如何更改Android中的应用程序中使用的图像的颜色和阴影

Question

In my Android App, I am using one image in background and also using some images of arrow. I have added the image in xml like below:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/main"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:background="@drawable/backgroundimage" >

    <LinearLayout
        android:id="@+id/tableRow1"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="0.20"
        android:background="@drawable/border"
        android:gravity="center_horizontal"
        android:weightSum="1" >

        <TextView
            android:id="@+id/textView11"
            android:layout_width="wrap_content"
            android:layout_height="match_parent"/>
        <ImageView
            android:id="@+id/imageView1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:contentDescription="@string/none"
            android:gravity="right"
            android:src="@drawable/navigation" />
    </LinearLayout>

Now I want to change the image colors from the Java Code with some provided color codes. The image background will recieve one color and the texture/shades/actual image portion will receive another color. I heard something about getting the alpha of the image and apply colors on the image checking where is white and where is gray. Not sure how to do that.

For example, I am including an image of the arrow. I want to change the background from white to different colors and also the arrow from to another color. Please suggest.

Also, is there any way to change the colors if the image is in the alpha mode where the background is transparent?

Answer 1

If you make the image background transparent (the white part), so you have only what you call the "image portion" visible, than you can change the background by either setBackground(Drawable) , setBackgroundColor(color) or setBackgroundResource(resource) (since the background will be visible through the transparent parts of the image).

To change the actual image color, use setColorFilter() , there are three different versions of this method, so you should be able to find one that suits your needs.

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To change a single image used as a background , make the base image red and green (or some other different colors that don't use several color channels. Black and white would not work) and get it as a Drawable . This is since the Drawable can have a ColorFilter , just like the ImageView . Give it a ColorMatrixColorFilter .

If the background part is red , and the foreground green , you can then use a matrix such as

[bR, aR, 0, 0,
 0, bG, aG, 0, 
 0, 0, bB, aB,
 0, 0, 0, bA,
 aA, 0, 0, 0]

where

background R,G,B,A = bR, bG, bB, bA
foreground R,G,B,A = aR, aG, aB, aA