应用程序在其他设备上崩溃，但在我的设备上没有

Question

我刚刚制作了一个应用程序并尝试在我的朋友（2-3）手机上调试apk / signed apk ...在大多数手机应用程序崩溃/强制关闭。对于一个朋友，它在第三次尝试工作..但现在又不起作用。在我的手机中，它工作正常，我从未使用模拟器进行调试。从一开始我就在手机中调试了应用程序。现在我卸载了应用程序，并使用apk给我的朋友安装了它。应用在我的手机中工作正常。我不知道什么是错的。

mainActivity

EditText name, phonenumber, address;
Button insert;
RequestQueue requestQueue;
Spinner spinner;
String insertUrl = "localhost";


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

    Spinner s = (Spinner) findViewById(R.id.spinner);
    s.setOnItemSelectedListener(new OnItemSelectedListener() {
        @Override
        public void onItemSelected(AdapterView<?> parent, View view, int position, long id)
        {


        }

        @Override
        public void onNothingSelected(AdapterView<?> parent) {

        }
    });

    /* CHECK INTERNET CONNECTION */
    boolean mobileNwInfo = false;
    ConnectivityManager conxMgr = (ConnectivityManager) getSystemService(CONNECTIVITY_SERVICE);
    try { mobileNwInfo = conxMgr.getActiveNetworkInfo().isConnected(); }
    catch (NullPointerException e) { mobileNwInfo = false; }
    if ( mobileNwInfo == false ) {
        Toast.makeText(this, "No Network, please check your connection. ", Toast.LENGTH_LONG).show();
    }
    /* CHECK INTERNET CONNECTION PROCEDURE DONE */


    name = (EditText) findViewById(R.id.editText);
    phonenumber= (EditText) findViewById(R.id.editText2);
    address = (EditText) findViewById(R.id.editText3);
    insert = (Button) findViewById(R.id.insert);
    requestQueue = Volley.newRequestQueue(getApplicationContext());
    spinner = (Spinner) findViewById(R.id.spinner);

    insert.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            final ProgressDialog pd = new ProgressDialog(MainActivity.this);
            pd.setMessage("Booking Service ....");
            pd.show();

            StringRequest request = new StringRequest(Request.Method.POST, insertUrl, new Response.Listener<String>() {
                @Override
                public void onResponse(String response) {

                    pd.hide();
                    System.out.println(response.toString());
                    name.setText("");
                    phonenumber.setText("");
                    address.setText("");
                    Toast.makeText(getApplicationContext(), "Service successfully booked !!", Toast.LENGTH_LONG).show();
                }
            }, new Response.ErrorListener() {
                @Override
                public void onErrorResponse(VolleyError error) {
                    pd.hide();
                    Toast.makeText(getApplicationContext(), "Error: Please try again later.", Toast.LENGTH_LONG).show();


                }
            }) {

                @Override
                protected Map<String, String> getParams() throws AuthFailureError {
                    Map<String, String> parameters = new HashMap<String, String>();
                    parameters.put("name", name.getText().toString());
                    parameters.put("phonenumber", phonenumber.getText().toString());
                    parameters.put("address", address.getText().toString());
                    parameters.put("service", spinner.getItemAtPosition(spinner.getSelectedItemPosition()).toString());

                    return parameters;
                }


            };
            requestQueue.add(request);

        }

    });


}

的build.gradle（模块：应用）

apply plugin: 'com.android.application'

android {
signingConfigs {
}
compileSdkVersion 23
buildToolsVersion "22.0.1"
defaultConfig {
    applicationId "practise.mysql_php_json"
    minSdkVersion 14
    targetSdkVersion 23
    versionCode 1
    versionName "1.0"
}
buildTypes {
    release {
        minifyEnabled false
        proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
    }
}
}

dependencies {
compile fileTree(include: ['*.jar'], dir: 'libs')
compile 'com.android.support:appcompat-v7:23.0.0'
compile 'com.mcxiaoke.volley:library:1.0.18'
compile 'com.android.support:design:23.0.1'   
 }

的build.gradle（项目：XXX）

// Top-level build file where you can add configuration options common to all sub-projects/modules.

buildscript {
repositories {
    jcenter()
}
dependencies {
    classpath 'com.android.tools.build:gradle:1.3.0'

    // NOTE: Do not place your application dependencies here; they belong
    // in the individual module build.gradle files
}
}

allprojects {
repositories {
    jcenter()
}
}

task clean(type: Delete) {
delete rootProject.buildDir
}

清单

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="in.co.bluecollar.bluecollar" >

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:theme="@style/AppTheme" >


    <activity
        android:name=".SplashActivity"
        android:label="@string/app_name"
        android:screenOrientation="portrait"
        android:theme="@android:style/Theme.Translucent.NoTitleBar" >
    <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>

    <activity
        android:name=".MainActivity"
        android:label="@string/app_name" >
    </activity>
</application>

</manifest>