我有一个在 android 中使用的 webview，我试图在单击按钮时触发 javascript。我正在尝试使用下面的代码将类的颜色更改为红色。但我似乎无法让它工作
final WebView wb=(WebView)findViewById(R.id.webView2);
wb.loadUrl("javascript:"
+ "var FunctionOne = function () {"
+ " try{document.getElementsByClassName('test')[0].style.color='red';}catch(e){}"
+ "};");
从kitkat 开始，使用evaluateJavascript 方法代替loadUrl 来调用javascript 函数，如下所示
if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.KITKAT) {
webView.evaluateJavascript("var FunctionOne = function () {"
+ " try{document.getElementsByClassName('test')[0].style.color='red';}catch(e){}"
+ "};", null);
} else {
webView.loadUrl("javascript:"
+ "var FunctionOne = function () {"
+ " try{document.getElementsByClassName('test')[0].style.color='red';}catch(e){}"
+ "};");
}
通过添加以下行为您的 webview 启用 Javascript
wb.getSettings().setJavaScriptEnabled(true);
活动_main.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<WebView
android:id="@+id/webView"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</RelativeLayout>
主活动.java
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import com.bluapp.androidview.R;
public class WebViewActivity3 extends AppCompatActivity {
private WebView webView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_web_view3);
webView = (WebView) findViewById(R.id.webView);
webView.setWebViewClient(new WebViewClient());
webView.getSettings().setJavaScriptEnabled(true);
webView.loadUrl("file:///android_asset/webview1.html");
webView.setWebViewClient(new WebViewClient(){
public void onPageFinished(WebView view, String weburl){
webView.loadUrl("javascript:testEcho('Javascript function in webview')");
}
});
}
}
资产/webview1.html
<!DOCTYPE html PUBLIC "-//WAPFORUM//DTD XHTML Mobile 1.0//EN" "http://www.wapforum.org/DTD/xhtml-mobile10.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head><title>WebView1</title>
<meta forua="true" http-equiv="Cache-Control" content="max-age=0"/>
</head>
<body style="background-color:#212121">
<script type="text/javascript">
function testEcho(p1){
document.write(p1);
}
</script>
</body>
</html>