如何调用另一活动的方法 [英] How to call a method in another activity

问题描述

我有一个关于在Android的实施计划活动之间的通信问题。

I have a question about communication between activities on implementation program of Android.

下面是二活动课。

public class HelloAndroidActivity extends TabActivity{
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        Resources res = getResources();
        TabHost tabHost = getTabHost();
        TabHost.TabSpec spec;
        Intent intent;

        intent = new Intent().setClass(this, Tab1Activity.class);
        spec = tabHost.newTabSpec("Tab1").setIndicator(
          "Tab1", res.getDrawable(R.drawable.ic_tab_icon))
          .setContent(intent);
        tabHost.addTab(spec);
    }
}

_

public class Tab1Activity extends ListActivity {
    private ArrayList<String> list = null;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);  

        list = new ArrayList<String>();
        setListAdapter(new ArrayAdapter<String>(this,  
                android.R.layout.simple_list_item_1, list)); 

        addColumn("one");
        addColumn("two");
        addColumn("three");
    }

    public void addColumn(String s){
        list.add(new String(s));
    }
}

HelloAndroidActivity是主要活动。 Tab1Activity是次活动，并显示列表视图。 HelloAndroidActivity包括Tab1Activity视图。

HelloAndroidActivity is main activity. Tab1Activity is sub activity and display listview. HelloAndroidActivity include Tab1Activity view.

我想要做的就是调用从HelloAndroidActivity addColumn的方法是什么， 因为HelloAndroidActivity加到像TwitterUserStreamAdapter新功能。 如果机器人从互联网上接收邮件， 应用程序发送消息到Tab1Activity。

What I want to do is calling addColumn method from HelloAndroidActivity, because HelloAndroidActivity is added to new function like TwitterUserStreamAdapter. If the android receive messages from internet, application send message to Tab1Activity.

不过，我不知道如何实现活动之间的通信。

However, I don't know how to implement communication between activities.

推荐答案

您可以通过使用意图，你可以把它的意图的额外活动之间的数据：

You can pass data between activities using intent, you could put it in the extras with the intent:

HelloAndroidActivity

intent.putExtra("callX", true);

Tab1Activity

Bundle extras = getIntent().getExtras();
if (extras != null) {
    boolean callX = extras.getBoolean("callX");
    if(callX) {
       X();
    }
}

修改 如果你需要的事件/监听器机制，它可以大致是这样的（没有编译这一点，但应该给你一个想法）：

EDIT If you need to event/listener mechanism it could be roughly like this(haven't compiled this, but should give you an idea):

public inerface MyEventListener {
    abstract void handleMyEvent();
}

public class Tab1Activity implements MyEventListener {

    public void handleMyEvent() {
        /*...*/
    }

    protected void onCreate(Bundle savedInstanceState) {
         /*...*/
         HelloAndroidActivity.addListener(this);
    }

    protected void  onDestroy() {
         /*...*/
         HelloAndroidActivity.removeListener(this);
    }
}


public class HelloAndroidActivity {
    static ArrayList<MyEventListener> listeners = new ArrayList<MyEventListener>();
    public static void addListener(MyEventListener listener) {
        listeners.add(listener);
    }
    public static void removeListener(MyEventListener listener) {
        listeners.remove(m);
    }

    public static void onEvent() {
        for(MyEventListener m : listeners) {
            m.handleMyEvent();
        }
    }
}

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