做更新的時候，把更新包拷貝到sd卡中，然後調用接口進行重新開機更新
File update_file = new File("/sdcard/update.zip");
try {
Log.d("WOW", "install " + update_file.getAbsolutePath());
RecoverySystem.installPackage(getBaseContext(), update_file);
} catch (IOException e) {
e.printStackTrace();
} 複制
之後進入Recovery模式後報錯：
Supported API: 3
charge_status 3, charged 0, status 0, capacity 62
Finding update package...
Opening update package...
E:unknow volume for path [/storage/emulated/0/update.zip]
E:failed to map file
Installation aborted. 複制
說是找不到
/storage/emulated/0
這個路徑？
因為上層用Java寫路徑的時候，擷取的是Android的路徑，我們知道，adb shell裡面是有
/sdcard
的路徑的，這個路徑實際上并不是插入的SD卡路徑，而是一個内置路徑。
内置路徑通過 ls -l 可以看到 /sdcard 的映射
lrwxrwxrwx 1 root root 21 1970-01-01 08:00 sdcard -> /storage/self/primary
也就是說下面幾個路徑是一樣的
/sdcard/
/storage/emulated/0
/storage/self/primary
而外置sd卡路徑是
/storage/0658-0900
是以，我們代碼裡寫的是
/sdcard
但是傳到Recovery的路徑就變成
/storage/emulated/0
了。
我們的需求是把更新包放到sdcard裡面去，是以就需要修改Recovery裡的檔案路徑。
實際要做的就是把獲得到的路徑裡面
/storage/emulated/0
替換成
/sdcard
即可：
Recovery裡面的sd卡路徑就是/sdcard/
if (update_package) {
// For backwards compatibility on the cache partition only, if
// we're given an old 'root' path "CACHE:foo", change it to
// "/cache/foo".
if (strncmp(update_package, "CACHE:", 6) == 0) {
int len = strlen(update_package) + 10;
char* modified_path = (char*)malloc(len);
if (modified_path) {
strlcpy(modified_path, "/cache/", len);
strlcat(modified_path, update_package+6, len);
printf("(replacing path \"%s\" with \"%s\")\n",
update_package, modified_path);
update_package = modified_path;
}
else
printf("modified_path allocation failed\n");
} else if(strncmp(update_package, "/storage/emulated/0/", 20) == 0) {
int len = strlen(update_package) + 20;
char* modified_path = (char*)malloc(len);
if (modified_path) {
strlcpy(modified_path, "/sdcard/", len);
strlcat(modified_path, update_package+20, len);
printf("(replacing path \"%s\" with \"%s\")\n",
update_package, modified_path);
update_package = modified_path;
}
else
printf("modified_path allocation failed\n");
} 複制
Ref https://blog.csdn.net/wed110/article/details/9943915?utm_source=blogxgwz1