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)
中-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。
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()...
同[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";
...
则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);
中 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 = 335544320
即 268435456 | 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 )
从 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:
PS: