Question

我尝试在设备上运行我的Android应用程序，我的登录崩溃了。 logcat显示此错误

09-12 21:32:12.289: E/AudioHardwareALSA(149): RE-OPEN AFTER STANDBY:: took 115 msecs
09-12 21:32:12.319: E/AndroidRuntime(4760): FATAL EXCEPTION: main
09-12 21:32:12.319: E/AndroidRuntime(4760): android.os.NetworkOnMainThreadException
09-12 21:32:12.319: E/AndroidRuntime(4760):     at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1099)
09-12 21:32:12.319: E/AndroidRuntime(4760):     at java.net.InetAddress.lookupHostByName(InetAddress.java:391)
09-12 21:32:12.319: E/AndroidRuntime(4760):     at java.net.InetAddress.getAllByNameImpl(InetAddress.java:242)
09-12 21:32:12.319: E/AndroidRuntime(4760):     at java.net.InetAddress.getAllByName(InetAddress.java:220)
09-12 21:32:12.319: E/AndroidRuntime(4760):     at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:137)
09-12 21:32:12.319: E/AndroidRuntime(4760):     at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164)
09-12 21:32:12.319: E/AndroidRuntime(4760):     at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119)
09-12 21:32:12.319: E/AndroidRuntime(4760):     at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:360)
09-12 21:32:12.319: E/AndroidRuntime(4760):     at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:555)
09-12 21:32:12.319: E/AndroidRuntime(4760):     at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:487)
09-12 21:32:12.319: E/AndroidRuntime(4760):     at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:465)
09-12 21:32:12.319: E/AndroidRuntime(4760):     at com.stts.sparetimetradingsystem.library.JSONParser.getJSONFromUrl(JSONParser.java:44)
09-12 21:32:12.319: E/AndroidRuntime(4760):     at com.stts.sparetimetradingsystem.library.UserFunctions.loginUser(UserFunctions.java:40)
09-12 21:32:12.319: E/AndroidRuntime(4760):     at com.stts.sparetimetradingsystem.LoginActivity$Login$1.run(LoginActivity.java:125)
09-12 21:32:12.319: E/AndroidRuntime(4760):     at android.os.Handler.handleCallback(Handler.java:605)
09-12 21:32:12.319: E/AndroidRuntime(4760):     at android.os.Handler.dispatchMessage(Handler.java:92)
09-12 21:32:12.319: E/AndroidRuntime(4760):     at android.os.Looper.loop(Looper.java:137)
09-12 21:32:12.319: E/AndroidRuntime(4760):     at android.app.ActivityThread.main(ActivityThread.java:4424)
09-12 21:32:12.319: E/AndroidRuntime(4760):     at java.lang.reflect.Method.invokeNative(Native Method)
09-12 21:32:12.319: E/AndroidRuntime(4760):     at java.lang.reflect.Method.invoke(Method.java:511)
09-12 21:32:12.319: E/AndroidRuntime(4760):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:787)
09-12 21:32:12.319: E/AndroidRuntime(4760):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:554)
09-12 21:32:12.319: E/AndroidRuntime(4760):     at dalvik.system.NativeStart.main(Native Method)

我哪里做错了？

修改

这是我的登录代码，它位于异步任务中，我可以知道我的异步任务是否正确编码：

// Background ASYNC Task to login by making HTTP Request
class Login extends AsyncTask<String, String, String> {

    // Before starting background thread Show Progress Dialog
    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        pDialog = new ProgressDialog(LoginActivity.this);
        pDialog.setMessage("Authenticating...");
        pDialog.setIndeterminate(false);
        pDialog.setCancelable(false);
        pDialog.show();
    }

    // Checking login in background
    protected String doInBackground(String... params) {
        runOnUiThread(new Runnable() {
            public void run() {

                String email = inputEmail.getText().toString();
                String password = inputPassword.getText().toString();
                UserFunctions userFunction = new UserFunctions();
                JSONObject json = userFunction.loginUser(email, password);

                // check for login response
                try {
                    if (json.getString(KEY_SUCCESS) != null) {
                        loginErrorMsg.setText("");
                        String res = json.getString(KEY_SUCCESS);
                        if (Integer.parseInt(res) == 1) {
                            validUser = true;
                            // user successfully logged in
                            // Store user details in SQLite Database
                            DatabaseHandler db = new DatabaseHandler(
                                    getApplicationContext());
                            JSONObject json_user = json
                                    .getJSONObject("user");

                            // Clear all previous data in database
                            userFunction
                                    .logoutUser(getApplicationContext());
                            db.addUser(json_user.getString(KEY_NAME),
                                    json_user.getString(KEY_EMAIL),
                                    json.getString(KEY_UID),
                                    json_user.getString(KEY_CREATED_AT));
                        } else {
                            // Error in login
                            loginErrorMsg
                                    .setText("Incorrect username/password");
                        }
                    }
                } catch (JSONException e) {
                    e.printStackTrace();
                }

            }
        });
        return null;
    }

    // After completing background task Dismiss the progress dialog
    protected void onPostExecute(String file_url) {
        // dismiss the dialog once done
        pDialog.dismiss();
        if (validUser == true) {
            loginErrorMsg.setText("");
            // Launch HomePage Screen
            Intent homepage = new Intent(getApplicationContext(),
                    HomepageActivity.class);

            // Close all views before launching HomePage
            homepage.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
            startActivity(homepage);

            // Close Login Screen
            finish();
        }
    }
}

Answer 1

Android不允许从android 3.0（Honeycomb）开始在主线程上进行网络调用。因此，您必须使用Asynctask进行网络呼叫。

要摆脱这种情况，您需要使用AsynTask进行网络调用。

Answer 2

您正在使用AsyncTask但在doInBackground中，您实际上是通过以下方式执行网络代码：

 runOnUiThread(new Runnable() { }

这就是为什么你最终得到这个例外的原因，你需要在没有它的情况下执行你的网络代码。我想你这样做是为了引用应用程序上下文，但只是通过AsyncTask构造函数提供它是相当简单的。

在真实设备上运行的Android应用程序崩溃了

2 个答案: