显示自定义的对话框

public class DialogActivity extends Activity {

    @Override
	protected void onCreate(Bundle savedInstanceState) {
     
        super.onCreate(savedInstanceState);
        
        requestWindowFeature(Window.FEATURE_LEFT_ICON);
        
       
        setContentView(R.layout.dialog_activity);
        
        getWindow().setFeatureDrawableResource(Window.FEATURE_LEFT_ICON, 
                android.R.drawable.ic_dialog_alert);
    }
}

dialog_activity.xml

<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/text"
    android:layout_width="match_parent" android:layout_height="match_parent"
    android:gravity="center_vertical|center_horizontal"
    android:text="@string/dialog_activity_text"/>

第一次看到没有layout布局的xml吧

关键在下面

  <activity android:name=".app.DialogActivity"
                android:label="@string/activity_dialog"
                android:theme="@android:style/Theme.Dialog">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.SAMPLE_CODE" />
            </intent-filter>
        </activity>

android:theme="@android:style/Theme.Dialog"

ok这么简单应该看的懂了吧   看不懂运行一下。。