• Android反编译 -- 错误代码还原


    PS:假设阅读体验不好,能够尝试Github版 (<-点左边)

    1. setColor(-16777216)

    反编译的代码中会有非常多setColor(int)的情况,比方setColor(-16777216),这个值比較特别,能轻易的查到Android文档中对这个整数的定义:

    public static final int BLACK.
    Added in API level 1
    Constant Value: -16777216 ( 0xff000000).

    也就是说setColor(-16777216)-16777216相应的颜色是BLACK(0xff000000),那么其它系统没有定义成某个颜色名的值呢?

    -16777216 相应 0xff000000
           -1 相应 0xffffffff
     0xffffff 的值 16777215
    
    那么对随意的 setColor(int)中的int值,我们能够:
    0xffffffff+(int)+1 或 0xffffffff-(-int+1) 
    
    则对于 :setColor(-16777216)
    可写成 :setColor(0xffffffff - 16777215)) 或 setColor(-16777216 + 1 + 0xffffffff))
    
    这样,我们就不用查文档寻找特定的颜色值。也能解决随意颜色的设置。

    Stackoverflow : How to set color using integer?

    2.MeasureSpec.makeMeasureSpec(xx, int)

    反编译的代码中MeasureSpec.makeMeasureSpec(xx, int)的第二个參数是个int类型的数,这个比較简单,直接看文档或者源代码就可以找到:

    源代码:

    
    public static class MeasureSpec {
            public static final int UNSPECIFIED = 0;
            public static final int EXACTLY = 1073741824;
            public static final int AT_MOST = -2147483648;
            ...
            }

    文档:

    public static final int AT_MOST
    Added in API level 1
    Measure specification mode: The child can be as large as it wants up to the specified size.
    Constant Value: -2147483648 (0x80000000)
    
    public static final int EXACTLY
    Added in API level 1
    Measure specification mode: The parent has determined an exact size for the child. The child is going to be given those bounds regardless of how big it wants to be.
    Constant Value: 1073741824 (0x40000000)
    
    public static final int UNSPECIFIED
    Added in API level 1
    Measure specification mode: The parent has not imposed any constraint on the child. It can be whatever size it wants.
    Constant Value: 0 (0x00000000)

    则对于:
    MeasureSpec.makeMeasureSpec(xx, 0)
    我们应该改动为
    MeasureSpec.makeMeasureSpec(xx, View.MeasureSpec.UNSPECIFIED)

    其它依次类推。

    3.setVisibility(int)

    这个同[2],看文档或者看源代码:

    public static final int VISIBLE = 0;
    public static final int INVISIBLE = 4;
    public static final int GONE = 8;

    则对于:setVisibility(0) ==> setVisibility(View.VISIBLE)

    其它依次类推。

    4.new Runnable()...

    反编译的代码中:

    new Runnable() {
        final /* synthetic */ AbstractButton a;
            {
            this.a = r1;
           }
    
           public final void run() {
              this.a.xxxxx();
           }
    };

    可直接去掉成员变量:

    new Runnable() {
           public final void run() {
              xxxxx();
           }
    };
    

    5.new Handler()...

    [4],直接去掉成员变量:

    new Handler() {
                final /* synthetic */ ButtonSave a;
    
                {
                    this.a = r1;
                }
    
                public final void handleMessage(Message message) {
                        this.a.xxx();
                }
            };
    //改动为
    new Handler() {
                public final void handleMessage(Message message) {
                    xxx();
                }
            };

    6.context.getSystemService("layout_inflater")

    直接看源代码就可以:

    public static final String POWER_SERVICE = "power";
    public static final String WINDOW_SERVICE = "window";
    public static final String LAYOUT_INFLATER_SERVICE = "layout_inflater";
    public static final String ACCOUNT_SERVICE = "account";
    public static final String ACTIVITY_SERVICE = "activity";
    public static final String ALARM_SERVICE = "alarm";
    public static final String NOTIFICATION_SERVICE = "notification";
    public static final String ACCESSIBILITY_SERVICE = "accessibility";
    ...

