android rro技术,自定义Android资源覆盖rro方案
1. framework层rro资源覆盖方案在\framework\base\core\jni\android_util_AssetManager.cpp中： before：12345678910111213141516171819202122232425262728291234567891011121314151617181920212223242526272829static void an.
1. framework层rro资源覆盖方案
在\framework\base\core\jni\android_util_AssetManager.cpp中： before：
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29static void android_content_AssetManager_init(JNIEnv* env, jobject clazz, jboolean isSystem)
{
if (isSystem) {
// Load frameworks-res.apk's overlay through regionalization environment
if (Environment::isSupported()) {
Environment* environment = new Environment();
if (environment != NULL) {
const char* overlay_dir = environment->getOverlayDir();
if (overlay_dir != NULL && strcmp(overlay_dir, "") != 0) {
ALOGD("Regionalization - getOverlayDir:%s", overlay_dir);
verifySystemIdmaps(overlay_dir);
}
delete environment;
}
}
verifySystemIdmaps(AssetManager::OVERLAY_DIR);
}
AssetManager* am = new AssetManager();
if (am == NULL) {
jniThrowException(env, "java/lang/OutOfMemoryError", "");
return;
}
am->addDefaultAssets();
ALOGV("Created AssetManager %p for Java object %p\n", am, clazz);
env->SetLongField(clazz, gAssetManagerOffsets.mObject, reinterpret_cast(am));
}
after：
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51static void android_content_AssetManager_init(JNIEnv* env, jobject clazz, jboolean isSystem) {
if (isSystem) {
// Load frameworks-res.apk's overlay through regionalization environment
if (Environment::isSupported()) {
Environment* environment = new Environment();
if (environment != NULL) {
const char* overlay_dir = environment->getOverlayDir();
if (overlay_dir != NULL && strcmp(overlay_dir, "") != 0) {
ALOGD("Regionalization - getOverlayDir:%s", overlay_dir);
verifySystemIdmaps(overlay_dir);
}
delete environment;
}
}
//在此处加入我们自己想要定制的overlay目录
if (customed) {//判断是否自定义overlay目录
char customed_overlay_dir[FILENAME_MAX] = {0};
char rro_ui[PROPERTY_VALUE_MAX];
//get ui schemes by property value
property_get("persist.customed.ui.rro.current", rro_ui, "");
//whether rro_ui value is null
if (strlen(rro_ui) > 0) {
memset(customed_overlay_dir, 0, FILENAME_MAX);
snprintf(customed_overlay_dir, FILENAME_MAX, "/vendor/Customedoverlay/%s", rro_ui);
customed_overlay_dir[FILENAME_MAX - 1] = '\0';
struct stat info;
//check whether customed_overlay_dir is a directory
if(stat(customed_overlay_dir, &info) == 0 && S_ISDIR(info.st_mode))
//if the property value equals "overlay", we will user the origin default directory.
if(!strcmp("overlay", rro_ui))
verifySystemIdmaps(customed_overlay_dir);
else
verifySystemIdmaps(AssetManager::OVERLAY_DIR);
else
verifySystemIdmaps(AssetManager::OVERLAY_DIR);
}
} else {
verifySystemIdmaps(AssetManager::OVERLAY_DIR);
}
}
AssetManager* am = new AssetManager();
if (am == NULL) {
jniThrowException(env, "java/lang/OutOfMemoryError", "");
return;
}
am->addDefaultAssets();
ALOGV("Created AssetManager %p for Java object %p\n", am, clazz);
env->SetLongField(clazz, gAssetManagerOffsets.mObject, reinterpret_cast(am));
}
由此可见，主要是在jni层的android_content_AssetManager_init函数这里来添加overlay apk的目录，Android默认的目录AssetManager::OVERLAY_DIR是/vendor/overlay，这里我们根据情况
1
1if (customed) {//判断是否自定义overlay目录
来确定是否需要修改。如果需要修改，这通过我自己定义的属性persist.customed.ui.rro.current来获取自定义目录。这个可以通过adb shell命令来进行set/get操作。
这样我的overlay目录就是/vendor/Customedoverlay/myUI.
2. App层rro资源覆盖方案
同理，对于自定义App层的RRO资源覆盖目录则是在\framework\base\services\core\Java\com\android\server\pm\PackageManagerService.java before：
1
2
3
4
5
6
7
8
9
1
2
3
4
5
6
7
8
9// Collect vendor overlay packages.
// (Do this before scanning any apps.) // For security and version matching reason, only consider // overlay packages if they reside in VENDOR_OVERLAY_DIR. File vendorOverlayDir = new File(VENDOR_OVERLAY_DIR);
scanDirTracedLI(vendorOverlayDir, mDefParseFlags
| PackageParser.PARSE_IS_SYSTEM
| PackageParser.PARSE_IS_SYSTEM_DIR
| PackageParser.PARSE_TRUSTED_OVERLAY, scanFlags | SCAN_TRUSTED_OVERLAY, 0);
after：
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28// Collect vendor overlay packages.
