launcher 配置

<application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@android:style/Theme.Holo.Light.NoActionBar.Fullscreen">
        <activity
            android:launchMode="singleTask"
            android:name=".MainActivity">
            <intent-filter android:priority="2">
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
                <category android:name="android.intent.category.HOME" />
                <category android:name="android.intent.category.DEFAULT" />
            </intent-filter>
        </activity>
    </application>

<activity
            android:name="com.android.launcher3.Launcher"
            android:launchMode="singleTask"
            android:clearTaskOnLaunch="true"
            android:stateNotNeeded="true"
            android:theme="@style/Theme"
            android:windowSoftInputMode="adjustPan"
            android:screenOrientation="nosensor">
            <intent-filter android:priority="2">
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.HOME" />
                <category android:name="android.intent.category.DEFAULT" />
                <category android:name="android.intent.category.MONKEY"/>
            </intent-filter>
</activity>

注意下 

<category android:name="android.intent.category.HOME" />

<category android:name="android.intent.category.DEFAULT" />

android:clearTaskOnLaunch="true"
android:stateNotNeeded="true"

<intent-filter android:priority="2">
起着不同的作用