FM Radio项目原创代码

最新推荐文章于 2023-05-23 14:07:31 发布

谷木幽月

最新推荐文章于 2023-05-23 14:07:31 发布

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分类专栏： android 文章标签： android linux 内核 fmradio jni

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本文介绍了一款基于Android NDK的FM收音机开发过程，包括使用JNI调用驱动实现功能模块，如打开/关闭收音机、扫描频道、播放指定频率的频道、调整音量、静音及获取信号强度等。提供了详细的代码实现，适合对Android NDK和FM收音机开发感兴趣的开发者参考。

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转载自 http://blog.youkuaiyun.com/zyw123/article/details/6891063

最近在做基于一款芯片的FM Radio.有了底层驱动，需要我做上层java代码，已经自己写jni调用驱动，实现FM Radio 的功能。

android　NDK开发就不介绍了，这样的可以有很多参考。我只是把我写的部分代码拿出来与大家分享。有做FM Ｒadio 的请参考，也可以提出意见。

首先要有功能代码：做了一个类

package com.mycompanyname.fm;

import android.util.Log;

public class FMFunction {
   private static final String TAG = "FMFunction";

   public FMFunction() {
       Log.i(TAG,"FMFunction created......");
   }

   public void openFm () {
       nativeOpenFM();
   }

   public void closeFm () {
       nativeCloseFM();
   }


   public int[] scanChannel() {
       return nativeScanChannel();
   }

   public void playChannel(int freq) {
       nativePlayChannel(freq);
   }

   public int getAudioVolume() {
       return nativeGetAudioVolume();
   }

   public void audioUp() {
       nativeAudioUp();
   }

   public void audioDown() {
       nativeAudioDown();
   }

   public void setMute() {
       nativeSetMute();
   }


   public int getRssiLevel() {
       return nativeGetRssiLevel();
   }

   //native function
   private native void nativeOpenFM();
   private native void nativeCloseFM();
    private native int [] nativeScanChannel();
    private native void nativePlayChannel(int freq);
    private native void nativeAudioUp();
    private native void nativeAudioDown();
    private native int nativeGetAudioVolume();
    private native void nativeSetMute();
    private native int nativeGetRssiLevel();

    static {
       Log.i(TAG,"loadLibrary carry out..............");
        System.loadLibrary("fmfunction-jni");
    }
}

这个类介绍了要用到的radio 功能。
openFm ()：打开radio

closeFm ()：关闭radio

scanChannel()：扫描所有频道

playChannel(int freq)：播放指定频率的频道

getAudioVolume()：取得当前音量值

audioUp()：提高音量

audioDown()：降低音量

setMute()：静音

getRssiLevel()：取得信号强度

只是简单的写了这些功能，这些功能对播放应该就可以了。

下面还要就这些上层功能做jni实现，jni调用驱动实现上述功能。

jni 代码如下：

#include <string.h>
#include <jni.h>
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <malloc.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/ioctl.h>
#include <linux/videodev2.h>
#include <android/log.h>
#define VIDIOC_S_HW_FREQ_SEEK 0x40305652

struct v4l2_hw_freq_seek {
   __u32              tuner;
   enum v4l2_tuner_type type;
   __u32              seek_upward;
   __u32              wrap_around;
   __u32              reserved[8];
};

/* parameters for driver use */
static int fd;
int ret;
struct v4l2_capability cap;
struct v4l2_tuner tuner;
struct v4l2_audio a;
struct v4l2_frequency f;
struct v4l2_queryctrl q;
struct v4l2_control c;
struct v4l2_hw_freq_seek seek;
unsigned int i;
unsigned int mute=0;
unsigned int volume = 0;
unsigned int freq = 87500000;

void Java_com_innofidei_fm_FMFunction_nativeOpenFM(JNIEnv* env,jobject thiz) {
    __android_log_write(ANDROID_LOG_INFO,"JNIMsg","nativeOpenFM init............");
    fd = open("/dev/radio0",O_RDONLY);
    if (fd < 0) {
         __android_log_print(ANDROID_LOG_INFO,"JNIMsg","nativeOpenFM init failed : %d ",fd);

