webview 与html5有几种交互方式

对于android初学者应该都了解webView这个组件。之前我也是对其进行了一些简单的了解，但是在一个项目中不得不用webview的时候，发现了webview的强大之处，今天就分享一下使用webview的一些经验。

1、首先了解一下webview。
webview介绍的原文如下：A View that displays web pages. This class is the basis upon which you can roll your own web browser or simply display some online content within your Activity. It uses the WebKit rendering engine to display web pages and includes methods to navigate forward and backward through a history, zoom in and out, perform text searches and more.
从上面你应该了解到了基本功能，也就是显示网页。之所以我说webview功能强大是因为它和js的交互非常方便，很简单就可以实现。

2、webview能做什么？
①webView可以利用html做界面布局，虽然目前还比较少人这么使用，不过我相信当一些客户端需要复杂的图文（图文都是动态生成）混排的时候它肯定是个不错的选择。
②直接显示网页，这功能当然也是它最基本的功能。
③和js交互。（如果你的js基础比java基础好的话那么采用这种方式做一些复杂的处理是个不错的选择）。

3、如何使用webview？
这里直接用一个svn上取下的demo，先上demo后讲解。demo的结构图如下：

WebViewDemo.java

package com.google.android.webviewdemo;

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.util.Log;
import android.webkit.JsResult;
import android.webkit.WebChromeClient;
import android.webkit.WebSettings;
import android.webkit.WebView;

/**
* Demonstrates how to embed a WebView in your activity. Also demonstrates how
* to have javascript in the WebView call into the activity, and how the activity
* can invoke javascript.
*

* In this example, clicking on the android in the WebView will result in a call into
* the activities code in {@link DemoJavaScriptInterface#clickOnAndroid()}. This code
* will turn around and invoke javascript using the {@link WebView#loadUrl(String)}
* method.
*

* Obviously all of this could have been accomplished without calling into the activity
* and then back into javascript, but this code is intended to show how to set up the
* code paths for this sort of communication.
*
*/
public class WebViewDemo extends Activity {

private static final String LOG_TAG = "WebViewDemo";

private WebView mWebView;

private Handler mHandler = new Handler();

@Override
public void onCreate(Bundle icicle) {
super.onCreate(icicle);
setContentView(R.layout.main);
mWebView = (WebView) findViewById(R.id.webview);

WebSettings webSettings = mWebView.getSettings();
webSettings.setSavePassword(false);
webSettings.setSaveFormData(false);
webSettings.setJavaScriptEnabled(true);
webSettings.setSupportZoom(false);

mWebView.setWebChromeClient(new MyWebChromeClient());

mWebView.addJavascriptInterface(new DemoJavaScriptInterface(), "demo");

mWebView.loadUrl("file:///android_asset/demo.html");
}

final class DemoJavaScriptInterface {

DemoJavaScriptInterface() {
}

/**
* This is not called on the UI thread. Post a runnable to invoke
* loadUrl on the UI thread.
*/
public void clickOnAndroid() {
mHandler.post(new Runnable() {
public void run() {
mWebView.loadUrl("javascript:wave()");
}
});

}
}

/**
* Provides a hook for calling "alert" from javascript. Useful for
* debugging your javascript.
*/
final class MyWebChromeClient extends WebChromeClient {
@Override
public boolean onJsAlert(WebView view, String url, String message, JsResult result) {
Log.d(LOG_TAG, message);
result.confirm();
return true;
}
}
}

demo.html

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