Android Studio的新手，启动画面错误

Question

I am new to Android Studio and to the OS and have been designing an application, I tried to add a splash screen to my application after creating the splash screen and adding it to my manifest file but I keep getting this error:

Could not identify launch activity: Default Activity not found Error while Launching activity

The tutorial I followed to get the splash screen provides no insight to correcting this error.

Below is my entire manifest file if someone could correct me I would be grateful.

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="gui.prog">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.DEFAULT" />
            </intent-filter>
        </activity>
        <activity android:name=".Display" ></activity>
        <activity android:name=".Signup" ></activity>
        <activity android:name=".Splash">
            <intent-filter>
                <action android:name="android.intent.category.MAIN"/>
                <category android:name="android.intent.category.LAUNCHER"/>
            </intent-filter>
</activity>
    </application>

</manifest>

Answer 1

Just copy paste file,

<?xml version="1.0" encoding="utf-8"?>

<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:supportsRtl="true"
    android:theme="@style/AppTheme">
    <activity android:name=".MainActivity"/>
    <activity android:name=".Display" ></activity>
    <activity android:name=".Signup" ></activity>
    <activity android:name=".Splash">
        <intent-filter>
            <action android:name="android.intent.category.MAIN"/>
            <category android:name="android.intent.category.LAUNCHER"/>
        </intent-filter>

It will work, as currently it is unable to know which activity is initial one.

Answer 2

What I like to do for a 'SplashActivity' is set my 'MainActivity' as a regular activity, and set my 'SplashActivity' as the default activity that will begin on launch.

My AndroidManifest.xml:

<activity android:name=".Splash">
    <intent-filter>
        <action android:name="android.intent.action.MAIN" />
        <category android:name="android.intent.category.HOME" />
        <category android:name="android.intent.category.LAUNCHER" />
    </intent-filter>
</activity> 
<activity android:name=".MainActivity" ></activity>

Then in my SplashActivity's 'onCreate' method:

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_splash);
    Thread timerThread = new Thread(){
        public void run(){
            try{
                sleep(2000);
            }catch(InterruptedException e){
                e.printStackTrace();
            }finally{
                Intent intent = new Intent(SplashActivity.this, MainActivity.class);
                startActivity(intent);
            }
        }
    };
    timerThread.start();
}

Answer 3

如果要使用spalsh屏幕活动启动应用，则不能在android清单文件中放置两个意图过滤器，而必须将意图过滤器放入启动活动中