Android 从EditText获取值的问题

我弹出一个对话框，用户在其中输入用户名和密码。出于测试目的，我想给出一条警告消息，其中包含用户在单击登录时在EditText中输入的用户名。但是，每当按下登录时，我的应用程序就会崩溃。 注意：如果我删除EditText并在单击Login时弹出toast消息，应用程序不会崩溃。 以下是我的实现：

public Dialog onCreateDialog(Bundle savedInstanceState){
        AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
        //get the layout inflater
        final LinearLayout loginLayout = (LinearLayout) findViewById(R.id.popup_signin);

        LayoutInflater inflater = getActivity().getLayoutInflater();

        builder.setView(inflater.inflate(R.layout.popup_signin, null))

                .setPositiveButton(R.string.signin, new DialogInterface.OnClickListener(){
                    @Override
                    public void onClick(DialogInterface dialog, int d){
                        //sign in the user...
                        String username = ((EditText) loginLayout.findViewById(R.id.username)).getText().toString();
                        //String password = ((EditText) findViewById(R.id.password)).getText().toString();
                        Toast.makeText(getApplicationContext(), "Hello World "+username, Toast.LENGTH_LONG).show();
                       // new PostLogin(username,password).execute();

                    }

弹出登录.xml

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/popup_signin"
    android:orientation="vertical"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:background="#FFFFFF">

<EditText
    android:id="@+id/username"
    android:inputType="text"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_marginTop="4dp"
    android:layout_marginLeft="4dp"
    android:layout_marginRight="4dp"
    android:layout_marginBottom="4dp"
    android:typeface="monospace"
    android:hint="enter your ID"/>

</LinearLayout>

---

您试图在loginLayout中查找EditText，该值为空。膨胀布局，然后将其指定给loginLayout。比如：

LayoutInflater inflater = getActivity().getLayoutInflater();
View loginLayout = inflater.inflate(R.layout.popup_signin, null);

builder.setView(loginLayout);
...

---

您的

EditText

为空，因为它是

popup\u-sign

的一部分，您可以从

loginLayout

获取它

因此，在您的情况下，您应该将XML布局膨胀成一个

视图对象

，然后在

视图

中找到

编辑文本

——然后您可以将视图传递给构建器。改变

 LayoutInflater inflater = getActivity().getLayoutInflater();
 builder.setView(inflater.inflate(R.layout.popup_signin, null))

到

在Onclick中

String username = ((EditText)loginLayout.findViewById(R.id.username)).getText().toString();

到

i、 e。
将代码重写为

public Dialog onCreateDialog(Bundle savedInstanceState){
        AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
        //get the layout inflater
        final LinearLayout loginLayout = (LinearLayout) findViewById(R.id.popup_signin);

        LayoutInflater inflater = getActivity().getLayoutInflater();
        final View view = (View) inflater.inflate(R.layout.popup_signin, null)
        builder.setView(view))

                .setPositiveButton(R.string.signin, new DialogInterface.OnClickListener(){
                    @Override
                    public void onClick(DialogInterface dialog, int d){
                        //sign in the user...
                        String username = ((EditText) view.findViewById(R.id.username)).getText().toString();
                        //String password = ((EditText) findViewById(R.id.password)).getText().toString();
                        Toast.makeText(getApplicationContext(), "Hello World "+username, Toast.LENGTH_LONG).show();
                       // new PostLogin(username,password).execute();

                    }

---

我使用了第一个答案和第二个答案的组合，结果成功了

LayoutInflater inflater = getActivity().getLayoutInflater();
View loginLayout = inflater.inflate(R.layout.popup_signin, null);

eFullName = (AppCompatEditText) loginLayout.findViewById(R.id.eName);

---

请同时发布布局文件。@girubai。请寄check@stud91乐于帮助，享受编码

String username = ((EditText) view.findViewById(R.id.username)).getText().toString();

public Dialog onCreateDialog(Bundle savedInstanceState){
        AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
        //get the layout inflater
        final LinearLayout loginLayout = (LinearLayout) findViewById(R.id.popup_signin);

        LayoutInflater inflater = getActivity().getLayoutInflater();
        final View view = (View) inflater.inflate(R.layout.popup_signin, null)
        builder.setView(view))

                .setPositiveButton(R.string.signin, new DialogInterface.OnClickListener(){
                    @Override
                    public void onClick(DialogInterface dialog, int d){
                        //sign in the user...
                        String username = ((EditText) view.findViewById(R.id.username)).getText().toString();
                        //String password = ((EditText) findViewById(R.id.password)).getText().toString();
                        Toast.makeText(getApplicationContext(), "Hello World "+username, Toast.LENGTH_LONG).show();
                       // new PostLogin(username,password).execute();

                    }

LayoutInflater inflater = getActivity().getLayoutInflater();
View loginLayout = inflater.inflate(R.layout.popup_signin, null);

eFullName = (AppCompatEditText) loginLayout.findViewById(R.id.eName);