我的应用程序正在我的Android模拟器上工作，但它不能在我的真实移动设备上工作

Question

My problem is when I run my application on a real mobile device the following error is displayed: com.android.volley.TimeoutError".However, it works perfectly by using the emulator of Android studio. Due to the fact that must of the time this error is caused by connectivity issues, am I using the correect ip for my application? ie

"private static String URL_REGIST ="http://10.0.2.2:81/android_register_login/register.php"; "

I am new to application development so any help would greatly be appreciated. Below is the code for register.java which makes use of register.php script which is used to perform registration

private EditText name,email,password,c_password;
private Button btn_regist;
private ProgressBar loading;
private static String URL_REGIST ="http://10.0.2.2:81/android_register_login/register.php";
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_register);
    loading = findViewById(R.id.loading);
    name= findViewById(R.id.name);
    email = findViewById(R.id.email);
    password = findViewById(R.id.password);
    c_password = findViewById(R.id.c_password);

    btn_regist =findViewById(R.id.btn_regist);

    btn_regist.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Regist();
        }
    });
}

private void Regist(){
    loading.setVisibility(View.VISIBLE);
    btn_regist.setVisibility(View.GONE);

    final String name = this.name.getText().toString().trim();
    final String email = this.email.getText().toString().trim();
    final String password = this.password.getText().toString().trim();

    StringRequest stringRequest = new StringRequest(Request.Method.POST, URL_REGIST,
            new Response.Listener<String>() {
                @Override
                public void onResponse(String response) {
                 try {
                     JSONObject jsonObject = new JSONObject(response);
                     String success = jsonObject.getString("success");

                     if(success.equals("1")){
                         Toast.makeText(RegisterActivity.this, "Account Created",Toast.LENGTH_SHORT).show();
                         loading.setVisibility(View.GONE);
                     }
                 }catch (JSONException e) {
                     e.printStackTrace();
                     Toast.makeText(RegisterActivity.this, "Register Error!" + e.toString(),Toast.LENGTH_SHORT).show();
                     loading.setVisibility(View.GONE);
                     btn_regist.setVisibility(View.VISIBLE);

                 }
                }
            },
            new Response.ErrorListener() {
                @Override
                public void onErrorResponse(VolleyError error) {

                    Toast.makeText(RegisterActivity.this, "Register Error!" + error.toString(),Toast.LENGTH_SHORT).show();
                    loading.setVisibility(View.GONE);
                    btn_regist.setVisibility(View.VISIBLE);
                }
            })
    {
        @Override
        protected Map<String, String> getParams() throws AuthFailureError {
            Map<String, String> params = new HashMap<>();
            params.put("name", name);
            params.put("email", email);
            params.put("password", password);

            return params;
        }
    };



    RequestQueue requestQueue = Volley.newRequestQueue(this);


    requestQueue.add(stringRequest);

}

}

Answer 1

That's the wrong IP address. 10.0.2.2 is only going to work on emulators, because that's the IP of the private network between the host and the emulator. For wifi, you need to use the real IP address and make sure the wifi network is set up to allow incoming connections on that IP/port. For cellular, you need to make sure that's the case all the way up to your ISP

Answer 2

If you are testing in Android 9 Pie then you will have to set a networkSecurityConfig in your Manifest application tag to allow all HTTP and HTTPS network connection. Also, check if you have provided INTERNET permission.

<?xml version="1.0" encoding="utf-8"?>
<manifest ... >
    <application android:networkSecurityConfig="@xml/network_security_config">


    </application>
</manifest>

Then in your xml folder you now have to create a file named network_security_config just like the way you have named it in the Manifest and from there the content of your file should be like this to enable all requests without encryptions:

<?xml version="1.0" encoding="utf-8"?>
<network-security-config>
    <base-config cleartextTrafficPermitted="true">
        <trust-anchors>
            <certificates src="system" />
        </trust-anchors>
    </base-config>
</network-security-config>

Answer 3

Most probably the error is due to a connectivity issue. https://10.0.2.2 must be your localhost IP address. The application running on your Android device can not connect to a localhost server.

Solutions :

• You can use ngrok. Basically, it creates a tunnel to your localhost through which you can connect to your localhost server. I have personally used this with my Flask API hosted on localhost
• You can also host your server on AWS (Amazon Web Services), Hostinger or on other cloud services. I have used Hostinger for hosting my API in PHP.