如何？ - 在同一文件执行GET之前，将字符串插入php文件

I have successfully connected my android app to a mysql database and did a read from the database which is displaying all the rows from a table in the app. I want to narrow this down so it only displays the rows which correspond with the users id. I have the usersID stored as a shared preference from when they log into the app. I need my php file to recognise the users id and then use this id as part of the query so it only displays the appropriate rows.I am having trouble trying to set this code up and would benefit from some help. Please see the php and java below.

PHP CODE:

<?php
include('conn.php');

if(isset($_GET['userId'])){//The PHP file doesnt work with these two lines
$getId = $_GET['userId'];

$query = "SELECT * FROM Cbt WHERE userId = '$getId'";
$result = mysqli_query($conn, $query);
$json_array = array();
while ($row = mysqli_fetch_assoc($result)){
$json_array[] =$row;
}
}
echo json_encode($json_array);

JAVA CODE:

  loginPref = getSharedPreferences("loginPref", Context.MODE_PRIVATE);
    final int userId = loginPref.getInt("userId", 0);

    textViewResult = findViewById(R.id.text_viewer_result);
    Gson gson = new GsonBuilder()
            .setLenient()
            .create();
    Retrofit retrofit = new Retrofit.Builder()
            .baseUrl("")
            .addConverterFactory(GsonConverterFactory.create(gson))
            .build();
    Api api = retrofit.create(Api.class);
    Call<List<WorkoutLogRecycler>> call = api.getLogs();
    call.enqueue(new Callback<List<WorkoutLogRecycler>>() {
        @Override
        public void onResponse(Call<List<WorkoutLogRecycler>> call,   Response<List<WorkoutLogRecycler>> response) {

            if (!response.isSuccessful()) {
                textViewResult.setText("Code:"+response.code());
                return;
            }

            List<WorkoutLogRecycler> workoutLogRecyclers =  response.body();
            for (WorkoutLogRecycler workoutLogRecycler : workoutLogRecyclers){
                String content ="";
                content += "cbtId: " + workoutLogRecycler.getCbtId() +"
";
                content += "userId: " + workoutLogRecycler.getUserId() +"
";
                content += "moodBefore: " + workoutLogRecycler.getMoodBefore() +"
";
                content += "automaticThought: " + workoutLogRecycler.getAutomaticThought() +"
";
                content += "distortions: " + workoutLogRecycler.getDistortions() +"
";
                content += "challengeTought: " + workoutLogRecycler.getChallengeThought() +"
";
                content += "alternativeThought: " + workoutLogRecycler.getAlternativeThought() +"
";
                content += "moodAfter: " + workoutLogRecycler.getMoodAfter() +"
";
                textViewResult.append(content);
            }
        }


        @Override
        public void onFailure(Call<List<WorkoutLogRecycler>> call,  Throwable t) {
        textViewResult.setText(t.getMessage());
        }
    });

API CODE:

public interface Api {

@FormUrlEncoded
@POST("insert.php")
Call<ResponseBody> insertLog(
        @Field("userId") int userId,
        @Field("moodBefore") int moodBefore,
        @Field("automaticThought") String automaticThought,
        @Field("distortions") int distortions,
        @Field("challengeThought") String challengeThought,
        @Field("alternativeThought") String alternativeThought,
        @Field("moodAfter") int moodAfter
);


@GET("read.php")
Call<List<WorkoutLogRecycler>> getLogs();

Ok so your API url getLogs() needs a parameter that will be passed to the php script

@GET("read.php")
Call<List<WorkoutLogRecycler>> getLogs(@Query("userId") String userId);

and then change the line

Call<List<WorkoutLogRecycler>> call = api.getLogs();
// to
Call<List<WorkoutLogRecycler>> call = api.getLogs(userId);

Check if it works. Basically you execute a request that is provided in the .baseUrl() but you don't attach any param to it. When you use GET on the server side, the url should contain some data attached. Like: https://www.api.com?userId=2.

Then $_GET['userId'] can extract userId value from the url.

Retrofit attach params for you using @Query adnotation.

From a first PHP sight, I can tell that you are not passing the $getId correctly within your query. What you should do is: $query = "SELECT * FROM Cbt WHERE userId = " . $getId;

Besides that, check this way of using mysqli queries by assigning them a variable.