Question

我是Android开发的初学者，我遇到了保存更改的问题，某些文本显示在某些TextView中。但对我来说更难一点。为了解释简单，我有2个活动，Activity1是主要的，Activity2是用户信息。在Activity1（Main）中，用户clic按钮（＆＃34;登录＆＃34;）然后他继续Activity2，用户可以输入他的个人信息，然后点击按钮（＆＃34;保存数据＆＃34;）然后我在数据库（SQLite）上添加他的数据，然后当用户点击另一个按钮（＆＃34; go＆＃34;）时，他返回Activity1我使用一个意图，以便在Activity1中的TextView上显示他的昵称a＆＃34;欢迎＆＃34; +昵称。但是当用户退出应用程序时，没有保存，更改没有使用昵称保存，但昵称始终在我的数据库中。

我会告诉你一些代码：活性2：

public class ProfilActivity extends Activity {

EditText editNickname; // We just work on the nickname so I just keep it
MyDatabase myDb;
Button bAddData, go;
public SharedPreferences prefs;
private String nicktobesaved;

@Override
public void onCreate(final Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    this.setContentView(R.layout.activity_profil);
    myDb = new MyDatabase(this);
    prefs = getSharedPreferences("sharedPreferences", Context.MODE_PRIVATE);

    editNickname = (EditText) findViewById(R.id.pseudo2);
    bAddData = (Button) findViewById(R.id.ajouter);

    nicktobesaved = prefs.getString("nickname", "");
    bAddData.setEnabled(prefs.getBoolean("isEnabled", true) ? true : false);

    AddData();
} // End onCreate()

public void changeNickname(View v) {
    // I delete this method who passed an intent
}

public void AddData() { // When user click on bAddData button
    bAddData.setOnClickListener(
            new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    nicktobesaved = prefs.getString("nickname", "");
                    nicktobesaved = editPseudo.getText().toString();

// The following code is just for save data on my database SQLite
                    boolean isInserted = myDb.insertData(editNickname.getText().toString());
                    if (isInserted == true) {
                        Toast.makeText(ProfilActivity.this, "Data saved", Toast.LENGTH_LONG).show();
                        prefs.edit().putBoolean("isEnabled", false).apply();
                        bAddData.setEnabled(false);
                    } else {
                        Toast.makeText(ProfilActivity.this, "Data not saved", Toast.LENGTH_LONG).show();
                    }
                }
            }
    );
}
}

活动1（主要活动）：

public class MainActivity extends Activity {

TextView tv;
Button login;
public SharedPreferences prefs;
private String nickname;

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

    prefs = getSharedPreferences("sharedPreferences", Context.MODE_PRIVATE);
    nickname = prefs.getString("nickname", "");

    login = (Button) findViewById(R.id.connexion);
    login.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent intentLogin = new Intent(MainActivity.this, ProfilActivity.class);
            startActivity(intentLogin);
        }
    });

    tv = (TextView)findViewById(R.id.pseudo);

if(nickname.equals("")) {
        tv.setText("Welcome");
    } else {
        tv.setText("Welcome " + nickname);
    }
}
}

Pseudo =昵称法文， Bienvenue =欢迎法语，感谢大家的帮助，我希望你能理解我的问题。 Pikkoro

Answer 1

我建议您使用Sharedpreferences存储基本信息，并阅读有关如何在Android上保存数据的一些教程或文档。这里我使用Sharedpreferences做了一个例子。希望它有所帮助！

import android.app.Activity;
import android.content.Context;
import android.content.SharedPreferences;
import android.graphics.Color;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

/**
 * Created by Hasan on 4.05.2017.
 */

public class ProfilActivity extends Activity {

    EditText editName, editNickname;
    Button bAddData;
    public SharedPreferences prefs;

    //To be saved elements in sharedpreferences!!!
    private String nicktobesaved, nametobesaved;

    @Override
    public void onCreate(final Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        this.setContentView(R.layout.activity_profil);
        prefs = getSharedPreferences("sharedPreferences", Context.MODE_PRIVATE);

        editName = (EditText) findViewById(R.id.name);
        editNickname = (EditText) findViewById(R.id.pseudo2);
        bAddData = (Button) findViewById(R.id.ajouter);

        //default values
        nametobesaved=prefs.getString("name", "");
        nicktobesaved=prefs.getString("nickname", "");

        bAddData.setEnabled(prefs.getBoolean("isEnabled", true) ? true : false);

        if(!nametobesaved.equals("")) {
            editName.setText(nametobesaved);
        }
        if (!nicktobesaved.equals("")){
            editNickname.setText(nicktobesaved);

        }

        AddData();
    } // End onCreate()

    public void AddData() { // When user click on bAddData button
        bAddData.setOnClickListener(
                new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        nametobesaved=prefs.getString("name", "");
                        nicktobesaved=prefs.getString("nickname", "");

                        nametobesaved= editName.getText().toString();
                        nicktobesaved= editNickname.getText().toString();

                        if(nametobesaved.equals("") || nicktobesaved.equals("")){
                            Toast.makeText(ProfilActivity.this, "Fill all spaces", Toast.LENGTH_LONG).show();
                        }else {

                            SharedPreferences.Editor editor = prefs.edit();
                            editor.putString("name", nametobesaved);
                            editor.putString("nickname", nicktobesaved);
                            editor.commit();

                            Toast.makeText(ProfilActivity.this, "Data saved", Toast.LENGTH_LONG).show();
                            prefs.edit().putBoolean("isEnabled", false).commit();


                            bAddData.setEnabled(false);
                        }

                    }
                }
        );
    }
}

将昵称保存到Sharedpreferences后，您需要在主要活动中加载它。它是这样的：

public class MainActivity extends Activity {

public static final int PROFIL_REQ = 1;
public static final String PSEUDO="nickname";
TextView tv;
Button login;

    //Sharedpreferences and nick name variables
    private SharedPreferences prefs;
    private String nickname;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    tv = (TextView)findViewById(R.id.pseudo);

            //Load or create sharedpreferences
        prefs = getSharedPreferences("sharedPreferences", Context.MODE_PRIVATE);
        nickname = prefs.getString("nickname", "");

        if(nickname.equals("")) {
            tv.setText("Welcome");
        }else{
            tv.setText("Welcome "+ nickname);
        }
    }

那是因为您删除了共享偏好编辑器。

public void AddData() { // When user click on bAddData button
    bAddData.setOnClickListener(
            new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    nicktobesaved = prefs.getString("nickname", "");
                    nicktobesaved = editPseudo.getText().toString();


//DO NOT DELETE HERE

                                    SharedPreferences.Editor editor = prefs.edit();

                                editor.putString("nickname", nicktobesaved);
                                editor.commit();

// The following code is just for save data on my database SQLite
                    boolean isInserted = myDb.insertData(editNickname.getText().toString());
                    if (isInserted == true) {
                        Toast.makeText(ProfilActivity.this, "Data saved", Toast.LENGTH_LONG).show();
                        prefs.edit().putBoolean("isEnabled", false).apply();
                        bAddData.setEnabled(false);
                    } else {
                        Toast.makeText(ProfilActivity.this, "Data not saved", Toast.LENGTH_LONG).show();
                    }
                }
            }
    );
}

SharedPreferences保存在EditText中输入的文本，并将其显示在另一个活动的TextView中

1 个答案: