getDrawable（）方法过时 替代

     context.getResources().getDrawable(R.mipmap.icon_my);
     官方推荐调用 
     context.getResources().getDrawable(R.mipmap.icon_my，theme);

只是过时了，并不影响使用，只是在特殊情况下，在Android4.1系统之前加载缩略图可能会出现异常，所以被谷歌废弃了。建议用以下方法代替：
ContextCompat.getDrawable(context,R.mipmap.indexz);

public class ContextCompat {
    /**
     * Return a drawable object associated with a particular resource ID.
     * 

     * Starting in {@link android.os.Build.VERSION_CODES#LOLLIPOP}, the returned
     * drawable will be styled for the specified Context's theme.
     *
     * @param id The desired resource identifier, as generated by the aapt tool.
     *            This integer encodes the package, type, and resource entry.
     *            The value 0 is an invalid identifier.
     * @return Drawable An object that can be used to draw this resource.
     */
    public static final Drawable getDrawable(Context context, int id) {
        final int version = Build.VERSION.SDK_INT;
        if (version >= 21) {
            return ContextCompatApi21.getDrawable(context, id);
        } else {
            return context.getResources().getDrawable(id);
        }
    }
}

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