如何处理IOException?

时间:2016-03-30 10:26:53

标签: java android ioexception google-tasks-api google-tasks

我正在尝试在我的应用程序中同步google任务。我创建了一个类来处理用于获取任务列表和所有任务相关方法的方法。

我想在UI中调用这些方法。

出于测试目的,我已经创建了一个扩展AsyncTask的类,我将该方法称为getTaskList。但这是一个例外,我认为我已经以错误的方式处理了它。

我想知道getTaskList的方法,提供的参数是listId。它应该从指定的id列表返回所有任务。

现在我应该如何传递列表的Id以测试它是否会返回所有任务?

现在我收到的错误是:

    FATAL EXCEPTION: AsyncTask #1
03-30 21:21:10.593 15993-16025/com.example.siddhi.taskdemo E/AndroidRuntime: Process: com.example.siddhi.taskdemo, PID: 15993
03-30 21:21:10.593 15993-16025/com.example.siddhi.taskdemo E/AndroidRuntime: java.lang.RuntimeException: An error occured while executing doInBackground()
03-30 21:21:10.593 15993-16025/com.example.siddhi.taskdemo E/AndroidRuntime:     at android.os.AsyncTask$3.done(AsyncTask.java:304)
03-30 21:21:10.593 15993-16025/com.example.siddhi.taskdemo E/AndroidRuntime:     at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355)
03-30 21:21:10.593 15993-16025/com.example.siddhi.taskdemo E/AndroidRuntime:     at java.util.concurrent.FutureTask.setException(FutureTask.java:222)
03-30 21:21:10.593 15993-16025/com.example.siddhi.taskdemo E/AndroidRuntime:     at java.util.concurrent.FutureTask.run(FutureTask.java:242)
03-30 21:21:10.593 15993-16025/com.example.siddhi.taskdemo E/AndroidRuntime:     at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
03-30 21:21:10.593 15993-16025/com.example.siddhi.taskdemo E/AndroidRuntime:     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
03-30 21:21:10.593 15993-16025/com.example.siddhi.taskdemo E/AndroidRuntime:     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
03-30 21:21:10.593 15993-16025/com.example.siddhi.taskdemo E/AndroidRuntime:     at java.lang.Thread.run(Thread.java:818)
03-30 21:21:10.593 15993-16025/com.example.siddhi.taskdemo E/AndroidRuntime:  Caused by: java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()
03-30 21:21:10.593 15993-16025/com.example.siddhi.taskdemo E/AndroidRuntime:     at android.os.Handler.<init>(Handler.java:200)
03-30 21:21:10.593 15993-16025/com.example.siddhi.taskdemo E/AndroidRuntime:     at android.os.Handler.<init>(Handler.java:114)
03-30 21:21:10.593 15993-16025/com.example.siddhi.taskdemo E/AndroidRuntime:     at android.widget.Toast$TN.<init>(Toast.java:344)
03-30 21:21:10.593 15993-16025/com.example.siddhi.taskdemo E/AndroidRuntime:     at android.widget.Toast.<init>(Toast.java:100)
03-30 21:21:10.593 15993-16025/com.example.siddhi.taskdemo E/AndroidRuntime:     at android.widget.Toast.makeText(Toast.java:258)
03-30 21:21:10.593 15993-16025/com.example.siddhi.taskdemo E/AndroidRuntime:     at com.example.siddhi.taskdemo.TestAsyncTask.doInBackground(TestAsyncTask.java:54)
03-30 21:21:10.593 15993-16025/com.example.siddhi.taskdemo E/AndroidRuntime:     at com.example.siddhi.taskdemo.TestAsyncTask.doInBackground(TestAsyncTask.java:25)
03-30 21:21:10.593 15993-16025/com.example.siddhi.taskdemo E/AndroidRuntime:     at android.os.AsyncTask$2.call(AsyncTask.java:292)
03-30 21:21:10.593 15993-16025/com.example.siddhi.taskdemo E/AndroidRuntime:     at java.util.concurrent.FutureTask.run(FutureTask.java:237)
03-30 21:21:10.593 15993-16025/com.example.siddhi.taskdemo E/AndroidRuntime:     at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231) 
03-30 21:21:10.593 15993-16025/com.example.siddhi.taskdemo E/AndroidRuntime:     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112) 
03-30 21:21:10.593 15993-16025/com.example.siddhi.taskdemo E/AndroidRuntime:     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587) 
03-30 21:21:10.593 15993-16025/com.example.siddhi.taskdemo E/AndroidRuntime:     at java.lang.Thread.run(Thread.java:818) 

