Develop Reference

Android Layout transparent layout background with underline

I am trying to have a layout background drawable, which will be only gradient underline with 1-2 dp height and rest is transparent, so the upper part will have the parent's background.
Here is what I have.
<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android>
<!-- underline color -->
<item>
<shape>
<gradient
android:startColor="#color/colorPrimaryDark"
android:endColor="#FFFFFFFF"
android:centerY="0.5"
android:angle="0"/>
</shape>
</item>
<!-- main color -->
<item android:bottom="2.5dp">
<shape android:shape="rectangle">
<solid android:color="#color/white" />
<padding
android:top="4dp"
android:bottom="4dp" />
</shape>
</item>
If I change the solid color in "main color" to transparent, whole background will be using "underline color" settings.

The technique you use to create a line on the bottom of the view works if the color of the layer overlaying the gradient layer is opaque. What you are trying to do is to apply a transparent layer that replaces (erases) the underlying gradient. That is not how it works: A transparent overlay leaves the underlying color, here a gradient, untouched.
Here is an alternate layer-list drawable that you can use for API 23+:
underline_drawable.xml
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
<item android:gravity="bottom">
<shape>
<size android:height="2dp" />
<gradient
android:angle="0"
android:centerY="0.5"
android:endColor="#FFFFFFFF"
android:startColor="#color/colorPrimaryDark" />
</shape>
</item>
</layer-list>
Here is what it looks like:
Prior to API 23, you can use the following custom drawable, but it must be set in code.
GradientUnderline.java
public class GradientUnderline extends Drawable {
private Shader mShader;
private final Paint mPaint;
private int mHeight = -1;
private int mStartColor = Color.BLACK;
private int mEndColor = Color.WHITE;
private int mLastWidth;
public GradientUnderline() {
mPaint = new Paint();
}
public GradientUnderline(int lineHeight, int startColor, int endColor) {
mPaint = new Paint();
mHeight = lineHeight;
mStartColor = startColor;
mEndColor = endColor;
}
#Override
public void draw(#NonNull Canvas canvas) {
if (mShader == null || getBounds().width() != mLastWidth) {
mLastWidth = getBounds().width();
mShader = new LinearGradient(0, 0, getBounds().width(), mHeight, mStartColor,
mEndColor, Shader.TileMode.CLAMP);
mPaint.setShader(mShader);
}
canvas.drawRect(0, getBounds().height() - mHeight, getBounds().width(),
getBounds().height(), mPaint);
}
#Override
public void setAlpha(int alpha) {
}
#Override
public void setColorFilter(#Nullable ColorFilter colorFilter) {
}
#Override
public int getOpacity() {
return PixelFormat.OPAQUE;
}
}
I missed the availability of android:gravity initially because it is not mentioned on the "Drawable Resources" page. It is mentioned, however, in the LayerDrawable documentation.

Why problem occurs: Shape at first item will draw the gradient in entire region. After setting colour to second item will hide the top item region except ay 2.5dp at bottom. So whenever you set transparent colour to second item it automatically show the top level item that is gradient region..
Here i suggest the way to use but you can set to fixed height in view.
<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
<item android:top="47dp">
<shape>
<gradient
android:startColor="#color/colorPrimaryDark"
android:endColor="#FFFFFFFF"
android:centerY="0.5"
android:angle="0"/>
</shape>
</item>
</layer-list>
View.xml
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="50dp"
android:background="#drawable/bottom_line">
</RelativeLayout>
Change size according to your needs..!
OUTPUT

Change xml drawables colors dynamically [duplicate]

