Android應用獲取系統屬性
在一個Android應用中因為要獲取系統的屬性, 比如說型號, model等一些屬性, 通過下列方法就可以獲取到.
使用adb shell prop可以查看Android系統的屬性.詳情看下圖
上面列出了很多屬性, 如果要在使用中使用該屬性, 比如說我是為了判斷該手機是不是魅族手機.
google在framework層提供了一個SystemProperties類, 該類位于框架層, 具體位置是frameworks/base/core/java/android/os/SystemProperties.java
該類提供了很詳細的訪問各種屬性的方法,所以我可以使用反射機制來獲取我想要的參數.
package me.chasel.utilsimport java.io.File; import java.lang.reflect.Method; import android.content.Context; import dalvik.system.DexFile;
public class SystemPropertiesProxy {
/* 根據給定Key獲取值. @return 如果不存在該key則返回空字符串 @throws IllegalArgumentException 如果key超過32個字符則拋出該異常 */ public static String get(Context context, String key) throws IllegalArgumentException {
String ret= "";
try{
ClassLoader cl = context.getClassLoader(); @SuppressWarnings("rawtypes") Class SystemProperties = cl.loadClass("android.os.SystemProperties");
//參數類型 @SuppressWarnings("rawtypes") Class[] paramTypes= new Class[1]; paramTypes[0]= String.class;
Method get = SystemProperties.getMethod("get", paramTypes);
//參數 Object[] params= new Object[1]; params[0]= new String(key);
ret= (String) get.invoke(SystemProperties, params);
}catch( IllegalArgumentException iAE ){ throw iAE; }catch( Exception e ){ ret= ""; //TODO }
return ret;
}
/* 根據Key獲取值. @return 如果key不存在, 并且如果def不為空則返回def否則返回空字符串 @throws IllegalArgumentException 如果key超過32個字符則拋出該異常 */ public static String get(Context context, String key, String def) throws IllegalArgumentException {
String ret= def;
try{
ClassLoader cl = context.getClassLoader(); @SuppressWarnings("rawtypes") Class SystemProperties = cl.loadClass("android.os.SystemProperties");
//參數類型 @SuppressWarnings("rawtypes") Class[] paramTypes= new Class[2]; paramTypes[0]= String.class; paramTypes[1]= String.class;
Method get = SystemProperties.getMethod("get", paramTypes);
//參數 Object[] params= new Object[2]; params[0]= new String(key); params[1]= new String(def);
ret= (String) get.invoke(SystemProperties, params);
}catch( IllegalArgumentException iAE ){ throw iAE; }catch( Exception e ){ ret= def; //TODO }
return ret;
}
/* 根據給定的key返回int類型值. @param key 要查詢的key @param def 默認返回值 @return 返回一個int類型的值, 如果沒有發現則返回默認值 @throws IllegalArgumentException 如果key超過32個字符則拋出該異常 */ public static Integer getInt(Context context, String key, int def) throws IllegalArgumentException {
Integer ret= def;
try{
ClassLoader cl = context.getClassLoader(); @SuppressWarnings("rawtypes") Class SystemProperties = cl.loadClass("android.os.SystemProperties");
//參數類型 @SuppressWarnings("rawtypes") Class[] paramTypes= new Class[2]; paramTypes[0]= String.class; paramTypes[1]= int.class;
Method getInt = SystemProperties.getMethod("getInt", paramTypes);
//參數 Object[] params= new Object[2]; params[0]= new String(key); params[1]= new Integer(def);
ret= (Integer) getInt.invoke(SystemProperties, params);
}catch( IllegalArgumentException iAE ){ throw iAE; }catch( Exception e ){ ret= def; //TODO }
return ret;
}
/* 根據給定的key返回long類型值. @param key 要查詢的key @param def 默認返回值 @return 返回一個long類型的值, 如果沒有發現則返回默認值 @throws IllegalArgumentException 如果key超過32個字符則拋出該異常 */ public static Long getLong(Context context, String key, long def) throws IllegalArgumentException {
Long ret= def;
try{
ClassLoader cl = context.getClassLoader(); @SuppressWarnings("rawtypes") Class SystemProperties= cl.loadClass("android.os.SystemProperties");
//參數類型 @SuppressWarnings("rawtypes") Class[] paramTypes= new Class[2]; paramTypes[0]= String.class; paramTypes[1]= long.class;
Method getLong = SystemProperties.getMethod("getLong", paramTypes);
//參數 Object[] params= new Object[2]; params[0]= new String(key); params[1]= new Long(def);
ret= (Long) getLong.invoke(SystemProperties, params);
}catch( IllegalArgumentException iAE ){ throw iAE; }catch( Exception e ){ ret= def; //TODO }
