检测首次运行 [英] Detect First Run

问题描述

我想检测是否我的应用程序已经运行之前，通过使用该code：

I am trying to detect if my app has been run before, by using this code:

（这是我的默认的Andr​​oid活动）

(This is in my default Android activity)

@Override
public void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);

    if (savedInstanceState == null) {
        Log.w("activity", "first time");
        setContentView(R.layout.activity_clean_weather);
    } else {

        Log.w("activity", "second time");
        setContentView(R.layout.activity_clean_weather);
    }


 }

当我第一次运行该应用程序，它说第一次，当我运行它第二次，第一次和第三次，第一次......

When I first run the app it says first time, when I run it a second time, first time, and a third, first time....

我使用的是实际的Andr​​oid设备，我不使用运行按钮各一次。我与Eclipse运行按钮运行应用程序一次，然后我关闭它的图标的应用程序和preSS在我的手机上。

I am using an actual Android device and I am not using the run button each time. I run the app once with the Eclipse run button, then I close the app and press on its icon on my phone.

是不是有什么毛病我code？

Is there something wrong with my code?

谢谢！

推荐答案

savedInstanceState 则多为状态之间的切换，如暂停/恢复，那种事。它必须由您来创建，也。

savedInstanceState is more for switching between states, like pausing/resuming, that kind of thing. It must always be created by you, also.

你想在这种情况下，什么是<一个href="http://developer.android.com/reference/android/content/Shared$p$pferences.html"><$c$c>Shared$p$pferences.

What you want in this case is SharedPreferences.

事情是这样的：

public static final String PREFS_NAME = "MyPrefsFile"; // Name of prefs file; don't change this after it's saved something

@Override
public void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);

    SharedPreferences settings = getSharedPreferences(PREFS_NAME, 0); // Get preferences file (0 = no option flags set)
    boolean firstRun = settings.getBoolean("firstRun", true); // Is it first run? If not specified, use "true"

    if (firstRun) {
        Log.w("activity", "first time");
        setContentView(R.layout.activity_clean_weather);

        SharedPreferences.Editor editor = settings.edit(); // Open the editor for our settings
        editor.putBoolean("firstRun", false); // It is no longer the first run
        editor.commit(); // Save all changed settings
    } else {
        Log.w("activity", "second time");
        setContentView(R.layout.activity_clean_weather);
    }

}

我基本上把这个code直接从用于存储文档选项​​并将其应用到你的情况。这是一个很好的概念，早期的学习。

I basically took this code directly from the documentation for Storage Options and applied it to your situation. It's a good concept to learn early.

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