Dialog详解

Dialog是所有对话框的基类，但Dialog并非继承自View，而是直接从Object构造出来的。Dialog调用是异步调用，所以showDialog()时不会阻碍UI线程。 

1. Activity托管对话框: 
      Android提供了创建对话框的快捷方式，在Activity中可以通过如showDialog(int dialogId)，dismissDialog(int dialogId)，onCreateDialog()，onPrepareDialog()，removeDialog()等方法来创建和管理对话框。 
      onCreateDialog(int dialogId)和onPrepareDialog(int dialogId, Dialog dialog)是Dialog的2个回调函数，showDialog()触发这两个回调函数的调用。同所有的onCreate()一样，其只在Dialog第一次生成的时候才会被调用，而onPrepareDialog()在每次执行showDialog()都会被调用（不管Dialog生成了没有）。如果你想要更新对话框的内容，你只要在onPrepareDialog()中作相应的工作就可以了，该方法会在对话框显示之前进行调用。 
      dismissDialog()方法是用来关闭对话框的；removeDialog()方法用来将对话框从Activity的托管中移除（如果对已经移除的对话框重新进行调用showDialog ，则该对话框将进行重新创建）。 

2. 常用Dialog 
（1）AlertDialog 
AlertDialog类是Dialog类的子类，它默认提供了3个按钮和一个文本消息，这些按钮可以按需要来使他们显示或隐藏。AlertDialog类中有一个内部静态类，名为“Builder”，Builder类提供了为对话框添加多选或单选列表，以及为这些列表添加事件处理的功能。另外，这个Builder类将AlertDialog对话框上的3个按钮按照他们的位置分别称呼为：PositiveButton, NeutralButton, NegativeButton。 
（2）ProgressDialog 
ProgressDialog.dialog = new ProgressDialog(context); 没有内部静态类，直接构造函数构造 

3. 一个很特别的Dialog（由Activity转换而来） ，具体请参见参考doc中android.R.style部分 
（1）AndroidManifest.xml中的activity的属性中增加：android :theme="@android :style/Theme.Dialog（ Activity的对话框主题）。可使Activity变为Dialog（浮动窗口）； 
（2）AndroidManifest.xml中的activity的属性中增加：android:theme="@android:style/Theme.Translucent"（Activity半透明主题）； 

4. 示例代码 
（1）自定义Dialog并获取Dialog中EditText的数据 

 public class MyDialog extends Dialog implements Button.OnClickListener {
     private Button okButton, cancelButton;
     private EditText nameEditText;
     private MyDialogListener listener;

     public MyDialog(Context context, MyDialogListener listener) {
         super(context);
         this.listener = listener;
     }
     protected void onCreate(Bundle savedInstanceState) {
         setContentView(R.layout.mydialog);

         okButton = (Button) findViewById(R.id.okButton);
         cancelButton = (Button) findViewById(R.id.cancelButton);
         okButton.setOnClickListener(this);
         cancelButton.setOnClickListener(this);

         nameEditText = (EditText) findViewById(R.id.nameEditText);
     }
     public void onClick(View v) {
         switch (v.getId()) {
         case R.id.okButton:
              listener.onOkClick(nameEditText.getText().toString());
              dismiss(); // 关闭Dialog
              break;
         case R.id.cancelButton:
              cancel(); // 取消Dialog, "取消"的含义是指不再需要执行对话框上的任何功能和动作, 取消对话框会自动调用dismiss()方法
              break;
         }
         /*
          * 当用户点击手机设备上的“返回”按钮时，屏幕上的对话框将会被取消，
          * 如果你想让你的对话框不在这种情况下被取消掉的话，你可以如下设置你的对话框：setCancelable(false);
          * 对话框的取消和关闭事件可以通过OnCancelListener和OnDismissListener两个监听器来被监听处理。
          */
     }

 }

 public class MainActivity extends Activity implements MyDialogListener {
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         MyDialog dialog = new MyDialog(this, this);
         dialog.show();
     }
     public void onCancelClick() {
     }
     public void onOkClick(String name) {
         Toast.makeText(this, name, Toast.LENGTH_LONG).show();
     }
 }

 interface MyDialogListener {
     public void onOkClick(String name);
     public void onCancelClick();
 }

mydialog.xml 

 <?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">
     <TextView
         android:id="@+id/nameMessage"
         android:layout_width="fill_parent"
         android:layout_height="wrap_content"
         android:text="Enter Name:"></TextView>
         <EditText
             android:id="@+id/nameEditText"
             android:layout_width="fill_parent"
             android:layout_height="wrap_content"
             android:textSize="18sp"></EditText>
         <LinearLayout
             android:id="@+id/buttonLayout"
             android:layout_width="fill_parent"
             android:layout_height="wrap_content"
             android:layout_gravity="center_horizontal">
             <Button
                 android:id="@+id/okButton"
                 android:layout_width="wrap_content"
                 android:layout_height="wrap_content"
                 android:text="OK">
             </Button>
             <Button
                 android:id="@+id/cancelButton"
                 android:layout_width="wrap_content"
                 android:layout_height="wrap_content"
                 android:text="Cancel">
             </Button>
      </LinearLayout>
 </LinearLayout>

 public class MainActivity2 extends Activity {
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);

