Question

我有一项服务，可以从我的webservice中删除一个对象并返回当前列表。每次我请求服务时，它都会更新我的textview（具有列表的大小）和适配器。问题是当我转到MainActivity并返回执行此服务的活动时，textview和适配器不再更新。

apiServices.deleteEmployee(new APIServices.BookmarkCallback() {
   @Override
   public void onSuccess(final ArrayList<Employee> list) {  

  remainingPeople.setText(getResources().getString(R.string.remaining_people) + list.size());
  adapter = new ArrayAdapter<>(getApplicationContext(), 
            android.R.layout.simple_list_item_1, list);
  employeesList.setAdapter(adapter);


}

在我的onCreate()方法上设置了代码。返回活动后仍会更新textview。

onCreate()方法：


 @Override
    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);


        // Remove notification bar
        this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);

        //set content view AFTER ABOVE sequence (to avoid crash)
        this.setContentView(R.layout.activity_count);

        remainingPeople = findViewById(R.id.peopleCounter);


        findBT();
        openBT();


        @SuppressWarnings("unchecked")
        ArrayList<Employee> list = (ArrayList<Employee>) getIntent()
                .getSerializableExtra(SEND_EMPLOYEES_LIST);


        remainingPeople.setText(getResources().getString(R.string.remaining_people) + list.size());

        employeesList = findViewById(R.id.employees_list);
        adapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, list);
        employeesList.setAdapter(adapter);


        beep = new ToneGenerator(AudioManager.STREAM_ALARM, 900);

        handler = new Handler(Looper.getMainLooper()) {
            @Override
            public void handleMessage(Message message) {
                switch (message.what) {
                    case READ_ARRAY_BYTE:
                        byte[] arrayBytes = new byte[message.arg1];
                        System.arraycopy(message.obj, 0, arrayBytes, 0, message.arg1);
                        try {
                            String epc = new String(arrayBytes, "UTF-8");
                            beep.stopTone();
                            epc = epc.substring(0, 24);
                            apiServices.deleteEmployee(new APIServices.BookmarkCallback() {
                                @Override
                                public void onSuccess(final ArrayList<Employee> list) {
                               //this part updates after the API response
                                    remainingPeople.setText(getResources().getString(R.string.remaining_people) + list.size());
                                    adapter = new ArrayAdapter<>(getApplicationContext(), android.R.layout.simple_list_item_1, list);
                                    employeesList.setAdapter(adapter);

                                }

                                @Override
                                public void onError() {

                                }
                            }, epc);
                        } catch (UnsupportedEncodingException e) {
                            e.printStackTrace();
                        }
                        break;


//...

Answer 1

尝试将更新textview而不是onResume()的过程放在onCreate()

@Override
 public void onResume(){ 
 super.onResume(); 
 // put your code here...
 }

Answer 2

我通过michiakig's answer找到了一个解决方案，可以将文本视图声明为static，但是我可能会遇到问题。因此，另一种方法是使用Activity.onSaveInstanceState保存。谢谢所有回答我的人。

返回某些活动时无法设置Textview

2 个答案: