当应用将用户引导至 activity 时调用 onCreate 和 onResume

Question

我有一个 activity 允许用户从自定义对话框和显示数据的列表视图中插入数据。在对话框中输入数据后，onResume 应该更新列表视图。问题在于，当应用将用户定向到 activity 时，它会同时调用 onCreate 和 onResume，并且在用户从对话框插入数据后不会调用 onResume。出了什么问题以及如何解决？

SubjectListActivity.java

public class SubjectListActivity extends AppCompatActivity implements NavigationView.OnNavigationItemSelectedListener {
        private static final String TAG = "SubjectListActivity";
        private Animation rotateOpen;
        private Animation rotateClose;
        private Animation fromBottom;
        private Animation toBottom;
        private DrawerLayout drawerLayout;
        private NavigationView navigationView;
        private Toolbar toolbar;
        private boolean clicked = false;
        private ListView lv_subjectList;
        private FloatingActionButton btn_subjectMenu, btn_subjectDelete, btn_subjectAdd;
        DatabaseHelper databaseHelper;
        ArrayList<SubjectListModel> arrayList;
        SubjectListAdapter subjectListAdapter;
    
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_subject_list);
            intViews();
            loadAnimation();
            databaseHelper = new DatabaseHelper(this);
            arrayList = new ArrayList<>();
            loadListView();
            setSupportActionBar(toolbar);
    
            navigationView.bringToFront();
            ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(this,drawerLayout,toolbar,R.string.navigation_drawer_open,R.string.navigation_drawer_close);
            drawerLayout.addDrawerListener(toggle);
            toggle.syncState();
    
            navigationView.setNavigationItemSelectedListener(this);
            navigationView.setCheckedItem(R.id.nav_home);
    
            btn_subjectAdd.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    openDialog();
                }
            });
            Log.i(TAG, "onCreate: ");
        }
    
        @Override
        protected void onResume() {
            super.onResume();
            Log.i(TAG, "onResume: ");
            loadListView();
            navigationView.setCheckedItem(R.id.nav_subjectList);
        }
    
        public void loadListView () {
            arrayList = databaseHelper.getAllSubjectListData();
            subjectListAdapter = new SubjectListAdapter(this, arrayList);
            lv_subjectList.setAdapter(subjectListAdapter);
        }
    
        private void intViews() {
            toolbar = findViewById(R.id.toolbar);
            drawerLayout = findViewById(R.id.drawer_layout);
            navigationView = findViewById(R.id.nav_view);
            btn_subjectAdd = findViewById(R.id.btn_subjectAdd);
            btn_subjectMenu = findViewById(R.id.btn_subjectMenu);
            btn_subjectDelete = findViewById(R.id.btn_subjectDelete);
            lv_subjectList = findViewById(R.id.lv_SubjectList);
        }
    
        public void openDialog () {
            SubjectListDialog subjectListDialog = new SubjectListDialog();
            subjectListDialog.show(getSupportFragmentManager(), "subject list dialog");
        }
    
        
    }

SubjectListDialog.java

    public class SubjectListDialog extends AppCompatDialogFragment {
        private EditText et_subjectCode, et_subjectName, et_creditHour;
        DatabaseHelper databaseHelper;
        private ListView lv_SubjectList;
        SubjectListAdapter subjectListAdapter;
        SubjectListActivity subjectListActivity;
        ArrayList<SubjectListModel> arrayList;
        @Override
        public Dialog onCreateDialog(Bundle savedInstanceState) {
            databaseHelper = new DatabaseHelper(getContext());
            AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
    
            LayoutInflater inflater = getActivity().getLayoutInflater();
            View view = inflater.inflate(R.layout.layout_subjectlist_dialog, null);
    
            builder.setView(view)
                    .setTitle("Add Subject")
                    .setNegativeButton("cancel", new DialogInterface.OnClickListener() {
                        @Override
                        public void onClick(DialogInterface dialogInterface, int i) {
    
                        }
                    })
                    .setPositiveButton("confirm", new DialogInterface.OnClickListener() {
                        @Override
                        public void onClick(DialogInterface dialogInterface, int i) {
                            insert();
                            SubjectListDialog.this.dismiss();
                        }
                    });
            et_subjectCode = view.findViewById(R.id.et_subjectCode);
            et_subjectName = view.findViewById(R.id.et_subjectName);
            et_creditHour = view.findViewById(R.id.et_creditHour);
            return builder.create();
        }
    
        public void insert() {
            boolean result = databaseHelper.insertSubjectList(et_subjectCode.getText().toString(), et_subjectName.getText().toString(),Integer.parseInt(et_creditHour.getText().toString()));
            if (result) {
                Toast.makeText(requireContext(), "Data has been added", Toast.LENGTH_SHORT).show();
            } else {
                Toast.makeText(requireContext(), "Please insert all the fields correctly", Toast.LENGTH_SHORT).show();
            }
        }
    }

Answer 1

完成输入后，您应该关闭对话框。在您的情况下，在调用 insert() 后调用 SubjectListDialog.this.dismiss()

Update - 对话框片段不会暂停 activity 它就像片段在 activity 本身的视图边界内膨胀一样。这可以通过使用 activity 自己的片段管理器添加到屏幕这一事实得到进一步证实，正如您在代码 subjectListDialog.show(getSupportFragmentManager(), "subject list dialog");

中所做的那样

当应用将用户引导至 activity 时调用 onCreate 和 onResume

onCreate and onResume were called when app direct user to an activity

android

oncreate

onresume