问题
I want to use a SeekBar (i.e. old school Java Slider) into a color gradient picker. I have seen some examples like this but they all require making new classes and such. There has got to be a way to modify or override the original classes. Or just replace the background with a gradient.
回答1:
I figured it out here is how you do it.
You create a standard seekbar in your XML.
<SeekBar
android:id="@+id/seekbar_font"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_margin="10px"
android:layout_below="@id/color_font_text"
android:max="100"
android:progress="50"></SeekBar>
Then you customize the seekbar in your onCreate() by creating a boxShape and then force a LinearGradient inside it.
LinearGradient test = new LinearGradient(0.f, 0.f, 300.f, 0.0f,
new int[] { 0xFF000000, 0xFF0000FF, 0xFF00FF00, 0xFF00FFFF,
0xFFFF0000, 0xFFFF00FF, 0xFFFFFF00, 0xFFFFFFFF},
null, TileMode.CLAMP);
ShapeDrawable shape = new ShapeDrawable(new RectShape());
shape.getPaint().setShader(test);
SeekBar seekBarFont = (SeekBar)findViewById(R.id.seekbar_font);
seekBarFont.setProgressDrawable( (Drawable)shape );
Here is an image of the current code up above SeekBar Color Gradient
回答2:
This is in addition to the solution provided using LinearGradient. Try this logic for translating the progress to rgb:
lineColorSeekbar.setMax(256*7-1);
lineColorSeekbar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
@Override
public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
if(fromUser){
int r = 0;
int g = 0;
int b = 0;
if(progress < 256){
b = progress;
} else if(progress < 256*2) {
g = progress%256;
b = 256 - progress%256;
} else if(progress < 256*3) {
g = 255;
b = progress%256;
} else if(progress < 256*4) {
r = progress%256;
g = 256 - progress%256;
b = 256 - progress%256;
} else if(progress < 256*5) {
r = 255;
g = 0;
b = progress%256;
} else if(progress < 256*6) {
r = 255;
g = progress%256;
b = 256 - progress%256;
} else if(progress < 256*7) {
r = 255;
g = 255;
b = progress%256;
}
lineColorSeekbar.setBackgroundColor(Color.argb(255, r, g, b));
}
}
@Override
public void onStartTrackingTouch(SeekBar seekBar) {
}
@Override
public void onStopTrackingTouch(SeekBar seekBar) {
}
});
来源:https://stackoverflow.com/questions/4342757/how-to-make-a-color-gradient-in-a-seekbar