原文说明
/**
* Called before the invocation of the method.
*
* <p>You can use {@link MethodHookParam#setResult} and {@link MethodHookParam#setThrowable}
* to prevent the original method from being called.
*
* <p>Note that implementations shouldn't call {@code super(param)}, it's not necessary.
*
* @param param Information about the method call.
* @throws Throwable Everything the callback throws is caught and logged.
*/
protected void beforeHookedMethod(MethodHookParam param) throws Throwable {}
/**
* Called after the invocation of the method.
*
* <p>You can use {@link MethodHookParam#setResult} and {@link MethodHookParam#setThrowable}
* to modify the return value of the original method.
*
* <p>Note that implementations shouldn't call {@code super(param)}, it's not necessary.
*
* @param param Information about the method call.
* @throws Throwable Everything the callback throws is caught and logged.
*/
protected void afterHookedMethod(MethodHookParam param) throws Throwable {}
/**
* Shortcut for replacing a method completely. Whatever is returned/thrown here is taken
* instead of the result of the original method (which will not be called).
*
* <p>Note that implementations shouldn't call {@code super(param)}, it's not necessary.
*
* @param param Information about the method call.
* @throws Throwable Anything that is thrown by the callback will be passed on to the original caller.
*/
@SuppressWarnings("UnusedParameters")
protected abstract Object replaceHookedMethod(MethodHookParam param) throws Throwable;翻译及总结
beforeHookedMethod 会在调用原方法前执行，如果使用setResult则跳过原方法，并返回setResult参数中的值。
afterHookedMethod 会在调用原方法后执行，setResult可改变返回值
replaceHookedMethod 会完全替换原方法，即原方法不执行，且返回值可以直接return，setResult不生效。
代码验证
需要被Hook的代码
至于返回值为什么用Integer ，因为在测试replaceHookedMethod的时候，给 int 赋 null 会崩……而 final是为了顺便验证下这个关键字会不会影响hook。
private void test(){
Integer ret = hkBefore(100);
Log.d(TAG, "hkBefore ret:" + ret);
ret = hkBeforeSetResult(200);
Log.d(TAG, "hkBeforeSetResult ret:" + ret);
ret = hkAfter(300);
Log.d(TAG, "hkAfter ret:" + ret);
ret = hkAfterSetResult(400);
Log.d(TAG, "hkAfterSetResult ret:" + ret);
ret = hkReplace(500);
Log.d(TAG, "hkReplace ret:" + ret);
ret = hkReplaceReturn(600);
Log.d(TAG, "hkReplaceReturn ret:" + ret);
ret = hkReplaceSetResult(700);
Log.d(TAG, "hkReplaceSetResult ret:" + ret);
}
public final Integer hkBefore(int a){
Log.d(TAG, "————————————————————————hkBefore print:" + a);
return a;
}
public final Integer hkBeforeSetResult(int a){
Log.d(TAG, "————————————————————————hkBeforeSetResult print:" + a);
return a;
}
public final Integer hkAfter(int a){
Log.d(TAG, "————————————————————————hkAfter print:" + a);
return a;
}
public final Integer hkAfterSetResult(int a){
Log.d(TAG, "————————————————————————hkAfterSetResult print:" + a);
return a;
}
public final Integer hkReplace(int a){
Log.d(TAG, "————————————————————————hkReplace print:" + a);
return a;
}
public final Integer hkReplaceReturn(int a){
Log.d(TAG, "————————————————————————hkReplaceReturn print:" + a);
return a;
}
public final Integer hkReplaceSetResult(int a){
Log.d(TAG, "————————————————————————hkReplaceSetResult print:" + a);
return a;
}xposed模块
public class XMain implements IXposedHookLoadPackage {
private final String TAG = "XposedMain";
@Override
public void handleLoadPackage(XC_LoadPackage.LoadPackageParam loadPackageParam) throws Throwable {
