri) {

        final boolean isKitKat = Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT;

        // DocumentProvider
        if (isKitKat && DocumentsContract.isDocumentUri(context, uri)) {
            // ExternalStorageProvider
            if (isExternalStorageDocument(uri)) {
                final String docId = DocumentsContract.getDocumentId(uri);
                final String[] split = docId.split(":");
                final String type = split[0];

                if ("primary".equalsIgnoreCase(type)) {
                    return Environment.getExternalStorageDirectory() + "/" + split[1];
                }

                // TODO handle non-primary volumes
            }
            // DownloadsProvider
            else if (isDownloadsDocument(uri)) {

                final String id = DocumentsContract.getDocumentId(uri);
                final Uri contentUri = ContentUris.withAppendedId(
                        Uri.parse("content://downloads/public_downloads"), Long.parseLong(id));

                return getDataColumn(context, contentUri, null, null);
            }
            // MediaProvider
            else if (isMediaDocument(uri)) {
                final String docId = DocumentsContract.getDocumentId(uri);
                final String[] split = docId.split(":");
                final String type = split[0];

                Uri contentUri = null;
                if ("image".equals(type)) {
                    contentUri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;
                } else if ("video".equals(type)) {
                    contentUri = MediaStore.Video.Media.EXTERNAL_CONTENT_URI;
                } else if ("audio".equals(type)) {
                    contentUri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
                }

                final String selection = "_id=?";
                final String[] selectionArgs = new String[] {
                        split[1]
                };

                return getDataColumn(context, contentUri, selection, selectionArgs);
            }
        }
        // MediaStore (and general)
        else if ("content".equalsIgnoreCase(uri.getScheme())) {
            return getDataColumn(context, uri, null, null);
        }
        // File
        else if ("file".equalsIgnoreCase(uri.getScheme())) {
            return uri.getPath();
        }

        return null;
    }

    public static String getDataColumn(Context context, Uri uri, String selection,
                                       String[] selectionArgs) {

        Cursor cursor = null;
        final String column = "_data";
        final String[] projection = {
                column
        };

        try {
            cursor = context.getContentResolver().query(uri, projection, selection, selectionArgs,
                    null);
            if (cursor != null && cursor.moveToFirst()) {
                final int column_index = cursor.getColumnIndexOrThrow(column);
                return cursor.getString(column_index);
            }
        } finally {
            if (cursor != null)
                cursor.close();
        }
        return null;
    }

    public static boolean isExternalStorageDocument(Uri uri) {
        return "com.android.externalstorage.documents".equals(uri.getAuthority());
    }

    public static boolean isDownloadsDocument(Uri uri) {
        return "com.android.providers.downloads.documents".equals(uri.getAuthority());
    }

    public static boolean isMediaDocument(Uri uri) {
        return "com.android.providers.media.documents".equals(uri.getAuthority());
    }
}

烧瓶：

import flask
import werkzeug

app = flask.Flask(__name__)

@app.route('/', methods = ['GET', 'POST'])
def handle_request():
    imagefile = flask.request.files['image']
    filename = werkzeug.utils.secure_filename(imagefile.filename)
    print("\nReceived image File name : " + imagefile.filename)
    imagefile.save(filename)
    return "Image Uploaded Successfully"

app.run(host="0.0.0.0", port=5000, debug=True)

标签： pythonandroidflask