问题
This question is kind of similar to other sharedpreferences questions but i don't really know how exactly to use it between different activities? Kindly provide the complete activity file if possible rather than just few lines of codes as i am noob in this field!
I have two activities. one is userprofile and another is edituserprofile. Whatever a user edits in edituserprofile, should be displayed in userprofile activity as soon as user click on save image button from the app bar of edituserprofile. sharedpreferences works perfectly in edituserprofile where user can see entered data and also able to change it as it is edittextview. However, i am not able to apply the same logic to userprofile activity. When i click on save button from edituserprofile, it takes me to userprofile and i can see the change that has made in edituserprofile but as soon as i exit the userprofile and relaunch it, data gets cleared in userprofile but not from edituserprofile! i want userprofile to save, display data from edituserprofile even user exit and re-launch the app!
Below is userprofile activity!
package com.example.android.coffeeshop6menus;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.TextView;
public class UserProfile extends AppCompatActivity {
public static final int Edit_Profile = 1;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_user_profile);
Toolbar userProfileToolbar = (Toolbar) findViewById(R.id.my_toolbar);
setSupportActionBar(userProfileToolbar);
SharedPreferences sharedpreferences = getPreferences(MODE_PRIVATE);
displayMessage(sharedpreferences.getString("nameKey", ""));
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.userprofile_menu, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.action_editProfile:
Intent userProfileIntent = new Intent(UserProfile.this, EditUserProfile.class);
startActivityForResult(userProfileIntent, Edit_Profile);
}
return true;
}
// Call Back method to get the Message form other Activity
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
switch (requestCode) {
case Edit_Profile:
if (resultCode == RESULT_OK) {
String name = data.getStringExtra("");
displayMessage(name);
}
break;
}
}
public void displayMessage(String message) {
TextView usernameTextView = (TextView) findViewById(R.id.importProfile);
usernameTextView.setText(message);
}
}
Below is edituserprofile activity that works perfect!
package com.example.android.coffeeshop6menus;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.support.design.widget.CoordinatorLayout;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.TextView;
public class EditUserProfile extends AppCompatActivity {
private CoordinatorLayout coordinatorLayout;
public static final String Name = "nameKey";
SharedPreferences sharedpreferences;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_edit_user_profile);
Toolbar userProfileToolbar = (Toolbar) findViewById(R.id.my_toolbar);
setSupportActionBar(userProfileToolbar);
TextView usernameTextView = (TextView) findViewById(R.id.username);
sharedpreferences = getSharedPreferences(Name, Context.MODE_PRIVATE);
if (sharedpreferences.contains(Name)) {
usernameTextView.setText(sharedpreferences.getString(Name, ""));
}
coordinatorLayout = (CoordinatorLayout) findViewById(R.id
.coordinatorLayout);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.editprofile_menu, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.action_save:
TextView usernameTextView = (TextView) findViewById(R.id.username);
String usernameString = usernameTextView.getText().toString();
SharedPreferences.Editor editor = sharedpreferences.edit();
editor.putString(Name, usernameString);
editor.apply();
Snackbar snackbar = Snackbar
.make(coordinatorLayout, "Saved!", Snackbar.LENGTH_LONG);
snackbar.show();
Intent userProfileIntent = new Intent(EditUserProfile.this, UserProfile.class);
userProfileIntent.putExtra("", usernameString);
setResult(RESULT_OK, userProfileIntent);
finish();
}
return true;
}
}
Below is the userprofile.xml file
<?xml version="1.0" encoding="utf-8"?>
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context="com.example.android.coffeeshop6menus.UserProfile">
<include
layout="@layout/toolbar"
android:layout_width="match_parent"
android:layout_height="match_parent"
/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="16dp"
android:text="Name"
android:textSize="20dp" />
<TextView
android:id="@+id/importProfile"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="16dp"
android:text="@string/userNameImport"
android:textSize="20dp" />
</LinearLayout>
</ScrollView>
Below is the edituserprofile xml file:
<ScrollView
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context="com.example.android.coffeeshop6menus.UserProfile">
<include
layout="@layout/toolbar"
android:layout_width="match_parent"
android:layout_height="match_parent"
/>
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="16dp"
android:text="User Profile"
android:textSize="20dp" />
</LinearLayout>
<EditText
android:id="@+id/username"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="16dp"
android:layout_marginTop="16dp"
android:cursorVisible="true"
android:hint="@string/EditTextHint"
android:inputType="textNoSuggestions" />
<EditText
android:id="@+id/usercontact"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="16dp"
android:layout_marginTop="16dp"
android:cursorVisible="true"
android:hint="@string/usercontactHint"
android:inputType="textNoSuggestions" />
<EditText
android:id="@+id/useremail"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="16dp"
android:layout_marginTop="16dp"
android:cursorVisible="true"
android:hint="@string/useremailHint"
android:inputType="textEmailAddress" />
</LinearLayout>
</ScrollView>
Kindly help!
回答1:
In your UserProfile class and everywhere else change -
SharedPreferences sharedpreferences = getPreferences(MODE_PRIVATE);
by this -
sharedpreferences = getSharedPreferences("nameKey", Context.MODE_PRIVATE);
And you are good to go !
回答2:
You are using sharedpreferences which are local to your two activities, as in docs for this method:
Retrieve a SharedPreferences object for accessing preferences that are private to this activity.
Solution is to use global sharedpreferences with:
SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
回答3:
A major dilemma is that you are using getPreferences() in UserProfile, but using getSharedPreferences() in EditUserProfile. The first method would only get key-value pairs for the UserProfile activity, while the second is for any part of the app to access. Switch getPreferences() to getSharedPreferences() and you should be good.
http://developer.android.com/guide/topics/data/data-storage.html#pref
From that website: public class Calc extends Activity { public static final String PREFS_NAME = "MyPrefsFile";
@Override
protected void onCreate(Bundle state){
super.onCreate(state);
. . .
// Restore preferences
SharedPreferences settings = getSharedPreferences(PREFS_NAME, 0);
boolean silent = settings.getBoolean("silentMode", false);
setSilent(silent);
}
@Override
protected void onStop(){
super.onStop();
// We need an Editor object to make preference changes.
// All objects are from android.context.Context
SharedPreferences settings = getSharedPreferences(PREFS_NAME, 0);
SharedPreferences.Editor editor = settings.edit();
editor.putBoolean("silentMode", mSilentMode);
// Commit the edits!
editor.commit();
}
来源：https://stackoverflow.com/questions/36047318/sharedpreferences-between-activities