Android编程之还原JD-GUI反编译后代码



jd-gui这款jar反编译软件，大家经常用到，它反编译后的代码可以重新生成java文件。但它反编译出的代码，在遇到部分java特定语句的时候就不容易被看懂了。

我这里就jd-gui反编译后代码的复原内容讲讲我的经验，与大家分享一下：

1、switch语句：

正常的switch语句：

[java]
view plaincopyprint?

public boolean onTouchEvent(MotionEvent event) {
final int y = (int) event.getY();
mBounceHack = false;
switch (event.getAction()) {
case MotionEvent.ACTION_UP:
if (!isVerticalScrollBarEnabled()) {
setVerticalScrollBarEnabled(true);
}
if (getFirstVisiblePosition() == 0 && mRefreshState != REFRESHING) {
if ((mRefreshView.getBottom() >= mRefreshViewHeight || mRefreshView
.getTop() >= 0) && mRefreshState == RELEASE_TO_REFRESH) {
mRefreshState = REFRESHING
prepareForRefresh();
onRefresh();
} else if (mRefreshView.getBottom() < mRefreshViewHeight
|| mRefreshView.getTop() <= 0) {
resetHeader();
setSelection(1);
}
}
break;
case MotionEvent.ACTION_DOWN:
mLastMotionY = y;
break;
case MotionEvent.ACTION_MOVE:
applyHeaderPadding(event);
break; case MotionEvent.ACTION_CANCEL:
break;
}
return super.onTouchEvent(event);
}

public boolean onTouchEvent(MotionEvent event) {
final int y = (int) event.getY();
mBounceHack = false;
switch (event.getAction()) {
case MotionEvent.ACTION_UP:
if (!isVerticalScrollBarEnabled()) {
setVerticalScrollBarEnabled(true);
}
if (getFirstVisiblePosition() == 0 && mRefreshState != REFRESHING) {
if ((mRefreshView.getBottom() >= mRefreshViewHeight || mRefreshView
.getTop() >= 0) && mRefreshState == RELEASE_TO_REFRESH) {
mRefreshState = REFRESHING
prepareForRefresh();
onRefresh();
} else if (mRefreshView.getBottom() < mRefreshViewHeight
|| mRefreshView.getTop() <= 0) {
resetHeader();
setSelection(1);
}
}
break;
case MotionEvent.ACTION_DOWN:
mLastMotionY = y;
break;
case MotionEvent.ACTION_MOVE:
applyHeaderPadding(event);
break;  case MotionEvent.ACTION_CANCEL:
break;
}
return super.onTouchEvent(event);
}

经过JD-GUI反编译后：

[java]
view plaincopyprint?

public boolean onTouchEvent(MotionEvent paramMotionEvent) { int i = (int) paramMotionEvent.getY(); this.mBounceHack = 0; switch (paramMotionEvent.getAction()) { default: case 1: case 0: case 2: } while (true) { return super.onTouchEvent(paramMotionEvent); if (!isVerticalScrollBarEnabled()) setVerticalScrollBarEnabled(1); if ((getFirstVisiblePosition() != 0) || (this.mRefreshState == 4)) continue; int j = this.mRefreshView.getBottom(); int k = this.mRefreshViewHeight; if (((j >= k) || (this.mRefreshView.getTop() >= 0)) && (this.mRefreshState == 3)) { this.mRefreshState = 4; prepareForRefresh(); onRefresh(); continue; } int m = this.mRefreshView.getBottom(); int n = this.mRefreshViewHeight; if ((m >= n) && (this.mRefreshView.getTop() > 0)) continue; resetHeader(); setSelection(1); continue; this.mLastMotionY = i; continue; applyHeaderPadding(paramMotionEvent); } }

public boolean onTouchEvent(MotionEvent paramMotionEvent) {
int i = (int) paramMotionEvent.getY();
this.mBounceHack = 0;
switch (paramMotionEvent.getAction()) {
default:
case 1:
case 0:
case 2:
}
while (true) {
return super.onTouchEvent(paramMotionEvent);
if (!isVerticalScrollBarEnabled())
setVerticalScrollBarEnabled(1);
if ((getFirstVisiblePosition() != 0) || (this.mRefreshState == 4))
continue;
int j = this.mRefreshView.getBottom();
int k = this.mRefreshViewHeight;
if (((j >= k) || (this.mRefreshView.getTop() >= 0))
&& (this.mRefreshState == 3)) {
this.mRefreshState = 4;
prepareForRefresh();
onRefresh();
continue;
}
int m = this.mRefreshView.getBottom();
int n = this.mRefreshViewHeight;
if ((m >= n) && (this.mRefreshView.getTop() > 0))
continue;
resetHeader();
setSelection(1);
continue;
this.mLastMotionY = i;
continue;
applyHeaderPadding(paramMotionEvent);
}
}

一、可以看到，反编译后的switch部分有了很大的变化，case部分都被打乱了。但这里还是有规律可循的，也就是说case部分的排列顺序是不会变的，如上例中case部分就是按照原来的保持不变。

二、接下来看while循环部分。这里面就包含了本该分别在case中的部分代码。首选将最开始的return取去，直接放到代码的最后面。然后看从return开始到第一个continue，这个就是第一个case中的代码部分，从第一个continue到第二个continue就是第二个case中的代码，以此类推。



注意：如果在这期间包含了if部分，里面的continue是不能作数的，要找最外层部分的continue。

上面的截图中可以看出，有的if部分中也会代有continue，但它是不能算做标识位的。关于if部分拆解，下面会有具体讲到。

2、if语句