我怎么能得到一个输入的文本输入布局作为共享的首选项，并打印他们在另一个活动？

Question

我正在尝试使用共享首选项并将我的数据发送到另一个活动中。当我单击注册文本视图时，应用程序崩溃并收到错误消息

Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.widget.EditText com.google.android.material.textfield.TextInputLayout.getEditText()' on a null object reference
        at com.example.irongym.RegistrationActivity.onCreate(RegistrationActivity.java:45)

在我使用EditText的其他情况下，我使用了类似的方法，而且很有效。我认为我尝试获取数据的方式是错误的，因为现在我使用的是TextInputLayout

这是我的注册活动。java（onCreate）

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    SharedPreferences file = getSharedPreferences("userData", MODE_PRIVATE);

    TextInputLayout nameField = findViewById(R.id.TextInputEditText);
    TextInputLayout passwordField = findViewById(R.id.PasswordInputEditText);
    TextInputLayout phoneField = findViewById(R.id.PhoneInputEditText);

    String na = file.getString("name", "");
    String pas = file.getString("password2", "");
    String ph = file.getString("phone", "");

    nameField.getEditText().setText(na); // This is line 45 from the error i get
    passwordField.getEditText().setText(pas);
    phoneField.getEditText().setText(ph);

这是我的注册活动.java按钮点击

public void confirmInput(View v) {
    SharedPreferences file = getSharedPreferences("userData", MODE_PRIVATE);
    SharedPreferences.Editor editor = file.edit();

    TextInputLayout nameField = findViewById(R.id.TextInputEditText);
    TextInputLayout passwordField = findViewById(R.id.PasswordInputEditText);
    TextInputLayout phoneField = findViewById(R.id.PhoneInputEditText);

    String name = nameField.getEditText().getText().toString();
    String password2 = passwordField.getEditText().getText().toString();
    String phone = phoneField.getEditText().getText().toString();

    editor.putString("name", name);
    editor.putString("password2", password2);
    editor.putString("phone", phone);

    editor.commit();
    
    Intent in = new Intent(this, LoginActivity.class);
    startActivity(in);
}

这是我的ProfileActivity.java，数据将在这里显示

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    binding = ActivityProfileBinding.inflate(getLayoutInflater());
    setContentView(binding.getRoot());

    setSupportActionBar(binding.toolbar);

    SharedPreferences file = getSharedPreferences("userData", MODE_PRIVATE);

    String we = file.getString("weight", "no-weight");
    String he = file.getString("height", "no-height");
    String na = file.getString("name", "no-name");
    String ph = file.getString("phone", "no-phone");
    String ps = file.getString("password2", "no-password");

    TextView tvWe = findViewById(R.id.tvWeight);
    TextView tvHe = findViewById(R.id.tvHeight);
    TextView tvNa = findViewById(R.id.tvName);
    TextView tvPh = findViewById(R.id.tvPhone);
    TextView tvPs = findViewById(R.id.tvPassword);

    tvWe.setText(we);
    tvHe.setText(he);
    tvNa.setText(na);
    tvPh.setText(ph);
    tvPs.setText(ps);

    binding.fab.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                    .setAction("Action", null).show();
        }
    });
}

Answer 1

您忘记在RegistrationActivity中调用setContentView