    } else {
         __android_log_print(ANDROID_LOG_INFO,"JNIMsg","nativeOpenFM init success");

    }
}

void Java_com_innofidei_fm_FMFunction_nativeCloseFM(JNIEnv* env,jobject thiz) {
    __android_log_write(ANDROID_LOG_INFO,"JNIMsg","nativeCloseFM .............");
    close(fd);
    return;
}

jintArray Java_com_innofidei_fm_FMFunction_nativeScanChannel(JNIEnv* env,jobject thiz) {
    __android_log_write(ANDROID_LOG_INFO,"JNIMsg","nativeScanChannel..... .......");

    jintArray result;
    result = (*env)->NewIntArray(env, 20);
    if (result == NULL) {
        return NULL;
    }

    /*init original array for recording frequency info */
    jint num[20];
    jint i = 0;
    for (;i<20;i++) {
        num[i] = 0;
    }

    /* set lowest frequency */
    f.frequency = freq *2 /125;
    f.type = V4L2_TUNER_RADIO;
   f.tuner = 0;
   ret = ioctl(fd,VIDIOC_S_FREQUENCY,&f);
    if (ret < 0) {
       __android_log_write(ANDROID_LOG_INFO,"JNIMsg","search frequency failed");
   } else {
        __android_log_print(ANDROID_LOG_INFO,"JNIMsg","search frequency success");
   }

    /*search channel,obtain frequency to enter array */
    jint j = 0;
    for (;j<20;j++) {
        seek.wrap_around = 1;
        seek.seek_upward = 0;
        seek.tuner = 0;
        ret = ioctl(fd,VIDIOC_S_HW_FREQ_SEEK,&seek);
        if (ret == 0) {
            f.tuner = 0;
            ret = ioctl(fd,VIDIOC_G_FREQUENCY,&f);
            if (ret < 0) {
               __android_log_print(ANDROID_LOG_INFO,"JNIGetFrequency","get frequency failed");
               break;
            } else {
                __android_log_print(ANDROID_LOG_INFO,"JNIMsg","get freq is %d",f.frequency);
                num[j] = f.frequency;
            }

        } else {
            break;
        }
    }

    (*env)->SetIntArrayRegion(env,result, 0, 20, num);
    return result;
}

void Java_com_innofidei_fm_FMFunction_nativePlayChannel(JNIEnv* env,jobject thiz,jint freq){
    __android_log_print(ANDROID_LOG_INFO,"JNIMsg","nativePlayChannel init......,freq is: %d",freq);

    f.frequency = freq;
   f.type = V4L2_TUNER_RADIO;
   f.tuner = 0;
   ret = ioctl(fd,VIDIOC_S_FREQUENCY,&f);
   if (ret < 0) {
       __android_log_write(ANDROID_LOG_INFO,"JNIMsg","nativePlay set frequency failed");
   } else {
        __android_log_print(ANDROID_LOG_INFO,"JNIMsg","nativePlay carry out success");
   }

   /*unmute */
   mute = 0;
    c.id = V4L2_CID_AUDIO_MUTE;
   c.value = mute;
   ret = ioctl(fd,VIDIOC_S_CTRL,&c);
   if (ret < 0) {
       __android_log_print(ANDROID_LOG_INFO,"JNIMsg","nativePlay can not unmute");
   } else {
        __android_log_print(ANDROID_LOG_INFO,"JNIMsg","nativePlay unmute success ");
    }

