[英]Shared Preferences Android Studio
对于下面的代码,我试图检索共享首选项,我认为它保存正确,但是当我返回登录屏幕时,所有数据都消失了。 当我回到这个屏幕时,我需要它保留下来。 所以我在个人资料页面上的三个单独的行中输入姓名、年龄和 ID。 然后我按下保存按钮然后按下操作栏上的返回到之前的页面。 当我回到个人资料页面时,我的信息应该仍然存在,但没有任何帮助?
package com.example.myprofile;
import android.content.Context;
import android.content.SharedPreferences;
import android.preference.PreferenceManager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
import java.sql.Savepoint;
public class Profile extends AppCompatActivity {
protected EditText NameEditText;
protected EditText AgeEditText;
protected EditText IDEditText;
protected Button saveButton;
protected Button settings_id;
String name;
String age;
String id;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_profile);
EditText mEdit = (EditText) findViewById(R.id.NameEditText);
mEdit.setEnabled(false);
EditText mEdit1 = (EditText) findViewById(R.id.AgeEditText);
mEdit1.setEnabled(false);
EditText mEdit2 = (EditText) findViewById(R.id.IDEditText);
mEdit2.setEnabled(false);
NameEditText = (EditText) findViewById(R.id.NameEditText);
AgeEditText = (EditText) findViewById(R.id.AgeEditText);
IDEditText = (EditText) findViewById(R.id.IDEditText);
settings_id = (Button) findViewById(R.id.settings_id);
saveButton = (Button) findViewById(R.id.SaveButton);
SharedPreferences prefs = getSharedPreferences(getString(R.string.ProfileName), Context.MODE_PRIVATE);
name = prefs.getString("userName", "");
age = prefs.getString("userAge", "");
id = prefs.getString("userID", "");
saveButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
String name = NameEditText.getText().toString();
String age = AgeEditText.getText().toString();
String id = IDEditText.getText().toString();
SharedPreferences sharedPreferences = getSharedPreferences(getString(R.string.ProfileName), Context.MODE_PRIVATE);
SharedPreferences.Editor editor = sharedPreferences.edit();
editor.putString(getString(R.string.ProfileName), name);
editor.putString(getString(R.string.ProfileAge), age);
editor.putString(getString(R.string.ProfileID), id);
editor.apply();
if (Integer.parseInt(age) < 18)
{
Toast toast1 = Toast.makeText(getApplicationContext(), "Invalid Age", Toast.LENGTH_LONG);
toast1.show();
}
else if (!name.isEmpty() && !age.isEmpty() && !id.isEmpty())
{
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
Toast toast = Toast.makeText(getApplicationContext(), "Name Saved!", Toast.LENGTH_LONG);
toast.show();
}
else
{
Toast toast2 = Toast.makeText(getApplicationContext(), "Incomplete Info", Toast.LENGTH_LONG);
toast2.show();
}
}
});
getSupportActionBar().setDisplayHomeAsUpEnabled(false);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.settings_id:
{
EditText mEdit = (EditText) findViewById(R.id.NameEditText);
mEdit.setEnabled(true);
EditText mEdit1 = (EditText) findViewById(R.id.AgeEditText);
mEdit1.setEnabled(true);
EditText mEdit2 = (EditText) findViewById(R.id.IDEditText);
mEdit2.setEnabled(true);
saveButton.setEnabled(Boolean.parseBoolean("True"));
}
default:
return super.onOptionsItemSelected(item);
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.menu, menu);
return true;
}
}
要保存数据,请使用以下代码示例
name = NameEditText.getText().toString();
age = AgeEditText.getText().toString();
id = IDEditText.getText().toString();
SharedPreferences prefs = getSharedPreferences(
"com.example.myprofile", Context.MODE_PRIVATE);
SharedPreferences.Editor editor = prefs.edit();
editor.putString("userName", name);
editor.putString("userAge", age);
editor.putString("userID", id);
editor.apply();
要检索数据,请使用以下代码示例
SharedPreferences prefs = getSharedPreferences(
"com.example.myprofile", Context.MODE_PRIVATE);
name = prefs.getString("userName", "");
age = prefs.getString("userAge", "");
id = prefs.getString("userID", "");
在onCreate
方法之前
String name;
String age;
String id;
解释:
getSharedPreferences
的第一个参数是你的包名,基本上是你代码中的第一行。SharedPreferences
实例,一个就够了SharedPreferences.Editor
实例,一个也足够了。key
,例如用于保存数据的用户名,因为您随后需要通过意图将密钥传递给其他活动,如果您打算这样做,为什么不发送用户名而不是钥匙?editor.apply()
而不是editor.commit()
onPause()
保存数据并在onResume()
检索它是很常见的,因此将它们声明为全局是有用的,以避免编写额外的代码行。尝试(在行尾应用()):
editor.putString(getString(R.string.ProfileName), name).apply();
editor1.putString(getString(R.string.ProfileAge), age).apply();
editor2.putString(getString(R.string.ProfileID), id).apply();
您正在使用特定字符串( getString(R.string.ProfileAge) ....)通过使用 commit() 或 apply() 在私有模式下将数据保存在共享首选项中:-
SharedPreferences sharedPreferences1 = getSharedPreferences(getString(R.string.ProfileAge), Context.MODE_PRIVATE);
SharedPreferences sharedPreferences2 = getSharedPreferences(getString(R.string.ProfileID), Context.MODE_PRIVATE);
但是您并不是要在必须使用的私有模式下使用这些字符串来获取该数据:-
SharedPreferences sharedPref = getSharedPreferences(getString(R.string.ProfileAge), Context.MODE_PRIVATE);
String name = sharedPref.getString("key", "defaultValue");
为了保存
SharedPreferences pref = getSharedPreferences("Name", Context.MODE_PRIVATE);
SharedPreferences.Editor editor = pref.edit();
editor.putBoolean("keyname",true);
editor.putString("keyname","string value");
editor.putInt("keyname","int value");
editor.putFloat("keyname","float value");
editor.putLong("keyname","long value");
editor.commit();
忘记
SharedPreferences pref = getSharedPreferences("Name", Context.MODE_PRIVATE);
pref.getString("keyname",null);
pref.getInt("keyname",0);
pref.getFloat("keyname",0);
pref.getBoolean("keyname",true);
pref.getLong("keyname",0);
对于单个删除
SharedPreferences pref = getSharedPreferences("Name", Context.MODE_PRIVATE);
SharedPreferences.Editor editor = pref.edit();
editor.remove("keyname");
editor.commit();
对于所有删除
SharedPreferences pref = getSharedPreferences("Name", Context.MODE_PRIVATE);
SharedPreferences.Editor editor = pref.edit();
editor.clear();
editor.commit();
您可以像这样使用共享偏好
优先保存数据
SharedPreferences share = getSharedPreferences("Data", Context.MODE_PRIVATE);
SharedPreferences.Editor edit = share.edit();
edit.putLong("user_id", 1);
edit.putString("token","1243434sfdfsf");
edit.commit();
从偏好中获取数据
SharedPreferences share = getSharedPreferences("Data", Context.MODE_PRIVATE);
share.getLong("user_id", 0);
share.getString("token", "");
您可以尝试此链接以获取更多详细信息: Android 中的共享首选项
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.