What I'm trying to achieve is to use a Drawable with a couple of layers inside it, but control some values at runtime such as the startColor for the gradient. Here's what I have in my_layered_shape.xml:
<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android" >
<item>
<shape android:shape="rectangle">
<stroke android:width="1dp" android:color="#FF000000" />
<solid android:color="#FFFFFFFF" />
</shape>
</item>
<item android:top="1dp" android:bottom="1dp">
<shape android:shape="rectangle">
<stroke android:width="1dp" android:color="#FF000000" />
<gradient
android:startColor="#FFFFFFFF"
android:centerColor="#FFFFFF88"
android:endColor="#FFFFFFFF"
android:gradientRadius="250"
android:centerX="1"
android:centerY="0"
android:angle="315"
/>
</shape>
</item>
</layer-list>
And if I use mMyImageView.setBackgroundResource(R.drawable.my_layered_shape) it works.
I don't mind splitting the xml if I have to, or doing the whole thing programatically as long as there's a way to get at the various color values. The concept I'm going for programmatically (i.e. my best shot at doing the same in code as this xml) is:
Drawable[] layers = new Drawable[2];
ShapeDrawable sd1 = new ShapeDrawable(new RectShape());
sd1.getPaint().setColor(0xFFFFFFFF);
sd1.getPaint().setStyle(Style.STROKE);
sd1.getPaint().setStrokeWidth(1);
// sd1.getPaint().somehow_set_stroke_color?
ShapeDrawable sd2 = new ShapeDrawable(new RectShape());
sd2.getPaint().setColor(0xFF000000);
sd2.getPaint().setStyle(Style.STROKE);
// sd2.getPaint().somehow_set_stroke_color?
// sd2.getPaint().somehow_set_gradient_params?
layers[0] = sd1;
layers[1] = sd2;
LayerDrawable composite = new LayerDrawable(layers);
mMyImageView.setBackgroundDrawable(composite);
Thanks.

It seems that is does not work with ShapeDrawable, but take a look at my GradientDrawable example:
GradientDrawable gd = new GradientDrawable(Orientation.BOTTOM_TOP, new int[]{Color.RED, Color.GREEN});
gd.setStroke(10, Color.BLUE);
You may also need following method:
gd.setGradientCenter(float x, float y);
gd.setGradientRadius(float gradientRadius);

Just gonna leave this here... Not tested yet
/**
* Created by Nedo on 09.04.2015.
*/
public class ShapeBuilder {
public static Drawable generateSelectorFromDrawables(Drawable pressed, Drawable normal) {
StateListDrawable states = new StateListDrawable();
states.addState(new int[]{ -android.R.attr.state_focused, -android.R.attr.state_pressed, -android.R.attr.state_selected}, normal);
states.addState(new int[]{ android.R.attr.state_pressed}, pressed);
states.addState(new int[]{ android.R.attr.state_focused}, pressed);
states.addState(new int[]{ android.R.attr.state_selected}, pressed);
return states;
}
public static Drawable generateShape(String colorTop, String colorBot, String colorStroke, int stokeSize, float strokeRadius) {
int top, bot, stroke;
top = Color.parseColor(colorTop);
bot = Color.parseColor(colorBot);
stroke = Color.parseColor(colorStroke);
GradientDrawable drawable = new GradientDrawable(GradientDrawable.Orientation.BOTTOM_TOP, new int[]{top, bot});
drawable.setStroke(stokeSize, stroke);
drawable.setCornerRadius(strokeRadius);
return drawable;
}
public static Drawable buildSelectorShapeFromColors(String colorNormalStroke, String colorNormalBackTop, String colorNormalBackBot,
String colorPressedStroke, String colorPressedBackTop, String colorPressedBackBot,
int strokeSize, float strokeRadius) {
Drawable pressed = generateShape(colorPressedBackTop, colorPressedBackBot, colorPressedStroke, strokeSize, strokeRadius);
Drawable normal = generateShape(colorNormalBackTop, colorNormalBackBot, colorNormalStroke, strokeSize, strokeRadius);
return generateSelectorFromDrawables(pressed, normal);
}
}
Edit: tested Now, had one mistake.
You actually have to describe every single state. If you group states they will only be triggered if all of them accure at once...

Setting Gradient Background programmatically

I have an image on which I'm putting a colored overlay, like this (the colors are taken from here):
layout/list_item_view.xml
<View
android:id="#+id/image_cover_gradient"
android:layout_width="fill_parent"
android:layout_height="80dip"
android:layout_alignParentTop="true"
android:layout_marginTop="70dp"
android:background="#drawable/gradient_blue"
/>
drawable/gradient_blue.xml
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item>
<shape>
<gradient
android:angle="90"
android:startColor="#color/CornflowerBlue"
android:endColor="#color/Transparent"
android:type="linear" />
</shape>
</item>
</selector>
This always puts a blue overlay (CornflowerBlue) and it works as expected.
Now I'm trying to do this programatically and followed some stackoverflow answers (such as this), but still can't make it work. Here's my code:
private void setColor(int color){
View gradientCover = view.findViewById(R.id.image_cover_gradient);
// this FAILS because it's a StateListDrawable
//GradientDrawable coverGd = (GradientDrawable) gradientCover.getBackground();
//coverGd.setColor(color);
//this doesn't seem to work either (I don't see any effect on the image)
GradientDrawable drawable = new GradientDrawable(
Orientation.BOTTOM_TOP, new int[] { color, resources.getColor(R.color.Transparent)
});
StateListDrawable sld = new StateListDrawable();
sld.addState(new int[] { android.R.attr.startColor, android.R.attr.endColor}, drawable);
gradientCover.setBackground(sld);
}