         AlertDialog dialog = new AlertDialog.Builder(this).create();
         dialog.setMessage("Do you play cricket?");
         dialog.setButton("Yes", new DialogInterface.OnClickListener() {
             public void onClick(DialogInterface dialog, int which) {
                 switch (which) {
                 case AlertDialog.BUTTON1:
                     break;
                 case AlertDialog.BUTTON2:
                     break;
                 }
             }
         });
         dialog.setButton2("No", new DialogInterface.OnClickListener() {
             public void onClick(DialogInterface dialog, int which) {
             }
         });
         dialog.show();
     }
 }

托管Dialog 

 public class MainActivity extends Activity {
     private Button button1, button2, button3, button4;
     private Button.OnClickListener listener1, listener2, listener3, listener4;
     private final int DIALOG1 = 1, DIALOG2 = 2, DIALOG3 = 3, DIALOG4 = 4;

     @Override
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.main);
         prepareListener();
     }

     protected Dialog onCreateDialog(int id) {
         switch (id) {
         case DIALOG1:
             return buildDialog(this, DIALOG1);
         case DIALOG2:
             return buildDialog(this, DIALOG2);
         case DIALOG3:
             return buildDialog(this, DIALOG3);
         case DIALOG4:
             return buildDialog(this, DIALOG4);
         }
         return null;
     }

     protected void onPrepareDialog(int id, Dialog dialog) {
         super.onPrepareDialog(id, dialog);
     }

     private Dialog buildDialog(Context context, int seq) {
         AlertDialog.Builder builder = new AlertDialog.Builder(context);
         builder.setIcon(R.drawable.alert_dialog_icon);
         if (DIALOG1 == seq) {
             builder.setTitle(R.string.alert_dialog_two_buttons_title);
             builder.setPositiveButton(R.string.alert_dialog_ok, new DialogInterface.OnClickListener() {
                 public void onClick(DialogInterface dialog, int which) {
                     setTitle(R.string.alert_dialog_ok);
                 }
             });
             builder.setNegativeButton(R.string.alert_dialog_cancel, new DialogInterface.OnClickListener() {
                 public void onClick(DialogInterface dialog, int which) {
                     setTitle(R.string.alert_dialog_cancel);
                 }
             });
         }
         if (DIALOG2 == seq) {
             builder.setTitle(R.string.alert_dialog_two_buttons_msg);
             builder.setMessage(R.string.alert_dialog_two_buttons2_msg);

             // AlertDialog最多只能有3个Button
             builder.setPositiveButton(R.string.alert_dialog_ok, new DialogInterface.OnClickListener() {
                 public void onClick(DialogInterface dialog, int which) {
                     setTitle(R.string.alert_dialog_ok);
                 }
             });
             builder.setNeutralButton(R.string.alert_dialog_something, new DialogInterface.OnClickListener() {
                 public void onClick(DialogInterface dialog, int which) {
                     setTitle(R.string.alert_dialog_something);
                 }
             });
             builder.setNegativeButton(R.string.alert_dialog_cancel, new DialogInterface.OnClickListener() {
                 public void onClick(DialogInterface dialog, int which) {
                     setTitle(R.string.alert_dialog_cancel);
                 }
             });
         }
         if (DIALOG3 == seq) {
             // LayoutInflater的inflate方法可以将一个XML布局变成一个View实例
             LayoutInflater inflater = LayoutInflater.from(this);
             View textEntryView = inflater.inflate(R.layout.alert_dialog_text_entry, null);
             builder.setTitle(R.string.alert_dialog_text_entry);

             // setView()真可以说是Dialog的一个精髓
             builder.setView(textEntryView);
             builder.setPositiveButton(R.string.alert_dialog_ok, new DialogInterface.OnClickListener() {
                 public void onClick(DialogInterface dialog, int which) {
                     setTitle(R.string.alert_dialog_ok);
                 }
             });
             builder.setNegativeButton(R.string.alert_dialog_cancel, new DialogInterface.OnClickListener() {
                 public void onClick(DialogInterface dialog, int which) {
                     setTitle(R.string.alert_dialog_cancel);
                 }
             });
         }
         if (DIALOG4 == seq) {
             ProgressDialog dialog = new ProgressDialog(context);
             dialog.setTitle("Downding the songs...");
             dialog.setMessage("Please Waiting...");
             return dialog;
         }
         return builder.create();
     }

     private boolean prepareListener() {
         // init button
         button1 = (Button) findViewById(R.id.button1);
         button2 = (Button) findViewById(R.id.button2);
         button3 = (Button) findViewById(R.id.button3);
         button4 = (Button) findViewById(R.id.button4);

