Created
February 19, 2017 18:28
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rainbowview.java
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public class MainActivity extends AppCompatActivity { | |
@Override | |
protected void onCreate(Bundle savedInstanceState) { | |
super.onCreate(savedInstanceState); | |
setContentView(R.layout.activity_main); | |
getWindow().getDecorView().getViewTreeObserver().addOnPreDrawListener( | |
new ViewTreeObserver.OnPreDrawListener() { | |
@Override | |
public boolean onPreDraw() { | |
final View view = findViewById(R.id.rainbow_view); | |
((ViewGroup) view.getParent()).getOverlay().add(new Drawable() { | |
{ | |
setBounds(view.getLeft(), view.getTop(), view.getRight(), view.getBottom()); | |
} | |
@Override | |
public void draw(Canvas canvas) { | |
Rect bounds = getBounds(); | |
float x = bounds.width() / 2.0f; | |
float y = bounds.height() / 2.0f; | |
Paint p = new Paint(); | |
p.setShader(new RadialGradient(x, y, Math.max(x, y), new int[] { | |
0x9fff0000, | |
0x9fffff00, | |
0x9f00ff00, | |
0x9f00ffff, | |
0x9f0000ff, | |
0x9fff00ff | |
}, new float[] { | |
0.0f, 0.20f, 0.40f, 0.60f, 0.80f, 1.00f | |
}, Shader.TileMode.REPEAT)); | |
// p.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SCREEN)); | |
canvas.drawRect(bounds, p); | |
} | |
@Override | |
public void setAlpha(int i) { | |
} | |
@Override | |
public void setColorFilter(ColorFilter colorFilter) { | |
} | |
@Override | |
public int getOpacity() { | |
return PixelFormat.TRANSLUCENT; | |
} | |
}); | |
getWindow().getDecorView().getViewTreeObserver().removeOnPreDrawListener(this); | |
return true; | |
} | |
}); | |
} | |
} |
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