Android setButtonDrawable()的兼容问题解决办法

Android  setButtonDrawable()的兼容问题解决办法

setButtonDrawable()的兼容问题

API16实现

 /**
  * Set the background to a given Drawable, identified by its resource id.
  *
  * @param resid the resource id of the drawable to use as the background
  */
 public void setButtonDrawable(int resid) {
  if (resid != 0 && resid == mButtonResource) {
   return;
  }

  mButtonResource = resid;

  Drawable d = null;
  if (mButtonResource != 0) {
   d = getResources().getDrawable(mButtonResource);
  }
  setButtonDrawable(d);
 }

 /**
  * Set the background to a given Drawable
  *
  * @param d The Drawable to use as the background
  */
 public void setButtonDrawable(Drawable d) {
  if (d != null) {
   if (mButtonDrawable != null) {
    mButtonDrawable.setCallback(null);
    unscheduleDrawable(mButtonDrawable);
   }
   d.setCallback(this);
   d.setState(getDrawableState());
   d.setVisible(getVisibility() == VISIBLE, false);
   mButtonDrawable = d;
   mButtonDrawable.setState(null);
   setMinHeight(mButtonDrawable.getIntrinsicHeight());
  }

  refreshDrawableState();
 }

API23实现

 /**
  * Sets a drawable as the compound button image given its resource
  * identifier.
  *
  * @param resId the resource identifier of the drawable
  * @attr ref android.R.styleable#CompoundButton_button
  */
 public void setButtonDrawable(@DrawableRes int resId) {
  final Drawable d;
  if (resId != 0) {
   d = getContext().getDrawable(resId);
  } else {
   d = null;
  }
  setButtonDrawable(d);
 }

 /**
  * Sets a drawable as the compound button image.
  *
  * @param drawable the drawable to set
  * @attr ref android.R.styleable#CompoundButton_button
  */
 @Nullable
 public void setButtonDrawable(@Nullable Drawable drawable) {
  if (mButtonDrawable != drawable) {
   if (mButtonDrawable != null) {
    mButtonDrawable.setCallback(null);
    unscheduleDrawable(mButtonDrawable);
   }

   mButtonDrawable = drawable;

   if (drawable != null) {
    drawable.setCallback(this);
    drawable.setLayoutDirection(getLayoutDirection());
    if (drawable.isStateful()) {
     drawable.setState(getDrawableState());
    }
    drawable.setVisible(getVisibility() == VISIBLE, false);
    setMinHeight(drawable.getIntrinsicHeight());
    applyButtonTint();
   }
  }
 }

结论

RadioButton和CheckBox都是Android app中常用的Widget，它们派生于CompoundButton，允许使用者自行设置背景和按钮的样式，不过，有时我们仅希望简单的设置一个有状态的背景，并隐藏其默认样式。可是，当我们调用setButtonDrawable(null)或setButtonDrawable(0)时，却发现完全没有效果。原来，CompoundButton的setButtonDrawable的代码实现中屏蔽了null或resid为0的Drawable，迫使我们必须传入有效的Drawable对象。

这时候，透明颜色就可以派上用场了：

button.setButtonDrawable(new ColorDrawable(Color.TRANSPARENT));

参考：

隐藏RadioButton, CheckBox图片 setButtonDrawable：

RadioButton和CheckBox都是Android app中常用的Widget，它们派生于CompoundButton，允许使用者自行设置背景和按钮的样式，不过，有时我们仅希望简单的设置一个有状态的背景，并隐藏其默认样式。可是，当我们调用setButtonDrawable(null)或setButtonDrawable(0)时，却发现完全没有效果。原来，CompoundButton的setButtonDrawable的代码实现中屏蔽了null或resid为0的Drawable，迫使我们必须传入有效的Drawable对象。

这时候，透明颜色就可以派上用场了：

button.setButtonDrawable(new ColorDrawable(Color.TRANSPARENT));

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