如何使用安卓音频管理器使用QAndroidJniObject到setSpeakerphoneOn(真)？

Question

我正在写qt手机应用程序，我需要设置speakerphoneOn与QAndroidJniObject，但我不知道如何正确地做它。

这是我目前正在做的事情，但是应用程序崩溃了。

package Loudspeaker;

import android.app.Activity;
import android.content.Context;
import android.media.AudioManager;

public class Speaker extends Activity
{
    private AudioManager audioManager;

    public Speaker()
    {
        this.audioManager = (AudioManager) getSystemService(Context.AUDIO_SERVICE);
    }

    public String speaker_on()
    {
        audioManager.setSpeakerphoneOn(true);
        return "DONE FROM JAVA";
    }

    public String speaker_off()
    {
        audioManager.setSpeakerphoneOn(false);
        return "DONE FROM JAVA";
    }
}

QAndroidJniObject someJavaObject = QAndroidJniObject("Loudspeaker/Speaker");
        QString as = someJavaObject.callObjectMethod<jstring>("speaker_on").toString();
        logfile1 << as.toStdString();

我是java的新手，发现它因为“扩展活动”而崩溃，但没有它就无法编译。

Answer 1

我找到了解决办法：

package MyJava;

import org.qtproject.qt5.android.QtNative;
import android.content.Context;
import android.media.AudioManager;

public class Speaker
{
    public Speaker()
    {
    }

    private static AudioManager am()
    {
        Context c = QtNative.activity().getApplicationContext();
        return (AudioManager)c.getSystemService(c.AUDIO_SERVICE);
    }

    public static void speaker_on()
    {
        am().setSpeakerphoneOn(true);
    }

    public static void speaker_off()
    {
        am().setSpeakerphoneOn(false);
    }
}

和

QAndroidJniObject::callStaticMethod<void>("MyJava/Speaker", "speaker_on");