WebView使用总结(应用函数与JS函数互相调用)

浏览数：46 / 时间：2015年06月09日

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:
Java代码

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:
Java代码

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:
Java代码

<?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:
Java代码

<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()"/>