确定Android应用程序是否是第一次使用

Question

我目前正在开发一个Android应用程序.当应用程序第一次启动时,我需要做一些事情,即代码仅在程序第一次启动时运行.

Answer 1

您可以使用SharedPreferences来确定它是否是"第一次"启动应用程序.只需使用布尔变量("my_first_time"),并在"第一次"任务结束时将其值更改为false.

这是我第一次打开应用程序时捕获的代码:

final String PREFS_NAME = "MyPrefsFile";

SharedPreferences settings = getSharedPreferences(PREFS_NAME, 0);

if (settings.getBoolean("my_first_time", true)) {
    //the app is being launched for first time, do something        
    Log.d("Comments", "First time");

             // first time task

    // record the fact that the app has been started at least once
    settings.edit().putBoolean("my_first_time", false).commit(); 
}

Answer 2

我建议不仅要存储布尔标志,还要存储完整的版本代码.这样,您也可以在开头查询它是否是新版本中的第一个开始.例如,您可以使用此信息显示"Whats new"对话框.

以下代码应该适用于"是一个上下文"(活动,服务,......)的任何android类.如果你喜欢有它在一个单独的(POJO)类,你可以描述考虑使用"静态上下文",这里的例子.

/**
 * Distinguishes different kinds of app starts: <li>
 * <ul>
 * First start ever ({@link #FIRST_TIME})
 * </ul>
 * <ul>
 * First start in this version ({@link #FIRST_TIME_VERSION})
 * </ul>
 * <ul>
 * Normal app start ({@link #NORMAL})
 * </ul>
 * 
 * @author schnatterer
 * 
 */
public enum AppStart {
    FIRST_TIME, FIRST_TIME_VERSION, NORMAL;
}

/**
 * The app version code (not the version name!) that was used on the last
 * start of the app.
 */
private static final String LAST_APP_VERSION = "last_app_version";

/**
 * Finds out started for the first time (ever or in the current version).<br/>
 * <br/>
 * Note: This method is <b>not idempotent</b> only the first call will
 * determine the proper result. Any subsequent calls will only return
 * {@link AppStart#NORMAL} until the app is started again. So you might want
 * to consider caching the result!
 * 
 * @return the type of app start
 */
public AppStart checkAppStart() {
    PackageInfo pInfo;
    SharedPreferences sharedPreferences = PreferenceManager
            .getDefaultSharedPreferences(this);
    AppStart appStart = AppStart.NORMAL;
    try {
        pInfo = getPackageManager().getPackageInfo(getPackageName(), 0);
        int lastVersionCode = sharedPreferences
                .getInt(LAST_APP_VERSION, -1);
        int currentVersionCode = pInfo.versionCode;
        appStart = checkAppStart(currentVersionCode, lastVersionCode);
        // Update version in preferences
        sharedPreferences.edit()
                .putInt(LAST_APP_VERSION, currentVersionCode).commit();
    } catch (NameNotFoundException e) {
        Log.w(Constants.LOG,
                "Unable to determine current app version from pacakge manager. Defenisvely assuming normal app start.");
    }
    return appStart;
}

public AppStart checkAppStart(int currentVersionCode, int lastVersionCode) {
    if (lastVersionCode == -1) {
        return AppStart.FIRST_TIME;
    } else if (lastVersionCode < currentVersionCode) {
        return AppStart.FIRST_TIME_VERSION;
    } else if (lastVersionCode > currentVersionCode) {
        Log.w(Constants.LOG, "Current version code (" + currentVersionCode
                + ") is less then the one recognized on last startup ("
                + lastVersionCode
                + "). Defenisvely assuming normal app start.");
        return AppStart.NORMAL;
    } else {
        return AppStart.NORMAL;
    }
}

它可以从这样的活动中使用:

public class MainActivity extends Activity {        
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        switch (checkAppStart()) {
        case NORMAL:
            // We don't want to get on the user's nerves
            break;
        case FIRST_TIME_VERSION:
            // TODO show what's new
            break;
        case FIRST_TIME:
            // TODO show a tutorial
            break;
        default:
            break;
        }

        // ...
    }
    // ...
}

可以使用此JUnit测试验证基本逻辑:

public void testCheckAppStart() {
    // First start
    int oldVersion = -1;
    int newVersion = 1;
    assertEquals("Unexpected result", AppStart.FIRST_TIME,
            service.checkAppStart(newVersion, oldVersion));

    // First start this version
    oldVersion = 1;
    newVersion = 2;
    assertEquals("Unexpected result", AppStart.FIRST_TIME_VERSION,
            service.checkAppStart(newVersion, oldVersion));

    // Normal start
    oldVersion = 2;
    newVersion = 2;
    assertEquals("Unexpected result", AppStart.NORMAL,
            service.checkAppStart(newVersion, oldVersion));
}

通过更多的努力,你可以测试android相关的东西(PackageManager和SharedPreferences).有兴趣写测试的人吗？:)

请注意,如果您没有android:versionCode在AndroidManifest.xml中乱搞,上面的代码将只能正常工作!

Answer 3

另一个想法是使用共享首选项中的设置.与检查空文件相同的一般想法,但是你没有漂浮的空文件,不用于存储任何东西

Answer 4

我解决了确定该应用程序是否是您第一次使用的问题，具体取决于它是否是更新。

\n\n

private int appGetFirstTimeRun() {\n    //Check if App Start First Time\n    SharedPreferences appPreferences = getSharedPreferences("MyAPP", 0);\n    int appCurrentBuildVersion = BuildConfig.VERSION_CODE;\n    int appLastBuildVersion = appPreferences.getInt("app_first_time", 0);\n\n    //Log.d("appPreferences", "app_first_time = " + appLastBuildVersion);\n\n    if (appLastBuildVersion == appCurrentBuildVersion ) {\n        return 1; //ya has iniciado la appp alguna vez\n\n    } else {\n        appPreferences.edit().putInt("app_first_time",\n                appCurrentBuildVersion).apply();\n        if (appLastBuildVersion == 0) {\n            return 0; //es la primera vez\n        } else {\n            return 2; //es una versi\xc3\xb3n nueva\n        }\n    }\n}\n

\n\n

计算结果：

\n\n

\n
• 0：如果这是第一次。
\n
• 1：它已经开始了。
\n
• 2：已经启动过一次，但不是那个版本，即是更新。
\n

\n