BluetoothChat中的StringOutOfBoundException示例

Question

在我的應用程序中，我使用來自BluetoothChat示例的類DeviceListActivity的稍微修改版本。該代碼工作以及所有我測試的設備上，但是當我發佈的應用程序，我開始收到這樣的報告：

java.lang.StringIndexOutOfBoundsException: String index out of range: -1 
at java.lang.String.substring(String.java:1555) 
at sword.games.highnoonf.activities.DeviceListActivity$1.onItemClick(DeviceListActivity.java:18 0) 
at android.widget.AdapterView.performItemClick(AdapterView.java:284) 
at android.widget.ListView.performItemClick(ListView.java:3388) 
at android.widget.AbsListView$PerformClick.run(AbsListView.java:1738) 
at android.os.Handler.handleCallback(Handler.java:587) 
at android.os.Handler.dispatchMessage(Handler.java:92) 
at android.os.Looper.loop(Looper.java:143) 
at android.app.ActivityThread.main(ActivityThread.java:5097) 
at java.lang.reflect.Method.invokeNative(Native Method) 
at java.lang.reflect.Method.invoke(Method.java:521) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626) 
at dalvik.system.NativeStart.main(Native Method) 

導致異常的功能是這樣的：

private OnItemClickListener mDeviceClickListener = new OnItemClickListener() { 
    public void onItemClick(AdapterView<?> av, View v, int arg2, long arg3)  {   
     // Cancel discovery because it's costly and we're about to connect 
     mBtAdapter.cancelDiscovery(); 

     // Get the device MAC address, which is the last 17 chars in the View 
     String info = ((TextView) v).getText().toString(); 
     String address = info.substring(info.length() - 17); 
     String devName = info.substring(0, info.length() - 17); 

     // Create the result Intent and include the MAC address 
     Intent intent = new Intent(); 
     intent.putExtra(EXTRA_DEVICE_ADDRESS, address); 
     intent.putExtra("DEVICE_NAME", devName); 

     // Set result and finish this Activity 
     setResult(Activity.RESULT_OK, intent); 
     finish(); 
    } 
}; 

休息的代碼是幾乎相同的DeviceListActivity的例子... 我希望有人可以解決這個問題或給我一個解釋，爲什麼發生這種情況... 謝謝...

編輯：該代碼已經檢查臨屋區t時的名稱存在和MAC地址的長度與線正確（如果有些事情不順心不添加電話，用戶不能點擊它）：

String name = device.getName(); 
String address = device.getAddress(); 

if(name == null) name = "Unknown"; 
else if (name.length() == 0) name = "Unknown"; 

if (address.length() == 17){ 
    mNewDevicesArrayAdapter.add(name + "\n" + address); 
} 

Answer 1

好像你info.length()少比尺寸。確保子串方法不會得到任何負值（s）作爲參數。將代碼的關鍵部分放在try/catch塊中以避免出現異常。