Android(安卓)直接通过JNI访问驱动

package com.yang.jniaccesshardware;import android.os.Bundle;import android.support.v7.app.AppCompatActivity;import android.view.View;import android.widget.Button;import android.widget.CheckBox;import android.widget.Toast;import com.yang.hardlibrary.HardControl;public class MainActivity extends AppCompatActivity {    private boolean led_on = false;    private Button button;    private CheckBox led1;    private CheckBox led2;    private CheckBox led3;    private CheckBox led4;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        button=(Button)findViewById(R.id.BUTTON);        HardControl.ledOpen();        led1=(CheckBox)findViewById(R.id.led1);        led2=(CheckBox)findViewById(R.id.led2);        led3=(CheckBox)findViewById(R.id.led3);        led4=(CheckBox)findViewById(R.id.led4);        button.setOnClickListener(new MyButtonListener());    }    class MyButtonListener implements View.OnClickListener {        @Override        public void onClick(View v) {            HardControl hardControl = new HardControl();//依赖硬件            led_on = !led_on;            if (led_on) {                button.setText("ALL OFF");                led1.setChecked(true);                led2.setChecked(true);                led3.setChecked(true);                led4.setChecked(true);                for (int i = 0; i < 4; i++)                    HardControl.ledCtrl(i, 1);            }            else {                button.setText("ALL ON");                led1.setChecked(false);                led2.setChecked(false);                led3.setChecked(false);                led4.setChecked(false);                for (int i = 0; i < 4; i++)                    HardControl.ledCtrl(i, 0);            }        }    }    public void onCheckboxClicked(View view) {        // Is the view now checked?        boolean checked = ((CheckBox) view).isChecked();        // Check which checkbox was clicked        switch(view.getId()) {            case R.id.led1:                if (checked)                {                    Toast.makeText(getApplicationContext(),"led1_on",Toast.LENGTH_LONG).show();                    HardControl.ledCtrl(1, 1);                }                else                {                    Toast.makeText(getApplicationContext(),"led1_off",Toast.LENGTH_LONG).show();                    HardControl.ledCtrl(1, 0);                }                break;            case R.id.led2:                if (checked)                {                    Toast.makeText(getApplicationContext(),"led1_on",Toast.LENGTH_LONG).show();                    HardControl.ledCtrl(2, 1);                }                else                {                    Toast.makeText(getApplicationContext(),"led1_off",Toast.LENGTH_LONG).show();                    HardControl.ledCtrl(2, 0);                }                break;            case R.id.led3:                if (checked)                {                    Toast.makeText(getApplicationContext(),"led1_on",Toast.LENGTH_LONG).show();                    HardControl.ledCtrl(3, 1);                }                else                {                    Toast.makeText(getApplicationContext(),"led1_off",Toast.LENGTH_LONG).show();                    HardControl.ledCtrl(3, 0);                }                break;            case R.id.led4:                if (checked)                {                    Toast.makeText(getApplicationContext(),"led1_on",Toast.LENGTH_LONG).show();                    HardControl.ledCtrl(4, 1);                }                else                {                    Toast.makeText(getApplicationContext(),"led1_off",Toast.LENGTH_LONG).show();                    HardControl.ledCtrl(4, 0);                }                break;        }    }}

package com.yang.hardlibrary;public class HardControl {    public static native int ledCtrl(int which, int status);    public static native int ledOpen();    public static native void ledClose();//申明三个本地方法。    static {        try {            System.loadLibrary("hardcontrol");        } catch (Exception e) {            e.printStackTrace();        }    }}

#include   /* /usr/lib/jvm/java-1.7.0-openjdk-amd64/include/ */#include #include #include #include #include #include #include   /* liblog *///__android_log_print(ANDROID_LOG_DEBUG, "JNIDemo", "native add ..."); #if 0typedef struct {    char *name;          /* Java里调用的函数名 */    char *signature;    /* JNI字段描述符, 用来表示Java里调用的函数的参数和返回值类型 */    void *fnPtr;          /* C语言实现的本地函数 */} JNINativeMethod;#endifstatic jint fd;jint ledOpen(JNIEnv *env, jobject cls){    fd = open("/dev/leds", O_RDWR);    __android_log_print(ANDROID_LOG_DEBUG, "LEDDemo", "native ledOpen : %d", fd);    if (fd >= 0)        return 0;    else        return -1;}void ledClose(JNIEnv *env, jobject cls){    __android_log_print(ANDROID_LOG_DEBUG, "LEDDemo", "native ledClose ...");    close(fd);}jint ledCtrl(JNIEnv *env, jobject cls, jint which, jint status){    int ret = ioctl(fd, status, which);    __android_log_print(ANDROID_LOG_DEBUG, "LEDDemo", "native ledCtrl : %d, %d, %d", which, status, ret);    return ret;}static const JNINativeMethod methods[] = {    {"ledOpen", "()I", (void *)ledOpen},    {"ledClose", "()V", (void *)ledClose},    {"ledCtrl", "(II)I", (void *)ledCtrl},};/* System.loadLibrary */JNIEXPORT jint JNICALLJNI_OnLoad(JavaVM *jvm, void *reserved){    JNIEnv *env;    jclass cls;    if ((*jvm)->GetEnv(jvm, (void **)&env, JNI_VERSION_1_4)) {        return JNI_ERR; /* JNI version not supported */    }    cls = (*env)->FindClass(env, "com/yang/hardlibrary/HardControl");    if (cls == NULL) {        return JNI_ERR;    }    /* 2. map java hello <-->c c_hello */    if ((*env)->RegisterNatives(env, cls, methods, sizeof(methods)/sizeof(methods[0])) < 0)        return JNI_ERR;    return JNI_VERSION_1_4;}

转载于:https://www.cnblogs.com/maogefff/p/7738084.html

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