防止后退按钮关闭我的应用程序

发布于 2024-11-17 18:10:00 字数 486 浏览 0 评论 0原文

我在应用程序的活动中使用以下代码来防止它关闭我的应用程序。

/* Prevent app from being killed on back */
    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {

        // Back?
        if (keyCode == KeyEvent.KEYCODE_BACK) {
            // Back
            moveTaskToBack(true);
        }

        // Return
        return super.onKeyDown(keyCode, event);

    }

它不起作用。该应用程序设置为兼容 Android 1.6（API 级别 4）。单击我的应用程序图标会在 Splash 活动（这是主活动）中重新启动我的应用程序。如何防止我的应用程序关闭？

原文

I am using the following code in my application's activity to prevent it from closing my app on back.

/* Prevent app from being killed on back */
    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {

        // Back?
        if (keyCode == KeyEvent.KEYCODE_BACK) {
            // Back
            moveTaskToBack(true);
        }

        // Return
        return super.onKeyDown(keyCode, event);

    }

It does not work. The app is set to be Android 1.6 (API Level 4) compatible. Clicking on my application icon restarts my app at a Splash activity (which is the Main). How can I prevent my app from closing on back?

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凌乱心跳 2024-11-24 18:10:00

更简洁的解决方案：-

@Override
public void onBackPressed() {
    // do nothing. We want to force user to stay in this activity and not drop out.
}

A more succinct solution:-

@Override
public void onBackPressed() {
    // do nothing. We want to force user to stay in this activity and not drop out.
}

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笔芯 2024-11-24 18:10:00

您是否尝试过将 super 调用放在 else 块中，以便仅在键不是 KEYCODE_BACK 时才调用它？

/* Prevent app from being killed on back */
    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {

        // Back?
        if (keyCode == KeyEvent.KEYCODE_BACK) {
            // Back
            moveTaskToBack(true);
            return true;
        }
        else {
            // Return
            return super.onKeyDown(keyCode, event);
        }
    }

但老实说，您不能依赖这一点，因为一旦您的应用程序被置于后台，系统随时可以回收它以回收内存。

Have you tried putting the super call in an else block so it is only called if the key is not KEYCODE_BACK ?

/* Prevent app from being killed on back */
    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {

        // Back?
        if (keyCode == KeyEvent.KEYCODE_BACK) {
            // Back
            moveTaskToBack(true);
            return true;
        }
        else {
            // Return
            return super.onKeyDown(keyCode, event);
        }
    }

In all honesty though, you can't rely on this because once your app is placed in the background, at any moment it could be recycled for the system to reclaim memory.

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烟凡古楼 2024-11-24 18:10:00

即使你可以这样做，你也不应该这样做。强制用户始终将您的应用程序保留在内存中并不是一个好主意，而且只会惹恼他们。

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淡水深流 2024-11-24 18:10:00

如果需要向后导航并防止关闭，则在 Android WebView 中使用：

@Override
public void onBackPressed() {
    if (mWebView.canGoBack()) {
        mWebView.goBack();
        return;
    }

    // Otherwise defer to system default behavior.
    super.onBackPressed();
}

If need to navigate back as well as preventing from closing, then in Android WebView use this:

@Override
public void onBackPressed() {
    if (mWebView.canGoBack()) {
        mWebView.goBack();
        return;
    }

    // Otherwise defer to system default behavior.
    super.onBackPressed();
}

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