android volley 和 asynchttpclient 在真实设备上失败，但在模拟器上工作

Question

大家好，我只是制作了一个使用 ICS_OPENVPN 库的 android 应用程序，但是当我制作 SplashActivity 以检查更新应用程序在模拟器上正常工作时，但是当我为已签名的 APK 生成并将其安装在真实设备上时，它不会切换到 MainActivity。

SplashActivity.java

package com.orangevpninfo.orangevpn;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AlertDialog;
import androidx.appcompat.app.AppCompatActivity;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.widget.Toast;
import com.airbnb.lottie.LottieAnimationView;
import com.android.volley.NetworkResponse;
import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.JsonObjectRequest;
import com.android.volley.toolbox.JsonRequest;
import com.android.volley.toolbox.Volley;
import com.google.android.gms.tasks.OnCompleteListener;
import com.google.android.gms.tasks.Task;
import com.google.firebase.iid.FirebaseInstanceId;
import com.google.firebase.iid.InstanceIdResult;
import com.google.gson.Gson;
import com.google.gson.JsonObject;
import com.loopj.android.http.AsyncHttpClient;
import com.loopj.android.http.JsonHttpResponseHandler;
import com.orangevpninfo.orangevpn.models.Version;
import cz.msebera.android.httpclient.Header;
import org.json.JSONArray;
import org.json.JSONObject;

public class SplashActivity extends AppCompatActivity {

    LottieAnimationView la_animation;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_splash);
        la_animation=findViewById(R.id.la_animation2);
        startAnimation(SplashActivity.this, R.id.la_animation2, R.anim.fade_in_1000, true);
        la_animation.cancelAnimation();
        la_animation.setAnimation(R.raw.loading2);
        la_animation.playAnimation();


        checkupdate2("1");




    }
    private void download(final String Link){
        AlertDialog alertDialog = new AlertDialog.Builder(SplashActivity.this).create();
        alertDialog.setTitle("New Version Available");
        alertDialog.setMessage("There is a New version of this App! Please select Update to Download directly new version and install it");
        alertDialog.setButton(AlertDialog.BUTTON_NEUTRAL, "Not Now",
                new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int which) {
                        dialog.dismiss();
                        finish();
                    }
                });
        alertDialog.setButton(AlertDialog.BUTTON_POSITIVE, "Update",
                new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int which) {
                        Intent a=new Intent(Intent.ACTION_VIEW, Uri.parse(Link));
                        startActivity(a);
                        finish();
                    }
                });
        alertDialog.show();
        //Intent i = new Intent(Intent.ACTION_VIEW);
        //i.setData(Uri.parse(Link));
        //startActivity(i);
    }

    private void checkupdate2(final String version){


        Request<JSONObject> jsonObjectRequest = new JsonObjectRequest(Request.Method.GET, "http://51.89.45.117/version/version.json",
                null, new Response.Listener<JSONObject>() {
            @Override
            public void onResponse(JSONObject response) {
                Log.d("Success", response.toString());
                Version ver=new Gson().fromJson(response.toString(), Version.class);
                if (ver.getVersion().equals(version)){
                    Intent a=new Intent(SplashActivity.this,MainActivity.class);
                    startActivity(a);
                    finish();

                }else{
                    download(ver.getLink());
                }
            }
        }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
                Log.d("Error", error.toString());

            }

        });
        RequestQueue requestQueue = Volley.newRequestQueue(getApplicationContext());
         requestQueue.add(jsonObjectRequest);

    }
    private void checkupdate(final String version){
        String url="http://51.89.45.117/version/version.json";
        AsyncHttpClient client = new AsyncHttpClient();
        client.setConnectTimeout(30);
        client.get(this,url,new JsonHttpResponseHandler(){
            @Override
            public void onSuccess(int statusCode, Header[] headers, JSONArray response) {
                super.onSuccess(statusCode, headers, response);

                Version[] ver=new Gson().fromJson(response.toString(), Version[].class);
                if (ver[0].getVersion().equals(version)){
                    Intent a=new Intent(SplashActivity.this,MainActivity.class);
                    startActivity(a);
                    finish();

                }else{

                    download(ver[0].getLink());
                }

            }

            @Override
            public void onSuccess(int statusCode, Header[] headers, JSONObject response) {
                super.onSuccess(statusCode, headers, response);
                Version ver=new Gson().fromJson(response.toString(), Version.class);
                if (ver.getVersion().equals(version)){
                    Intent a=new Intent(SplashActivity.this,MainActivity.class);
                    startActivity(a);
                    finish();

                }else{
                    download(ver.getLink());
                }
            }

            @Override
            public void onFailure(int statusCode, Header[] headers, Throwable throwable, JSONArray errorResponse) {
                super.onFailure(statusCode, headers, throwable, errorResponse);

                Version[] ver=new Gson().fromJson(errorResponse.toString(), Version[].class);
                if (ver[0].getVersion().equals(version)){
                    Intent a=new Intent(SplashActivity.this,MainActivity.class);
                    startActivity(a);
                    finish();

