Android应用程序获取权限无法正常运行

Question

写了一个获取联系人和联系人的电话号码然后显示在小程序中，但在获得Android 6的权限后无法显示数据，重启程序才能正常读取。我认为它应该存在访问问题，因为重启后权限不需要问什么时候可以正常读取，并且需要弹出对话框询问，同时允许访问权限但仍然无法显示，但重启后。 / p>

 public class MainActivity extends AppCompatActivity {
 
    ListView contactsView;
 
    ArrayAdapter<String> adapter;
 
    List<String> contactsList = new ArrayList<String>();
 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
        contactsView = (ListView) findViewById(R.id.contacts_view);
        adapter = new ArrayAdapter<String>(this, android.R.layout.
                simple_list_item_1, contactsList);
        contactsView.setAdapter(adapter);
        insertDummyContactWrapper();
    }
 
    final private int REQUEST_CODE_ASK_PERMISSIONS = 123;
 
    private void insertDummyContactWrapper() {
        int hasWriteContactsPermission = checkSelfPermission(Manifest.permission.READ_CONTACTS);
        if (hasWriteContactsPermission != PackageManager.PERMISSION_GRANTED) {
            requestPermissions(new String[] {Manifest.permission.READ_CONTACTS},
                    REQUEST_CODE_ASK_PERMISSIONS);
            return;
        }
        readContacts();
    }
 
    @Override
    public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
        switch (requestCode) {
            case REQUEST_CODE_ASK_PERMISSIONS:
                if (grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                    // Permission Granted
                    readContacts();
                } else {
                    // Permission Denied
                    Toast.makeText(MainActivity.this, "READ_CONTACTS Denied", Toast.LENGTH_SHORT)
                            .show();
                }
                break;
            default:
                super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        }
    }
 
    public void readContacts() {
        Cursor cursor = null;
        try {
            cursor = getContentResolver().query(ContactsContract.CommonDataKinds.Phone.CONTENT_URI,
                    null, null, null, null);
            while (cursor.moveToNext()) {
                String displayName = cursor.getString(cursor.getColumnIndex(ContactsContract.
                        CommonDataKinds.Phone.DISPLAY_NAME));
                String number = cursor.getString(cursor.getColumnIndex(ContactsContract.
                        CommonDataKinds.Phone.NUMBER));
                contactsList.add(displayName + "\n" + number);
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (cursor != null) {
                cursor.close();
            }
        }
    }