Question

我一直在尝试创建一个使用导航抽屉的计算器应用程序。我有6个片段，每个片段都有> index4 [[1]] [1] 2，用于从用户那里获取输入。

但是，当我运行该应用程序并在EditText中键入一些值（任何片段都没有关系）并更改该片段并返回到我之前输入值的先前片段时，输入的值将消失并恢复默认值。

我该如何解决这个问题？

MainActivity.java

EditTexts

TankBilgileriFragment

package com.example.testnavigation;

import android.content.Intent;
import android.os.Bundle;

import com.google.android.material.floatingactionbutton.FloatingActionButton;
import com.google.android.material.snackbar.Snackbar;

import android.view.MenuItem;
import android.view.View;

import androidx.annotation.NonNull;
import androidx.core.view.GravityCompat;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentManager;
import androidx.fragment.app.FragmentTransaction;
import androidx.navigation.NavController;
import androidx.navigation.Navigation;
import androidx.navigation.ui.AppBarConfiguration;
import androidx.navigation.ui.NavigationUI;

import com.google.android.material.navigation.NavigationView;

import androidx.drawerlayout.widget.DrawerLayout;

import androidx.appcompat.app.AppCompatActivity;
import androidx.appcompat.widget.Toolbar;

import android.view.Menu;

public class MainActivity extends AppCompatActivity implements MyListener{

     private AppBarConfiguration mAppBarConfiguration;

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

        Toolbar toolbar = findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);


        DrawerLayout drawer = findViewById(R.id.drawer_layout);
        NavigationView navigationView = findViewById(R.id.nav_view);

        mAppBarConfiguration = new AppBarConfiguration.Builder(
                R.id.nav_gubreler, R.id.nav_sonuc, R.id.nav_hedef, R.id.nav_oranlar, R.id.nav_tankbilgileri, R.id.nav_cevirme)
                .setDrawerLayout(drawer)
                .build();
        NavController navController = Navigation.findNavController(this, R.id.nav_host_fragment);
        NavigationUI.setupActionBarWithNavController(this, navController, mAppBarConfiguration);
        NavigationUI.setupWithNavController(navigationView, navController);

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onSupportNavigateUp() {
        NavController navController = Navigation.findNavController(this, R.id.nav_host_fragment);
        return NavigationUI.navigateUp(navController, mAppBarConfiguration)
                || super.onSupportNavigateUp();
    }


}

GubrelerFragment

package com.example.testnavigation;

import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.EditText;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.fragment.app.Fragment;

public class TankBilgileriFragment extends Fragment {
    EditText tet1, tet2;
    double tet1v, tet2v;

    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {

        View v=inflater.inflate(R.layout.fragment_tankbilgileri, container, false);
        tet1=(EditText) v.findViewById(R.id.tet1); tet1v=Double.parseDouble(tet1.getText().toString()); tet2=(EditText) v.findViewById(R.id.tet2); double tet2v=Double.parseDouble(tet2.getText().toString());
        return v;
    }
}

fragment_gubreler.xml

    package com.example.testnavigation;

    import android.os.Bundle;
    import android.view.LayoutInflater;
    import android.view.View;
    import android.view.ViewGroup;
    import android.widget.Button;
    import android.widget.EditText;

    import androidx.annotation.NonNull;
    import androidx.annotation.Nullable;
    import androidx.fragment.app.Fragment;

    import java.text.DecimalFormat;


    public class GubrelerFragment extends Fragment{

        Button gbtnSifirla, gbtnHesapla, gbtnKaydet;
        EditText get1, get2, get3, get4, get5, get6, get7, get8, get9, get10, get11, get12, get13, get14, get15, get16;

        @Nullable
        @Override
        public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {

            View v=inflater.inflate(R.layout.fragment_gubreler, container, false);


            gbtnHesapla=(Button) v.findViewById(R.id.gbtnHesapla); gbtnSifirla=(Button) v.findViewById(R.id.gbtnSifirla); gbtnKaydet=(Button) v.findViewById(R.id.gbtnKaydet);
            get1=(EditText) v.findViewById(R.id.get1);   get2=(EditText) v.findViewById(R.id.get2);   get3=(EditText) v.findViewById(R.id.get3);   get4=(EditText) v.findViewById(R.id.get4);   get5=(EditText) v.findViewById(R.id.get5);
            get6=(EditText) v.findViewById(R.id.get6);   get7=(EditText) v.findViewById(R.id.get7);   get8=(EditText) v.findViewById(R.id.get8);   get9=(EditText) v.findViewById(R.id.get9);   get10=(EditText) v.findViewById(R.id.get10);
            get11=(EditText) v.findViewById(R.id.get11); get12=(EditText) v.findViewById(R.id.get12); get13=(EditText) v.findViewById(R.id.get13); get14=(EditText) v.findViewById(R.id.get14); get15=(EditText) v.findViewById(R.id.get15);
            get16=(EditText) v.findViewById(R.id.get16);

            return v;
        }
@Override
    public void onActivityCreated(@Nullable Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        if (savedInstanceState!=null){
        get1.setText(savedInstanceState.getString("key1"));}
    }

    @Override
    public void onSaveInstanceState(@NonNull Bundle outState) {
        super.onSaveInstanceState(outState);
        outState.putString("key1",get1.getText().toString());
    }
    }

Answer 1

您需要了解“ saveInstance”

-keepclassmembers class ** {
    @org.greenrobot.eventbus.Subscribe public *;
}

Answer 2

我使用SharedPreferences解决了我的问题。我在Fragment和onClick方法中添加了一个按钮，用于保存具有SharedPreferences的值，并在onCreateView内还原值（在返回v;之前），因此即使我关闭该应用程序或更改任何其他碎片值，仍然保留。

如何在片段的edittext中保存输入值？

2 个答案: