详细分析Android中实现Zygote的源码

// 1. 创建虚拟机 if (startVm(&mJavaVM, &env) != 0) {

return; }

onVmCreated(env);

// 2. 注册JNI函数 if (startReg(env) < 0) {

ALOGE("Unable to register all android nativesn"); return;

}

jclass stringClass; jobjectArray strArray;

jstring classNameStr; jstring optionsStr;

stringClass = env->FindClass("java/lang/String");

assert(stringClass != NULL); // 创建一个有两个元素的String数组，用Java代码表示为:String[] strArray = new String[2];

strArray = env->NewObjectArray(2, stringClass, NULL); assert(strArray != NULL);

classNameStr = env->NewStringUTF(className); assert(classNameStr != NULL);

// 设置第一个元素为"com.android.internal.os.ZygoteInit" env->SetObjectArrayElement(strArray, 0, classNameStr);

optionsStr = env->NewStringUTF(options); // 设置第二个元素为"start-system-server"

env->SetObjectArrayElement(strArray, 1, optionsStr);

// 将字符串"com.android.internal.os.ZygoteInit"转换为"com/android/internal/os/ZygoteInit" char* slashClassName = toSlashClassName(className);

jclass startClass = env->FindClass(slashClassName); if (startClass == NULL) {

ALOGE("JavaVM unable to locate class '%s'n", slashClassName); } else {

jmethodID startMeth = env->GetStaticMethodID(startClass, "main", "([Ljava/lang/String;)V"); if (startMeth == NULL) {

ALOGE("JavaVM unable to find main() in '%sn'", className); } else {

// 3. // 通过JNI调用java函数，注意调用的是main函数，所属的类是"com.android.internal.os.ZygoteInit".

// 传递的参数是"com.android.internal.os.ZygoteInit true" env->CallStaticVoidMethod(startClass, startMeth, strArray);