   /*obtain current volume*/
   c.id = V4L2_CID_AUDIO_VOLUME;
   ret = ioctl(fd,VIDIOC_G_CTRL,&c);
   if (ret < 0) {
       __android_log_print(ANDROID_LOG_INFO,"JNIMsg","get ctrl failed");
   } else {
        __android_log_print(ANDROID_LOG_INFO,"JNIMsg","current volume is : %d",c.value);
   }
}

void Java_com_innofidei_fm_FMFunction_nativeAudioUp(JNIEnv* env,jobject thiz) {
    __android_log_write(ANDROID_LOG_INFO,"JNIMsg","nativeAudioUp...............");
    c.id = V4L2_CID_AUDIO_VOLUME;
   ret = ioctl(fd,VIDIOC_G_CTRL,&c);
   if (ret < 0) {
       __android_log_print(ANDROID_LOG_INFO,"JNIMsg","get ctrl failed");
   } else {
        __android_log_print(ANDROID_LOG_INFO,"JNIMsg","current volume is : %d",c.value);
        volume = c.value;
   }
    c.id = V4L2_CID_AUDIO_VOLUME;
    if (volume < 15) {
        c.value = ++volume;
    }
   volume %=0x0f;
   ret = ioctl(fd,VIDIOC_S_CTRL,&c);
   if (ret < 0) {
       __android_log_write(ANDROID_LOG_INFO,"JNIMsg","set volume ctrl failed");
   }
   __android_log_print(ANDROID_LOG_INFO,"JNIMsg","after up, volume: %d",volume);
   return;
}

void Java_com_innofidei_fm_FMFunction_nativeAudioDown(JNIEnv* env,jobject thiz) {
    __android_log_write(ANDROID_LOG_INFO,"JNIMsg","nativeAudioDown.............");
    c.id = V4L2_CID_AUDIO_VOLUME;
   ret = ioctl(fd,VIDIOC_G_CTRL,&c);
   if (ret < 0) {
       __android_log_print(ANDROID_LOG_INFO,"JNIMsg","get ctrl failed");
   } else {
        __android_log_print(ANDROID_LOG_INFO,"JNIMsg","current volume is : %d",c.value);
        volume = c.value;
   }
    c.id = V4L2_CID_AUDIO_VOLUME;
    if (volume > 0) {
        c.value = --volume;
    }
   volume %=0x0f;
   ret = ioctl(fd,VIDIOC_S_CTRL,&c);
   if (ret < 0) {
       __android_log_write(ANDROID_LOG_INFO,"JNIMsg","set volume ctrl failed");
   }
   __android_log_print(ANDROID_LOG_INFO,"JNIMsg","after down, volume: %d",volume);
   return;
}

void Java_com_innofidei_fm_FMFunction_nativeSetMute(JNIEnv* env,jobject thiz) {
    __android_log_print(ANDROID_LOG_INFO,"JNIMsg","nativeSetMute init..................mute value is : %d",mute);
    if (mute == 0) {
          mute = 1;
    } else {
        mute = 0;
    }
    c.id = V4L2_CID_AUDIO_MUTE;
   c.value = mute;
   ret = ioctl(fd,VIDIOC_S_CTRL,&c);
   if (ret < 0) {
       __android_log_write(ANDROID_LOG_INFO,"JNIMsg","set mute ctrl failed");
   }
   __android_log_print(ANDROID_LOG_INFO,"JNIMsg","set mute ctrl success");
   return;
}

jint Java_com_innofidei_fm_FMFunction_nativeGetAudioVolume(JNIEnv* env,jobject thiz) {
    __android_log_print(ANDROID_LOG_INFO,"JNIMsg","nativeGetAudioVolume............");
    c.id = V4L2_CID_AUDIO_VOLUME;
   ret = ioctl(fd,VIDIOC_G_CTRL,&c);
   if (ret < 0) {
       __android_log_write(ANDROID_LOG_INFO,"JNIMsg","get ctrl failed");
       return ret;
   }
   __android_log_print(ANDROID_LOG_INFO,"JNIMsg","volume is %d",c.value);
    return c.value;
}

jint Java_com_innofidei_fm_FMFunction_nativeGetRssiLevel(JNIEnv* env,jobject thiz) {
    __android_log_print(ANDROID_LOG_INFO,"JNIMsg","nativeGetRssiLevel init................................");
    tuner.index = 0;
    ret = ioctl(fd,VIDIOC_G_TUNER,&tuner);
    __android_log_print(ANDROID_LOG_INFO,"JNIMsg","rssi level is %d",tuner.signal);
    return tuner.signal;
}