如何在应用程序启动"新鲜"时显示启动画面？

    android:name=".MainActivity"
    android:theme="@style/SplashTheme">
   <intent-filter>
       <action android:name="android.intent.action.MAIN" />
       <category android:name="android.intent.category.LAUNCHER" />
    </intent-filter>
</activity>

    <item name="android:windowBackground">@drawable/splash_background</item>
</style>

    <item android:drawable="@color/colorPrimary"/>
    <item>
        <bitmap
            android:gravity="center"
            android:src="@mipmap/ic_launcher"/>
    </item>
</layer-list>

    android:name=".SplashActivity"
    android:theme="@style/SplashTheme">
   <intent-filter>
       <action android:name="android.intent.action.MAIN" />
       <category android:name="android.intent.category.LAUNCHER" />
    </intent-filter>
</activity>

    <item name="android:windowBackground">@drawable/splash_background</item>
</style>

    <item android:drawable="@color/colorPrimary"/>
    <item>
        <bitmap
            android:gravity="center"
            android:src="@mipmap/ic_launcher"/>
    </item>
</layer-list>

public class SplashActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_splash);

        new Handler().postDelayed(new Runnable() {
            @Override
            public void run() {
                Intent intent = new Intent(SplashActivity.this, MainActivity.class);
                startActivity(intent);
                finish();
            }
        }, 2000);
    }
}