我正在做SharedPreferences助手类，以使我的代码看起来不错。
diff --git a/app/src/main/java/com/example/android/app/MainActivity.java
b/app/src/main/java/com/example/android/app/MainActivity.java
index 36c85c8d1f780dd7b0a6dacada717524e95bf7d4..174badb785e6f28b0d9ecd32164a7153b5f2acd5 100755
--- a/app/src/main/java/com/example/android/app/MainActivity.java
+++ b/app/src/main/java/com/example/android/app/MainActivity.java
@@ -393,7 +393,7 @@ public class MainActivity extends BaseActivity
*/
public void showLoginFragment(boolean setAsActive) {
- showFragment(LoginFragment_.builder().setAsActive(setAsActive)
+ showFragment(LandingFragment_.builder().setAsActive(setAsActive)
, true
, "login"
, true
问题是我应该将这些方法设置为静态并在每个方法中初始化SharedPreferences或更好地保留它不是静态的，并从其他类调用SharedPreferencesHelper类一次吗？感谢
答案 0 :(得分：3)
我不会保留对上下文的引用。我宁愿将JsonResponseMixin及其Step 1: Go to Help -> Install New Software -> click on 'Add'
Step 2: On pop-up fill these below details:
Name: JavaDecompiler
Location: http://jd.benow.ca/jd-eclipse/update/
Step 3: Click on checkbox - Java Decomplier Eclipse Plug-in.
Step 4: Click -> Next -> Next -> Accept The Agreement -> Finish
Step 5: Click on check-box -> Accept the trust certificate -> OK
Step 6: Restart the eclipse.
保留为助手类的静态成员。这样，每次需要读取/写入SharedPreference时，您都不需要实例化Editor。更进一步的是使用Application SharedPreferencesHelper（带有您的自定义Application子类）来初始化SharedPreference和Context，这是您第一次访问帮助程序本身。这就是我如何塑造它
答案 1 :(得分：2)
使用此：
public class SharedPreferencesHelper {
public static final String FILE_NAME = "APP_PREFERENCES";
public static void put(Context context, String key, Object object) {
SharedPreferences sp = context.getSharedPreferences(FILE_NAME, Context.MODE_PRIVATE);
SharedPreferences.Editor editor = sp.edit();
if (object instanceof String) {
editor.putString(key, (String) object);
} else if (object instanceof Integer) {
editor.putInt(key, (Integer) object);
} else if (object instanceof Boolean) {
editor.putBoolean(key, (Boolean) object);
} else if (object instanceof Float) {
editor.putFloat(key, (Float) object);
} else if (object instanceof Long) {
editor.putLong(key, (Long) object);
} else {
editor.putString(key, object.toString());
}
SharedPreferencesCompat.apply(editor);
}
public static Object get(Context context, String key, Object defaultObject) {
SharedPreferences sp = context.getSharedPreferences(FILE_NAME, Context.MODE_PRIVATE);
if (defaultObject instanceof String) {
return sp.getString(key, (String) defaultObject);
} else if (defaultObject instanceof Integer) {
return sp.getInt(key, (Integer) defaultObject);
} else if (defaultObject instanceof Boolean) {
return sp.getBoolean(key, (Boolean) defaultObject);
} else if (defaultObject instanceof Float) {
return sp.getFloat(key, (Float) defaultObject);
} else if (defaultObject instanceof Long) {
return sp.getLong(key, (Long) defaultObject);
}
return null;
}
public static void remove(Context context, String key) {
SharedPreferences sp = context.getSharedPreferences(FILE_NAME, Context.MODE_PRIVATE);
SharedPreferences.Editor editor = sp.edit();
editor.remove(key);
SharedPreferencesCompat.apply(editor);
}
public static void clear(Context context) {
SharedPreferences sp = context.getSharedPreferences(FILE_NAME, Context.MODE_PRIVATE);
SharedPreferences.Editor editor = sp.edit();
editor.clear();
SharedPreferencesCompat.apply(editor);
}
public static boolean contains(Context context, String key) {
SharedPreferences sp = context.getSharedPreferences(FILE_NAME, Context.MODE_PRIVATE);
return sp.contains(key);
}
public static Map<String, ?> getAll(Context context) {
SharedPreferences sp = context.getSharedPreferences(FILE_NAME, Context.MODE_PRIVATE);
return sp.getAll();
}
private static class SharedPreferencesCompat {
private static final Method sApplyMethod = findApplyMethod();
@SuppressWarnings({"unchecked", "rawtypes"})
private static Method findApplyMethod() {
try {
Class clz = SharedPreferences.Editor.class;
return clz.getMethod("apply");
} catch (NoSuchMethodException e) {
e.printStackTrace();
}
return null;
}
public static void apply(SharedPreferences.Editor editor) {
try {
if (sApplyMethod != null) {
sApplyMethod.invoke(editor);
return;
}
} catch (IllegalArgumentException | IllegalAccessException | InvocationTargetException e) {
e.printStackTrace();
}
editor.commit();
}
}
}
答案 2 :(得分：1)
如果Context是一个“全局”上下文，我会使用静态类，并从上下文中获取值非常长且（有点）邪恶。这样，从静态类获取值将更容易，而不会在错误的情况下重复执行相同操作而不会出错。
至于转动SharedPreferencesHelper静态，这是一个很好的方法：
public class SharedPreferencesHelper {
private SharedPreferencesHelper(Context context){
}
private static void ensureNotNull(Context context) {
if (context == null) {
throw new IllegalArgumentException("Context is null.");
}
}
public static boolean isLogged(Context context, String prefs){
ensureNotNull(context);
