在Android的webview中定制js的alert,confirm和prompt对话框的方法

http://618119.com/archives/2010/12/20/199.html 

1.首先继承android.webkit.WebChromeClient实现MyWebChromeClient。 

2.在MyWebChromeClient.java中覆盖onJsAlert,onJsConfirm,onJsPrompt三个方法。 

3.在初始化Webview时设置调用webview.setWebChromeClient(new MyWebChromeClient()); 

4.在Webview载入的html中使用window.alert,window.confirm,window.prompt方法，系统弹出的将是自定义实现的对应对话框。 

MyWebChromeClient.java的代码如下： 

import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.DialogInterface.OnCancelListener;
import android.content.DialogInterface.OnClickListener;
import android.content.DialogInterface.OnKeyListener;
import android.graphics.Bitmap;
import android.os.Message;
import android.util.Log;
import android.view.KeyEvent;
import android.webkit.JsPromptResult;
import android.webkit.JsResult;
import android.webkit.WebChromeClient;
import android.webkit.WebView;
import android.widget.EditText;

/**
 * http://618119.com/archives/2010/12/20/199.html
 */

//****************************************************************************
public class MyWebChromeClient extends WebChromeClient {
    @Override
    public void onCloseWindow(WebView window) {
        super.onCloseWindow(window);
    }

    @Override
    public boolean onCreateWindow(WebView view, boolean dialog,
            boolean userGesture, Message resultMsg) {
        return super.onCreateWindow(view, dialog, userGesture, resultMsg);
    }

    /**
     * 覆盖默认的window.alert展示界面，避免title里显示为“：来自file:////”
     */
    public boolean onJsAlert(WebView view, String url, String message,
            JsResult result) {
        final AlertDialog.Builder builder = new AlertDialog.Builder(view.getContext());

        builder.setTitle("对话框")
                .setMessage(message)
                .setPositiveButton("确定", null);

        // 不需要绑定按键事件
        // 屏蔽keycode等于84之类的按键
        builder.setOnKeyListener(new OnKeyListener() {
            public boolean onKey(DialogInterface dialog, int keyCode,KeyEvent event) {
                Log.v("onJsAlert", "keyCode==" + keyCode + "event="+ event);
                return true;
            }
        });
        // 禁止响应按back键的事件
        builder.setCancelable(false);
        AlertDialog dialog = builder.create();
        dialog.show();
        result.confirm();// 因为没有绑定事件，需要强行confirm,否则页面会变黑显示不了内容。
        return true;
        // return super.onJsAlert(view, url, message, result);
    }

    public boolean onJsBeforeUnload(WebView view, String url,
            String message, JsResult result) {
        return super.onJsBeforeUnload(view, url, message, result);
    }

    /**
     * 覆盖默认的window.confirm展示界面，避免title里显示为“：来自file:////”
     */
    public boolean onJsConfirm(WebView view, String url, String message,
            final JsResult result) {
        final AlertDialog.Builder builder = new AlertDialog.Builder(view.getContext());
        builder.setTitle("对话框")
                .setMessage(message)
                .setPositiveButton("确定",new OnClickListener() {
                            public void onClick(DialogInterface dialog,int which) {
                                result.confirm();
                            }
                        })
                .setNeutralButton("取消", new OnClickListener() {
                    public void onClick(DialogInterface dialog, int which) {
                        result.cancel();
                    }
                });
        builder.setOnCancelListener(new OnCancelListener() {
            @Override
            public void onCancel(DialogInterface dialog) {
                result.cancel();
            }
        });

        // 屏蔽keycode等于84之类的按键，避免按键后导致对话框消息而页面无法再弹出对话框的问题
        builder.setOnKeyListener(new OnKeyListener() {
            @Override
            public boolean onKey(DialogInterface dialog, int keyCode,KeyEvent event) {
                Log.v("onJsConfirm", "keyCode==" + keyCode + "event="+ event);
                return true;
            }
        });
        // 禁止响应按back键的事件
        // builder.setCancelable(false);
        AlertDialog dialog = builder.create();
        dialog.show();
        return true;
        // return super.onJsConfirm(view, url, message, result);
    }

    /**
     * 覆盖默认的window.prompt展示界面，避免title里显示为“：来自file:////”
     * window.prompt('请输入您的域名地址', '618119.com');
     */
    public boolean onJsPrompt(WebView view, String url, String message,
            String defaultValue, final JsPromptResult result) {
        final AlertDialog.Builder builder = new AlertDialog.Builder(view.getContext());

        builder.setTitle("对话框").setMessage(message);

        final EditText et = new EditText(view.getContext());
        et.setSingleLine();
        et.setText(defaultValue);
        builder.setView(et)
                .setPositiveButton("确定", new OnClickListener() {
                    public void onClick(DialogInterface dialog, int which) {
                        result.confirm(et.getText().toString());
                    }

                })
                .setNeutralButton("取消", new OnClickListener() {
                    public void onClick(DialogInterface dialog, int which) {
                        result.cancel();
                    }
                });

        // 屏蔽keycode等于84之类的按键，避免按键后导致对话框消息而页面无法再弹出对话框的问题
        builder.setOnKeyListener(new OnKeyListener() {
            public boolean onKey(DialogInterface dialog, int keyCode,KeyEvent event) {
                Log.v("onJsPrompt", "keyCode==" + keyCode + "event="+ event);
                return true;
            }
        });

        // 禁止响应按back键的事件
        // builder.setCancelable(false);
        AlertDialog dialog = builder.create();
        dialog.show();
        return true;
        // return super.onJsPrompt(view, url, message, defaultValue,
        // result);
    }

    @Override
    public void onProgressChanged(WebView view, int newProgress) {
        super.onProgressChanged(view, newProgress);
    }

    @Override
    public void onReceivedIcon(WebView view, Bitmap icon) {
        super.onReceivedIcon(view, icon);
    }

    @Override
    public void onReceivedTitle(WebView view, String title) {
        super.onReceivedTitle(view, title);
    }

    @Override
    public void onRequestFocus(WebView view) {
        super.onRequestFocus(view);
    }
}