Question

快速提问：我有一个活动组。在该活动组内，我有一项活动。如果我在此活动中按回来。调用活动的onBackPressed方法 - 不是活动组onBackPressed - 为什么？

编辑：得到了答案，但问题仍然存在。下面是我原始问题的代码和解释：

我在TabHost中使用ActivityGroups，因此被“强制”覆盖onBackPressed。通过按下我的手机并按下我的tabhost上的标签，我可以毫无问题地浏览我的应用程序。但按Back后我无法与界面交互。一旦我再次按下tabhost上的其中一个标签，我就可以正常地与所有内容进行交互。为什么会这样？我是否需要覆盖onResume？

相关代码

SettingsActivityGroup：

public class SettingsActivityGroup extends ActivityGroup 
{
// Keep this in a static variable to make it accessible for all the nested activities, lets them manipulate the view
public static SettingsActivityGroup group;

// Need to keep track of the history if you want the back-button to work properly, don't use this if your activities requires a lot of memory.
private ArrayList<View> history;

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

    // Allocate history
    this.history = new ArrayList<View>();

    // Set group
    group = this;             

    // Start root (first) activity
    Intent myIntent = new Intent(this, SettingsActivity.class); // Change to the first activity of your ActivityGroup
    myIntent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
    ReplaceView("SettingsActivity", myIntent);
}

/*
 * Replace the activity with a new activity and add previous one to history
 */
public void ReplaceView(String pId, Intent pIntent)
{
    Window window = getLocalActivityManager().startActivity(pId, pIntent);
    View view = (window != null) ? window.getDecorView() : null;

    // Add the old activity to the history
    history.add(view);

    // Set content view to new activity
    setContentView(view);
}

/*
 * Go back from previous activity or close application if there is no previous activity
 */
public void back()
{
    if(history.size() > 1)
    {
        // Remove previous activity from history
        history.remove(history.size()-1);

        // Go to activity
        View view = history.get(history.size() - 1);
        Activity activity = (Activity) view.getContext();

        // "Hack" used to determine when going back from a previous activity
        // This is not necessary, if you don't need to redraw an activity when going back
        activity.onWindowFocusChanged(true);
        // Set content view to new activity
        setContentView(view);
    }
    else
    {
        // Close the application
        finish();

    }
}
/*
 * Overwrite the back button
 */
@Override
public void onBackPressed() 
{
    // Go one back, if the history is not empty
    // If history is empty, close the application
    SettingsActivityGroup.group.back();

    return;
}
}

SettingsActivityGroup（CallForwardActivity）的任意子项

public class CallForwardActivity extends ListActivity 
{
....
    @Override
    public void onBackPressed() 
    {
        // Go one back, if the history is not empty
        // If history is empty, close the application
        SettingsActivityGroup.group.back();

        return;
    }

}

Answer 1

因为我认为调用当前所选活动的onBackPressed（）是所希望的行为。

值得注意的是，不推荐使用ActivityGroup，但我认为你编写的是＆lt; 3.0并且不喜欢使用支持库。

关于您编辑过的问题：本网站上的另一个问题引用本文作为一个很好的ActivityGroup示例，我同意http://ericharlow.blogspot.com/2010/09/experience-multiple-android-activities.html 这个例子只是在按下后退时调用当前活动的finish（），并让os重新启动上一个活动，这比你正在做的更简单，并且希望有效！您也可以在您的子活动中调用getParent（）以避免使用该静态引用（这样看起来更容易读给我！）。

ActivityGroups的onBackPressed（）行为

1 个答案: