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Android 的property系统类似于linux的环境变量#xff0c;但是更加精细。可以通过adb 设置和读取 property#xff0c;同时也可以在代码 (JAVA/C/C) 中设置和获取属性。这有助于我们在运行时控制代码执行逻辑。比如打开 测试开关 或者 dump源数据文件。 工…前言
Android 的property系统类似于linux的环境变量但是更加精细。可以通过adb 设置和读取 property同时也可以在代码 (JAVA/C/C) 中设置和获取属性。这有助于我们在运行时控制代码执行逻辑。比如打开 测试开关 或者 dump源数据文件。 工程关联
库文件libcutils
头文件#include cutils/properties.h 使用
/* property_get: returns the length of the value which will never be
** greater than PROPERTY_VALUE_MAX - 1 and will always be zero terminated.
** (the length does not include the terminating zero).
**
** If the property read fails or returns an empty value, the default
** value is used (if nonnull).
*/
int property_get(const char* key, char* value, const char* default_value);/* property_get_bool: returns the value of key coerced into a
** boolean. If the property is not set, then the default value is returned.
**
* The following is considered to be true (1):
** 1, true, y, yes, on
**
** The following is considered to be false (0):
** 0, false, n, no, off
**
** The conversion is whitespace-sensitive (e.g. off will not be false).
**
** If no property with this key is set (or the key is NULL) or the boolean
** conversion fails, the default value is returned.
**/
int8_t property_get_bool(const char *key, int8_t default_value);/* property_get_int64: returns the value of key truncated and coerced into a
** int64_t. If the property is not set, then the default value is used.
**
** The numeric conversion is identical to strtoimax with the base inferred:
** - All digits up to the first non-digit characters are read
** - The longest consecutive prefix of digits is converted to a long
**
** Valid strings of digits are:
** - An optional sign character or -
** - An optional prefix indicating the base (otherwise base 10 is assumed)
** -- 0 prefix is octal
** -- 0x / 0X prefix is hex
**
** Leading/trailing whitespace is ignored. Overflow/underflow will cause
** numeric conversion to fail.
**
** If no property with this key is set (or the key is NULL) or the numeric
** conversion fails, the default value is returned.
**/
int64_t property_get_int64(const char *key, int64_t default_value);/* property_get_int32: returns the value of key truncated and coerced into an
** int32_t. If the property is not set, then the default value is used.
**
** The numeric conversion is identical to strtoimax with the base inferred:
** - All digits up to the first non-digit characters are read
** - The longest consecutive prefix of digits is converted to a long
**
** Valid strings of digits are:
** - An optional sign character or -
** - An optional prefix indicating the base (otherwise base 10 is assumed)
** -- 0 prefix is octal
** -- 0x / 0X prefix is hex
**
** Leading/trailing whitespace is ignored. Overflow/underflow will cause
** numeric conversion to fail.
**
** If no property with this key is set (or the key is NULL) or the numeric
** conversion fails, the default value is returned.
**/
int32_t property_get_int32(const char *key, int32_t default_value);/* property_set: returns 0 on success, 0 on failure
*/
int property_set(const char *key, const char *value);int property_list(void (*propfn)(const char *key, const char *value, void *cookie), void *cookie);
