Question

如何从“OtherClass”中获取“somevariable”的值？可以/我应该使用Activity的上下文，因为我在下面尝试了吗？

public class ParentActivity extends Activity {
  //This variable is reused by multiple Activities inheriting form this class
  protected static String somevariable = "text";   
  ...
}

public class MyActivity extends ParentActivity {
  @Override
  public void onCreate(Bundle icicle) {
  super.onCreate(icicle);
  myObject = new OtherClass(this);
  myObject.doSomething();
  ...
  }

...
}

public class OtherClass(){
  private Context c;
  private String b;

  OtherClass(Context context) {
    c = context;
  }

    doSomething() {
        // This does NOT work. 
        // How can I get somevariable from the ParentActivity????
        b = c.somevariable;   
    }
}

Answer 1

如果您想要访问课程somevariable中定义的特定ParentActivity，那么您应该尝试将其作为ParentActivity.somevariable访问，因为它已声明为static：

public class OtherClass { // Why were there extra parentheses ()
  private Context c;
  private String b;

  OtherClass(Context context) {
    c = context;
  }

  doSomething(){
  b = ParentActivity.somevariable; // Try this at home ;)
  }

}

Answer 2

你可以像这样传递变量：

public void doSomething(String someVariable){
  b = someVariable;   
}

Answer 3

a = ParentActivity.somevarible;

应该有用。

类如何从包含复合类的父类（扩展Activity）引用变量？

3 个答案: