java.lang.NoSuchFieldError: no "Ljava/lang/String;" field JNI

Question

Good day. Please tell me what I'm doing wrong. Implemented getting keys from android / provider / Settings $ System. Keys like ACCELEROMETER_ROTATION look no problem (those described https://developer.android.com/reference/android/provider/Settings.System) but such as sms_delivered_sound, he refuses to search. Writes an error.

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.woodman.testlibsettingsv2, PID: 31133
    java.lang.NoSuchFieldError: no "Ljava/lang/String;" field "sms_delivered_sound" in class "Landroid/provider/Settings$System;" or its superclasses
        at com.example.woodman.testlibsettingsv2.frmMain.GetSystemKyesString(Native Method)
        at com.example.woodman.testlibsettingsv2.frmMain.onCreate(frmMain.java:32)
        at android.app.Activity.performCreate(Activity.java:7210)
        at android.app.Activity.performCreate(Activity.java:7201)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1272)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2926)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3081)
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78)
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108)
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1831)
        at android.os.Handler.dispatchMessage(Handler.java:106)
        at android.os.Looper.loop(Looper.java:193)
        at android.app.ActivityThread.main(ActivityThread.java:6806)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:547)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:873)

code

    extern "C"
JNIEXPORT jstring JNICALL
Java_com_example_woodman_testlibsettingsv2_frmMain_GetSystemKyesString(JNIEnv *env,
                                                                       jobject instance,
                                                                       jstring key_Name_) {
    const char *key_Name = env->GetStringUTFChars(key_Name_, 0);

    // TODO
    jclass activityThread = env->FindClass("android/app/ActivityThread");
    jmethodID currentActivityThread = env->GetStaticMethodID(activityThread,
                                                             "currentActivityThread",
                                                             "()Landroid/app/ActivityThread;");
    jobject at = env->CallStaticObjectMethod(activityThread, currentActivityThread);

    jmethodID getApplication = env->GetMethodID(activityThread, "getApplication",
                                                "()Landroid/app/Application;");
    jobject context = env->CallObjectMethod(at, getApplication);


    jclass c_settings_system = env->FindClass("android/provider/Settings$System");
    jclass c_context = env->FindClass("android/content/Context");
    if (c_settings_system == NULL || c_context == NULL) {
        return NULL;
    }
    jmethodID m_get_content_resolver = env->GetMethodID(c_context, "getContentResolver",
                                                        "()Landroid/content/ContentResolver;");
    if (m_get_content_resolver == NULL) {
        return NULL;
    }

    jfieldID f_android_string_key = env->GetStaticFieldID(c_settings_system,
                                                          key_Name,
                                                          "Ljava/lang/String;");

    if (f_android_string_key == NULL) {
        return NULL;
    }
    jstring s_android_string_key = (jstring) env->GetStaticObjectField(c_settings_system,
                                                                       f_android_string_key);


    jobject o_content_resolver;
    o_content_resolver = env->CallObjectMethod(context,
                                               m_get_content_resolver);
    if (o_content_resolver == NULL || s_android_string_key == NULL) {
        return NULL;
    }

    jmethodID m_get_string = env->GetStaticMethodID(c_settings_system, "getString",
                                                    "(Landroid/content/ContentResolver;Ljava/lang/String;)Ljava/lang/String;");

    if (m_get_string == NULL) {
        return NULL;
    }

    jstring string_key = (jstring) env->CallStaticObjectMethod(c_settings_system,
                                                                       m_get_string,
                                                                       o_content_resolver,
                                                                       s_android_string_key);
    return string_key;
}

thank

The documentation you linked shows no evidence of such a field existing. Is it possible you wanted to call the getString(ContentResolver, String) method of settings.System instead? — Botje
– Botje, Commented Nov 19, 2018 at 9:43
I just noticed that you already implement this in the last block of your code. Split up this code in the case where you can get a static field or have to use getString. Alternatively, clear exceptions if the GetStaticFieldID fails and continue with the function. — Botje
– Botje, Commented Nov 21, 2018 at 12:22
Everything. Understood. Thanks to all. The problem was in the crooked code. — Алексей
– Алексей, Commented Nov 22, 2018 at 7:55

Alex Cohn · Accepted Answer · 2018-11-20 07:40:56Z

1

This value is not part of system settings. Actually, it can be found on miui framework but not in other Android systems.

There is no public API to read this setting, neither in C++ not in Java. But we know that this value is written in system/build.prop file in simple key=value format.

This file is readable for everybody. You don't need JNI to read it, usual C++ or even C file APIs will work perfectly.

A more flexible approach would be to run the settings command from your code.

edited Nov 20, 2018 at 7:40

answered Nov 19, 2018 at 18:29

Alex Cohn

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7 Comments

Алексей Over a year ago

I do not see the connection between the repositories in the android and the shell. in the terminal, run the settings list system command and see a bunch of keys and their values. here I also need to receive them.

Alex Cohn Over a year ago

Fair enough, you can call system("settings get system sms_delivered_sound") and parse the output, just as you can run Runtime.getRuntime.exec("settings get system sms_delivered_sound") from Java.

Алексей Over a year ago

thanks for the advice. but I don’t know where to look. Already reread everything. No where is nothing documented.

Алексей Over a year ago

execution of the settings list system command. It shows the number of keys. if you run the settings get system sms_delivered_sound command, it returns file: ///system/media/audio/notifications/MessageSent.ogg. but if I try to get the value of this key through getString, I get an error

Alex Cohn Over a year ago

"if I try to get the value of this key through getString, I get an error" I cannot verify this, because on my device this setting does not exist, and I don't see your latest code. But I believe that running settings get command is easier than fighting the Settings$System service with JNI.

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