return ret;
}
/* 根據給定的key返回boolean類型值. 如果值為 'n', 'no', '0', 'false' or 'off' 返回false. 如果值為'y', 'yes', '1', 'true' or 'on' 返回true. 如果key不存在, 或者是其它的值, 則返回默認值. @param key 要查詢的key @param def 默認返回值 @return 返回一個boolean類型的值, 如果沒有發現則返回默認值 @throws IllegalArgumentException 如果key超過32個字符則拋出該異常 / public static Boolean getBoolean(Context context, String key, boolean def) throws IllegalArgumentException {
Boolean ret= def;
try{
ClassLoader cl = context.getClassLoader(); @SuppressWarnings("rawtypes") Class SystemProperties = cl.loadClass("android.os.SystemProperties");
//參數類型 @SuppressWarnings("rawtypes") Class[] paramTypes= new Class[2]; paramTypes[0]= String.class; paramTypes[1]= boolean.class;
Method getBoolean = SystemProperties.getMethod("getBoolean", paramTypes);
//參數 Object[] params= new Object[2]; params[0]= new String(key); params[1]= new Boolean(def);
ret= (Boolean) getBoolean.invoke(SystemProperties, params);
}catch( IllegalArgumentException iAE ){ throw iAE; }catch( Exception e ){ ret= def; //TODO }
return ret;
}
/* 根據給定的key和值設置屬性, 該方法需要特定的權限才能操作. @throws IllegalArgumentException 如果key超過32個字符則拋出該異常 @throws IllegalArgumentException 如果value超過92個字符則拋出該異常 */ public static void set(Context context, String key, String val) throws IllegalArgumentException {
try{
@SuppressWarnings("unused") DexFile df = new DexFile(new File("/system/app/Settings.apk")); @SuppressWarnings("unused") ClassLoader cl = context.getClassLoader(); @SuppressWarnings("rawtypes") Class SystemProperties = Class.forName("android.os.SystemProperties");
//參數類型 @SuppressWarnings("rawtypes") Class[] paramTypes= new Class[2]; paramTypes[0]= String.class; paramTypes[1]= String.class;
Method set = SystemProperties.getMethod("set", paramTypes);
//參數 Object[] params= new Object[2]; params[0]= new String(key); params[1]= new String(val);
set.invoke(SystemProperties, params);
}catch( IllegalArgumentException iAE ){ throw iAE; }catch( Exception e ){ //TODO }
} }</pre>
這是第一種方法, 這也是一種萬能的方法.
當然如果不是非常必要的話, 建議還是不要使用這樣的萬能方法.
第二種方法是其它如果只是要簡單的判斷是否為魅族手機的話, 完全可以調用google提供的api來做.
android.os.Build.BRAND使用上面的屬性如果是魅族手機的話返回返回Meizu.
這是和我使用adb shell prop看到的屬性是一致的, 可以看下圖
看到該類的源碼也可以看到如下內容
public class Build { /* Value used for when a build property is unknown. / public static final String UNKNOWN = "unknown";/* Either a changelist number, or a label like "M4-rc20". / public static final String ID = getString("ro.build.id");
/* A build ID string meant for displaying to the user / public static final String DISPLAY = getString("ro.build.display.id");
/* The name of the overall product. / public static final String PRODUCT = getString("ro.product.name");
/* The name of the industrial design. / public static final String DEVICE = getString("ro.product.device");
/* The name of the underlying board, like "goldfish". / public static final String BOARD = getString("ro.product.board");
/* The name of the instruction set (CPU type + ABI convention) of native code. / public static final String CPU_ABI = getString("ro.product.cpu.abi");
/* The name of the second instruction set (CPU type + ABI convention) of native code. / public static final String CPU_ABI2 = getString("ro.product.cpu.abi2");
/* The manufacturer of the product/hardware. / public static final String MANUFACTURER = getString("ro.product.manufacturer");
/* The brand (e.g., carrier) the software is customized for, if any. / public static final String BRAND = getString("ro.product.brand");
/* The end-user-visible name for the end product. / public static final String MODEL = getString("ro.product.model");
/* The system bootloader version number. / public static final String BOOTLOADER = getString("ro.bootloader");</pre>
通過以上兩種方法基本上可以解決掉該問題了.
