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On Android startup, obtain a Bluetooth adapter and check if it is 

enabled.
This commit is contained in:
Greg 2019-10-28 15:18:18 -04:00
parent f036c5e134
commit 820186e132
2 changed files with 132 additions and 4 deletions
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39
ble_android.go
View File

@ -1,14 +1,22 @@
package ble
import (
"log"
"gioui.org/app"
)
/*
#include <jni.h>
*/
import "C"
// Types required for ble.go
type bleState string
type bleHandle struct {
adapter C.jobject
class C.jclass
}
type Peripheral struct {
@ -22,12 +30,16 @@ type Characteristic string
// Internal global variables
var jvmContext uintptr
// Functions required by API
//Init needs to be called before the BLE library can be used. On Android we
//need to set up the JVM by calling setJVM in jni_android.go.
func Init() {
log.Print("ble.Init()")
h := app.PlatformHandle()
jvmContext = h.Context
setJVM(h.JVM, h.Context)
}
@ -98,6 +110,31 @@ func (p Peripheral) SetNotifyValue(c Characteristic) {
//Bluetooth API.
func NewBLE() *BLE {
ps := Peripherals{items: make([]PeripheralListItem, 0)}
return &BLE{events: make(chan interface{}), peripherals: ps}
h := bleHandle{}
RunInJVM(func(env *JNIEnv) {
h.adapter = GetBluetoothAdapter(env, jvmContext)
h.class = JniGetObjectClass(env, h.adapter)
})
ret := &BLE{
events: make(chan interface{}),
peripherals: ps,
handle: h,
}
//check if Bluetooth is enabled and if so, send an UpdateStateEvent
go func() {
RunInJVM(func(env *JNIEnv) {
mid := JniGetMethodID(env, h.class, "isEnabled", "()Z")
en := JniCallBooleanMethod(env, h.adapter, mid)
if en {
log.Print("It's enabled!")
ret.events <-UpdateStateEvent{"powered on"}
} else {
log.Print("It's not enabled")
}
})
}()
return ret
}

