findViewById
时间: 2023-08-05 21:01:56 浏览: 57
findViewById 是 Android 中的一个方法,用于在布局文件中查找指定 ID 的视图控件对象。它的语法如下:
```java
View findViewById(int id)
```
其中,参数 id 是在布局文件中定义的视图控件的 ID,返回值类型为 View 或其子类。通常,在 Activity 中调用该方法来获取布局文件中的视图控件对象,以便进一步操作。例如:
```java
TextView textView = findViewById(R.id.textview);
```
上面的代码通过 findViewById 方法获取布局文件中 ID 为 textview 的 TextView 控件对象。
相关问题
FindViewbyid
FindViewById is a method used in Android development to find the view with a specific ID in the current hierarchy. It is used to get a reference to a view object so that it can be manipulated programmatically.
For example, if you have a TextView with an ID of "textView1" in your layout file, you can use the following code to get a reference to it:
```
TextView myTextView = (TextView) findViewById(R.id.textView1);
```
This code finds the view with the ID "textView1" and assigns it to the variable "myTextView". Once you have a reference to the view, you can manipulate its properties, such as setting its text or changing its visibility.
It's important to note that FindViewById can only be used after the view has been inflated, which typically happens in the onCreate() method of an Activity. If you try to use FindViewById before the view has been inflated, you'll get a null pointer exception.
button findViewById
这是一个在 Android 开发中常用的方法,用于在布局文件中找到指定 ID 的按钮视图,并将其与代码中的按钮对象绑定起来。具体的代码实现如下:
```
Button button = findViewById(R.id.button_id);
```
其中,`button_id` 是布局文件中按钮视图的 ID,`Button` 是 Android 中的一个 UI 控件类,通过这个方法可以获取到这个按钮对象,从而对其进行各种操作,比如设置点击事件监听器、修改按钮文本等等。