Java android textview在AlertDialog中获得NullPointerException

当我试图用TextView自定义AlertDialog时，我得到了一个NullPointerException。我想知道为什么会这样？调用setText方法时，TextView似乎还没有初始化。如果是，如果使用LayoutFlater，何时初始化TextView

非常感谢

以下是Java代码：

   listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
            LayoutInflater layoutInflater = getLayoutInflater();
            View layout = layoutInflater.inflate(R.layout.dialog_desc, null);
            AlertDialog.Builder alertDialog = new AlertDialog.Builder(MainActivity.this).setTitle("Description");
            alertDialog.setView(layout);

            TextView descTextView = (TextView) findViewById(R.id.desc_text);
            String descString = itemData.get(position).get("desc");
            descTextView.setText(descString);

            alertDialog.show();
        }
    });

改变

到

这个

应该由

TextView descTextView = (TextView) layout.findViewById(R.id.desc_text);

---

descTextView中存在NullPointerException。你需要按照下面回答中的建议去做！谢谢你的回答。但为什么我必须在findViewById之前添加布局？我们调用findViewById之前是否有默认布局对象？@Chanson

TextView

来自充气布局，因此您需要用充气视图初始化。为什么要发布重复的答案

04-28 13:27:44.794  12896-12896/com.example.chanson.listview E/AndroidRuntime﹕ FATAL EXCEPTION: main
java.lang.NullPointerException
        at com.example.chanson.listview.main.MainActivity$5.onItemClick(MainActivity.java:99)
        at android.widget.AdapterView.performItemClick(AdapterView.java:298)
        at android.widget.AbsListView.performItemClick(AbsListView.java:1147)
        at android.widget.AbsListView$PerformClick.run(AbsListView.java:2979)
        at android.widget.AbsListView$1.run(AbsListView.java:3755)
        at android.os.Handler.handleCallback(Handler.java:615)
        at android.os.Handler.dispatchMessage(Handler.java:92)
        at android.os.Looper.loop(Looper.java:153)
        at android.app.ActivityThread.main(ActivityThread.java:5000)
        at java.lang.reflect.Method.invokeNative(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:511)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:821)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:584)
        at dalvik.system.NativeStart.main(Native Method)

 TextView descTextView = (TextView) findViewById(R.id.desc_text);

 TextView descTextView = (TextView) layout.findViewById(R.id.desc_text);

TextView descTextView = (TextView) findViewById(R.id.desc_text);

TextView descTextView = (TextView) layout.findViewById(R.id.desc_text);