97
jni_android.go
View File

@ -1,7 +1,7 @@
package ble
/*
#cgo LDFLAGS: -landroid
#cgo LDFLAGS: -landroid -llog
#include <stdlib.h>
#include <jni.h>
@ -10,6 +10,13 @@ package ble
static jobject gClassLoader;
static jmethodID gFindClassMethod;
jclass
GetObjectClass(JNIEnv* env, jobject obj) {
jclass cls = (*env)->GetObjectClass(env, obj);
cls = (*env)->NewGlobalRef(env, cls);
return cls;
}
void
SetLoader(JNIEnv* env, jobject context) {
jclass cclass = (*env)->GetObjectClass(env, context);
@ -20,6 +27,68 @@ SetLoader(JNIEnv* env, jobject context) {
gFindClassMethod = (*env)->GetMethodID(env, lclass, "findClass", "(Ljava/lang/String;)Ljava/lang/Class;");
}
jobject
GetBluetoothAdapter(JNIEnv* env, jobject ctx) {
jclass cls = (*env)->GetObjectClass(env, ctx);
if (cls == NULL) {
__android_log_write(ANDROID_LOG_DEBUG, "gio", "GetBluetoothAdapter(): Can't get context class");
return NULL;
}
jfieldID id = (*env)->GetStaticFieldID(env, cls, "BLUETOOTH_SERVICE", "Ljava/lang/String;");
if (id == NULL) {
__android_log_write(ANDROID_LOG_DEBUG, "gio", "GetBluetoothAdapter(): Can't get field ID");
return NULL;
}
jstring btsrv = (jstring)(*env)->GetStaticObjectField(env, cls, id);
if (btsrv == NULL) {
__android_log_write(ANDROID_LOG_DEBUG, "gio", "GetBluetoothAdapter(): Can't get static object field");
return NULL;
}
jmethodID mid = (*env)->GetMethodID(env, cls, "getSystemService", "(Ljava/lang/String;)Ljava/lang/Object;");
if (mid == NULL) {
__android_log_write(ANDROID_LOG_DEBUG, "gio", "GetBluetoothAdapter(): Can't get method ID");
return NULL;
}
jobject manager = (*env)->CallObjectMethod(env, ctx, mid, btsrv);
if (manager == NULL) {
__android_log_write(ANDROID_LOG_DEBUG, "gio", "GetBluetoothAdapter(): Can't get bluetooth manager");
return NULL;
}
cls = (*env)->GetObjectClass(env, manager);
if (cls == NULL) {
__android_log_write(ANDROID_LOG_DEBUG, "gio", "GetBluetoothAdapter(): Can't get class of bluetooth manager");
return NULL;
}
mid = (*env)->GetMethodID(env, cls, "getAdapter", "()Landroid/bluetooth/BluetoothAdapter;");
if (mid == NULL) {
__android_log_write(ANDROID_LOG_DEBUG, "gio", "GetBluetoothAdapter(): Can't get methodID for getAdapter()");
return NULL;
}
jobject ad = (*env)->CallObjectMethod(env, manager, mid);
if (ad == NULL) {
__android_log_write(ANDROID_LOG_DEBUG, "gio", "GetBluetoothAdapter(): Can't get adapter");
} else {
__android_log_write(ANDROID_LOG_DEBUG, "gio", "GetBluetoothAdapter(): Found");
}
ad = (*env)->NewGlobalRef(env, ad);
return ad;
}
jstring
GetObjectStaticStringField(JNIEnv* env, jobject obj, char* fld) {
jclass cls = (*env)->GetObjectClass(env, obj);
if (cls == NULL) {
__android_log_write(ANDROID_LOG_DEBUG, "gio", "GetObjectStaticStringField(): Can't get class");
return NULL;
}
jfieldID id = (*env)->GetStaticFieldID(env, cls, fld, "Ljava/lang/String;");
if (id == NULL) {
__android_log_write(ANDROID_LOG_DEBUG, "gio", "GetObjectStaticStringField(): Can't find FieldID");
return NULL;
}
return (jstring)(*env)->GetStaticObjectField(env, cls, id);
}
jclass
FindClass(JNIEnv* env, char* name) {
jstring strClassName = (*env)->NewStringUTF(env, name);
@ -36,6 +105,10 @@ void CallVoidMethod(JNIEnv *env, jobject obj, jmethodID methodID) {
(*env)->CallVoidMethod(env, obj, methodID);
}
jboolean CallBooleanMethod(JNIEnv *env, jobject obj, jmethodID mid) {
return (*env)->CallBooleanMethod(env, obj, mid);
}
jint CallIntMethod(JNIEnv *env, jobject obj, jmethodID methodID) {
return (*env)->CallIntMethod(env, obj, methodID);
}
@ -74,7 +147,7 @@ type JNIEnv = C.JNIEnv
func setJVM(jvm, context uintptr) {
log.Print("set theJVM")
theJVM = (*C.JavaVM)(unsafe.Pointer(jvm))
log.Printf("theJVM = %d", uintptr(unsafe.Pointer(theJVM)))
//log.Printf("theJVM = %d", uintptr(unsafe.Pointer(theJVM)))
RunInJVM(func(env *C.JNIEnv) {
C.SetLoader(env, (C.jobject)(context))
})
@ -86,10 +159,28 @@ func FindClass(env *C.JNIEnv, name string) C.jclass {
return C.FindClass((*C.JNIEnv)(env), cname)
}
func JniGetObjectClass(env *C.JNIEnv, obj C.jobject) C.jclass {
return C.GetObjectClass(env, obj)
}
func JniGetObjectStaticStringField(env *C.JNIEnv, obj C.jobject, fld string) C.jstring {
cstring := C.CString(fld)
defer C.free(unsafe.Pointer(cstring))
return C.GetObjectStaticStringField(env, obj, cstring)
}
func GetBluetoothAdapter(env *C.JNIEnv, ctx uintptr) C.jobject {
return C.GetBluetoothAdapter(env, (C.jobject)(ctx))
}
func JniCallVoidMethod(env *C.JNIEnv, obj C.jobject, methodID C.jmethodID) {
C.CallVoidMethod(env, obj, methodID)
}
func JniCallBooleanMethod(env *C.JNIEnv, obj C.jobject, methodID C.jmethodID) bool {
return C.CallBooleanMethod(env, obj, methodID) == 0
}
func JniCallIntMethod(env *C.JNIEnv, obj C.jobject, methodID C.jmethodID) int {
return (int)(C.CallIntMethod(env, obj, methodID))
}
@ -111,7 +202,7 @@ func RunInJVM(f func(env *C.JNIEnv)) {
defer runtime.UnlockOSThread()
var env *C.JNIEnv
var detach bool
log.Printf("RunInJVM(): theJVM = %d", uintptr(unsafe.Pointer(theJVM)))
//log.Printf("RunInJVM(): theJVM = %d", uintptr(unsafe.Pointer(theJVM)))
if res := C.GetEnv(theJVM, &env, C.JNI_VERSION_1_6); res != C.JNI_OK {
if res != C.JNI_EDETACHED {
panic(fmt.Errorf("JNI GetEnv failed with error %d", res))