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：

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);
}
}