Launch Mode

standard:

每次執行startActivity,每個Activity都是新的實體

singleTop:

若startActivity的對象在目前顯示的畫面時,不產生新的實體

範例

(以下B Activity的LaunchMode為singleTop)

LAUNCHER(A Activity) Task:A
start B Activity Task:A-B
start B Activity Task:A-B
start A Activity Task:A-B-A
start B Activity Task:A-B-A-B
backPress Task:A-A
backPress Task:A
backPress Task:None
Finished

singleTask:

該Activity存在於主Task中,每個taskId是相同,且為唯一實體

範例

(以下B Activity的LaunchMode為singleTask)

LAUNCHER(A Activity) Task:A
start B Activity Task:A-B
start A Activity Task:A-B-A
start B Activity Task:A-A-B
backPress Task:A-A
backPress Task:A
backPress Task:None
Finished

singleInstance:

該Activity會存於在與主Task不同的Task中且為唯一實體,不同activity taskId會不同

範例

(以下B Activity的LaunchMode為singleInstance)

LAUNCHER(A Activity) Task:A(1)
start B Activity Task:A(1)-B(2)
start A Activity Task:A(1)-B(2)-A(1)
backPress Task:B(2)-A(1)
backPress Task:B(2)
backPress Task:None
Finished

使用方法:

修改manifests,以下以standard為例

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

    <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.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity
            android:name=".SecondActivity"
            android:launchMode="standard" />
    </application>

</manifest>