java - Android AsyncTask doInBackground 适用于 1 部手机，但不适用于其他手机

Question

我有一个应用程序在我的 Samsung Galaxy S7 7.0 版 API 24 中运行正常。但是当我在华为 CAM-L03 6.0 版 API 23 中尝试它时它不起作用。

基本上我有这样一个类:

public class Sender extends AsyncTask {...}

具有onPreExecute、doInBackground 和onPostExecute 方法，用于使用互联网与php 文件进行通信。当我在 Samsung Galaxy S7 上运行它并执行 Toast.makeText 时，以每种方法在屏幕上显示文本时，它工作得非常好。但是当我在华为 CAM-L03 上运行它时，只显示来自 onPreExecute 和 onPostExecute 的文本，但从未进入 doInBackground，我不知道为什么。

调用类我这样做:

Sender s = new Sender(MainActivity.this, URL_Total);

s.execute();

---

不知道是版本问题，还是SDK问题，还是其他问题。感谢您的帮助。

这是我的build.gradle:

apply plugin: 'com.android.application'

android {
    compileSdkVersion 26
    defaultConfig {
        applicationId "com.example.pruebainsp"
        minSdkVersion 15
        targetSdkVersion 22
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    implementation fileTree(include: ['*.jar'], dir: 'libs')
    implementation 'com.android.support:appcompat-v7:26.1.0'
    implementation 'com.android.support.constraint:constraint-layout:1.0.2'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'com.android.support.test:runner:1.0.1'
    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.1'
    implementation 'com.android.support:design:26.1.0'
    implementation files('libs/PhotoUtil.jar')
    implementation files('libs/GenAsync.1.2.jar')
}

---

编辑 1: toast 消息并不是真正的问题..我只是为 View 添加它们，只是为了检查方法。真正的麻烦是 DoInBackground 不运行或做任何事情。

这是 Sender 类的代码。对于三星 Galaxy S7，它会进入 if (MainActivity.ResponseWeb != null)，但在华为 CAM-L03 中，ResponseWeb 始终为空，因此每次我收到消息 Toast。 makeText(c, "Error: response "+ MainActivity.ResponseWeb , Toast.LENGTH_SHORT).show();，永远不要为连接做private String send()，因为doInBackground 在这里不起作用(仅在华为手机中)。

GO TO EDIT 2

---

编辑 2:我用日志更新了代码，所以这里是:

public class Sender extends AsyncTask<Void,Void,String> {
    Context c;
    String urlAddress;
    ProgressDialog pd;
    String fileTodosUsers = "TodosUsuarios";

    private static final String TAG = Sender.class.getSimpleName();
    /*
            1.OUR CONSTRUCTOR
    2.RECEIVE CONTEXT,URL ADDRESS AND EDITTEXTS FROM OUR MAINACTIVITY
    */
    public Sender(Context c, String urlAddress) {
        this.c = c;
        this.urlAddress = urlAddress;
        //Log.v(TAG, "Mensaje 2");
    }
    /*
   1.SHOW PROGRESS DIALOG WHILE DOWNLOADING DATA
    */
    @Override
    protected void onPreExecute() {
        Log.i(TAG, "OnPre");
        super.onPreExecute();
        pd=new ProgressDialog(c);
        pd.setTitle("En Proceso");
        pd.setMessage("Procesando datos...Espere por favor");
        pd.show();
    }
    /*
    1.WHERE WE SEND DATA TO NETWORK
    2.RETURNS FOR US A STRING
     */
    @Override
    protected String doInBackground(Void... params) {
        Log.i(TAG, "doInBack");
        return this.send();
    }
    /*
  1. CALLED WHEN JOB IS OVER
  2. WE DISMISS OUR PD
  3.RECEIVE A STRING FROM DOINBACKGROUND
   */
    @Override
    protected void onPostExecute(String response) {
        Log.i(TAG, "onPost");
        super.onPostExecute(response);
        MainActivity.ResponseWeb = response;

        if (MainActivity.ResponseWeb != null) {
         //...
         //HERE CODE DO SOME STUFF
         //...
        }
        else {
            Toast.makeText(c, "Error: response " + MainActivity.ResponseWeb , Toast.LENGTH_SHORT).show();
        }
        pd.dismiss();
    }
    
