Android Chromium: Unsuccessful attempt to get C + + Sktypeface object from Typeface.java class

This means that the Java activity layer's user-defined default font through standard Framework/jni is not passed to the chromium kernel.

The basic idea is to obtain the current default font settings for the Java layer system through Typeface.default, get the native_instance handle through the Java dynamic Reflection call, and then try to get the sktypeface* pointer with JNI C + + code. Call Sktypeface::serialize to serialize to a temporary font file, then return the path to Java and re-upload it to the Chromium kernel code.

Section 2 Core Demo code:

Awsettings.java:

#if enable_user_overrides_fontfallback//hacker techniques to get the current system's default typeface and apply it to C            Hromium/skia Kernel code: @CalledByNative private static Long Getdefaulttypefacenativepointer () {try{            Android.graphics.Typeface defaulttypeface = Android.graphics.Typeface.DEFAULT;            Java.lang.reflect.Field Field = null;            field = Android.graphics.Typeface.class.getDeclaredField ("native_instance");            LONG ret = 0;            if (android.os.build.version.sdk_int>=21) {//5.0+ ret = Field.getlong (defaulttypeface);            }else{//4.4-ret = Field.getint (defaulttypeface);//boost to Long}            LOG.I (TAG, "android.graphics.typeface.default.native_instance=" +ret);        return ret;            }catch (Exception e) {log.e (TAG, E.getmessage (), E);        return 0; }}//private Boolean Suseroverridesfontfallbackenabled = false;    private static native String Nativegettempuseroverridesfontfallbackpath (); public void setuseroverridesfontfallbackenabled (Boolean enable) {if (enable) {String Path = awsettings            . Nativegettempuseroverridesfontfallbackpath ();        Setuseroverridesfontfallback (True, path);        }else{Setuseroverridesfontfallback (False, ""); }}//#if

aw_settings.cc:

#if enable_user_overrides_fontfallbackstatic jstring Gettempuseroverridesfontfallbackpath (JNIEnv* env, Jclass clazz)    {VLOG (0) << "Gettempuseroverridesfontfallbackpath enter";    Jlong Native_instance_pointer = Java_awsettings_getdefaulttypefacenativepointer (env); if (native_instance_pointer==0) {VLOG (0) << "Gettempuseroverridesfontfallbackpath      Getdefaulttypefacenativepointer failed! ";    return 0;    }//sktypeface* typeface = (sktypeface*) (int) Native_instance_pointer; Alert:this C + + Sktypeface is got from the framework layer, it may not be having the same ABI compatibility with Chromioum ' s    Internal Skia Library typefaceimpl* Typefaceimpl = (typefaceimpl*) native_instance_pointer; sktypeface* typeface = 0;    Todo:cannot get sktypeface* from typefaceimpl*//i need a writable path!    FilePath Cache_dir_filepath;    /*bool ret = */base::android::getcachedirectory (&cache_dir_filepath); FilePath Temp_filepath = Cache_dir_filepath. Append (FilePath ("tEst.ttf.ser ")); <--todo:generate this std::string gen_temp_path = Temp_filepath.    Asutf8unsafe (); Const char* Temp_path = Gen_temp_path.c_str ();    "/data/local/test.ttf.ser";    VLOG (0) << "Gettempuseroverridesfontfallbackpath gen_temp_path=" <<temp_path;    Skfilewstream Wstream (Temp_path);    Typeface->serialize (&wstream);//may fail, but we don ' t know!    scopedjavalocalref<jstring> Jpath = convertutf8tojavastring (env, Temp_path); Return Jpath.  Release (); } #endif

Unfortunately, Native_instance actually corresponds to an opaque typefaceimpl*, which may also be inaccessible under JNI. Even if you can access it, you will not get sktypeface* from typefaceimpl*.

Android Chromium: Unsuccessful attempt to get C + + Sktypeface object from Typeface.java class