/**
* Generates Dalvik bytecode equivalent to the following method. public static void hello() { int
* a = 0xabcd; int b = 0xaaaa; int c = a - b; String s = Integer.toHexString(c);
* System.out.println(s); int i=Function.run(); return; }
*/
private static void generateHelloMethod(DexMaker dexMaker, TypeId<?> declaringType) {
// Lookup some types we'll need along the way.
TypeId<System> systemType = TypeId.get(System.class);
TypeId<PrintStream> printStreamType = TypeId.get(PrintStream.class);
// TypeId<Function> function=TypeId.get(Function.class);
// Identify the 'hello()' method on declaringType.
MethodId hello = declaringType.getMethod(TypeId.VOID, "hello");
// Declare that method on the dexMaker. Use the returned Code instance
// as a builder that we can append instructions to.
Code code = dexMaker.declare(hello, Modifier.STATIC | Modifier.PUBLIC);
// Declare all the locals we'll need up front. The API requires this.
Local<Integer> a = code.newLocal(TypeId.INT);
Local<Integer> b = code.newLocal(TypeId.INT);
Local<Integer> c = code.newLocal(TypeId.INT);
Local<String> s = code.newLocal(TypeId.STRING);
Local<PrintStream> localSystemOut = code.newLocal(printStreamType);
Local<Integer> i = code.newLocal(TypeId.INT);
// Local<Function> localFunction=code.newLocal(function);
// int a = 0xabcd;
code.loadConstant(a, 0xabcd);
// int b = 0xaaaa;
code.loadConstant(b, 0xaaad);
// int c = a - b;
code.op(BinaryOp.SUBTRACT, c, a, b);
// String s = Integer.toHexString(c);
MethodId<Integer, String> toHexString =
TypeId.get(Integer.class).getMethod(TypeId.STRING, "toHexString", TypeId.INT);
code.invokeStatic(toHexString, s, c);
// int i=Function.run();
MethodId<Function, Integer> run =
TypeId.get(Function.class).getMethod(TypeId.INT, "run", TypeId.INT);
code.invokeStatic(run, i, b);
// System.out.println(s);
FieldId<System, PrintStream> systemOutField = systemType.getField(printStreamType, "out");
code.sget(systemOutField, localSystemOut);
MethodId<PrintStream, Void> printlnMethod =
printStreamType.getMethod(TypeId.VOID, "println", TypeId.STRING);
code.invokeVirtual(printlnMethod, null, localSystemOut, s);
// code.invokeVirtual(printlnMethod, null, localSystemOut, s);
// return;
code.returnVoid();
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
DexMaker dexMaker = new DexMaker();
File dexOutputDir = getDir("dex", 0);
System.out.println("create dexmaker");
System.out.println(Environment.getExternalStorageDirectory().toString());
// Generate a HelloWorld class.
TypeId<?> helloWorld = TypeId.get("LHelloWorld;");
dexMaker.declare(helloWorld, "HelloWorld.generated", Modifier.PUBLIC, TypeId.OBJECT);
generateHelloMethod(dexMaker, helloWorld);
// Create the dex file and load it.
File outputDir = new File(dexOutputDir.getAbsolutePath());
ClassLoader loader;
try {
System.out.println("load class");
loader = dexMaker.generateAndLoad(this.getClassLoader(), outputDir);
Class<?> helloWorldClass = loader.loadClass("HelloWorld");
// Execute our newly-generated code in-process.
helloWorldClass.getMethod("hello").invoke(null);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalAccessException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalArgumentException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InvocationTargetException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (NoSuchMethodException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public static void main(String[] args) throws Exception {
DexMaker dexMaker = new DexMaker();
// Generate a HelloWorld class.
TypeId<?> helloWorld = TypeId.get("LHelloWorld;");
dexMaker.declare(helloWorld, "HelloWorld.generated", Modifier.PUBLIC, TypeId.OBJECT);
generateHelloMethod(dexMaker, helloWorld);
// Create the dex file and load it.
File outputDir = Environment.getExternalStorageDirectory();
ClassLoader loader =
dexMaker.generateAndLoad(HelloWorldMaker.class.getClassLoader(), outputDir);
Class<?> helloWorldClass = loader.loadClass("HelloWorld");
// Execute our newly-generated code in-process.
Log.d("helloWorldClass.getMethod(\"hello\").invoke(null);");
helloWorldClass.getMethod("hello").invoke(null);
}
