ColorDrawable extension that aims to bring newer features of the ColorDrawable to the older versions of Android like the ones prior than HoneyComb (API LEVEL 11).

ColorDrawableCompat.java

package uk.co.enomis.app.compat;
 
import android.annotation.TargetApi;
import android.graphics.Color;
import android.graphics.drawable.ColorDrawable;
import android.os.Build;
import android.util.Log;
 
import java.lang.reflect.Field;
 
/**
 * ColorDrawable extension that aims to bring newer features of the ColorDrawable
 * to the older versions of Android like the ones prior than HoneyComb (API LEVEL 11).
 * <p/>
 * Created by Simone Casagranda - 30/04/14
 */
public class ColorDrawableCompat extends ColorDrawable {
 
    /**
     * Tag used for logging purposes.
     */
    private static final String TAG_LOG = ColorDrawableCompat.class.getName();
 
    public ColorDrawableCompat() {
    }
 
    public ColorDrawableCompat(int color) {
        super(color);
    }
 
    /**
     * Gets the drawable's color value.
     *
     * @return The color to draw, Color.TRANSPARENT will be returned on pre-Honeycomb version if something fails.
     */
    @TargetApi(Build.VERSION_CODES.HONEYCOMB)
    public int getColor() {
        // Get color is available only on Honeycomb onwards
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
            return super.getColor();
        } else {
            int color = Color.TRANSPARENT;
            try {
                final Object state = get(this, getClass().getSuperclass().getDeclaredField("mState"));
                final Field useColor = state.getClass().getDeclaredField("mUseColor");
                final boolean useAccessible = useColor.isAccessible();
                if (!useAccessible) {
                    useColor.setAccessible(true);
                }
                color = useColor.getInt(state);
                if (!useAccessible) {
                    useColor.setAccessible(false);
                }
            } catch (Exception e) {
                Log.e(TAG_LOG, "Cannot complete getColor() on VERSION_CODE=" + Build.VERSION.SDK_INT, e);
            }
            return color;
        }
    }
 
    /**
     * Sets the drawable's color value. This action will clobber the results of prior calls to setAlpha(int)
     * on this object, which side-affected the underlying color.
     * <p/>
     * NB: If something fails it will result without any color update.
     *
     * @param color The color to draw.
     */
    @TargetApi(Build.VERSION_CODES.HONEYCOMB)
    public void setColor(int color) {
        // Set color is available only on Honeycomb onwards
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
            super.setColor(color);
        } else {
            try {
                final Object state = get(this, getClass().getSuperclass().getDeclaredField("mState"));
                // Getting the required fields and enabling them if needed
                final Field baseField = state.getClass().getDeclaredField("mBaseColor");
                final boolean baseAccessible = baseField.isAccessible();
                if (!baseAccessible) {
                    baseField.setAccessible(true);
                }
                final Field useField = state.getClass().getDeclaredField("mUseColor");
                final boolean useAccessible = useField.isAccessible();
                if (!useAccessible) {
                    useField.setAccessible(true);
                }
                // Getting and updating the fields
                final int baseColor = baseField.getInt(state);
                final int useColor = useField.getInt(state);
                if (baseColor != color || useColor != color) {
                    baseField.setInt(state, color);
                    useField.setInt(state, color);
                    invalidateSelf();
                }
                // Restoring any prior state
                if (!baseAccessible) {
                    baseField.setAccessible(false);
                }
                if (!useAccessible) {
                    useField.setAccessible(false);
                }
            } catch (Exception e) {
                Log.e(TAG_LOG, "Cannot complete setColor(" + color + ") on VERSION_CODE=" + Build.VERSION.SDK_INT, e);
            }
        }
    }
 
 
    /**
     * Get the values of a {@link java.lang.reflect.Field}.
     *
     * @param parent used to get value.
     * @param field  where the value should be taken.
     * @return the value or null if something goes wrong.
     */
    private static Object get(Object parent, Field field) {
        if (field == null) {
            return null;
        }
        Object value = null;
        try {
            // Checking the accessibility of the field
            boolean accessible = field.isAccessible();
            if (!accessible) {
                field.setAccessible(true);
                value = field.get(parent);
                field.setAccessible(false);
            } else {
                value = field.get(parent);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return value;
    }
 
}