Android自定义对话框

Android给我们提供了 AlertDialog类，使我们可以很容易地通过它的内部类Builder构建弹出式对话框。但是有时候为了给用户更好的体验，可能需要更改Dialog的外观和结构。解决的办法是自定义AlertDialog和AlertDialog.Builder类。
Android提供的默认Dialog如下图所示：



1、定义对话框的外观

我们想实现的自定义对话框如下图所示：


这里我们要实现的Dialog支持：

• 通过外部String或Resource命名Title
• 通过外部String、layout、Resource定义对话框内容
• 设置了positive和negative按钮及监听器

2、定义Layout、Theme和Style

对话框通过自定义布局（layout）渲染其内容，布局文件中定义了用于显示标题的TextView、显示内容的TextView，以及两个按钮。

<?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:minWidth="280dip"
    android:layout_height="wrap_content">
 
    <LinearLayout 
        android:orientation="vertical"
        android:background="@drawable/header"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content">
 
        <TextView
            style="@style/DialogText.Title"
            android:id="@+id/title"
            android:paddingRight="8dip"
            android:paddingLeft="8dip"
            android:background="@drawable/title"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"/>
 
    </LinearLayout>
 
    <LinearLayout 
        android:id="@+id/content"
        android:orientation="vertical"
        android:background="@drawable/center"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content">
 
        <TextView
            style="@style/DialogText"
            android:id="@+id/message"
            android:padding="5dip"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"/>
 
    </LinearLayout>
 
    <LinearLayout 
        android:orientation="horizontal"
        android:background="@drawable/footer"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content">
 
        <Button 
            android:id="@+id/positiveButton"
            android:layout_marginTop="3dip"
            android:layout_width="0dip"
            android:layout_weight="1"
            android:layout_height="wrap_content"
            android:singleLine="true"/>
 
        <Button 
            android:id="@+id/negativeButton"
            android:layout_marginTop="3dip"
            android:layout_width="0dip"
            android:layout_weight="1"
            android:layout_height="wrap_content"
            android:singleLine="true"/>
 
    </LinearLayout>
 
</LinearLayout>

根部的LinearLayou宽度被设置为fill_parent，并且最小宽度为280dp，从而使对话框的宽度始终是设备屏幕宽度的87.5%。

自定义主题应该声明对话框为floating ，并且使用了自定义背景和自定义标题视图。

<?xml version="1.0" encoding="utf-8"?>
<resources>
 
    <style name="Dialog" parent="android:style/Theme.Dialog">
        <item name="android:windowBackground">@null</item>
        <item name="android:windowNoTitle">true</item>
        <item name="android:windowIsFloating">true</item>
    </style>
 
</resources>

然后我们需要定义标题和内容的外观

<?xml version="1.0" encoding="utf-8"?>
<resources>
 
    <style name="DialogText">
        <item name="android:textColor">#FF000000</item>
        <item name="android:textSize">12sp</item>
    </style>
 
    <style name="DialogText.Title">
        <item name="android:textSize">16sp</item>
        <item name="android:textStyle">bold</item>
    </style>
 
</resources>

3、定义Dialog和Builder类
我们自定义的Builder类最好和AlterDialog.Bulider类有相同的方法，以便使用方便。

package net.androgames.blog.sample.customdialog.dialog;
 
import net.androgames.blog.sample.customdialog.R;
import android.app.Dialog;
import android.content.Context;
import android.content.DialogInterface;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup.LayoutParams;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.TextView;
 
/**
 * 
 * Create custom Dialog windows for your application
 * Custom dialogs rely on custom layouts wich allow you to 
 * create and use your own look & feel.
 * 
 * Under GPL v3 : http://www.gnu.org/licenses/gpl-3.0.html
 * 
 * @author antoine vianey
 *
 */
public class CustomDialog extends Dialog {
 
    public CustomDialog(Context context, int theme) {
        super(context, theme);
    }
 
    public CustomDialog(Context context) {
        super(context);
    }
 
    /**
     * Helper class for creating a custom dialog
     */
    public static class Builder {
 
        private Context context;
        private String title;
        private String message;
        private String positiveButtonText;
        private String negativeButtonText;
        private View contentView;
 
        private DialogInterface.OnClickListener 
                        positiveButtonClickListener,
                        negativeButtonClickListener;
 
        public Builder(Context context) {
            this.context = context;
        }
 
        /**
         * Set the Dialog message from String
         * @param title
         * @return
         */
        public Builder setMessage(String message) {
            this.message = message;
            return this;
        }
 
        /**
         * Set the Dialog message from resource
         * @param title
         * @return
         */
        public Builder setMessage(int message) {
            this.message = (String) context.getText(message);
            return this;
        }
 
        /**
         * Set the Dialog title from resource
         * @param title
         * @return
         */
        public Builder setTitle(int title) {
            this.title = (String) context.getText(title);
            return this;
        }
 
        /**
         * Set the Dialog title from String
         * @param title
         * @return
         */
        public Builder setTitle(String title) {
            this.title = title;
            return this;
        }
 
        /**
         * Set a custom content view for the Dialog.
         * If a message is set, the contentView is not
         * added to the Dialog...
         * @param v
         * @return
         */
        public Builder setContentView(View v) {
            this.contentView = v;
            return this;
        }
 
