android - 如何在活动形式非活动类中调用方法

Question

我有一个活动和非活动类。如何从非Activity类调用Activity类中的方法

public class MainActivity extends Activity {
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main2);

        DataClass dc = new DataClass();
        dc.show();                  
    }

    public void call(ArrayList<String> arr) {
       // Some code...
    }
}

---

public class DataClass {

    public void show(ArrayList<String> array) {
        // Here I want to send this ArrayList values into the call
        // method in activity class.

       MainActivity act = new MainActivity();
       act.call(array);                  
    }
}

Answer 1

只需在 DateClass 中创建一个回调接口。

public DateClass {
    public interface IDateCallback {
        void call(ArrayList<String> arr);
    }  

    private IDateCallback callerActivity;

    public DateClass(Activity activity) {  
        callerActivity = (IDateCallback)activity;  
    }
...  
}  

public void show(ArrayList<String> array) {            
    callerActivity.Call(array);  
    ...  
}

//And implements it inside your activity.

public class MainActivity extends Activity 
        implements IDateCallback {  

    public void call(ArrayList<String> arr) {

    }  
}

Answer 2

好吧，你可以做几件事。我认为对您来说最简单的方法是Context像DataClass这样发送：

DataClass dc =new DataClass();
dc.show(this);

并在您DataClass将上下文保存到全局 varContext context中。然后像这样使用它：

((MainActivity)context).call(array);

Answer 3

((MainActivity)getContext).array();

Answer 4

只需制作一个像这样的单例：

TeacherDashboardSingleton：

public class TeacherDashboardSingleton {
public  Teacher_Dashboard aa;
private static final TeacherDashboardSingleton ourInstance = new TeacherDashboardSingleton();
   public static TeacherDashboardSingleton getInstance() {
        return ourInstance;
    }
}

我的活动类：

onCreate(....){
 ....
   TeacherDashboardSingleton.getInstance().aa = this;
....
}

这将创建一个与活动相同实例的对象

现在您可以在任何地方使用它