As #pskink suggested - removing the StateListDrawable solved it:
GradientDrawable drawable = new GradientDrawable(
Orientation.BOTTOM_TOP, new int[] { color, resources.getColor(R.color.Transparent)
});
gradientCover.setBackground(drawable);

Get a textView background color with ShapeDrawable

I have a textview with the background defined in a xml file.
<TextView
android:id="#+id/event_tvColor"
android:layout_width="40dip"
android:layout_height="40dip"
android:text=" "
android:background="#drawable/et_style_color_service_edit"
android:clickable="true"
/>
xml file : et_style_color_service_edit.xml
<?xml version="1.0" encoding="UTF-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="oval">
<solid android:color="#color/eventColor"/>
<stroke android:width="0sp" android:color="#FFFFFF" />
<size android:width="20dp"
android:height="20dp"/>
</shape>
And i need to get the color that the view have in a one time.
ShapeDrawable sc = (ShapeDrawable)tvColor.getBackground();
...............
Note that i need to use ShapeDrawable and not GradientDrawable.
Thank you for your help and time.
Solution........
Solution The xml loads into the app as a gradientdrawable and not as a shapedrawable. We have to define the shapeDrawable in java
ShapeDrawable sd = new ShapeDrawable(new RectShape);
sd.getPaint().setColor(0xFF0000FF);
if anyone have a better solution can tell.

After further research, there currently is no way of getting the xml loaded ShapeDrawable's color. What you have to do is just track your color changes so you know what color you are setting it to, ie:
int currentColor = Color.WHITE; //this is the default color (color set in xml)
public void changeColor() {
if (currentColor == Color.WHITE) {
currentColor = Color.BLUE;
} else {
currentColor = Color.WHITE;
}
GradientDrawable gd = (GradientDrawable)tvColor.getBackground();
gd.setColor(currentColor);
}

Android Gradient drawable programmatically

I have a gradient drawable defined in xml that I use it as a background, like this:
<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
<item android:bottom="4dp">
<shape>
<gradient
android:startColor="#color/blue"
android:endColor="#color/dark_blue"
android:angle="270" />
</shape>
</item>
<item android:top="98dp">
<shape>
<gradient
android:startColor="#color/black"
android:endColor="#color/transparent_black"
android:angle="270" />
</shape>
</item>
</layer-list>
I need to implement this programmatically. I have tried to use a GradientDrawable as follows (this method is implemented on a custom view):
int[] colors1 = {getResources().getColor(R.color.black), getResources().getColor(R.color.trasparent_black)};
GradientDrawable shadow = new GradientDrawable(Orientation.TOP_BOTTOM, colors1);
shadow.setBounds(0,98, 0, 0);
int[] colors = new int[2];
colors[0] = getResources().getColor(R.color.blue);
colors[1] = getResources().getColor(R.color.dark_blue);
GradientDrawable backColor = new GradientDrawable(Orientation.TOP_BOTTOM, colors);
backColor.setBounds(0, 0,0, 4);
//finally create a layer list and set them as background.
Drawable[] layers = new Drawable[2];
layers[0] = backColor;
layers[1] = shadow;
LayerDrawable layerList = new LayerDrawable(layers);
setBackgroundDrawable(layerList);
The problem is that it seems that setting the bounds is useless or doesn't work the same way as (android:top, android:bottom xml parameters). The resulting background is each layer painted from top to bottom, one above the other.
I want to generate something like this:

Found the answer!. Possible duplicate Multi-gradient shapes.
Replaced:
backColor.setBounds(0, 0,0, 4);
shadow.setBounds(0,98, 0, 0);
for
layerList.setLayerInset(0, 0, 0, 0, 4);
layerList.setLayerInset(1, 0, 98, 0, 0);