WebView使用总结1

1.当只用WebView的时候,最先注意的当然是在配置文件中添加访问因特网的权限;

2.如果访问的页面中有Javascript,必须设置支持Javascript:
 

   webview.getSettings().setJavaScriptEnabled(true);
  

3.如果希望点击链接由自己处理而不是新开Android的系统browser中响应该链接.给WebView添加一个事件监听对象(WebViewClient)并重写其中的一些方法 shouldOverrideUrlLoading对网页中超链接按钮的响应

mWebView.setWebViewClient(new WebViewClient() {
/**
* Show in webview not system webview.
*/
public boolean shouldOverrideUrlLoading(WebView view, String url) {
    view.loadUrl(url);
    return super.shouldOverrideUrlLoading(view, url);
}
}

    这样就保证了每次打开的页面都是在WebView实例中显示运行的;

4.在显示WebView时,点击手机Back时,会完全退出当前Activity,如果想退到历史浏览页面:重写back监听:

public boolean onKeyDown(int keyCode, KeyEvent event) {
 WebView mWebView = (WebView) findViewById(R.id.browser);
 if ((keyCode == KeyEvent.KEYCODE_BACK) && mWebView.canGoBack()) {
     mWebView.goBack();
     return true;
  }
 return super.onKeyDown(keyCode, event);
}

5.Android SDK提供了一个schema前缀为"file:///android_asset/".WebView遇到这样的schema,就去当前包中的 assets目录中找内容.如:"file:///android_asset/demo.html"
下面一段代码是对网页中JS的类似Alert()类的函数进行相应的重写响应:

webView.setWebChromeClient(new WebChromeClient() {
			public boolean onJsAlert(WebView view, String url, String message,
					final JsResult result) {
				AlertDialog.Builder b = new AlertDialog.Builder(BrowserJs.this);
				b.setTitle("Alert");
				b.setMessage(message);
				b.setPositiveButton(android.R.string.ok,
						new AlertDialog.OnClickListener() {
							public void onClick(DialogInterface dialog,
									int which) {
								result.confirm();
							}
						});
				b.setCancelable(false);
				b.create();
				b.show();
				return true;
			};

			@Override
			public boolean onJsConfirm(WebView view, String url,
					String message, final JsResult result) {
				AlertDialog.Builder b = new AlertDialog.Builder(BrowserJs.this);
				b.setTitle("Confirm");
				b.setMessage(message);
				b.setPositiveButton(android.R.string.ok,
						new AlertDialog.OnClickListener() {
							public void onClick(DialogInterface dialog,
									int which) {
								result.confirm();
							}
						});
				b.setNegativeButton(android.R.string.cancel,
						new DialogInterface.OnClickListener() {
							public void onClick(DialogInterface dialog,
									int which) {
								result.cancel();
							}
						});
				b.setCancelable(false);
				b.create();
				b.show();
				return true;
			};

			@Override
			public boolean onJsPrompt(WebView view, String url, String message,
					String defaultValue, final JsPromptResult result) {
				final LayoutInflater factory = LayoutInflater
						.from(BrowserJs.this);
				final View v = factory.inflate(
						R.layout.prompt_dialog, null);
				((TextView) v.findViewById(R.id.prompt_message_text))
						.setText(message);
				((EditText) v.findViewById(R.id.prompt_input_field))
						.setText(defaultValue);

				AlertDialog.Builder b = new AlertDialog.Builder(BrowserJs.this);
				b.setTitle("Prompt");
				b.setView(v);
				b.setPositiveButton(android.R.string.ok,
						new AlertDialog.OnClickListener() {
							public void onClick(DialogInterface dialog,
									int which) {
								String value = ((EditText) v
										.findViewById(R.id.prompt_input_field))
										.getText().toString();
								result.confirm(value);
							}
						});
				b.setNegativeButton(android.R.string.cancel,
						new DialogInterface.OnClickListener() {
							public void onClick(DialogInterface dialog,
									int which) {
								result.cancel();
							}
						});
				b.setOnCancelListener(new DialogInterface.OnCancelListener() {
					public void onCancel(DialogInterface dialog) {
						result.cancel();
					}
				});
				b.show();
				return true;
			};

			public void onProgressChanged(WebView view, int newProgress) {
				BrowserJs.this.getWindow().setFeatureInt(
						Window.FEATURE_PROGRESS, newProgress * 100);
				super.onProgressChanged(view, newProgress);
			}

			public void onReceivedTitle(WebView view, String title) {
				BrowserJs.this.setTitle(title);
				super.onReceivedTitle(view, title);
			}
		});

		go.setOnClickListener(new OnClickListener() {
			public void onClick(View view) {
				String url = text.getText().toString();
				webView.loadUrl(url);
			}
		});
		webView.loadUrl("file:///android_asset/index.html");

在上述代码中,用到的prompt_dialog.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
	android:gravity="center_horizontal" android:orientation="vertical"
	android:layout_width="fill_parent" android:layout_height="wrap_content">
	<TextView android:id="@+id/prompt_message_text"
		android:layout_width="fill_parent" android:layout_height="wrap_content" />
	<EditText android:id="@+id/prompt_input_field"
		android:layout_width="fill_parent" android:layout_height="wrap_content"
		android:selectAllOnFocus="true" android:scrollHorizontally="true"
		android:minWidth="250dp" />
</LinearLayout>

还有assets中的Html文件:

<html>
<script type="text/javascript">
  function onAlert(){
	  alert("This is a alert sample from html");
  }
  function onConfirm(){
	  var b=confirm("are you sure to login?");
	  alert("your choice is "+b);
  }
  function onPrompt(){
	  var b=prompt("please input your password","aaa");
	  alert("your input is "+b);
  }
</script>
<pre>
<input type="button" value="alert" onclick="onAlert()"/>
<input type="button" value="confirm" onclick="onConfirm()"/>
<input type="button" value="prompt" onclick="onPrompt()"/>

<a href="http://www.google.com"/>Google</a>
</pre>
</html>