主要活动:

  public class MainActivity extends AppCompatActivity {
        GoogleAccountCredential mCredential;
        public TextView mOutputText;
        ProgressDialog mProgress;

        static final int REQUEST_ACCOUNT_PICKER = 1000;
        static final int REQUEST_AUTHORIZATION = 1001;
        static final int REQUEST_GOOGLE_PLAY_SERVICES = 1002;
        private static final String PREF_ACCOUNT_NAME = "accountName";
        private static final String[] SCOPES = { TasksScopes.TASKS };
        public com.google.api.services.tasks.Tasks mService = null;
        /**
         * Create the main activity.
         * @param savedInstanceState previously saved instance data.
         */
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            LinearLayout activityLayout = new LinearLayout(this);
            LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams(
                    LinearLayout.LayoutParams.MATCH_PARENT,
                    LinearLayout.LayoutParams.MATCH_PARENT);
            activityLayout.setLayoutParams(lp);
            activityLayout.setOrientation(LinearLayout.VERTICAL);
            activityLayout.setPadding(16, 16, 16, 16);

            ViewGroup.LayoutParams tlp = new ViewGroup.LayoutParams(
                    ViewGroup.LayoutParams.WRAP_CONTENT,
                    ViewGroup.LayoutParams.WRAP_CONTENT);

            mOutputText = new TextView(this);
            mOutputText.setLayoutParams(tlp);
            mOutputText.setPadding(16, 16, 16, 16);
            mOutputText.setVerticalScrollBarEnabled(true);
            mOutputText.setMovementMethod(new ScrollingMovementMethod());
            activityLayout.addView(mOutputText);

            mProgress = new ProgressDialog(this);
            mProgress.setMessage("Calling Google Tasks API ...");

            setContentView(activityLayout);

            // Initialize credentials and service object.
            SharedPreferences settings = getPreferences(Context.MODE_PRIVATE);
            mCredential = GoogleAccountCredential.usingOAuth2(
                    getApplicationContext(), Arrays.asList(SCOPES))
                    .setBackOff(new ExponentialBackOff())
                    .setSelectedAccountName(settings.getString(PREF_ACCOUNT_NAME, null));

            HttpTransport transport = AndroidHttp.newCompatibleTransport();
            JsonFactory jsonFactory = JacksonFactory.getDefaultInstance();
            mService = new com.google.api.services.tasks.Tasks.Builder(
                    transport, jsonFactory, mCredential)
                    .setApplicationName("Google Tasks API Android Quickstart")
                    .build();
        }


        /**
         * Called whenever this activity is pushed to the foreground, such as after
         * a call to onCreate().
         */
        @Override
        protected void onResume() {
            super.onResume();
            if (isGooglePlayServicesAvailable()) {
                refreshResults();
            } else {
                mOutputText.setText("Google Play Services required: " +
                        "after installing, close and relaunch this app.");
            }
        }

        /**
         * Called when an activity launched here (specifically, AccountPicker
         * and authorization) exits, giving you the requestCode you started it with,
         * the resultCode it returned, and any additional data from it.
         * @param requestCode code indicating which activity result is incoming.
         * @param resultCode code indicating the result of the incoming
         *     activity result.
         * @param data Intent (containing result data) returned by incoming
         *     activity result.
         */
        @Override
        protected void onActivityResult(
                int requestCode, int resultCode, Intent data) {
            super.onActivityResult(requestCode, resultCode, data);
            switch(requestCode) {
                case REQUEST_GOOGLE_PLAY_SERVICES:
                    if (resultCode != RESULT_OK) {
                        isGooglePlayServicesAvailable();
                    }
                    break;
                case REQUEST_ACCOUNT_PICKER:
                    if (resultCode == RESULT_OK && data != null &&
                            data.getExtras() != null) {
                        String accountName =
                                data.getStringExtra(AccountManager.KEY_ACCOUNT_NAME);
                        if (accountName != null) {
                            mCredential.setSelectedAccountName(accountName);
                            SharedPreferences settings =
                                    getPreferences(Context.MODE_PRIVATE);
                            SharedPreferences.Editor editor = settings.edit();
                            editor.putString(PREF_ACCOUNT_NAME, accountName);
                            editor.apply();
                        }
                    } else if (resultCode == RESULT_CANCELED) {
                        mOutputText.setText("Account unspecified.");
                    }
                    break;
                case REQUEST_AUTHORIZATION:
                    if (resultCode != RESULT_OK) {
                        chooseAccount();
                    }
                    break;
            }

            super.onActivityResult(requestCode, resultCode, data);
        }

        /**
         * Attempt to get a set of data from the Google Tasks API to display. If the
         * email address isn't known yet, then call chooseAccount() method so the
         * user can pick an account.
         */
        private void refreshResults() {
            if (mCredential.getSelectedAccountName() == null) {
                chooseAccount();
            } else {
                if (isDeviceOnline()) {
                    new TestAsyncTask(mCredential, MainActivity.this).execute();
                } else {
                    mOutputText.setText("No network connection available.");
                }
            }
        }
        /**
         * Starts an activity in Google Play Services so the user can pick an
         * account.
         */
        private void chooseAccount() {
            startActivityForResult(
                    mCredential.newChooseAccountIntent(), REQUEST_ACCOUNT_PICKER);
        }

