Android / Java |导航抽屉的 TextView .setText 无法通过 SharedPreferences 工作

Question

我有一个 Fragment 允许用户更改他们的用户名，该用户名将显示在导航抽屉内的 TextView 中。片段 'SettingsFragment' 在 MainActivity 中膨胀。

SettingsFragment 有一个 EditText，用户可以在其中输入他们的用户名和一个应用更改的按钮。导航抽屉是在 MainActivity 中创建的，因此我设置了 SharedPreferences 以将用户名发送到 MainActivity。然后我继续使用 .setText(username) 更改导航抽屉中的 TextView，但是没有任何反应。 但是当我重新启动应用程序时，导航抽屉的 TextView 更改为用户在 EditText 中输入的实际用户名。

SettingsFragment.java:

public class SettingsFragment extends Fragment {


public SettingsFragment() {
    // Required empty public constructor
}


@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    final View view = inflater.inflate(R.layout.fragment_settings, container, false);

    final TextInputEditText teiUserName = view.findViewById(R.id.teiUserName);
    final TextView tvEditTextSub = view.findViewById(R.id.tvEditTextSubstitute);
    Button btnApplyChanges = view.findViewById(R.id.btnApplyChanges);

    btnApplyChanges.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

            final String user_name = String.valueOf(teiUserName.getText());

            tvEditTextSub.setText(user_name);

            SharedPreferences.Editor editor = getActivity().getSharedPreferences("myPrefs", MODE_PRIVATE).edit();
            editor.putString("name", user_name);
            editor.apply();

        }
    });

    return view;
}}

SettingsFragment XML:

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:padding="10dp"
tools:context="com.miguelpeachey.marketplacesimulator.Fragments.SettingsFragment">

<RelativeLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <android.support.design.widget.TextInputEditText
        android:id="@+id/teiUserName"
        android:layout_width="248dp"
        android:layout_height="wrap_content"
        android:layout_above="@+id/btnApplyChanges"
        android:layout_marginBottom="28dp"
        android:text="User"
        android:textColorHint="#000" />

    <Button
        android:id="@+id/btnApplyChanges"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_centerHorizontal="true"
        android:layout_marginBottom="28dp"
        android:background="#33993f"
        android:padding="12dp"
        android:text="Apply Changes"
        android:textColor="#FFF" />

</RelativeLayout>

MainActivity.java:

public class MainActivity extends AppCompatActivity implements NavigationView.OnNavigationItemSelectedListener {

Fragment fragment;

SharedPreferences sharedPreferences;

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

    Toolbar toolbar = findViewById(R.id.toolbar);
    DrawerLayout drawer = findViewById(R.id.drawer_layout);
    NavigationView navigationView = findViewById(R.id.nav_view);
    View headerView = navigationView.getHeaderView(0);
    final TextView tvDrawerUsername = headerView.findViewById(R.id.tvDrawerUsername);
    setSupportActionBar(toolbar);

    sharedPreferences = getSharedPreferences("myPrefs", Context.MODE_PRIVATE);

    final String usernameID = sharedPreferences.getString("name", "User");

    if (drawer.isDrawerOpen(GravityCompat.START)) {
        tvDrawerUsername.setText(usernameID);
    }}

MainActivity.java中有更多代码，但没有必要包含它。

在MainActivity.java中，我也试过：

if (drawer.isDrawerOpen(GravityCompat.START)) {
        tvDrawerUsername.setText(usernameID);
    }

但在重新启动应用程序后，它甚至没有更改 Navigation Drawer 的 TextView (tvDrawerUsername)。

总之，应用不会在点击按钮后立即更新 tvDrawerUsername，只有在我重新启动应用后才会更新。

Answer 1

尝试在 SettingsFragment class 定义中定义 TextView 属性：

public class SettingsFragment extends Fragment {

TextView tv;

public SettingsFragment() {
    // Required empty public constructor
}

在同一个 class 上为此属性定义一个 setter :

public void setTextView(TextView tv){
    this.tv = tv
}

然后从您的 activity 初始化您的 fragment 和 textView 后，通过您刚刚创建的 setter 传递 textView :

fragment = new SettingsFragment();
fragment.setTextView(tvDrawerUsername);

最后在你的 onlick() 方法中添加 textView.setText(user_name); :

 btnApplyChanges.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                final String user_name = String.valueOf(teiUserName.getText());

                tvEditTextSub.setText(user_name);

                SharedPreferences.Editor editor = getActivity().getSharedPreferences("myPrefs", MODE_PRIVATE).edit();
                editor.putString("name", user_name);
                editor.apply();
                textView.setText(user_name);

            }
        });

希望对您有所帮助

Answer 2

试试这个：

public class MainActivity extends AppCompatActivity implements NavigationView.OnNavigationItemSelectedListener {

Fragment fragment;

SharedPreferences sharedPreferences;

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

    sharedPreferences = getSharedPreferences("myPrefs", Context.MODE_PRIVATE);Toolbar toolbar = findViewById(R.id.toolbar);
    DrawerLayout drawer = findViewById(R.id.drawer_layout);
    NavigationView navigationView = findViewById(R.id.nav_view);
    View headerView = navigationView.getHeaderView(0);
    final TextView tvDrawerUsername = headerView.findViewById(R.id.tvDrawerUsername);

    ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
                this, drawer, null, "navigation_drawer_open", "navigation_drawer_close") {
            public void onDrawerClosed(View view) {
                super.onDrawerClosed(view);
                // Do whatever you want here
            }

            public void onDrawerOpened(View drawerView) {
                super.onDrawerOpened(drawerView);

                final String usernameID = sharedPreferences.getString("name", "User");
                tvDrawerUsername.setText(usernameID);
            }
        };
    drawer.addDrawerListener(toggle);
    toggle.syncState();
    setSupportActionBar(toolbar);
}

Android / Java |导航抽屉的 TextView .setText 无法通过 SharedPreferences 工作

Android / Java | Navigation Drawer's TextView .setText not working through SharedPreferences

java

android

textview

sharedpreferences

navigation-drawer