在项目中遇到JQuery注入后，执行无效的问题。
我们知道必须在网页加载完成后，也就是在onPageFinished()方法被调用后才能执行被注入的JS。
但是在有些手机上并不能成功执行，我的解决方案是设置一秒延迟后注入JS，成功了！why，i dont know...
WebView注入JS的封装
JSUtil.java
import android.app.Activity;
import android.webkit.ValueCallback;
import android.webkit.WebView;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
public class JSUtil {
public static JSUtil instance;
private WebView webview;
private String juqueryContent;
public static JSUtil getInstance(WebView webView) {
if (instance == null) {
instance = new JSUtil(webView);
} else {
instance.webview = webView;
}
return instance;
}
private JSUtil(WebView webView) {
webview = webView;
try {
InputStream in = webView.getContext().getAssets().open("jquery.min.js");
byte buff[] = new byte[1024];
ByteArrayOutputStream fromFile = new ByteArrayOutputStream();
do {
int numread = in.read(buff);
if (numread <= 0) {
break;
}
fromFile.write(buff, 0, numread);
} while (true);
juqueryContent = fromFile.toString();
} catch (IOException e) {
e.printStackTrace();
}
}
/**
* 注入jquery
*/
public void injectJquery(final InjectCallback injectCallback) {
webview.loadUrl("javascript:" + juqueryContent);
webview.postDelayed(new Runnable() {
@Override
public void run() {
injectCallback.onSuccess();
}
},1000);
}
interface InjectCallback {
void onSuccess();
void onFail();
}
/**
* 原生设置dom值
*/
public void js_dom_setValueById(String id, String value) {
String js = "javascript:document.getElementById('" + id + "').value = '" + value + "'";
loadJs(js);
}
/**
* 原生设置dom值
*/
public void js_dom_setValueByName(String name, String value) {
String js = "javascript:document.getElementsByName('" + name + "').value = '" + value + "'";
loadJs(js);
}
/**
* js原生dom点击(通过id查找)
*/
public void js_dom_click_byId(String id) {
String js = "javascript:document.getElementById('" + id + "').click();";
webview.evaluateJavascript(js, null);
}
/**
* js原生dom点击(通过类查找)
*/
public void js_dom_click_byClass(String cls) {
String js = "javascript:document.getElementsByClassName('" + cls + "').click();";
webview.evaluateJavascript(js, null);
}
/**
* jquerydom点击(通过id查找)
*/
public void jquery_dom_click_byId(String id) {
String js = "var newscript = document.createElement(\"script\");";
js += "newscript.src=\"/jquery/1.12.4/jquery.min.js\";";
js += "document.body.appendChild(newscript);";
js += "newscript.οnlοad=function(){$('#" + id + "').click();};";
webview.evaluateJavascript(js, null);
}
/**
* jquery脚本执行
*/
public void jquery_dom(String jscontent) {
String js = "var newscript = document.createElement(\"script\");";
js += "newscript.src=\"/jquery/1.12.4/jquery.min.js\";";
js += "document.body.appendChild(newscript);";
js += "newscript.οnlοad=function(){" + jscontent + "};";
webview.evaluateJavascript(js, null);
}
/**
* jquerydom点击(通过类查找)
*/
public void jquery_dom_click_byClass(String cls) {
String js = "var newscript = document.createElement(\"script\");";
js += "newscript.src=\"/jquery/1.12.4/jquery.min.js\";";
js += "document.body.appendChild(newscript);";
js += "newscript.οnlοad=function(){$('." + cls + "').click();};";
webview.evaluateJavascript(js, null);
}
/**
* jquery设置dom值
*/
public void jquery_dom_setValue(String id, String value) {
String js = "var newscript = document.createElement(\"script\");";
js += "newscript.src='/jquery/1.12.4/jquery.min.js';";
js += "document.body.appendChild(newscript);";
js += "newscript.οnlοad=function(){$('#" + id + "').val('" + value + "');};";
webview.evaluateJavascript(js, null);
}
}
执行注入
webview.setWebViewClient(new WebViewClient() {
@Override
public boolean shouldOverrideUrlLoading(WebView view, String url) {
LogUtil.logD("当前的url："+url);
view.loadUrl(url);
return true;
}
@Override
public void onReceivedError(WebView view, int errorCode, String description, String failingUrl) {
super.onReceivedError(view, errorCode, description, failingUrl);
LogUtil.logE(errorCode + ": " + description);
webview.loadUrl("file:///android_asset/404.html");
}
@Override
public void onPageStarted(WebView view, String url, Bitmap favicon) {
super.onPageStarted(view, url, favicon);
LogUtil.logD("开始加载网页:" + url);
if (!dialog.isShowing()) {
dialog.show();
}
}
@Override
public void onPageFinished(WebView view, final String url) {
super.onPageFinished(view, url);
dialog.dismiss();
LogUtil.logD("加载完成 URL：" + url);
webview.postDelayed(new Runnable() {
@Override
public void run() {
JSUtil.getInstance(webview).injectJquery(new JSUtil.InjectCallback() {
@Override
public void onSuccess() {
LogUtil.logD("执行登录：点击首页登录");
webview.evaluateJavascript("var link=$('#nav-logobar-greeting').attr('href');if(link){window.location=link;}else{$('#gwm-SignIn-button').click();}", null);
}
@Override
public void onFail() {
}
});
}
}, 1000);
}
});
注意上面的onPageFinished方法中延迟操作，如果不加这个延迟，webview.evaluateJavascript根本无法执行(找不到“$定义”)
