问题
I am building an Android application which connects with a Bluetooth module. When the application is created, a thread to connect to the module is executed. When i rotate the phone, the application restarts and the connection thread is run again. To get around this, I added
android:configChanges="orientation|screenSize"
android:windowSoftInputMode="adjustResize|stateHidden"
to the Android manifest file. Now the application doesn't get restarted, but a ScrollView I used in the activity does not scroll. Any idea to get the scrollview scrollable and prevent the application from restarting?
Here is my XML file
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<ScrollView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fillViewport="true"
android:layout_above="@+id/imageView">
<LinearLayout
android:id="@+id/linear"
android:layout_width="fill_parent"
android:layout_height="match_parent"
android:layout_above="@+id/imageView"
android:background="#bf000000"
android:orientation="vertical"
tools:context=".MainActivity">
<TextView
android:id="@+id/txtReceive1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:visibility="gone" />
<TableLayout
android:id="@+id/table"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#fff3f3f2"
android:shrinkColumns="*"
android:stretchColumns="*">
<TableRow>
<TextView
android:layout_width="wrap_content"
android:gravity="center"
android:padding="8dip"
android:text="CH" />
<TextView
android:layout_width="wrap_content"
android:gravity="center"
android:padding="8dip"
android:text="kWh" />
<TextView
android:layout_width="wrap_content"
android:gravity="center"
android:padding="8dip"
android:text="Load" />
<TextView
android:layout_width="wrap_content"
android:gravity="center"
android:padding="8dip"
android:text="Date" />
</TableRow>
<TableRow>
<TextView
android:id="@+id/t11"
android:layout_width="wrap_content"
android:gravity="center"
android:padding="8dip"
android:text="1" />
<TextView
android:id="@+id/t12"
android:layout_width="wrap_content"
android:gravity="center"
android:padding="8dip" />
<TextView
android:id="@+id/t13"
android:layout_width="wrap_content"
android:gravity="center"
android:padding="8dip" />
<TextView
android:id="@+id/t14"
android:layout_width="wrap_content"
android:gravity="center"
android:padding="8dip" />
</TableRow>
<TableRow>
<TextView
android:id="@+id/t21"
android:layout_width="wrap_content"
android:gravity="center"
android:padding="8dip"
android:text="2" />
<TextView
android:id="@+id/t22"
android:layout_width="wrap_content"
android:gravity="center"
android:padding="8dip" />
<TextView
android:id="@+id/t23"
android:layout_width="wrap_content"
android:gravity="center"
android:padding="8dip" />
<TextView
android:id="@+id/t24"
android:layout_width="wrap_content"
android:gravity="center"
android:padding="8dip" />
</TableRow>
<TableRow>
<TextView
android:id="@+id/t31"
android:layout_width="wrap_content"
android:gravity="center"
android:padding="8dip"
android:text="3" />
<TextView
android:id="@+id/t32"
android:layout_width="wrap_content"
android:gravity="center"
android:padding="8dip" />
<TextView
android:layout_width="wrap_content"
android:gravity="center"
android:padding="8dip" />
<TextView
android:id="@+id/t34"
android:layout_width="wrap_content"
android:gravity="center"
android:padding="8dip" />
</TableRow>
<TableRow>
<TextView
android:id="@+id/t41"
android:layout_width="wrap_content"
android:gravity="center"
android:padding="8dip"
android:text="4" />
<TextView
android:id="@+id/t42"
android:layout_width="wrap_content"
android:gravity="center"
android:padding="8dip" />
<TextView
android:id="@+id/t43"
android:layout_width="wrap_content"
android:gravity="center"
android:padding="8dip" />
<TextView
android:id="@+id/t44"
android:layout_width="wrap_content"
android:gravity="center"
android:padding="8dip" />
</TableRow>
<TableRow>
<TextView
android:id="@+id/t51"
android:layout_width="wrap_content"
android:gravity="center"
android:padding="8dip"
android:text="5" />
<TextView
android:id="@+id/t52"
android:layout_width="wrap_content"
android:gravity="center"
android:padding="8dip" />
<TextView
android:id="@+id/t53"
android:layout_width="wrap_content"
android:gravity="center"
android:padding="8dip" />
<TextView
android:id="@+id/t54"
android:layout_width="wrap_content"
android:gravity="center"
android:padding="8dip" />
</TableRow>
</TableLayout>
<TextView
android:id="@+id/txtReceive"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_below="@+id/table"
android:background="#ff8c00"
android:padding="6dip" />
<LinearLayout
android:id="@+id/lin2"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:paddingTop="5dp"
android:visibility="visible"
android:weightSum="2">
<LinearLayout
android:id="@+id/rel"
android:layout_width="fill_parent"
android:layout_height="match_parent"
android:layout_weight="1"
android:orientation="vertical"
android:visibility="visible"
android:weightSum="4">
<RelativeLayout
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_weight="1">
<Button
android:id="@+id/imageButton1"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="@drawable/btn_01_small"
android:textColor="#ffa5ff45" />
<TextView
android:id="@+id/textView3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignTop="@+id/imageButton1"
android:layout_centerHorizontal="true"
android:text="Channel"
android:textSize="22sp" />
<TextView
android:id="@+id/textView9"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBottom="@+id/imageButton1"
android:layout_centerHorizontal="true"
android:text="0"
android:textColor="#ffa5ff45"
android:textSize="22sp" />
</RelativeLayout>
<RelativeLayout
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_weight="1">
<Button
android:id="@+id/imageButton2"