Log.d(TAG, "hook app: " + loadPackageParam.packageName);
if (loadPackageParam.packageName.equals("com.bloguan.democity")) {
Log.d(TAG, "hook ");
XposedHelpers.findAndHookMethod("com.bloguan.democity.demo.DTest", loadPackageParam.classLoader, "hkBefore", int.class, new XC_MethodHook() {
@Override
protected void beforeHookedMethod(MethodHookParam param) throws Throwable {
int a = (int) param.args[0];
param.args[0] = a + 1;
}
});
XposedHelpers.findAndHookMethod("com.bloguan.democity.demo.DTest", loadPackageParam.classLoader, "hkBeforeSetResult", int.class, new XC_MethodHook() {
@Override
protected void beforeHookedMethod(MethodHookParam param) throws Throwable {
int a = (int) param.args[0];
param.args[0] = a + 1;
param.setResult(a + 2);
}
});
XposedHelpers.findAndHookMethod("com.bloguan.democity.demo.DTest", loadPackageParam.classLoader, "hkAfter", int.class, new XC_MethodHook() {
@Override
protected void afterHookedMethod(MethodHookParam param) throws Throwable {
int a = (int) param.args[0];
param.args[0] = a + 1;
}
});
XposedHelpers.findAndHookMethod("com.bloguan.democity.demo.DTest", loadPackageParam.classLoader, "hkAfterSetResult", int.class, new XC_MethodHook() {
@Override
protected void afterHookedMethod(MethodHookParam param) throws Throwable {
int a = (int) param.args[0];
param.args[0] = a + 1;
param.setResult(a + 2);
}
});
XposedHelpers.findAndHookMethod("com.bloguan.democity.demo.DTest", loadPackageParam.classLoader, "hkReplace", int.class, new XC_MethodReplacement() {
@Override
protected Object replaceHookedMethod(MethodHookParam param) throws Throwable {
return null;
}
});
XposedHelpers.findAndHookMethod("com.bloguan.democity.demo.DTest", loadPackageParam.classLoader, "hkReplaceReturn", int.class, new XC_MethodReplacement() {
@Override
protected Object replaceHookedMethod(MethodHookParam param) throws Throwable {
int a = (int) param.args[0];
return a + 1;
}
});
XposedHelpers.findAndHookMethod("com.bloguan.democity.demo.DTest", loadPackageParam.classLoader, "hkReplaceSetResult", int.class, new XC_MethodReplacement() {
@Override
protected Object replaceHookedMethod(MethodHookParam param) throws Throwable {
int a = (int) param.args[0];
param.args[0] = a + 1;
param.setResult(a + 2);
return a + 3;
}
});
Log.d(TAG, "hook success ");
}
}
}xposed模块安装过程就不赘述了，既然有此一问，说明xposed已经用上了。
执行结果
12-18 16:20:22.878 2054-2054/com.bloguan.democity D/TEST: ————————————————————————hkBefore print:101 12-18 16:20:22.883 2054-2054/com.bloguan.democity D/TEST: hkBefore ret:101 12-18 16:20:22.883 2054-2054/com.bloguan.democity D/TEST: hkBeforeSetResult ret:202 12-18 16:20:22.883 2054-2054/com.bloguan.democity D/TEST: ————————————————————————hkAfter print:300 12-18 16:20:22.884 2054-2054/com.bloguan.democity D/TEST: hkAfter ret:300 12-18 16:20:22.884 2054-2054/com.bloguan.democity D/TEST: ————————————————————————hkAfterSetResult print:400 12-18 16:20:22.884 2054-2054/com.bloguan.democity D/TEST: hkAfterSetResult ret:402 12-18 16:20:22.884 2054-2054/com.bloguan.democity D/TEST: hkReplace ret:null 12-18 16:20:22.884 2054-2054/com.bloguan.democity D/TEST: hkReplaceReturn ret:601 12-18 16:20:22.884 2054-2054/com.bloguan.democity D/TEST: hkReplaceSetResult ret:703
打印不算太乱吧 = =
结论即上面说的，具体流程各位可以自己细看。
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