    context.getSystemService("layout_inflater") ==> context.getSystemService(Context.LAYOUT_INFLATER_SERVICE)

    其它依次类推。

    7.intent.setFlags(335544320)

    先看源代码:

    Intent implements Parcelable, Cloneable  {
        public static final int FLAG_GRANT_READ_URI_PERMISSION = 1;
        public static final int FLAG_GRANT_WRITE_URI_PERMISSION = 2;
        public static final int FLAG_FROM_BACKGROUND = 4;
        public static final int FLAG_DEBUG_LOG_RESOLUTION = 8;
        public static final int FLAG_EXCLUDE_STOPPED_PACKAGES = 16;
        public static final int FLAG_INCLUDE_STOPPED_PACKAGES = 32;
        public static final int FLAG_ACTIVITY_NO_HISTORY = 1073741824;
        public static final int FLAG_ACTIVITY_SINGLE_TOP = 536870912;
        public static final int FLAG_ACTIVITY_NEW_TASK = 268435456;
        public static final int FLAG_ACTIVITY_MULTIPLE_TASK = 134217728;
        public static final int FLAG_ACTIVITY_CLEAR_TOP = 67108864;
        public static final int FLAG_ACTIVITY_FORWARD_RESULT = 33554432;
        public static final int FLAG_ACTIVITY_PREVIOUS_IS_TOP = 16777216;
        public static final int FLAG_ACTIVITY_EXCLUDE_FROM_RECENTS = 8388608;
        public static final int FLAG_ACTIVITY_BROUGHT_TO_FRONT = 4194304;
        public static final int FLAG_ACTIVITY_RESET_TASK_IF_NEEDED = 2097152;
        public static final int FLAG_ACTIVITY_LAUNCHED_FROM_HISTORY = 1048576;
        public static final int FLAG_ACTIVITY_CLEAR_WHEN_TASK_RESET = 524288;
        public static final int FLAG_ACTIVITY_NO_USER_ACTION = 262144;
        public static final int FLAG_ACTIVITY_REORDER_TO_FRONT = 131072;
        public static final int FLAG_ACTIVITY_NO_ANIMATION = 65536;
        public static final int FLAG_ACTIVITY_CLEAR_TASK = 32768;
        public static final int FLAG_ACTIVITY_TASK_ON_HOME = 16384;
        public static final int FLAG_RECEIVER_REGISTERED_ONLY = 1073741824;
        public static final int FLAG_RECEIVER_REPLACE_PENDING = 536870912;
        public static final int FLAG_RECEIVER_FOREGROUND = 268435456;

    那么对于intent.setFlags(int);int值是上面四种之中的一个的话就比較简单,比如:

    intent.setFlags(536870912); ==> intent.setFlags(PendingIntent.FLAG_NO_CREATE);

    可是遇到一个比較特别的:intent.setFlags(335544320);

    源代码里根本没有这样一个值啊,事实上intent.setFlags( A | B )是能够使用|(或运算)的,那么:

    
    10000000000000000000000000000 = 268435456
                        |               |
      100000000000000000000000000 =  67108864
    10100000000000000000000000000 = 335544320268435456 | 67108864 = 335544320

    从而:

    intent.setFlags(335544320);==>

    intent.setFlags( FLAG_ACTIVITY_NEW_TASK | FLAG_ACTIVITY_CLEAR_TOP )

    或者

    intent.setFlags( FLAG_RECEIVER_FOREGROUND | FLAG_ACTIVITY_CLEAR_TOP )

    Codota 中搜索intent.setFlags(335544320);看到的是第一种情况。结合intent.setFlags()的使用方法,应该也是第一种情况。

    相关资料:

    http://farwmarth.com/2013/04/23/android%20反编译和代码解读/

    PS:

    本文已整理到Github上,欢迎提交很多其它代码!
    你能够关注的我GithubCSDN微博

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  • 原文地址:https://www.cnblogs.com/yangykaifa/p/7279292.html
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