步骤：
1.定义一个Activity, 例如： WebViewActivity 在AndroidManifest 中定义自己的拉起协议
<activity android:name=".WebViewActivity">
<intent-filter>
<action android:name="android.intent.action.VIEW"/>
<category android:name="android.intent.category.BROWSABLE"/>
<category android:name="android.intent.category.DEFAULT"/>
<date android:scheme="wva"
android:host="action"
android:path="/webview"/>
</intent-filter>
</activity>2.在网页中标签中或其他
<a class="test" href="wva://action/webview ">测试</a>##### 注：WebView中 setWebViewClient不用设置 webViewClient为null时系统会设置NullWebViewClient 核心代码： WebViewContentsClientAdapter
void setWebViewClient(WebClient client) {
if(client != null){
mWebViewClient = client;
} else{
mWebViewClient = new NullWebViewClient();
}
}NullWebViewClient 处理未能识别的协议 shouldOverrideUrlLoading 方法
public boolean shouldOverrideUrlLoading(WebView view, String url){
Intent intent;
// Perform generic parsing of the URI to turn it into an Intent.
try {
intent = Intent.parseUri(url, Intent.URI_INTENT_SCHEME);
} catch (URISyntaxException ex) {
Log.w(TAG, "Bad URI " + url + ": " + ex.getMessage());
return false;
}
// Sanitize the Intent, ensuring web pages can not bypass browser
// security (only access to BROWSABLE activities).
intent.addCategory(Intent.CATEGORY_BROWSABLE);
intent.setComponent(null);
// Pass the package name as application ID so that the intent from the
// same application can be opened in the same tab.
intent.putExtra(Browser.EXTRA_APPLICATION_ID,
view.getContext().getPackageName());
try {
view.getContext().startActivity(intent);
} catch (ActivityNotFoundException ex) {
Log.w(TAG, "No application can handle " + url);
return false;
}
return true;
}