Question

我有一个Fragment，允许用户更改其用户名，该用户名将显示在导航抽屉内的TextView中。片段“ SettingsFragment”在MainActivity中被夸大。

SettingsFragment具有一个EditText，用户可以在其中输入其用户名和一个按钮来应用更改。导航抽屉是在MainActivity中创建的，因此我设置了SharedPreferences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，但是什么也没有发生。 但是当我重新启动该应用程序时，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中包含更多代码，但无需包含它。

在MainActivity.java中，我也尝试过：

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

但是重新启动应用程序后，它甚至都没有更改导航抽屉的TextView（tvDrawerUsername）。

总而言之，该应用程序不会在单击按钮后立即更新tvDrawerUsername，而只是在我重新启动该应用程序之后。

Answer 1

尝试这个：

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);
}

Answer 2

尝试在TextView类定义上定义SettingsFragment属性：

public class SettingsFragment extends Fragment {

TextView tv;

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

在同一类上为此属性定义一个设置器：

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

从您的活动开始，在初始化fragment和textView之后，通过刚刚创建的设置器传递textView：

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

最后在您的textView.setText(user_name);方法内添加onlick()：

 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);

            }
        });

希望这会有所帮助

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

2 个答案: