麻煩與彈出窗口的onclick

Question

我工作的彈出窗口上，我有兩個imagebuttons.at開始一切都看起來不錯，但是當我把onclick事件對我的兩個圖像按鈕比我的應用程序崩潰。我不明白爲什麼onclick會導致錯誤。下面是我的代碼：

protected void popup() { 

RelativeLayout viewGroup(RelativeLayout)MainActivity.this.findViewById(R.id.popup); 
LayoutInflater layoutInflater = (LayoutInflater)MainActivity.this.getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
View layout = layoutInflater.inflate(R.layout.popup, viewGroup); 
final PopupWindow popup = new PopupWindow(this); 
popup.setContentView(layout); 

popup.setWidth(WindowManager.LayoutParams.WRAP_CONTENT); 
popup.setHeight(WindowManager.LayoutParams.WRAP_CONTENT); 
popup.setBackgroundDrawable(null); 
popup.setFocusable(true); 
popup.showAtLocation(layout, Gravity.CENTER, 1, 1); 
popcash = (ImageButton)findViewById(R.id.popcash); 
popcash.setOnClickListener(new OnClickListener() { 

    @Override 
    public void onClick(View v) { 


     Toast.makeText(getApplicationContext(), "on click image button", Toast.LENGTH_LONG).show(); 

    } 
}); 

popcoin = (ImageButton) findViewById(R.id.popcoin); 
popcoin.setOnClickListener(new OnClickListener() { 

    @Override 
    public void onClick(View v) { 
     Log.e("hi", "there"); 

    } 
}); 



} 

但我得到以下錯誤

04-25 17:18:13.856: E/AndroidRuntime(1521): java.lang.NullPointerException 
04-25 17:18:13.856: E/AndroidRuntime(1521):  at   com.example.scratchcarddemo.MainActivity.popup(MainActivity.java:304) 
04-25 17:18:13.856: E/AndroidRuntime(1521):  at com.example.scratchcarddemo.MainActivity$2.onTouch(MainActivity.java:225) 
04-25 17:18:13.856: E/AndroidRuntime(1521):  at android.view.View.dispatchTouchEvent(View.java:3762) 
04-25 17:18:13.856: E/AndroidRuntime(1521):  at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:863) 
04-25 17:18:13.856: E/AndroidRuntime(1521):  at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:863) 
04-25 17:18:13.856: E/AndroidRuntime(1521):  at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:863) 
04-25 17:18:13.856: E/AndroidRuntime(1521):  at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:863) 
04-25 17:18:13.856: E/AndroidRuntime(1521):  at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:863) 
04-25 17:18:13.856: E/AndroidRuntime(1521):  at  com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:1671) 
04-25 17:18:13.856: E/AndroidRuntime(1521):  at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1107) 
04-25 17:18:13.856: E/AndroidRuntime(1521):  at android.app.Activity.dispatchTouchEvent(Activity.java:2086) 
04-25 17:18:13.856: E/AndroidRuntime(1521):  at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:1655) 
04-25 17:18:13.856: E/AndroidRuntime(1521):  at android.view.ViewRoot.handleMessage(ViewRoot.java:1785) 
04-25 17:18:13.856: E/AndroidRuntime(1521):  at android.os.Handler.dispatchMessage(Handler.java:99) 
04-25 17:18:13.856: E/AndroidRuntime(1521):  at android.os.Looper.loop(Looper.java:123) 
04-25 17:18:13.856: E/AndroidRuntime(1521):  at android.app.ActivityThread.main(ActivityThread.java:4627) 
04-25 17:18:13.856: E/AndroidRuntime(1521):  at java.lang.reflect.Method.invokeNative(Native Method) 
04-25 17:18:13.856: E/AndroidRuntime(1521):  at java.lang.reflect.Method.invoke(Method.java:521) 
04-25 17:18:13.856: E/AndroidRuntime(1521):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868) 
04-25 17:18:13.856: E/AndroidRuntime(1521):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626) 
04-25 17:18:13.856: E/AndroidRuntime(1521):  at dalvik.system.NativeStart.main(Native Method) 

Answer 1

你應該改變這種

popcash = (ImageButton)findViewById(R.id.popcash); 

隨着

popcash = (ImageButton)layout.findViewById(R.id.popcash); 

，改變這個

popcoin = (ImageButton) findViewById(R.id.popcoin); 

與

popcoin = (ImageButton) layout.findViewById(R.id.popcoin); 

這是因爲你的兩個按鈕從view layout你inflated到來。

Answer 2

使用此

popcash = (ImageButton)popup.findViewById(R.id.popcash); 
    popcoin = (ImageButton)popup.findViewById(R.id.popcoin);