java - null return Intent on android编程

Question

我在 android studio 中编写了一个简单的程序，并从 Intent 创建了一个对象。但我不知道为什么它返回 null ??

在 MainActivity.java 中，我将用户名和密码发送到 ProfileActivity.java。但是 Log.i 显示为空!但 token 不为空

com.example.sayres.myapplication2.ProfileActivity: onCreate User Name: null Password: null Token: 22546874569

主要 Activity .java:

public class MainActivity extends AppCompatActivity implements View.OnClickListener {
    public static final String INTENT_USER_NAME_KYE = "user_name_key";
    public static final String INTENT_USER_PASSWORD_KYE = "password_key";

    protected final String TAG = "====>";

    private EditText editTextUserName, editTextPassword;
    private Button buttonLogin, buttonExit;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initView();


    }


    @Override
    public void onClick(View v) {
        switch (v.getId()) {
            case R.id.btnLogin:
                getUserInfo();
                break;
            case R.id.btnExit:
                finish();
                break;
        }


    }



    private void initView() {
        editTextUserName = (EditText) findViewById(R.id.editUserName);
        editTextPassword = (EditText) findViewById(R.id.editPassword);
        buttonExit = (Button) findViewById(R.id.btnExit);
        buttonLogin = (Button) findViewById(R.id.btnLogin);

        buttonLogin.setOnClickListener(this);
        buttonExit.setOnClickListener(this);
    }


    private void getUserInfo() {
        String userName = editTextUserName.getText().toString();
        String password = editTextPassword.getText().toString();
        editTextUserName.setText("");
        editTextPassword.setText("");


        String msg = "";
        if (userName.isEmpty() || password.isEmpty()) {
            msg = "Insert UserName And Password !!!";
        } else {
            msg = "Welcome " + userName;
            // TODO: 1/7/2017 go to ProfileActivity !!!

            Intent intent = new Intent(this, ProfileActivity.class);
            intent.putExtra("INTENT_USER_NAME_KYE", userName);
            intent.putExtra("INTENT_USER_PASSWORD_KYE", password);

            Bundle bundle = new Bundle();
            bundle.putString("user_token", "22546874569");
            intent.putExtras(bundle);

            startActivity(intent);
            finish();
        }

        Log.i(TAG, "UserName= " + userName + "\t" + "Password= " + password);
        Toast.makeText(MainActivity.this, msg, Toast.LENGTH_LONG).show();
    }

}

ProfileActivity.java:

public class ProfileActivity extends AppCompatActivity {
    private static final String TAG = ProfileActivity.class.getName();
    private TextView textViewUserName, textViewPassword, textViewAge, textViewSex;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_profile);
//        initviews();
        Intent intent = getIntent();
        String userName = intent.getStringExtra(MainActivity.INTENT_USER_NAME_KYE);
        String password = intent.getStringExtra(MainActivity.INTENT_USER_PASSWORD_KYE);

//        System.out.println("User Name iS:"+userName);
        Bundle extras = intent.getExtras();
        String user_token = extras.getString("user_token");

        Log.i(TAG, "onCreate " + "User Name: " + userName + " Password: " + password + " Token: " + user_token);
    }

Answer 1

intent.putExtra("INTENT_USER_NAME_KYE", userName);
intent.putExtra("INTENT_USER_PASSWORD_KYE", password);

您使用的是文字 "INTENT_USER_NAME_KYE" 作为 intent 键，而不是用于阅读附加内容的 INTENT_USER_NAME_KYE 字段的值:

String userName = intent.getStringExtra(MainActivity.INTENT_USER_NAME_KYE);
String password = intent.getStringExtra(MainActivity.INTENT_USER_PASSWORD_KYE);

删除 "。