Android MediaScannerJNI source code

Android MediaScannerJNI source code
1. Introduction

For MediaScannerJNI's position in MediaScanner, refer
Android MediaScanner Overview
MediaScanner JNI File Name:
Android_media_MediaScanner.cpp
Location:
Frameworksasemediajniandroid_media_MediaScanner.cpp
Android_media_MediaScanner is a bridge between the JAVA layer and the server layer.

In android_media_MediaScanner, MyMediaScannerClient is a bridge between the Native layer and the JAVA layer to call android/media/MediaScannerClient. <喎?http: www.bkjia.com kf ware vc " target="_blank" class="keylink"> VcD4NCjxzdmcgaGVpZ2h0PQ = "260" version = "1.1" width = "634" xmlns = "http://www.w3.org/2000/svg"> Created with Rapha limit l 2.1.0 (Java) MediaScanner (Java) MediaScanner (Native) android_media_MediaScanner (Native) android_media_MediaScanner (C ++) MediaScanner (C ++) MediaScanner Media_jni MyMediaScannerClient 2. Initialization

During MediaScanner. java initialization, the core of the call is to create a StagefrightMediaScanner

static {        System.loadLibrary(media_jni);        native_init();    }    public MediaScanner(Context c) {        native_setup();        ......    }

Native_init corresponds to android_media_MediaScanner_native_init
Native_setup corresponds to android_media_MediaScanner_native_setup

static voidandroid_media_MediaScanner_native_setup(JNIEnv *env, jobject thiz){    ALOGV(native_setup);    MediaScanner *mp = new StagefrightMediaScanner;    ......    env->SetLongField(thiz, fields.context, (jlong)mp);}

3. android_media_MediaScanner_processDirectory

Call MediaScanner. cpp to implement processDirectory.
Use scanDirectories in MediaScanner. java. For details, see section 6th of Android MediaScanner source code parsing.
Its function is implemented through the processDirectory of MediaScanner. cpp.

static voidandroid_media_MediaScanner_processDirectory(        JNIEnv *env, jobject thiz, jstring path, jobject client){    MediaScanner *mp = getNativeScanner_l(env, thiz);    .......    const char *pathStr = env->GetStringUTFChars(path, NULL);    MyMediaScannerClient myClient(env, client);    MediaScanResult result = mp->processDirectory(pathStr, myClient);    env->ReleaseStringUTFChars(path, pathStr);}

4. android_media_MediaScanner_processFile

Call StageFrightMediaScanner. cpp to implement processFile.

static voidandroid_media_MediaScanner_processFile(        JNIEnv *env, jobject thiz, jstring path,        jstring mimeType, jobject client){    // Lock already hold by processDirectory    MediaScanner *mp = getNativeScanner_l(env, thiz);    const char *pathStr = env->GetStringUTFChars(path, NULL);    const char *mimeTypeStr =        (mimeType ? env->GetStringUTFChars(mimeType, NULL) : NULL);    ........    MyMediaScannerClient myClient(env, client);    MediaScanResult result = mp->processFile(pathStr, mimeTypeStr, myClient);}

5. MyMediaScannerClient

Reference three interfaces: scanFile, handleStringTag, and setMimeType in android/media/MediaScannerClient

        jclass mediaScannerClientInterface =                env->FindClass(kClassMediaScannerClient);        if (mediaScannerClientInterface == NULL) {            ALOGE(Class %s not found, kClassMediaScannerClient);        } else {            mScanFileMethodID = env->GetMethodID(                                    mediaScannerClientInterface,                                    scanFile,                                    (Ljava/lang/String;JJZZ)V);            mHandleStringTagMethodID = env->GetMethodID(                                    mediaScannerClientInterface,                                    handleStringTag,                                    (Ljava/lang/String;Ljava/lang/String;)V);            mSetMimeTypeMethodID = env->GetMethodID(                                    mediaScannerClientInterface,                                    setMimeType,                                    (Ljava/lang/String;)V);        }