在Android中运行for循环时出现错误

Question

我是编程的初学者。我想开发一个简单的android应用程序，而我只想在我的代码中运行一个for循环。 Logcat中出现错误，我无法弄清楚这是怎么回事

这是我的Mainactivity .java代码

package com.tuts.prakash.retrofittutorial.activity;

import android.app.ProgressDialog;
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

import com.tuts.prakash.retrofittutorial.R;
import com.tuts.prakash.retrofittutorial.adapter.CustomAdapter;
import com.tuts.prakash.retrofittutorial.menu;
import com.tuts.prakash.retrofittutorial.model.RetroPhoto;
import com.tuts.prakash.retrofittutorial.network.GetDataService;
import com.tuts.prakash.retrofittutorial.network.RetrofitClientInstance;
import com.tuts.prakash.retrofittutorial.payment;
import com.tuts.prakash.retrofittutorial.userRegister;

import java.util.List;

import retrofit2.Call;
import retrofit2.Callback;
import retrofit2.Response;

public class MainActivity extends AppCompatActivity {

    private CustomAdapter adapter;
    private RecyclerView recyclerView;
    ProgressDialog progressDoalog;
    private TextView textView7;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        textView7 = findViewById(R.id.textView7);
        progressDoalog = new ProgressDialog(MainActivity.this);
        progressDoalog.setMessage("Loading....");
        progressDoalog.show();

        /*Create handle for the RetrofitInstance interface*/
        GetDataService service = RetrofitClientInstance.getRetrofitInstance().create(GetDataService.class);

        Call<List<RetroPhoto>> call = service.getAllPhotos();
        call.enqueue(new Callback<List<RetroPhoto>>() {

            @Override
            public void onResponse(Call<List<RetroPhoto>> call, Response<List<RetroPhoto>> response) {
                progressDoalog.dismiss();
                generateDataList(response.body());
            }

            @Override
            public void onFailure(Call<List<RetroPhoto>> call, Throwable t) {
                progressDoalog.dismiss();
                Toast.makeText(MainActivity.this, "Something went wrong...Please try later!", Toast.LENGTH_SHORT).show();
            }
        });

        Button btn= (Button) findViewById(R.id.pay);

        btn.setOnClickListener(
                new Button.OnClickListener() {
                    public void onClick(View v) {
                        startActivity(new Intent(MainActivity.this, payment.class));
                    }
                }
        );

        createSum();


    }

    /*Method to generate List of data using RecyclerView with custom adapter*/
    private void generateDataList(List<RetroPhoto> photoList) {

        recyclerView = findViewById(R.id.customRecyclerView);
        adapter = new CustomAdapter(this,photoList);
        RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(MainActivity.this);
        recyclerView.setLayoutManager(layoutManager);
        recyclerView.setAdapter(adapter);




    }

   private void createSum() {
        int sum = 0;

       for(int l=0; l<=5; l++){
           sum =  sum +1;
       }


        updateUI(sum);
    }

    private void updateUI(int sum) {
        this.textView7.setText(sum);
    }
}

我在onCreate中叫createSum。

这是Logcat中给出的错误

  --------- beginning of crash
08-15 11:26:02.467 4746-4746/com.tuts.prakash.retrofittutorial E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.tuts.prakash.retrofittutorial, PID: 4746
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.tuts.prakash.retrofittutorial/com.tuts.prakash.retrofittutorial.activity.MainActivity}: android.content.res.Resources$NotFoundException: String resource ID #0x6
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2325)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387)
        at android.app.ActivityThread.access$800(ActivityThread.java:151)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303)
        at android.os.Handler.dispatchMessage(Handler.java:102)
        at android.os.Looper.loop(Looper.java:135)
        at android.app.ActivityThread.main(ActivityThread.java:5254)
        at java.lang.reflect.Method.invoke(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:372)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
     Caused by: android.content.res.Resources$NotFoundException: String resource ID #0x6
        at android.content.res.Resources.getText(Resources.java:299)
        at android.widget.TextView.setText(TextView.java:4132)
        at com.tuts.prakash.retrofittutorial.activity.MainActivity.updateUI(MainActivity.java:108)
        at com.tuts.prakash.retrofittutorial.activity.MainActivity.createSum(MainActivity.java:104)
        at com.tuts.prakash.retrofittutorial.activity.MainActivity.onCreate(MainActivity.java:74)
        at android.app.Activity.performCreate(Activity.java:5990)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2278)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387) 
        at android.app.ActivityThread.access$800(ActivityThread.java:151) 
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303) 
        at android.os.Handler.dispatchMessage(Handler.java:102) 
        at android.os.Looper.loop(Looper.java:135) 
        at android.app.ActivityThread.main(ActivityThread.java:5254) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at java.lang.reflect.Method.invoke(Method.java:372) 
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698) 

由于我是编程的初学者，请帮助我解决此错误。