        /**
         * Checks whether the device currently has a network connection.
         * @return true if the device has a network connection, false otherwise.
         */
        private boolean isDeviceOnline() {
            ConnectivityManager connMgr =
                    (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
            NetworkInfo networkInfo = connMgr.getActiveNetworkInfo();
            return (networkInfo != null && networkInfo.isConnected());
        }

        /**
         * Check that Google Play services APK is installed and up to date. Will
         * launch an error dialog for the user to update Google Play Services if
         * possible.
         * @return true if Google Play Services is available and up to
         *     date on this device; false otherwise.
         */
        private boolean isGooglePlayServicesAvailable() {
            final int connectionStatusCode =
                    GooglePlayServicesUtil.isGooglePlayServicesAvailable(this);
            if (GooglePlayServicesUtil.isUserRecoverableError(connectionStatusCode)) {
                showGooglePlayServicesAvailabilityErrorDialog(connectionStatusCode);
                return false;
            } else if (connectionStatusCode != ConnectionResult.SUCCESS ) {
                return false;
            }
            return true;
        }

        /**
         * Display an error dialog showing that Google Play Services is missing
         * or out of date.
         * @param connectionStatusCode code describing the presence (or lack of)
         *     Google Play Services on this device.
         */
        void showGooglePlayServicesAvailabilityErrorDialog(
                final int connectionStatusCode) {
            Dialog dialog = GooglePlayServicesUtil.getErrorDialog(
                    connectionStatusCode,
                    MainActivity.this,
                    REQUEST_GOOGLE_PLAY_SERVICES);
            dialog.show();
        }

    }

TestAsyncTask

  public class TestAsyncTask extends AsyncTask<Void, Void, List<Task>>{

    private com.google.api.services.tasks.Tasks mService = null;
    private Exception mLastError = null;
    private MainActivity activity;
    private com.google.api.services.tasks.Tasks client = null;

    public TestAsyncTask(GoogleAccountCredential credential, MainActivity activity) {
        HttpTransport transport = AndroidHttp.newCompatibleTransport();
        JsonFactory jsonFactory = JacksonFactory.getDefaultInstance();
        mService = new com.google.api.services.tasks.Tasks.Builder(
                transport, jsonFactory, credential)
                .setApplicationName("Google Tasks API Android Quickstart")
                .build();
        this.activity = activity;
    }

    protected List<Task> doInBackground(Void... params) {

        GTaskSyncer gTaskSyncer = new GTaskSyncer(activity);

        List<Task> result = new ArrayList<>();

        try {

            result = gTaskSyncer.getTaskList("Bdjxxuj");

        } catch (IOException e) {

            Toast.makeText(activity,"IO Exception",Toast.LENGTH_SHORT).show();
        }
        return result;
    }


    @Override
    protected void onPostExecute(List<Task> output) {
        activity.mProgress.hide();
        if (output == null || output.size() == 0) {
            activity.mOutputText.setText("No results returned.");
        } else {
            activity.mOutputText.setText(TextUtils.join("\n", output));
        }
    }
}

GTaskSyncer

 public class GTaskSyncer
{

    final MainActivity activity;
    final com.google.api.services.tasks.Tasks mService;
    private Exception mLastError = null;



    GTaskSyncer(MainActivity activity) {
        this.activity = activity;
        mService = activity.mService;
    }

    public List<TaskList> getAllTaskList() throws IOException
    {
        List<TaskList> result = new ArrayList<TaskList>();

        TaskLists taskLists = mService.tasklists().list().execute();

        for (TaskList taskList : taskLists.getItems()) {

                result.add(taskList);
        }

        return result;

    }


    public TaskList createList() throws IOException
    {

        TaskList taskList = new TaskList();

        taskList =  activity.mService.tasklists().insert(taskList).execute();

        return taskList;
    }

    public Task createTask(String listId) throws IOException
    {

        Task task = new Task();

        task =   activity.mService.tasks().insert(listId, task).execute();

        return  task;
    }

    public Task getTask(String listId,String taskId) throws IOException
    {

        Task task =   activity.mService.tasks().get(listId, taskId).execute();

        return task;
    }

    public List<Task> getTaskList(String listId) throws IOException {


        List<Task> result = new ArrayList<Task>();

        List<Task> tasks = mService.tasks().list(listId).execute().getItems();

        if (tasks != null) {

            for (Task task : tasks) {

                result.add(task);
            }
        } else {

            Toast.makeText(activity, "No tasks.", Toast.LENGTH_SHORT).show();
        }

        return result;
    }

}

请帮助..

1 个答案:

答案 0 :(得分:1)

您无法在后台主题中显示祝酒词。

使用它:

   Handler handler = new Handler(Looper.getMainLooper());
   handler.post(new Runnable() {
        @Override
        public void run() {
            Toast.makeText(activity, "No tasks.", Toast.LENGTH_SHORT).show();
        }
    });