                }else{

                    download(ver[0].getLink());
                }

            }

            @Override
            public void onFailure(int statusCode, Header[] headers, Throwable throwable, JSONObject errorResponse) {
                super.onFailure(statusCode, headers, throwable, errorResponse);
                Toast.makeText(SplashActivity.this, "success Jobj", Toast.LENGTH_SHORT).show();
                Version ver=new Gson().fromJson(errorResponse.toString(), Version.class);
                if (ver.getVersion().equals(version)){
                    Intent a=new Intent(SplashActivity.this,MainActivity.class);
                    startActivity(a);
                    SplashActivity.this.finish();

                }else{
                    download(ver.getLink());
                }

            }

            @Override
            public void onFailure(int statusCode, Header[] headers, String responseString, Throwable throwable) {
                super.onFailure(statusCode, headers, responseString, throwable);
                Intent a=new Intent(SplashActivity.this,MainActivity.class);
                startActivity(a);
                SplashActivity.this.finish();
            }

            @Override
            public void onSuccess(int statusCode, Header[] headers, String responseString) {
                super.onSuccess(statusCode, headers, responseString);
                Intent a=new Intent(SplashActivity.this,MainActivity.class);
                startActivity(a);
                SplashActivity.this.finish();
            }
        });
    }
    public void startAnimation(Context ctx, int view, int animation, boolean show) {
        final View Element = findViewById(view);
        if (show) {
            Element.setVisibility(View.VISIBLE);
        } else {
            Element.setVisibility(View.INVISIBLE);
        }
        Animation anim = AnimationUtils.loadAnimation(ctx, animation);
        Element.startAnimation(anim);
    }
}

Crashlytics 中的排球错误

Fatal Exception: java.lang.NullPointerException
Attempt to invoke virtual method 'boolean java.lang.String.equals(java.lang.Object)' on a null object reference
com.orangevpninfo.orangevpn.SplashActivity$3.onResponse (SplashActivity.java:17)
com.android.volley.toolbox.JsonRequest.deliverResponse (JsonRequest.java:17)
com.android.volley.ExecutorDelivery$ResponseDeliveryRunnable.run (ExecutorDelivery.java:2)
android.os.Handler.handleCallback (Handler.java:751)
android.os.Handler.dispatchMessage (Handler.java:95)
android.os.Looper.loop (Looper.java:154)
android.app.ActivityThread.main (ActivityThread.java:6138)
java.lang.reflect.Method.invoke (Method.java)
com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run (ZygoteInit.java:893)
com.android.internal.os.ZygoteInit.main (ZygoteInit.java:783)

AsyncHttpClient 错误 Crashlytics

Fatal Exception: java.lang.RuntimeException
java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String org.json.JSONObject.toString()' on a null object reference
com.loopj.android.http.AsyncHttpResponseHandler.onUserException (AsyncHttpResponseHandler.java:28)
com.loopj.android.http.AsyncHttpResponseHandler$ResponderHandler.handleMessage (AsyncHttpResponseHandler.java)
android.os.Handler.dispatchMessage (Handler.java:102)
android.os.Looper.loop (Looper.java:154)
android.app.ActivityThread.main (ActivityThread.java:6138)
java.lang.reflect.Method.invoke (Method.java)
com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run (ZygoteInit.java:893)
com.android.internal.os.ZygoteInit.main (ZygoteInit.java:783)

Caused by java.lang.NullPointerException
Attempt to invoke virtual method 'java.lang.String org.json.JSONObject.toString()' on a null object reference
com.orangevpninfo.orangevpn.SplashActivity$4.onFailure (SplashActivity.java)
com.loopj.android.http.JsonHttpResponseHandler.onFailure (JsonHttpResponseHandler.java:19)
com.loopj.android.http.AsyncHttpResponseHandler.handleMessage (AsyncHttpResponseHandler.java:19)
com.loopj.android.http.AsyncHttpResponseHandler$ResponderHandler.handleMessage (AsyncHttpResponseHandler.java)
android.os.Handler.dispatchMessage (Handler.java:102)
android.os.Looper.loop (Looper.java:154)
android.app.ActivityThread.main (ActivityThread.java:6138)
java.lang.reflect.Method.invoke (Method.java)
com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run (ZygoteInit.java:893)
com.android.internal.os.ZygoteInit.main (ZygoteInit.java:783)

Answer 1

看起来您得到的响应是 null 或 ver.getVersion() 也可能返回 null。由于ver.getVersion().equals(version)这条语句存在空指针异常。

您可以尝试两种可能的方法-

1. 您是否在发布时打开了 ProGaurd？如果是，在Version模型类中添加规则或添加@Keep注解。

2. 如果第一步被选中，你必须检查来自服务器的响应是否有效。检查有效响应始终是一个好习惯。只需添加if (response == null) 并使用日志调试您的代码。