Create set_log_android.go

examples/others/android/example/set_log_android.go

@@ -0,0 +1,77 @@
+//go:build android
+
+package main
+
+/*
+#cgo LDFLAGS: -landroid -llog
+#include <android/log.h>
+#include <stdlib.h>
+*/
+import "C"
+import (
+	"bufio"
+	"log"
+	"os"
+	"syscall"
+	"unsafe"
+)
+
+// from fyne 
+func init() {
+	log.SetOutput(infoWriter{})
+	// android logcat includes all of log.LstdFlags
+	log.SetFlags(log.Flags() &^ log.LstdFlags)
+	r, w, err := os.Pipe()
+	if err != nil {
+		panic(err)
+	}
+	stderr = w
+	if err := syscall.Dup3(int(w.Fd()), int(os.Stderr.Fd()), 0); err != nil {
+		panic(err)
+	}
+	go lineLog(r, C.ANDROID_LOG_ERROR)
+
+	r, w, err = os.Pipe()
+	if err != nil {
+		panic(err)
+	}
+	stdout = w
+	if err := syscall.Dup3(int(w.Fd()), int(os.Stdout.Fd()), 0); err != nil {
+		panic(err)
+	}
+	go lineLog(r, C.ANDROID_LOG_INFO)
+}
+
+var (
+	ctag = C.CString("raylib")
+	// Store the writer end of the redirected stderr and stdout
+	// so that they are not garbage collected and closed.
+	stderr, stdout *os.File
+)
+
+type infoWriter struct{}
+
+func (infoWriter) Write(p []byte) (n int, err error) {
+	cstr := C.CString(string(p))
+	C.__android_log_write(C.ANDROID_LOG_INFO, ctag, cstr)
+	C.free(unsafe.Pointer(cstr))
+	return len(p), nil
+}
+
+func lineLog(f *os.File, priority C.int) {
+	const logSize = 1024 // matches android/log.h.
+	r := bufio.NewReaderSize(f, logSize)
+	for {
+		line, _, err := r.ReadLine()
+		str := string(line)
+		if err != nil {
+			str += " " + err.Error()
+		}
+		cstr := C.CString(str)
+		C.__android_log_write(priority, ctag, cstr)
+		C.free(unsafe.Pointer(cstr))
+		if err != nil {
+			break
+		}
+	}
+}