如何创建采用Android preferences一次性欢迎屏幕？ [英] How to create a one-time welcome screen using Android preferences?

问题描述

我想创建一个屏幕，在应用程序启动后只显示一次。随后，那么它只会显示在主屏幕。我实现这一点的方法只是检查preferences并设置基于一个标志当前布局。是否有任何抽奖背上来实现这种方式？有没有更好的办法？

  @覆盖
    公共无效的onCreate（包savedInstanceState）{
        super.onCreate（savedInstanceState）;
        //这里是主要布局
        的setContentView（R.layout.main）;

        米preFS = preferenceManager.getDefaultShared preferences（本）;

        //第二个参数是默认情况下使用的preference无法找到
        布尔welcomeScreenShown = M prefs.getBoolean（welcomeScreenShown preF，假）;

        如果（！welcomeScreenShown）{
            //这里我设置的一次性布局
            的setContentView（R.layout.popup_message）;
            共享preferences.Editor编辑= M prefs.edit（）;
            editor.putBoolean（welcomeScreenShown preF，真正的）;
            editor.commit（）; //非常重要，保存preference
        }
    }
 

解决方案

试着用应用程序版本code 。下面是我用一个例子code;

 共享preferences共享preferences = getShared preferences（版本，0）;
    INT savedVersion code =共享preferences.getInt（版本code，0）;

    INT appVershion code = 0;

    尝试 {
        。appVershion code = getPackageManager（）getPackageInfo（getPackageName（），0）.version code;

    }赶上（nnfe的NameNotFoundException）{
        Log.w（TAG，$异常的appVershion code CAZ：+ nnfe）;
    }

    如果（savedVersion code == appVershion code）{
        Log.d（TAG，$$ savedVersion code == appVershion code）;
    }其他{
        Log.d（TAG，$$ savedVersion code = appVershion code！）;

        共享preferences.Editor共享preferencesEditor =共享preferences.edit（）;
        共享preferencesEditor.putInt（版本code，appVershion code）;
        共享preferencesEditor.commit（）;

        构建alertDialogBu​​ilder =新生成器（本）;
        alertDialogBu​​ilder.setTitle（版本）;
        alertDialogBu​​ilder.setMessage（这是一次显示对话框）;

        alertDialogBu​​ilder.setNeutralButton（关闭，新OnClickListener（）{

            @覆盖
            公共无效的onClick（DialogInterface对话，诠释它）{
                Log.d（TAG，$$的onClick）;

            }
        }）;

        alertDialogBu​​ilder.show（）;
    }
 

I'd like to create a screen that only shows once after the application starts. Afterward, then it will only show the main screen. The way I implemented this was just to check the preferences and set the current layout based on a flag. Are there any draw backs to implementing it this way? Is there a better way?

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        //Here is the main layout
        setContentView(R.layout.main);      

        mPrefs = PreferenceManager.getDefaultSharedPreferences(this);

        // second argument is the default to use if the preference can't be found
        Boolean welcomeScreenShown = mPrefs.getBoolean(welcomeScreenShownPref, false);

        if (!welcomeScreenShown) {
            //Here I set the one-time layout
            setContentView(R.layout.popup_message);             
            SharedPreferences.Editor editor = mPrefs.edit();
            editor.putBoolean(welcomeScreenShownPref, true);
            editor.commit(); // Very important to save the preference
        }
    }

解决方案

Try with Application version code. Below is an example code that I have used;

    SharedPreferences sharedPreferences = getSharedPreferences("version", 0);
    int savedVersionCode = sharedPreferences.getInt("VersionCode", 0);

    int appVershionCode = 0;

    try {
        appVershionCode = getPackageManager().getPackageInfo(getPackageName(), 0).versionCode;

    } catch (NameNotFoundException nnfe) {
        Log.w(TAG, "$ Exception caz of appVershionCode : " + nnfe);
    }   

    if(savedVersionCode == appVershionCode){
        Log.d(TAG, "$$ savedVersionCode == appVershionCode");
    }else{
        Log.d(TAG, "$$ savedVersionCode != appVershionCode");

        SharedPreferences.Editor sharedPreferencesEditor = sharedPreferences.edit();
        sharedPreferencesEditor.putInt("VersionCode", appVershionCode);
        sharedPreferencesEditor.commit();

        Builder alertDialogBuilder = new Builder(this);
        alertDialogBuilder.setTitle("Version");
        alertDialogBuilder.setMessage("This is one time show dialog box ");

        alertDialogBuilder.setNeutralButton("Close", new OnClickListener() {

            @Override
            public void onClick(DialogInterface dialog, int which) {
                Log.d(TAG, "$$ onClick");

            }
        });

        alertDialogBuilder.show();
    }

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