让Activity单例运行

修改AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
	package="com.go7j.sns" android:versionCode="1"
	android:versionName="1.0">
	<application android:icon="@drawable/icon"
		android:label="@string/app_name">
		<activity android:name=".MainActivity"
			android:label="@string/app_name"
			android:theme="@android:style/Theme.NoTitleBar.Fullscreen"
			android:launchMode="singleInstance">
			<intent-filter>
				<action android:name="android.intent.action.MAIN" />
				<category
					android:name="android.intent.category.DEFAULT" />
			</intent-filter>
		</activity>
	</application>
	<uses-sdk android:minSdkVersion="7" />
</manifest>

关键在activity中加入

android:launchMode="singleInstance"