java - Android EditText 空指针异常

Question

我需要从放置在对话框中的 EditText 中获取数据。
当我尝试访问它时，我捕获了 NullPointerException。

这是我的代码:

public class MainActivity extends Activity {

    int imgW  ;
    int imgH  ;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    public void OnToolButtonClick(View button)
    {
        switch (button.getId())
        {
        case R.id.btn1:

            final Dialog commentDialog = new Dialog(this);
            commentDialog.setContentView(R.layout.reply);
            Button okBtn = (Button) commentDialog.findViewById(R.id.ok);

            okBtn.setOnClickListener(new View.OnClickListener() {

                @Override
                public void onClick(View v) {

                    final    EditText     w=  (EditText)findViewById(R.id.dialogW);
                    final    EditText     h=  (EditText) findViewById(R.id.dialogH);

                    try {
                        imgW =  Integer.parseInt(w.getText().toString());
                        imgH = Integer.parseInt( h.getText().toString());   

                    }
                    catch (NumberFormatException e) {
                        imgH=0;
                        imgW=0;
                    }

                    Log.i("Size" ,  " w "+ imgW + " h " + imgH);
                    //  drawing_panel_params

                    commentDialog.dismiss();
                }
            });
            Button cancelBtn = (Button) commentDialog.findViewById(R.id.cancel);
            cancelBtn.setOnClickListener(new View.OnClickListener() {

                @Override
                public void onClick(View v) {

                    commentDialog.dismiss();
                }
            });

            commentDialog.show();

            break;
        }
    }
}
}

主要布局

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.edittext.MainActivity$PlaceholderFragment" >

    <Button
        android:id="@+id/btn1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:clickable="true"
        android:onClick="OnToolButtonClick"
        android:text="@string/Start_dialog" />

</RelativeLayout>

对话框布局

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:background="#ffffff"
    android:orientation="vertical" >

    <EditText
        android:id="@+id/dialogW"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:hint="@string/Wight"
        android:lines="3"
        android:textColor="#000000" />

    <EditText
        android:id="@+id/dialogH"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:hint="@string/Height"
        android:lines="3"
        android:textColor="#000000" />

    <LinearLayout
        android:layout_width="fill_parent"
        android:layout_height="fill_parent" >

        <Button
            android:id="@+id/ok"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="@android:string/ok" />

        <Button
            android:id="@+id/cancel"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="@android:string/cancel" />
    </LinearLayout>

</LinearLayout>

我想知道为什么会发生这种情况..??

Answer 1

改变

 final EditText w= (EditText)findViewById(R.id.dialogW);
 final EditText h= (EditText)findViewById(R.id.dialogH);

至

 final EditText w= (EditText)commentDialog.findViewById(R.id.dialogW);
 final EditText h= (EditText)commentDialog.findViewById(R.id.dialogH);

您的 dialogW 和 dialogH 位于 reply 布局中，该布局在 commentDialog 中膨胀。您需要使用 View 来扩充 EditText 所在的布局