ClassCastException:android.widget.Button [英] ClassCastException: android.widget.Button

问题描述

我在这里有一个非常非常奇怪的问题.

I have a really really really strange issue here.

我有这行代码:

SeekBar mProgressBar =  (SeekBar) findViewById(R.id.SeekBar);

并引发 ClassCastException:android.widget.Button ，如标题所示. XML文件如下所示:

And it throws a ClassCastException: android.widget.Button as the title indicates. The XML file looks like this:

...
<SeekBar
android:id="@+id/SeekBar"
android:layout_height="wrap_content"
android:layout_width="fill_parent"
/>
...

如果我将代码更改为

Button mProgressBar =  (Button) findViewById(R.id.SeekBar);

有效"(例如，单行有效.由于其他原因，程序现在失败，因为它现在是一个按钮).我在另一个文件中有 exact 相同的行，没有问题.知道有什么问题吗?

It "works" (e.i that single line works. The programs then fails for other reasons because it's now a button). I have the exact same line in another file without problems. Any idea what could be wrong?

推荐答案

必须是已过时的自动生成的R类.有时候，它变得一团糟，我刚才才知道.尝试清理项目并再次重建.或更改布局XML中的内容并保存，Eclipse应该刷新R类(也就是说，如果您使用的是eclipse).

Must be an outdated auto-generated R class. Sometimes it gets messed up, i had it just moments ago. Try to clean the project and rebuild again. Or change something in the layout XML and save, Eclipse should refresh the R class (that is, if you're using eclipse).

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