如何设置阿尔法值可绘制在StateListDrawable？ [英] How to set alpha value for drawable in a StateListDrawable?

问题描述

我想换一个绘制的alpha值时，它是pssed $ P $。 所以，我创建了两个可绘制，并把它们放在一个StateListDrawable，并设置为pressed状态的α值。但它只是不工作。

  StateListDrawable内容=新StateListDrawable（）;
可绘制contentSelected = this.getResources（）。getDrawable（
R.drawable.content_background）;
。contentSelected.mutate（）setAlpha（100）;

。可绘制contentNormal = this.getResources（）getDrawable（R.drawable.content_background）;

content.addState（新INT [] {android.R.attr.state_ pressed}，contentSelected）;
content.addState（新INT [] {} android.R.attr.state_enabled，contentNormal）;

的ImageButton按钮=（的ImageButton）view.findViewById（R.id.content_thumbnail）;
button.setImageDrawable（内容）;
 

更新： 我最后的解决方案是创建BitmapDrawable的子类这样的， 并更改 onStateChange（）法的alpha值。

 公共AlphaAnimatedDrawable（资源资源，位图位图）{
    超（资源，位图）;
    this.setState（新INT [] {android.R.attr.state_ pressed，android.R.attr.state_selected，
            android.R.attr.state_enabled}）;
}

私有静态最终诠释preSSED_ALPHA = 180;
私有静态最终诠释REGULAR_ALPHA = 255;

@覆盖
保护布尔onStateChange（INT []州）{

    对于（INT状态：状态）{
        如果（国家== android.R.attr.state_ pressed）{
            setAlpha（preSSED_ALPHA）;
        }否则，如果（国家== android.R.attr.state_selected）{
            setAlpha（REGULAR_ALPHA）;
        }否则，如果（国家== android.R.attr.state_enabled）{
            setAlpha（REGULAR_ALPHA）;
        }
    }
    返回true;
}
 

解决方案

这为我工作。

  StateListDrawable绘制=新StateListDrawable（）;

  位图enabledBitmap =（（BitmapDrawable）米康）.getBitmap（）;

  //设置阿尔法直接只是没有工作，所以我们得出一个新的位图！
  位图disabledBitmap = Bitmap.createBitmap（
      mIcon.getIntrinsicWidth（），
      mIcon.getIntrinsicHeight（），Config.ARGB_8888）;
  帆布油画=新的Canvas（disabledBitmap）;

  涂料粉刷=新的油漆（）;
  paint.setAlpha（126）;
  canvas.drawBitmap（enabledBitmap，0，0，油漆）;

  BitmapDrawable禁用=新BitmapDrawable（mContext.getResources（），disabledBitmap）;

  drawable.addState（新INT [] {} -android.R.attr.state_enabled，禁用）;
  drawable.addState（StateSet.WILD_CARD，米康）;
 

I want to change a drawable's alpha value when it is pressed. So I create two drawables and put them in a StateListDrawable and set the alpha value for the pressed state. But it just doesn't work.

StateListDrawable content = new StateListDrawable();
Drawable contentSelected = this.getResources().getDrawable(
R.drawable.content_background);
contentSelected.mutate().setAlpha(100);

Drawable contentNormal = this.getResources().getDrawable(R.drawable.content_background);

content.addState(new int[] { android.R.attr.state_pressed }, contentSelected);
content.addState(new int[] { android.R.attr.state_enabled }, contentNormal);

ImageButton button = (ImageButton) view.findViewById(R.id.content_thumbnail);
button.setImageDrawable(content);

Update: My final solution is to create a subclass of BitmapDrawable like this, and change the alpha value in the onStateChange() method.

public AlphaAnimatedDrawable(Resources res, Bitmap bitmap) {
    super(res, bitmap);
    this.setState(new int[] { android.R.attr.state_pressed, android.R.attr.state_selected,
            android.R.attr.state_enabled });
}

private static final int PRESSED_ALPHA = 180;
private static final int REGULAR_ALPHA = 255;

@Override
protected boolean onStateChange(int[] states) {

    for (int state : states) {
        if (state == android.R.attr.state_pressed) {
            setAlpha(PRESSED_ALPHA);
        } else if (state == android.R.attr.state_selected) {
            setAlpha(REGULAR_ALPHA);
        } else if (state == android.R.attr.state_enabled) {
            setAlpha(REGULAR_ALPHA);
        }
    }
    return true;
}

解决方案

This worked for me

  StateListDrawable drawable = new StateListDrawable();

  Bitmap enabledBitmap = ((BitmapDrawable)mIcon).getBitmap();

  // Setting alpha directly just didn't work, so we draw a new bitmap!
  Bitmap disabledBitmap = Bitmap.createBitmap(
      mIcon.getIntrinsicWidth(),
      mIcon.getIntrinsicHeight(), Config.ARGB_8888);
  Canvas canvas = new Canvas(disabledBitmap);

  Paint paint = new Paint();
  paint.setAlpha(126);
  canvas.drawBitmap(enabledBitmap, 0, 0, paint);

  BitmapDrawable disabled = new BitmapDrawable(mContext.getResources(), disabledBitmap);

  drawable.addState(new int[] { -android.R.attr.state_enabled}, disabled);
  drawable.addState(StateSet.WILD_CARD, mIcon);

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