android:launchMode="singleTask"
android中launcherMode有4中属性也可以称为四种启动模式:standard(默认), singleTop,singleTask和 singleInstance;
<activity android:name="com.air.chinesetea.HomeActivity" android:launchMode="singleTask" android:screenOrientation="portrait" android:windowSoftInputMode="adjustUnspecified|stateHidden" > </activity>