Android:如何以编程方式创建StateListDrawable

Question

我有一个GridView来显示一些对象,并且在视觉上每个对象都有一个图像图标和一个文本标签.我还希望图像图标在单击时具有一些"推动和弹出"效果,也就是说,按下时,图像将向右下方移动一小段距离,并在释放后返回其原始位置.

对象(及其图像图标)来自某些动态源.我的直觉是为每个项创建一个StateListDrawable,它有两种状态:是否按下.对于GridView项目视图,我会使用一个Button,它可以容纳Drawable和一个标签,完全满足我的要求.

我定义了一个item类来包装原始对象:

public class GridItem<T> {

    public static final int ICON_OFFSET = 4;

    private StateListDrawable mIcon;
    private String mLabel;
    private T mObject;

    public Drawable getIcon() {
        return mIcon;
    }

    public void setIcon(Drawable d) {
        if (null == d) {
            mIcon = null;
        }else if(d instanceof StateListDrawable) {
            mIcon = (StateListDrawable) d;
        } else {
            InsetDrawable d1 = new InsetDrawable(d, 0, 0, ICON_OFFSET, ICON_OFFSET);
            InsetDrawable d2 = new InsetDrawable(d, ICON_OFFSET, ICON_OFFSET, 0, 0);
            mIcon = new StateListDrawable();
            mIcon.addState(new int[] { android.R.attr.state_pressed }, d2);
            mIcon.addState(StateSet.WILD_CARD, d1);
            //This won't help either: mIcon.addState(new int[]{}, d1);
        }
    }

    public String getLabel() {
        return mLabel;
    }

    public void setLabel(String l) {
        mLabel = l;
    }

    public T getObject() {
        return mObject;
    }

    public void setObject(T o) {
        mObject = o;
    }

}

现在的问题是,当我触摸一个网格项时,图标"移动"就像我预期的那样,但是当我的手指抬起离开项目时它不会恢复原来的位置.

我的问题是:如何以编程方式创建一个StateListDrawable等效于一个从XML资源膨胀的状态

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:state_pressed="true"
          android:drawable="@drawable/image_pressed" />  
    <item android:drawable="@drawable/image_normal" />
</selector>

？

Answer 1

如果你的drawable只是位图,你可以通过编程方式绘制它们,现在它应该有帮助,但是我想知道InsetDrawable这里使用的问题是什么,基本上使用BitmapDrawables以编程方式绘制的准备,你需要修改你的方法来接受位图b

        Bitmap bc1 = Bitmap.createBitmap(b.getWidth() + ICON_OFFSET, b.getHeight() + ICON_OFFSET, Bitmap.Config.ARGB_8888);
        Canvas c1 = new Canvas(bc1);
        c1.drawBitmap(b, 0, 0, null);
        Bitmap bc2 = Bitmap.createBitmap(b.getWidth() + ICON_OFFSET, b.getHeight() + ICON_OFFSET, Bitmap.Config.ARGB_8888);
        Canvas c2 = new Canvas(bc2);
        c2.drawBitmap(b, ICON_OFFSET, ICON_OFFSET, null);

        mIcon = new StateListDrawable();
        mIcon.addState(new int[] { android.R.attr.state_pressed },  new BitmapDrawable(bc2));
        mIcon.addState(StateSet.WILD_CARD, new BitmapDrawable(bc1));

Answer 2

我可以看到答案已被接受.如果你想动态分配来自用户的按钮颜色的正常和按下状态,我正在分享.然后你可以调用这个函数:

public static StateListDrawable convertColorIntoBitmap(String pressedColor, String normalColor){


        /*Creating bitmap for color which will be used at pressed state*/
        Rect rectPressed = new Rect(0, 0, 1, 1);

        Bitmap imagePressed = Bitmap.createBitmap(rectPressed.width(), rectPressed.height(), Config.ARGB_8888);
        Canvas canvas = new Canvas(imagePressed);       
        int colorPressed = Color.parseColor(pressedColor);
        Paint paintPressed = new Paint();
        paintPressed.setColor(colorPressed);
        canvas.drawRect(rectPressed, paintPressed);
        RectF bounds = new RectF();
        bounds.round(rectPressed);

        /*Creating bitmap for color which will be used at normal state*/
        Rect rectNormal = new Rect(0, 0, 1, 1);     
        Bitmap imageNormal = Bitmap.createBitmap(rectNormal.width(), rectNormal.height(), Config.ARGB_8888);
        Canvas canvasNormal = new Canvas(imageNormal);
        int colorNormal = Color.parseColor(normalColor);
        Paint paintNormal = new Paint();
        paintNormal.setColor(colorNormal);
        canvasNormal.drawRect(rectNormal, paintNormal);


        /*Now assigning states to StateListDrawable*/
        StateListDrawable stateListDrawable= new StateListDrawable();
        stateListDrawable.addState(new int[]{android.R.attr.state_pressed}, new BitmapDrawable(imagePressed));
        stateListDrawable.addState(StateSet.WILD_CARD, new BitmapDrawable(imageNormal));

        return stateListDrawable;

    }

现在您只需将其设置为文本视图或按钮背景,如下所示:

 if(android.os.Build.VERSION.SDK_INT>=16){
        yourbutton.setBackground(convertColorIntoBitmap("#CEF6CE00","#4C9D32"));        

            }else{

yourbutton.setBackgroundDrawable(convertColorIntoBitmap("#CEF6CE00","#4C9D32"));
    }

在这里,您可以看到动态传递颜色所需的一切,我们已经完成了.希望这会有所帮助:)你可以在这里找到它的要点:)