    
    /*
    SEND DATA OVER THE NETWORK
    RECEIVE AND RETURN A RESPONSE
     */
    private String send()
    {
        Log.i(TAG, "On Send 1");
        //CONNECT
        HttpURLConnection con=Connector.connect(urlAddress);
        Log.i(TAG, "On Send 2");
        if(con==null)
        {
            Log.i(TAG, "On Send 3");
            return null;
        }
        try
        {
            Log.i(TAG, "On Send 4");
            OutputStream os=con.getOutputStream();
            Log.i(TAG, "On Send 5");
            //WRITE
            BufferedWriter bw=new BufferedWriter(new OutputStreamWriter(os,"UTF-8"));
            Log.i(TAG, "On Send 6");
            bw.flush();
            Log.i(TAG, "On Send 7");
            //RELEASE RES
            bw.close();
            Log.i(TAG, "On Send 8");
            os.close();
            Log.i(TAG, "On Send 9");
            //HAS IT BEEN SUCCESSFUL?
            int responseCode=con.getResponseCode();
            Log.i(TAG, "On Send 10");
            Log.i(TAG, "responseCode = " + responseCode);
            if(responseCode==con.HTTP_OK)
            {
                Log.i(TAG, "On Send 11");
                //GET EXACT RESPONSE
                BufferedReader br=new BufferedReader(new InputStreamReader(con.getInputStream()));
                Log.i(TAG, "On Send 12");
                StringBuffer response=new StringBuffer();
                Log.i(TAG, "On Send 13");
                String line;
                Log.i(TAG, "On Send 14");
                //READ LINE BY LINE
                while ((line=br.readLine()) != null)
                {
                    Log.i(TAG, "On Send 15");
                    response.append(line);
                }
                //RELEASE RES
                Log.i(TAG, "On Send 16");
                br.close();
                Log.i(TAG, "On Send 17");
                return response.toString();
            }else
            {
                Log.i(TAG, "On Send 18");
            }
        } catch (IOException e) {
            Log.i(TAG, "On Send 19");
            e.printStackTrace();
        }
        Log.i(TAG, "On Send 20");
        return null;
    }

这是 logcat:

04-04 15:34:01.402 20341-20341/com.example.pruebainsp I/Sender: OnPre
04-04 15:34:01.445 20341-20550/com.example.pruebainsp I/Sender: doInBack
04-04 15:34:01.445 20341-20550/com.example.pruebainsp I/Sender: On Send 1
04-04 15:34:01.445 20341-20550/com.example.pruebainsp I/Sender: On Send 2
04-04 15:34:01.446 20341-20550/com.example.pruebainsp I/Sender: On Send 4
04-04 15:34:01.561 20341-20550/com.example.pruebainsp I/Sender: On Send 5
04-04 15:34:01.562 20341-20550/com.example.pruebainsp I/Sender: On Send 6
04-04 15:34:01.562 20341-20550/com.example.pruebainsp I/Sender: On Send 7
04-04 15:34:01.562 20341-20550/com.example.pruebainsp I/Sender: On Send 8
04-04 15:34:01.562 20341-20550/com.example.pruebainsp I/Sender: On Send 9
04-04 15:34:01.700 20341-20550/com.example.pruebainsp I/Sender: On Send 10
04-04 15:53:57.934 27226-27436/com.example.pruebainsp I/Sender: responseCode = 403
04-04 15:34:01.700 20341-20550/com.example.pruebainsp I/Sender: On Send 18
04-04 15:34:01.700 20341-20550/com.example.pruebainsp I/Sender: On Send 20
04-04 15:34:02.214 20341-20341/com.example.pruebainsp I/Sender: onPost

Answer 1

doInBackground() 顾名思义在后台线程中执行任务。理想情况下，您不能在后台线程上执行 UI 相关操作。一些三星设备倾向于允许这样做，这很奇怪。在某些手机上，它会直接导致您的应用崩溃。

为了使其适用于所有设备，您可以:

@Override
protected Object doInBackground(Object[] objects) {
    activityObj.runOnUiThread(new Runnable() {
        @Override
        public void run() {
            Toast.makeText(contet, "Hello", Toast.LENGTH_LONG).show();
            }
    });
    return null;
}

或

@Override
protected Object doInBackground(Object[] objects) {
        new Handler(Looper.getMainLooper()).post(new Runnable() {
            @Override
            public void run() {
                Toast.makeText(getApplicationContext(), "Hello", Toast.LENGTH_LONG).show();
            }
        });
}