共享SharedPreferences

Question

我有两个活动，即MainActivity和OKActivity。MainActivity静态地检查password，并让您转到OKActivity。我在OKActivity中使用了SharedPrefrences将password更改为新的one。

public class MainActivity extends Activity {


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

    final EditText password = (EditText) findViewById(R.id.editText_Password);
    Button enter = (Button) findViewById(R.id.button);

    enter.setOnClickListener(new OnClickListener() {




        @Override
        public void onClick(View arg0) {

            String user_pass;
            user_pass = password.getText().toString();

                if (user_pass.isEmpty()) {
                    AlertDialog.Builder dialogBuilder = new AlertDialog.Builder(MainActivity.this);
                        dialogBuilder.setIcon(R.drawable.ic_launcher);
                        dialogBuilder.setTitle("Oops!");
                        dialogBuilder.setMessage("Password Field Cannot Be Empty");
                        dialogBuilder.setPositiveButton("OK", null);
                        dialogBuilder.show();
                    }
                else
                    if (user_pass.equals("123")) {
                    Toast.makeText(MainActivity.this, "Welcome!", Toast.LENGTH_SHORT).show();
                    Intent I = new Intent("com.mavenmaverick.password.OKActivity");
                    startActivity(I);
                    }
                else
                        if(user_pass != ("123")){
                        Toast.makeText(MainActivity.this, "Incorrect", Toast.LENGTH_SHORT).show();
                        AlertDialog.Builder dialogBuilder = new AlertDialog.Builder(MainActivity.this);
                            dialogBuilder.setIcon(R.drawable.ic_launcher);
                            dialogBuilder.setTitle("Oops!");
                            dialogBuilder.setMessage("Incorrect Password");
                            dialogBuilder.setPositiveButton("OK", null);
                            dialogBuilder.show();
                    }

        }
    });

}

public class OKActivity extends Activity {

EditText newPassword;
String newUserPassword;

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

    newPassword = (EditText) findViewById(R.id.new_password);
    newUserPassword = newPassword.getText().toString();


    getpasswordSharedPreferences();

    Button changePassword = (Button) findViewById(R.id.button_change);

    changePassword.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View arg0) {
            newUserPassword = newPassword.getText().toString();
            getpasswordSharedPreferences();
            setSharedPreferences();

        }
    });

}

private String getpasswordSharedPreferences() {

    SharedPreferences userPassword = getSharedPreferences("USER_PASSWORD", MODE_PRIVATE);
    String password = userPassword.getString("THE_PASSWORD", "123");
    return password;

}

private void setSharedPreferences() {
    SharedPreferences userPassword = getSharedPreferences("USER_PASSWORD", MODE_PRIVATE);
    SharedPreferences.Editor password_edior = userPassword.edit();
    password_edior.putString("THE_PASSWORD", newUserPassword);
    password_edior.commit();
    Toast.makeText(OKActivity.this, "Password Change Succesful", Toast.LENGTH_SHORT).show();
    AlertDialog.Builder dialogBuilder = new AlertDialog.Builder(OKActivity.this);
        dialogBuilder.setIcon(R.drawable.ic_launcher);
        dialogBuilder.setTitle("Done!");
        dialogBuilder.setMessage("New Password : "+newUserPassword);
        dialogBuilder.setPositiveButton("OK", null);
        dialogBuilder.show();

}

如何访问OKActivity中的SharedPrefrences获取密码，并在我的MainActivity中使用它来允许访问，从而在用户交互周期中实现动态。

Answer 1

在这两个活动中，你会得到相同的方法。使用相同的标签来获取你的SharedPreferences。

private String getpasswordSharedPreferences() {

    SharedPreferences userPassword = getSharedPreferences("USER_PASSWORD", MODE_PRIVATE);
    String password = userPassword.getString("THE_PASSWORD", "123");
    return password;

}

也许你可以把这个方法放在其他类中，当你想从所有活动中调用的时候:你也可以把你的set方法放在这里，例如：

public class SharedPrefs {
   private static final String SHARED_PREF = "USER_PASSWORD";
   private static final String KEY_PASSWORD = "THE_PASSWORD";

   public static void getStoredSharedPref(Context context, String key, String value) {

    SharedPreferences sharedPref = context.getSharedPreferences(SHARED_PREF, Context.MODE_PRIVATE);
    SharedPreferences.Editor editor = sharedPref.edit();

    editor.putString(propertyKey, value);
    editor.commit();
    }
 }

然后调用你的活动

 SharedPrefs.getStoredSharedPref(context, SharedPrefsUtils.KEY_PASSWORD,"1234");

Answer 2

只需在OKActivity和MainActivity中访问SharedPreferences即可。诀窍是使用相同的标记名-在你的例子中是'USER_PASSWORD‘。

看看这个--> SharedPreferences

Answer 3

创建一个SharedPrefrences.java //然后我们可以在需要的时候使用

public class SharedPrefrences {

public static void saveData(String name, String value, Context context) {

    try {

        SharedPreferences settings = context
                .getSharedPreferences(Configuration.getPrefsName(), 0);

        SharedPreferences.Editor editor = settings.edit();

        editor.putString(name, value);
        editor.commit();
    } catch (NullPointerException ignored) {

    }

}

public static String getData(String name, Context context) {

    try {


        SharedPreferences settings = context
                .getSharedPreferences(Configuration.getPrefsName(), 0);

        return settings.getString(name, "");
    } catch (NullPointerException ignored) {
        return "";
    }

}

 }

//在MainActivity中

   SharedPrefrences.saveData("Password","123456", getApplicationContext());

//在OKActivity中

   String passwordfromMainActivty = PreferencesUtils.getData("Password", getApplicationContext());

//添加新密码

     SharedPrefrences.saveData("NewPassword","abcd", getApplicationContext());