la classe postato come risposta dell'utente Void ha un sacco di cose inutili. Ecco la mia classe che utilizza la riflessione su android.os.SystemProperties:
/*
* Copyright (C) 2015 Jared Rummler
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/**
* Gives access to the system properties store. The system properties store contains a list of
* string key-value pairs.
*/
public class SystemProperties {
private static final Class<?> SP = getSystemPropertiesClass();
/**
* Get the value for the given key.
*/
public static String get(String key) {
try {
return (String) SP.getMethod("get", String.class).invoke(null, key);
} catch (Exception e) {
return null;
}
}
/**
* Get the value for the given key.
*
* @return if the key isn't found, return def if it isn't null, or an empty string otherwise
*/
public static String get(String key, String def) {
try {
return (String) SP.getMethod("get", String.class, String.class).invoke(null, key, def);
} catch (Exception e) {
return def;
}
}
/**
* Get the value for the given key, returned as a boolean. Values 'n', 'no', '0', 'false' or
* 'off' are considered false. Values 'y', 'yes', '1', 'true' or 'on' are considered true. (case
* sensitive). If the key does not exist, or has any other value, then the default result is
* returned.
*
* @param key
* the key to lookup
* @param def
* a default value to return
* @return the key parsed as a boolean, or def if the key isn't found or is not able to be
* parsed as a boolean.
*/
public static boolean getBoolean(String key, boolean def) {
try {
return (Boolean) SP.getMethod("getBoolean", String.class, boolean.class)
.invoke(null, key, def);
} catch (Exception e) {
return def;
}
}
/**
* Get the value for the given key, and return as an integer.
*
* @param key
* the key to lookup
* @param def
* a default value to return
* @return the key parsed as an integer, or def if the key isn't found or cannot be parsed
*/
public static int getInt(String key, int def) {
try {
return (Integer) SP.getMethod("getInt", String.class, int.class).invoke(null, key, def);
} catch (Exception e) {
return def;
}
}
/**
* Get the value for the given key, and return as a long.
*
* @param key
* the key to lookup
* @param def
* a default value to return
* @return the key parsed as a long, or def if the key isn't found or cannot be parsed
*/
public static long getLong(String key, long def) {
try {
return (Long) SP.getMethod("getLong", String.class, long.class).invoke(null, key, def);
} catch (Exception e) {
return def;
}
}
private static Class<?> getSystemPropertiesClass() {
try {
return Class.forName("android.os.SystemProperties");
} catch (ClassNotFoundException shouldNotHappen) {
return null;
}
}
private SystemProperties() {
throw new AssertionError("no instances");
}
}
Se il collegamento del codice sorgente sopra riportato non funziona, puoi provare questo http://androidxref.com/4.3_r2.1/xref/frameworks/base/core/java/android/os/SystemProperties.java – Vins
@Jim Blackler: potresti spiegare di più sulla seconda soluzione. come posso creare il mio SDK? –