         // init listener
         listener1 = new Button.OnClickListener() {
             public void onClick(View v) {
                 showDialog(DIALOG1);
             }
         };
         listener2 = new Button.OnClickListener() {
             public void onClick(View v) {
                 showDialog(DIALOG2);
             }
         };
         listener3 = new Button.OnClickListener() {
             public void onClick(View v) {
                 showDialog(DIALOG3);
             }
         };
         listener4 = new Button.OnClickListener() {
             public void onClick(View v) {
                 showDialog(DIALOG4);
             }
         };

         // bind listener
         button1.setOnClickListener(listener1);
         button2.setOnClickListener(listener2);
         button3.setOnClickListener(listener3);
         button4.setOnClickListener(listener4);
         return true;
     }
 }

alert_dialog_text_entry.xml 

 <?xml version="1.0" encoding="utf-8"?>
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:orientation="vertical"
     android:layout_width="fill_parent"
     android:layout_height="fill_parent"
     >
     <!-- android:textAppearance：设置字体, 系统自带的字体 -->
     <!-- android:capitalize：设置大小写；none首字母小写；words首字母大写 -->
     <TextView android:id="@+id/username_view"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_marginLeft="20dip"
         android:layout_marginRight="20dip"
         android:text="用户名"
         android:textAppearance="?android:attr/textAppearanceMedium"
     />
     <EditText android:id="@+id/username_edit"
         android:layout_width="fill_parent"
         android:layout_height="wrap_content"
         android:layout_marginLeft="20dip"
         android:layout_marginRight="20dip"
         android:capitalize="words"
         android:textAppearance="?android:attr/textAppearanceMedium"
     />
     <TextView android:id="@+id/password_view"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_marginLeft="20dip"
         android:layout_marginRight="20dip"
         android:text="密码"
         android:textAppearance="?android:attr/textAppearanceMedium"
     />
     <EditText android:id="@+id/password_edit"
         android:layout_width="fill_parent"
         android:layout_height="wrap_content"
         android:layout_marginLeft="20dip"
         android:layout_marginRight="20dip"
         android:capitalize="none"
         android:password="true"
         android:textAppearance="?android:attr/textAppearanceMedium"
     />
 </LinearLayout>

去除对话框Dialog白色边框 
使用样式文件，在values 目录下新建styles.xml文件，编写如下代码： 

 <resources>
     <style name="dialog" parent="@android:style/Theme.Dialog">
          <item name="android:windowFrame">@null</item>
         <item name="android:windowIsFloating">true</item>
         <item name="android:windowIsTranslucent">false</item>
         <item name="android:windowNoTitle">true</item>
         <item name="android:background">@android:color/black</item>
         <item name="android:windowBackground">@null</item>
         <item name="android:backgroundDimEnabled">false</item>
     </style>
 </resources>

调用时，使用AlerDialog的接口类，Dialog 接口编写如下代码： 

 Dialog dialog = new Dialog(SetActivity.this, R.style.dialog);
        dialog.setContentView(R.layout.test);
        dialog.show();

下面我们查看一下Dialog的源码文件，里面的构造函数为如下： 

 public Dialog(Context context, int theme) {
         mContext = new ContextThemeWrapper(
             context, theme == 0 ? com.android.internal.R.style.Theme_Dialog : theme);
         mWindowManager = (WindowManager)context.getSystemService("window");
         Window w = PolicyManager.makeNewWindow(mContext);
         mWindow = w;
         w.setCallback(this);
         w.setWindowManager(mWindowManager, null, null);
         w.setGravity(Gravity.CENTER);
         mUiThread = Thread.currentThread();
         mDismissCancelHandler = new DismissCancelHandler(this);
     }

这里面我们可以看出，Android 使用了默认的构造函数为Dialog 设置样式，如果没有为其设置样式，即默认加载事先编写好的样式文件，Dialog 一共由多个9.png的图片构成，大部分都是带有边框的9.png图片，所以就是为什么我们上边的样式文件要将其背景去除掉。 
前后效果对比 
未设置前： 
 
设置后： 
 

模式对话框Dialog背景的透明度&黑暗度设置方法 
设置透明度： 

 WindowManager.LayoutParams lp=dialog.getWindow().getAttributes();
 lp.alpha=1.0f;
 dialog.getWindow().setAttributes(lp);

alpha在0.0f到1.0f之间。1.0完全不透明，0.0f完全透明 
设置黑暗度： 

 dialog.setContentView(R.layout.dialog);
 WindowManager.LayoutParams lp=dialog.getWindow().getAttributes();
 lp.dimAmount=1.0f;
 dialog.getWindow().setAttributes(lp);
 dialog.getWindow().addFlags(WindowManager.LayoutParams.FLAG_DIM_BEHIND);

Android 之 ProgressDialog 
http://blog.csdn.net/dadahacker/archive/2011/02/25/6208368.aspx 

Android 对话框(Dialog)大全 建立你自己的对话框 

http://www.cnblogs.com/salam/archive/2010/11/15/1877512.html

转来的