Android 如何以编程方式将 selectableItemBackground 添加到 ImageButton？
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How do I add selectableItemBackground to an ImageButton programmatically?
提问by abc32112
android.R.attr.selectableItemBackground exists, but how do I add it programatically to an ImageButton?
android.R.attr.selectableItemBackground 存在，但如何以编程方式将其添加到 ImageButton？
Also, how would I go about finding the answer in the documentation? It's mentioned here, but I don't see any explanation of how it's actually used. Actually, I rarely seem to find the documentation useful, but I'm hoping that's my fault and not that of the documentation.
另外，我将如何在文档中找到答案？这里提到了它，但我没有看到有关它实际使用方式的任何解释。实际上，我似乎很少发现文档有用，但我希望这是我的错，而不是文档的错。
回答by Timu?in
Here is an example using answer here: How to get the attr reference in code?
这是一个使用答案的示例：How to get the attr reference in code?
// Create an array of the attributes we want to resolve
// using values from a theme
// android.R.attr.selectableItemBackground requires API LEVEL 11
int[] attrs = new int[] { android.R.attr.selectableItemBackground /* index 0 */};
// Obtain the styled attributes. 'themedContext' is a context with a
// theme, typically the current Activity (i.e. 'this')
TypedArray ta = obtainStyledAttributes(attrs);
// Now get the value of the 'listItemBackground' attribute that was
// set in the theme used in 'themedContext'. The parameter is the index
// of the attribute in the 'attrs' array. The returned Drawable
// is what you are after
Drawable drawableFromTheme = ta.getDrawable(0 /* index */);
// Finally free resources used by TypedArray
ta.recycle();
// setBackground(Drawable) requires API LEVEL 16,
// otherwise you have to use deprecated setBackgroundDrawable(Drawable) method.
imageButton.setBackground(drawableFromTheme);
// imageButton.setBackgroundDrawable(drawableFromTheme);
回答by Andrey T
If you are using AppCompat you could use following code:
如果您使用的是 AppCompat，则可以使用以下代码：
int[] attrs = new int[]{R.attr.selectableItemBackground};
TypedArray typedArray = context.obtainStyledAttributes(attrs);
int backgroundResource = typedArray.getResourceId(0, 0);
view.setBackgroundResource(backgroundResource);
typedArray.recycle();
回答by maohieng
This works for me with my TextView:
这对我有用TextView：
// Get selectable background
TypedValue typedValue = new TypedValue();
getTheme().resolveAttribute(R.attr.selectableItemBackground, typedValue, true);
clickableTextView.setClickable(true);
clickableTextView.setBackgroundResource(typedValue.resourceId);
Because I use AppCompat library, I use R.attr.selectableItemBackgroundnot android.R.attr.selectableItemBackground.
因为我使用 AppCompat 库，所以我R.attr.selectableItemBackground不使用android.R.attr.selectableItemBackground.
I think typedValue.resourceIdholds all drawables from selectableItemBackgroundthan using TypeArray#getResourceId(index, defValue)or TypeArray#getDrawable(index)which are retrieve only a drawable at the given index.
我认为typedValue.resourceId所有的可绘制对象都来自selectableItemBackground使用TypeArray#getResourceId(index, defValue)或TypeArray#getDrawable(index)仅在给定的index.
回答by Sergio Serra
Try this method:
试试这个方法：
public Drawable getDrawableFromAttrRes(int attrRes, Context context) {
TypedArray a = context.obtainStyledAttributes(new int[] {attrRes});
try {
return a.getDrawable(0);
} finally {
a.recycle();
}
}
// Then just call it like this:
// 然后就这样调用它：
getDrawableFromAttrRes(R.attr.selectableItemBackground, context)
// Example
ViewCompat.setBackground(view,getDrawableFromAttrRes(R.attr.selectableItemBackground, context))
