無法從Android開關組件的onClicked方法中獲取關聯的TextView值

Question

當同一父視圖（列表視圖）內的Switch組件切換時，我試圖從視圖(TextView)獲取值。當開關切換被調用的方法是：

public void onSwitchClicked(View list) { 

     Switch mySwitch = (Switch) list.findViewById(R.id.tgl_status); 

     // Is the toggle on? 
     boolean on = ((Switch) mySwitch).isChecked(); 

     if (on) { 
      Toast.makeText(getApplicationContext(), "TURN ON: Request sent.", Toast.LENGTH_LONG).show(); 

     } else { 
      Toast.makeText(getApplicationContext(), "TURN OFF: Request sent.", Toast.LENGTH_LONG).show(); 

     } 
} 

這多少代碼工作正常，但是當我嘗試檢索組件的一個TextView值，它是存在於同一個列表視圖，程序崩潰。這裏是我正在試圖做到這一點（我把onSwitchClicked()方法體中的代碼）：

TextView tV = (TextView) list.findViewById(R.id.pid); 
String pid = tV.getText().toString(); 

考慮列表視圖的XML：

<?xml version="1.0" encoding="utf-8"?> 
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    android:layout_width="fill_parent" 
    android:layout_height="65dip" 
    android:orientation="vertical" 
    android:layout_centerVertical="true" 
    > 

    <!-- Product id (pid) - will be HIDDEN - used to pass to other activity --> 
    <TextView 
     android:id="@+id/pid" <!-- **this is the value I want** ... --> 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:visibility="gone" /> 

    <TextView 
     android:id="@+id/name" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:paddingTop="6dip" 
     android:paddingLeft="6dip" 
     android:textSize="17dip" 
     android:textStyle="bold" /> 

    <TextView 
     android:id="@+id/statusT" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:paddingLeft="6dip" 
     android:textSize="17dip" 
     android:layout_below="@+id/name" 
     /> 

    <Switch <!-- **when this Switch is toggled** --> 
     android:id="@+id/tgl_status" 
     android:layout_alignParentRight="true" 
     android:layout_width="125dp" 
     android:layout_height="wrap_content" 
     android:layout_marginRight="6dip" 
     android:layout_centerVertical="true" 
     android:textOff="OFF" 
     android:textOn="ON" 
     android:onClick="onSwitchClicked" 
     /> 

</RelativeLayout> 

我想pid的TextView的價值被分配到pid字符串。我怎樣才能做到這一點？

這裏的logcat的：

W/dalvikvm(7749): threadid=1: thread exiting with uncaught exception (group=0x41560ba8) 
E/AndroidRuntime(7749): FATAL EXCEPTION: main 
E/AndroidRuntime(7749): Process: com.iotautomationtech.androidapp, PID: 7749 
E/AndroidRuntime(7749): java.lang.IllegalStateException: Could not execute method of the activity 
E/AndroidRuntime(7749):  at android.view.View$1.onClick(View.java:3823) 
E/AndroidRuntime(7749):  at android.view.View.performClick(View.java:4438) 
E/AndroidRuntime(7749):  at android.widget.CompoundButton.performClick(CompoundButton.java:100) 
E/AndroidRuntime(7749):  at android.view.View$PerformClick.run(View.java:18422) 
E/AndroidRuntime(7749):  at android.os.Handler.handleCallback(Handler.java:733) 
E/AndroidRuntime(7749):  at android.os.Handler.dispatchMessage(Handler.java:95) 
E/AndroidRuntime(7749):  at android.os.Looper.loop(Looper.java:136) 
E/AndroidRuntime(7749):  at android.app.ActivityThread.main(ActivityThread.java:5001) 
E/AndroidRuntime(7749):  at java.lang.reflect.Method.invokeNative(Native Method) 
E/AndroidRuntime(7749):  at java.lang.reflect.Method.invoke(Method.java:515) 
E/AndroidRuntime(7749):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785) 
E/AndroidRuntime(7749):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601) 
E/AndroidRuntime(7749):  at dalvik.system.NativeStart.main(Native Method) 
E/AndroidRuntime(7749): Caused by: java.lang.reflect.InvocationTargetException 
E/AndroidRuntime(7749):  at java.lang.reflect.Method.invokeNative(Native Method) 
E/AndroidRuntime(7749):  at java.lang.reflect.Method.invoke(Method.java:515) 
E/AndroidRuntime(7749):  at android.view.View$1.onClick(View.java:3818) 
E/AndroidRuntime(7749):  ... 12 more 
E/AndroidRuntime(7749): Caused by: java.lang.NullPointerException 
E/AndroidRuntime(7749):  at com.iotautomationtech.androidapp.AllDevicesActivity.onSwitchClicked(AllDevicesActivity.java:100) 
E/AndroidRuntime(7749):  ... 15 more 

一些幫助？

Answer 1

onSwitchClicked(View switchView)接收到交換機視圖作爲參數。

您正在查找的switchView和TextView位於相同的相關佈局中。所以這裏是如何獲得textView：

public void onSwitchClicked(View switchView) { 
     RelativeLayout relativeLayout = (RelativeLayout)switchView.getParent(); 
     TextView tV = (TextView)relativeLayout.findViewById(R.id.pid); 
     String pid = tV.getText().toString(); 
     ... 
}