android:layout_width="fill_parent"
android:layout_height="match_parent"
android:background="@drawable/btn_02"
android:textColor="#ffa5ff45" />
<TextView
android:id="@+id/textView6"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignTop="@+id/imageButton2"
android:layout_centerHorizontal="true"
android:text="kWh"
android:textSize="22sp" />
<TextView
android:id="@+id/textView10"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBottom="@+id/imageButton2"
android:layout_centerHorizontal="true"
android:text="000.0"
android:textColor="#ffa5ff45"
android:textSize="22sp" />
</RelativeLayout>
<RelativeLayout
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_weight="1">
<Button
android:id="@+id/imageButton3"
android:layout_width="fill_parent"
android:layout_height="match_parent"
android:background="@drawable/btn_03"
android:textColor="#ffa5ff45" />
<TextView
android:id="@+id/textView7"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignTop="@+id/imageButton3"
android:layout_centerHorizontal="true"
android:text="Load"
android:textSize="22sp" />
<TextView
android:id="@+id/textView11"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBottom="@+id/imageButton3"
android:layout_centerHorizontal="true"
android:text="000"
android:textColor="#ffa5ff45"
android:textSize="22sp" />
</RelativeLayout>
<RelativeLayout
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_weight="1">
<Button
android:id="@+id/imageButton4"
android:layout_width="fill_parent"
android:layout_height="match_parent"
android:background="@drawable/btn_04_small" />
<TextView
android:id="@+id/textView8"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignTop="@+id/imageButton4"
android:layout_centerHorizontal="true"
android:text="Days"
android:textSize="22sp" />
<TextView
android:id="@+id/textView12"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBottom="@+id/imageButton4"
android:layout_centerHorizontal="true"
android:text="000"
android:textColor="#ffa5ff45"
android:textSize="22sp" />
</RelativeLayout>
</LinearLayout>
<LinearLayout
android:id="@+id/rel2"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_alignParentRight="true"
android:layout_below="@+id/txtReceive"
android:layout_weight="1"
android:orientation="vertical"
android:visibility="visible"
android:weightSum="4">
<RelativeLayout
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_weight="1">
<Button
android:id="@+id/imageButton12"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="@drawable/btn_01_small"
android:textColor="#ffa5ff45" />
<TextView
android:id="@+id/textView32"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignTop="@+id/imageButton12"
android:layout_centerHorizontal="true"
android:text="Auto ON"
android:textSize="22sp" />
<TextView
android:id="@+id/textView92"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBottom="@+id/imageButton12"
android:layout_centerHorizontal="true"
android:text="00:00"
android:textColor="#ffa5ff45"
android:textSize="22sp" />
</RelativeLayout>
<RelativeLayout
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_weight="1">
<Button
android:id="@+id/imageButton22"
android:layout_width="fill_parent"
android:layout_height="match_parent"
android:background="@drawable/btn_04_small"
android:textColor="#ffa5ff45" />
<TextView
android:id="@+id/textView62"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignTop="@+id/imageButton22"
android:layout_centerHorizontal="true"
android:text="Auto OFF"
android:textSize="22sp" />
<TextView
android:id="@+id/textView102"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBottom="@+id/imageButton22"
android:layout_centerHorizontal="true"
android:text="00:00"
android:textColor="#ffa5ff45"
android:textSize="22sp" />
</RelativeLayout>
<RelativeLayout
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_weight="1">
<Button
android:id="@+id/imageButton31"
android:layout_width="fill_parent"
android:layout_height="match_parent"
android:layout_marginBottom="-14dp"
android:layout_marginTop="7dp"
android:background="@drawable/send_btn_01"
android:text="SET TIME"
android:textSize="22sp" />
</RelativeLayout>
<RelativeLayout
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_weight="1">
<Button
android:id="@+id/imageButton32"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="-7dp"
android:background="@drawable/send_btn_01"
android:padding="0dp"
android:scaleType="matrix"
android:text="RECHARGE"
android:textSize="22sp" />
</RelativeLayout>
</LinearLayout>
</LinearLayout>
</LinearLayout>
</ScrollView>
<ImageView
android:id="@+id/imageView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:adjustViewBounds="true"
android:background="#bf000000"
android:src="@drawable/base_irya_left1" />
回答1:
Activities get destroyed and recreated on screen rotation, and you probably want this as it resizes all your UI elements properly.
Create your Bluetooth connection/thread in a separate singleton class so it becomes independent of the activity, or make its relevant activity members static.
However, be sure to destroy it properly so it doesn't leak/persist beyond the legitimate application lifecycle.
回答2:
The application isn't restarted when the screen rotates, the activity is.
Caution: Your activity will be destroyed and recreated each time the user rotates the screen. When the screen changes orientation, the system destroys and recreates the foreground activity because the screen configuration has changed and your activity might need to load alternative resources (such as the layout).
http://developer.android.com/training/basics/activity-lifecycle/recreating.html
Can you show us the XML declaration of the ScrollView?
来源：https://stackoverflow.com/questions/31070889/scrollview-not-scrolling-and-application-restart-on-orientation-change