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

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：

package com.lizongbo.mwebdev.android;

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;

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:////"
	 */
	@Override
	public boolean onJsAlert(WebView view, String url, String message,JsResult result) {
		final AlertDialog.Builder builder = new AlertDialog.Builder(view.getContext());
		builder.setTitle("Android webview测试alert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() {
			@Override
			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);
	}

	@Override
	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:////"
	 */
	@Override
	public boolean onJsConfirm(WebView view, String url, String message,final JsResult result) {
		final AlertDialog.Builder builder = new AlertDialog.Builder(view.getContext());
		builder.setTitle("Android webview测试confirm对话框").setMessage(message).setPositiveButton("确定", new OnClickListener() {
			@Override
			public void onClick(DialogInterface dialog, int which) {
				result.confirm();
			}
		}).setNeutralButton("取消", new OnClickListener() {
			@Override
			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');
	 */
	@Override
	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("Android webview测试prompt对话框").setMessage(message);
		final EditText et = new EditText(view.getContext());
		et.setSingleLine();
		et.setText(defaultValue);
		builder.setView(et);
		builder.setPositiveButton("确定", new OnClickListener() {
			@Override
			public void onClick(DialogInterface dialog, int which) {
				result.confirm(et.getText().toString());
			}
		}).setNeutralButton("取消", new OnClickListener() {
			@Override
			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() {
			@Override
			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);
	}

}