尝试使用Android生成对话框

Question

Anyone know why my button isn't showing up in the dialog window?

    Dialog d = new Dialog(AddContact.this);

    LayoutInflater li = (LayoutInflater) getSystemService(Service.LAYOUT_INFLATER_SERVICE);
    ViewGroup contentView = (ViewGroup) li.inflate(R.layout.dialog,null);

    d.setContentView(contentView);
    d.setTitle("Please correct these errors:");

    TextView error = (TextView) contentView.findViewById(R.id.textView1);
    Button closer = (Button) contentView.findViewById(R.id.button1);

    closer.setText("Close");
    error.setText(errorMessage);
    d.show();

This my dialog.xml layout file:

<?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="wrap_content"
    android:orientation="vertical" android:padding="5dp">

    <TextView android:text="TextView" android:id="@+id/textView1"
        android:layout_height="fill_parent" android:layout_width="fill_parent" />

    <Button android:text="Button" android:id="@+id/button1"
        android:layout_width="wrap_content" android:layout_height="wrap_content"
        android:gravity="center" />

</LinearLayout>

What do I need to do so my button shows in the dialog window?

Answer 1

Your dialog is not visible when you use findViewById() , which means that the view with that id is not yet in your view hierachy and can not be found. This results in error beeing null , which will throw a NullPointerException in the following line.

You can solve this by inflating the layout seperately and use findViewById() on the inflated view.

Dialog d = new Dialog(AddContact.this);
LayoutInflater li = (LayoutInflater) getSystemService(Service.LAYOUT_INFLATER_SERVICE);
ViewGroup contentView = (ViewGroup)  li.inflate(R.layout.dialog, null);
d.setContentView(contentView);
d.setTitle("Please correct these errors:");
error = (TextView) contentView.findViewById(R.id.textView1);
error.setText(errorMessage);
d.show();