由网友(潮流)分享简介:在以下codeI得到线9月10日与findViewById()一个NullPointerException异常。在我的主类我只是实例化一个对象,从这个类,使用.getFrom()In the following code i get a NullPointerException on lines 9/10 with...
在以下codeI得到线9月10日与findViewById()一个NullPointerException异常。 在我的主类我只是实例化一个对象,从这个类,使用.getFrom()
In the following code i get a NullPointerException on lines 9/10 with findViewById(). In my main class I just instantiated an object from this class, to use .getFrom()
public class UserInteraction extends Activity {
EditText etFrom;
int from;
EditText etTill;
int till;
public UserInteraction(){
etFrom = (EditText)findViewById(R.id.et_from);
etTill = (EditText)findViewById(R.id.et_till);
}
public int getFrom() {
String s = etFrom.getText().toString();
int i = Integer.parseInt(s);
return i;
}
public int getTill() {
String s = etTill.getText().toString();
int i = Integer.parseInt(s);
return i;
}
时认为内容查看在我的主类中设置..? 可能是什么原因?
Is it that the contentView is set in my main class ..? What could be the cause ?
推荐答案
在的setContentView
方法应被调用适当的布局之前调用 findViewById
。它通常被称为的onCreate(包savedInstance)
方法。
The setContentView
method should be called with appropriate layout before calling findViewById
. It is usually called in onCreate(Bundle savedInstance)
method.
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