        /**
         * Set the positive button resource and it's listener
         * @param positiveButtonText
         * @param listener
         * @return
         */
        public Builder setPositiveButton(int positiveButtonText,
                DialogInterface.OnClickListener listener) {
            this.positiveButtonText = (String) context
                    .getText(positiveButtonText);
            this.positiveButtonClickListener = listener;
            return this;
        }
 
        /**
         * Set the positive button text and it's listener
         * @param positiveButtonText
         * @param listener
         * @return
         */
        public Builder setPositiveButton(String positiveButtonText,
                DialogInterface.OnClickListener listener) {
            this.positiveButtonText = positiveButtonText;
            this.positiveButtonClickListener = listener;
            return this;
        }
 
        /**
         * Set the negative button resource and it's listener
         * @param negativeButtonText
         * @param listener
         * @return
         */
        public Builder setNegativeButton(int negativeButtonText,
                DialogInterface.OnClickListener listener) {
            this.negativeButtonText = (String) context
                    .getText(negativeButtonText);
            this.negativeButtonClickListener = listener;
            return this;
        }
 
        /**
         * Set the negative button text and it's listener
         * @param negativeButtonText
         * @param listener
         * @return
         */
        public Builder setNegativeButton(String negativeButtonText,
                DialogInterface.OnClickListener listener) {
            this.negativeButtonText = negativeButtonText;
            this.negativeButtonClickListener = listener;
            return this;
        }
 
        /**
         * Create the custom dialog
         */
        public CustomDialog create() {
            LayoutInflater inflater = (LayoutInflater) context
                    .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            // instantiate the dialog with the custom Theme
            final CustomDialog dialog = new CustomDialog(context, 
            		R.style.Dialog);
            View layout = inflater.inflate(R.layout.dialog, null);
            dialog.addContentView(layout, new LayoutParams(
                    LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT));
            // set the dialog title
            ((TextView) layout.findViewById(R.id.title)).setText(title);
            // set the confirm button
            if (positiveButtonText != null) {
                ((Button) layout.findViewById(R.id.positiveButton))
                        .setText(positiveButtonText);
                if (positiveButtonClickListener != null) {
                    ((Button) layout.findViewById(R.id.positiveButton))
                            .setOnClickListener(new View.OnClickListener() {
                                public void onClick(View v) {
                                    positiveButtonClickListener.onClick(
                                    		dialog, 
                                            DialogInterface.BUTTON_POSITIVE);
                                }
                            });
                }
            } else {
                // if no confirm button just set the visibility to GONE
                layout.findViewById(R.id.positiveButton).setVisibility(
                        View.GONE);
            }
            // set the cancel button
            if (negativeButtonText != null) {
                ((Button) layout.findViewById(R.id.negativeButton))
                        .setText(negativeButtonText);
                if (negativeButtonClickListener != null) {
                    ((Button) layout.findViewById(R.id.negativeButton))
                            .setOnClickListener(new View.OnClickListener() {
                                public void onClick(View v) {
                                    positiveButtonClickListener.onClick(
                                    		dialog, 
                                            DialogInterface.BUTTON_NEGATIVE);
                                }
                            });
                }
            } else {
                // if no confirm button just set the visibility to GONE
                layout.findViewById(R.id.negativeButton).setVisibility(
                        View.GONE);
            }
            // set the content message
            if (message != null) {
                ((TextView) layout.findViewById(
                		R.id.message)).setText(message);
            } else if (contentView != null) {
                // if no message set
                // add the contentView to the dialog body
                ((LinearLayout) layout.findViewById(R.id.content))
                        .removeAllViews();
                ((LinearLayout) layout.findViewById(R.id.content))
                        .addView(contentView, 
                                new LayoutParams(
                                        LayoutParams.WRAP_CONTENT, 
                                        LayoutParams.WRAP_CONTENT));
            }
            dialog.setContentView(layout);
            return dialog;
        }
 
    }
 
}

4、使用自定义的Bulider类

/**
 * Build the desired Dialog
 * CUSTOM or DEFAULT
 */
@Override
public Dialog onCreateDialog(int dialogId) {
    Dialog dialog = null;
    switch (dialogId) {
        case CUSTOM_DIALOG :
            CustomDialog.Builder customBuilder = new
                CustomDialog.Builder(CustomDialogActivity.this);
            customBuilder.setTitle("Custom title")
                .setMessage("Custom body")
                .setNegativeButton("Cancel", 
                        new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int which) {
                        CustomDialogActivity.this
                        .dismissDialog(CUSTOM_DIALOG);
                    }
                })
                .setPositiveButton("Confirm", 
                        new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int which) {
                        dialog.dismiss();
                    }
                });
            dialog = customBuilder.create();
            break;
        case DEFAULT_DIALOG :
            AlertDialog.Builder alertBuilder = new
                AlertDialog.Builder(CustomDialogActivity.this);
            alertBuilder.setTitle("Default title")
                .setMessage("Default body")
                .setNegativeButton("Cancel", 
                		new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int which) {
                        dialog.dismiss();
                    }
                })
                .setPositiveButton("Confirm", 
                		new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int which) {
                        CustomDialogActivity.this
                        .dismissDialog(DEFAULT_DIALOG);
                    }
                });
            dialog = alertBuilder.create();
            break;
    }
    return dialog;
}