return context.getSharedPreferences(prefs,Context.MODE_PRIVATE)
.getBoolean("LOGGED",false);
}
public static void setLogged(Context context, String prefs){
ensureNotNull(context);
context.getSharedPreferences(prefs,Context.MODE_PRIVATE)
.edit().putBoolean("LOGGED",true).apply();
}
}
答案 3 :(得分：0)
我最终得到了单例模式，当时只保留了一个实例：
import android.content.Context;
import android.support.annotation.NonNull;
public class SharedPrefsUtil {
private static SharedPrefsUtil instance;
private static final String PREFS_NAME = "default_preferences";
public synchronized static SharedPrefsUtil getInstance() {
if (instance == null) {
instance = new SharedPrefsUtil();
}
return instance;
}
private SharedPrefsUtil() {
}
public boolean isLoggedIn(@NonNull Context context) {
return context.getSharedPreferences(PREFS_NAME, Context.MODE_PRIVATE)
.getBoolean("LOGGED", false);
}
public void setLoggedIn(@NonNull Context context, boolean value) {
context.getSharedPreferences(PREFS_NAME, Context.MODE_PRIVATE)
.edit().putBoolean("LOGGED", value).apply();
}
}
请注意，使用Dagger库可以轻松实现相同的单例。
答案 4 :(得分：0)
这对我有用：
object SharedPreferenceHelper {
private val PREF_FILE = "SharedPreference"
enum class StringValues(val defValue: String) {
Test1("");
fun set(context: Context, value: String) {
context.getSharedPreferences(PREF_FILE, Context.MODE_PRIVATE).edit().putString(name, value).apply()
}
fun get(context: Context): String? = context.getSharedPreferences(PREF_FILE, Context.MODE_PRIVATE).getString(name, defValue)
}
enum class IntValues(val defValue: Int) {
Test1(0);
fun set(context: Context, value: Int) {
context.getSharedPreferences(PREF_FILE, Context.MODE_PRIVATE).edit().putInt(name, value).apply()
}
fun get(context: Context): Int = context.getSharedPreferences(PREF_FILE, Context.MODE_PRIVATE).getInt(name, defValue)
}
enum class LongValues(val defValue: Long) {
Test1(0);
fun set(context: Context, value: Long) {
context.getSharedPreferences(PREF_FILE, Context.MODE_PRIVATE).edit().putLong(name, value).apply()
}
fun get(context: Context): Long = context.getSharedPreferences(PREF_FILE, Context.MODE_PRIVATE).getLong(name, defValue)
}
enum class FloatValues(val defValue: Float) {
Test1(0f);
fun set(context: Context, value: Float) {
context.getSharedPreferences(PREF_FILE, Context.MODE_PRIVATE).edit().putFloat(name, value).apply()
}
fun get(context: Context): Float = context.getSharedPreferences(PREF_FILE, Context.MODE_PRIVATE).getFloat(name, defValue)
}
enum class BooleanValues(val defValue: Boolean) {
Test1(true);
fun set(context: Context, value: Boolean) {
context.getSharedPreferences(PREF_FILE, Context.MODE_PRIVATE).edit().putBoolean(name, value).apply()
}
fun get(context: Context): Boolean = context.getSharedPreferences(PREF_FILE, Context.MODE_PRIVATE).getBoolean(name, defValue)
}
}
答案 5 :(得分：-1)
这个课程可以帮到你。
import android.content.Context;
import android.content.SharedPreferences;
import android.content.SharedPreferences.Editor;
import android.preference.PreferenceManager;
//import android.preference.PreferenceManager;
public class SharedPreference {
private static SharedPreference sharedPreference;
public static final String PREFS_NAME = "AOP_PREFS";
public static final String PREFS_KEY = "AOP_PREFS_String";
public static SharedPreference getInstance()
{
if (sharedPreference == null)
{
sharedPreference = new SharedPreference();
}
return sharedPreference;
}
public SharedPreference() {
super();
}
public void save(Context context, String text , String Key) {
SharedPreferences settings;
Editor editor;
//settings = PreferenceManager.getDefaultSharedPreferences(context);
settings = context.getSharedPreferences(PREFS_NAME, Context.MODE_PRIVATE); //1
editor = settings.edit(); //2
editor.putString(Key, text); //3
editor.commit(); //4
}
public String getValue(Context context , String Key) {
SharedPreferences settings;
String text = "";
// settings = PreferenceManager.getDefaultSharedPreferences(context);
settings = context.getSharedPreferences(PREFS_NAME, Context.MODE_PRIVATE);
text = settings.getString(Key, "");
return text;
}
public void clearSharedPreference(Context context) {
SharedPreferences settings;
Editor editor;
//settings = PreferenceManager.getDefaultSharedPreferences(context);
settings = context.getSharedPreferences(PREFS_NAME, Context.MODE_PRIVATE);
editor = settings.edit();
editor.clear();
editor.commit();
}
public void removeValue(Context context , String value) {
SharedPreferences settings;
Editor editor;
settings = context.getSharedPreferences(PREFS_NAME, Context.MODE_PRIVATE);
editor = settings.edit();
editor.remove(value);
editor.commit();
}
}
你可以得到这样的价值。
String KeeLogin = SharedPreference.getInstance().getValue(getApplicationContext(), "YOUR_KEY");
并存储数据就像这样
SharedPreference.getInstance().save(LoginScreen.this,"VALUE","YOUR_KEY");
希望它能帮到你:)。