setColorFilter（relativeFactor、PorterDuff.Mode.MULTIPLY）;相対的因子0-100％

Question

私はsetColorFilter(colorX, PorterDuff.Mode.MULTIPLY);を行う方法を知っています。colorX is defined like 0x00000000 to 0xFFFFFFFFです。

しかし、0から100までの値があり、これらを変換しようとすると、これを動作させることはできません。

float x1 = (float) ((100 - x)/100.0); 
float x2 = x1 * 0xFFFFFFFF; 
int relativeFactor = (int) x2; 
Btn1.getBackground().setColorFilter(relativeFactor, PorterDuff.Mode.MULTIPLY); 

ここで何が問題になっています： - ステップバイステップ - しかし、動作しません

これは私が試したものです（100は100％の透明度を意味しますか）？どうもありがとう！

Answer 1

元のコードが混在モードを誤って実行していて、オーバーフローしています。あなたには、いくつかのlongキャストし、使用する必要があります。

float x2 = x1 * (float)0x0FFFFFFFFL; 
long relativeFactor = (long) x2 & 0X0FFFFFFFFL; 

は、ここでは浮動小数点に頼らない溶液です：

public static void main(String[] args) { 
    // TODO Auto-generated method stub 
    final long onepct = 0x0FFFFFFFFL/100L; 
    final long error = 0x0FFFFFFFFL-(100*onepct); 
    System.out.println("onepct=" + Long.toString(onepct,16) + ",error=" + Long.toString(error,16)); 
    for (int x = 0; x <= 100; x++) { 
     final long x2 = 0x0FFFFFFFFL - onepct*x; 
     final long relativeFactor = (long) x2 & 0xFFFFFFFF; 
     System.out.println("x=" + x + ", x2=" + x2 + ", rf=" + Long.toString(relativeFactor, 16)); 
    } 
} 

それはローエンドで95でオフになっています。ゼロが必要な場合は、それをテストすることができます。実際に値をダンプすることを自由に感じてください....

onepct=28f5c28,error=5f 
x=0, x2=4294967295, rf=ffffffff 
x=1, x2=4252017623, rf=fd70a3d7 
x=2, x2=4209067951, rf=fae147af 
x=3, x2=4166118279, rf=f851eb87 
x=4, x2=4123168607, rf=f5c28f5f 
x=5, x2=4080218935, rf=f3333337 
x=6, x2=4037269263, rf=f0a3d70f 
x=7, x2=3994319591, rf=ee147ae7 
x=8, x2=3951369919, rf=eb851ebf 
x=9, x2=3908420247, rf=e8f5c297 
x=10, x2=3865470575, rf=e666666f 
x=11, x2=3822520903, rf=e3d70a47 
x=12, x2=3779571231, rf=e147ae1f 
x=13, x2=3736621559, rf=deb851f7 
x=14, x2=3693671887, rf=dc28f5cf 
x=15, x2=3650722215, rf=d99999a7 
x=16, x2=3607772543, rf=d70a3d7f 
x=17, x2=3564822871, rf=d47ae157 
x=18, x2=3521873199, rf=d1eb852f 
x=19, x2=3478923527, rf=cf5c2907 
x=20, x2=3435973855, rf=ccccccdf 
x=21, x2=3393024183, rf=ca3d70b7 
x=22, x2=3350074511, rf=c7ae148f 
x=23, x2=3307124839, rf=c51eb867 
x=24, x2=3264175167, rf=c28f5c3f 
x=25, x2=3221225495, rf=c0000017 
x=26, x2=3178275823, rf=bd70a3ef 
x=27, x2=3135326151, rf=bae147c7 
x=28, x2=3092376479, rf=b851eb9f 
x=29, x2=3049426807, rf=b5c28f77 
x=30, x2=3006477135, rf=b333334f 
x=31, x2=2963527463, rf=b0a3d727 
x=32, x2=2920577791, rf=ae147aff 
x=33, x2=2877628119, rf=ab851ed7 
x=34, x2=2834678447, rf=a8f5c2af 
x=35, x2=2791728775, rf=a6666687 
x=36, x2=2748779103, rf=a3d70a5f 
x=37, x2=2705829431, rf=a147ae37 
x=38, x2=2662879759, rf=9eb8520f 
x=39, x2=2619930087, rf=9c28f5e7 
x=40, x2=2576980415, rf=999999bf 
x=41, x2=2534030743, rf=970a3d97 
x=42, x2=2491081071, rf=947ae16f 
x=43, x2=2448131399, rf=91eb8547 
x=44, x2=2405181727, rf=8f5c291f 
x=45, x2=2362232055, rf=8cccccf7 
x=46, x2=2319282383, rf=8a3d70cf 
x=47, x2=2276332711, rf=87ae14a7 
x=48, x2=2233383039, rf=851eb87f 
x=49, x2=2190433367, rf=828f5c57 
x=50, x2=2147483695, rf=8000002f 
x=51, x2=2104534023, rf=7d70a407 
x=52, x2=2061584351, rf=7ae147df 
x=53, x2=2018634679, rf=7851ebb7 
x=54, x2=1975685007, rf=75c28f8f 
x=55, x2=1932735335, rf=73333367 
x=56, x2=1889785663, rf=70a3d73f 
x=57, x2=1846835991, rf=6e147b17 
x=58, x2=1803886319, rf=6b851eef 
x=59, x2=1760936647, rf=68f5c2c7 
x=60, x2=1717986975, rf=6666669f 
x=61, x2=1675037303, rf=63d70a77 
x=62, x2=1632087631, rf=6147ae4f 
x=63, x2=1589137959, rf=5eb85227 
x=64, x2=1546188287, rf=5c28f5ff 
x=65, x2=1503238615, rf=599999d7 
x=66, x2=1460288943, rf=570a3daf 
x=67, x2=1417339271, rf=547ae187 
x=68, x2=1374389599, rf=51eb855f 
x=69, x2=1331439927, rf=4f5c2937 
x=70, x2=1288490255, rf=4ccccd0f 
x=71, x2=1245540583, rf=4a3d70e7 
x=72, x2=1202590911, rf=47ae14bf 
x=73, x2=1159641239, rf=451eb897 
x=74, x2=1116691567, rf=428f5c6f 
x=75, x2=1073741895, rf=40000047 
x=76, x2=1030792223, rf=3d70a41f 
x=77, x2=987842551, rf=3ae147f7 
x=78, x2=944892879, rf=3851ebcf 
x=79, x2=901943207, rf=35c28fa7 
x=80, x2=858993535, rf=3333337f 
x=81, x2=816043863, rf=30a3d757 
x=82, x2=773094191, rf=2e147b2f 
x=83, x2=730144519, rf=2b851f07 
x=84, x2=687194847, rf=28f5c2df 
x=85, x2=644245175, rf=266666b7 
x=86, x2=601295503, rf=23d70a8f 
x=87, x2=558345831, rf=2147ae67 
x=88, x2=515396159, rf=1eb8523f 
x=89, x2=472446487, rf=1c28f617 
x=90, x2=429496815, rf=199999ef 
x=91, x2=386547143, rf=170a3dc7 
x=92, x2=343597471, rf=147ae19f 
x=93, x2=300647799, rf=11eb8577 
x=94, x2=257698127, rf=f5c294f 
x=95, x2=214748455, rf=ccccd27 
x=96, x2=171798783, rf=a3d70ff 
x=97, x2=128849111, rf=7ae14d7 
x=98, x2=85899439, rf=51eb8af 
x=99, x2=42949767, rf=28f5c87 
x=100, x2=95, rf=5f