// (Do this before scanning any apps.)
// For security and version matching reason, only consider
// overlay packages if they reside in VENDOR_OVERLAY_DIR.
File vendorOverlayDir;
if(customed) {
String CUMTOMED_OVERLAY_DIR = VENDOR_OVERLAY_DIR;
String rroUi = SystemProperties.get("persist.customed.ui.rro.current");
Slog.d(TAG, "**rroUi**:" + rroUi);
if(rroUi != null && !rroUi.equals("")) {
try {
String tmpOverlay = "/vendor/Customedoverlay/" + rroUi;
File tmpFile = new File(tmpOverlay);
if(tmpFile.isDirectory() && !rroUi.equals("overlay")) {
CUMTOMED_OVERLAY_DIR = tmpOverlay;
}
} catch (Exception ex) {
Slog.e(TAG, "Failed to set CPoverlay dir: " + ex.getMessage());
}
}
vendorOverlayDir = new File(CUMTOMED_OVERLAY_DIR);
} else {
vendorOverlayDir = new File(VENDOR_OVERLAY_DIR);
}
scanDirTracedLI(vendorOverlayDir, mDefParseFlags
| PackageParser.PARSE_IS_SYSTEM
| PackageParser.PARSE_IS_SYSTEM_DIR
| PackageParser.PARSE_TRUSTED_OVERLAY, scanFlags | SCAN_TRUSTED_OVERLAY, 0);
在阅读代码寻找线索的过程中，通过查看网上的资料，最初确认的是/system/vendor/overlay这个目录，这里是原生系统中用来存放overlay apk的地方。通过在Linux中使用grep搜索命令来grep -nrs “/system/vendor/overlay”来查找线索。在Environment.cpp中有这个目录的使用，
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33static const char* OVERLAY_DIR = "/system/vendor/overlay";
const char* Environment::getOverlayDir(void)
{
if (mPackagesCount != 0 && mStoragePos != NULL && mPackages != NULL) {
for (int i = mPackagesCount-1; i >= 0; i--) {
memset(mMediaFile, 0, PATH_MAX);
strlcpy(mOverlayDir, mStoragePos, PATH_MAX);
strlcat(mOverlayDir, "/", PATH_MAX);
strlcat(mOverlayDir, mPackages[i], PATH_MAX);
strlcat(mOverlayDir, OVERLAY_DIR, PATH_MAX);
if (kIsDebug) {
ALOGD("Environment::getOverlayDir() = %s\n", mOverlayDir);
}
// Check if PackageFrameworksRes dir exists.
char overlayFile[PATH_MAX];
memset(overlayFile, 0, PATH_MAX);
strlcpy(overlayFile, mOverlayDir, PATH_MAX);
strlcat(overlayFile, "/", PATH_MAX);
strlcat(overlayFile, mPackages[i], PATH_MAX);
strlcat(overlayFile, "FrameworksRes", PATH_MAX);
if (access(overlayFile, R_OK) == 0) {
if (kIsDebug) {
ALOGD("Environment::getOverlayDir() - overlayFile exists!\n");
}
return mOverlayDir;
}
}
}
return NULL;
}
一步一步阅读代码才发现，最终也定位到了\framework\base\core\jni\android_util_AssetManager.cpp中，但却是下面这段代码：
1
2
3
4
5
6
7
8
9
10
11
12
13
1
2
3
4
5
6
7
8
9
10
11
12
13if (isSystem) {
// Load frameworks-res.apk's overlay through regionalization environment
if (Environment::isSupported()) {
Environment* environment = new Environment();
if (environment != NULL) {
const char* overlay_dir = environment->getOverlayDir();
if (overlay_dir != NULL && strcmp(overlay_dir, "") != 0) {
ALOGD("Regionalization - getOverlayDir:%s", overlay_dir);
verifySystemIdmaps(overlay_dir);
}
delete environment;
}
}
通过修改Environment.cpp中的
1
1static const char* OVERLAY_DIR = "/system/vendor/Customedoverlay";
但经过验证并没有效果。因此否定之前的设想，在通过查找，得知Android系统在init.rc文件中将/vendor 链接到了system/vendor：
1
2
1
2# Link /vendor to /system/vendor for devices without a vendor partition.
symlink /system/vendor /vendor
因此也把/vendor/overlay链接到了/system/vendor/overlay。所以后来换成搜索/vendor/overlay来寻找线索，并最终得出以上结论。
为开发者提供学习成长、分享交流、生态实践、资源工具等服务，帮助开发者快速成长。
更多推荐
0
0- 0
已为社区贡献4条内容
所有评论(0)