如何使用 Android 首选项创建一次性欢迎屏幕？

Question

我想创建一个仅在应用程序启动后显示一次的屏幕。之后，它将只显示主屏幕。我实现这一点的方式只是检查首选项并根据标志设置当前布局。以这种方式实施它有什么缺点吗？有没有更好的办法？

    @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
        }
    }

Answer 1

尝试使用应用程序版本代码。下面是我使用的示例代码；

    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();
    }

Answer 2

您可以使用下面的代码代替共享首选项，我也使用过很多次它会完美运行它只在应用程序第一次启动时显示一次

public class SplashActivity extends Activity {
protected boolean _isActive = true;
protected int _splashTime = 3000; //SplashActivity will be visible for 2s
final String TAG = "SplashActivity";


public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.splash_activity);



    //a separate thread to manage splash screen
    final Thread splashThread = new Thread() {

        public void run() {

            try {
                int wait = 0;

                while (_isActive && (_splashTime > wait)) { //will show only on the first time
                    sleep(100);

                    if (_isActive) {
                        wait += 100;
                    }
                }
            } catch (InterruptedException e) {
                Log.d(TAG, e.getMessage());

            } finally {
                startActivity(new Intent(SplashActivity.this, MainActivityAbs.class));
                finish();
            }
        }
    };
    splashThread.start();
}

//if a user clicks on a back btnOrder, do not show splash screen

public boolean onTouchEvent(MotionEvent event) {
    if (event.getAction() == MotionEvent.ACTION_DOWN) {
        _isActive = false;
    }
    return true;
}