Android 同一线程错误上的 WebView 方法
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WebView methods on same thread error
提问by Johan Hoeksma
I have a android program (Java + html in a webview). I can call from the javascript to the Java code. But the other way around stopped working (after updating in eclipse).
我有一个 android 程序（webview 中的 Java + html）。我可以从 javascript 调用 Java 代码。但反过来停止工作（在 eclipse 中更新后）。
So this is what I'm trying to do
所以这就是我想要做的
- Make a webview (worked)
- calling in javascript to AndroidFunction.test(); (worked)
- the java test() function call webView.loadUrl("javascript:helloBack()"); (! not working anymore)
- 制作一个网页视图（工作）
- 在 javascript 中调用 AndroidFunction.test(); （工作）
- java test() 函数调用 webView.loadUrl("javascript:helloBack()"); （！不再工作了）
I tried to let it work with the WebView in the MainActivity, but it didnt work.
我试图让它与 MainActivity 中的 WebView 一起工作，但它没有工作。
MainActivity.java
主活动.java
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
final WebView webView = (WebView)findViewById(R.id.webView);
webView.getSettings().setJavaScriptEnabled(true);
webView.setWebChromeClient(new WebChromeClient());
WebSettings webSettings = webView.getSettings();
webSettings.setJavaScriptEnabled(true);
javascr = new Javascript(this, webView);
webView.addJavascriptInterface(javascr, "AndroidFunction");
webView.loadUrl("file:///android_asset/www/index.html");
....
}
Javascript.java
Javascript.java
public class Javascript {
Context cont;
WebView webView;
Javascript(Context c, WebView w) {
cont = c;
webView = w;
}
// function called in the javascript by AndroidFunction.test();
public void test() {
// Breaking point!!!
webView.loadUrl("javascript:helloBack()");
}
Error:
错误：
03-24 11:47:50.103: W/WebView(21026): at com.android.org.chromium.base.SystemMessageHandler.handleMessage(SystemMessageHandler.java:27)
03-24 11:47:50.103: W/WebView(21026): java.lang.Throwable: A WebView method was called on thread 'JavaBridge'. All WebView methods must be called on the same thread. (Expected Looper Looper{41ab68f8} called on Looper{41bb70a8}, FYI main Looper is Looper{41ab68f8})
03-24 11:47:50.103: W/WebView(21026): at android.webkit.WebView.checkThread(WebView.java:2063)
03-24 11:47:50.103: W/WebView(21026): at android.webkit.WebView.loadUrl(WebView.java:794)
03-24 11:47:50.103: W/WebView(21026): at com.example.hellobt.Javascript.test(Javascript.java:24)
03-24 11:47:50.103: W/WebView(21026): at com.android.org.chromium.base.SystemMessageHandler.nativeDoRunLoopOnce(Native Method)
03-24 11:47:50.103: W/WebView(21026): at com.android.org.chromium.base.SystemMessageHandler.handleMessage(SystemMessageHandler.java:27)
03-24 11:47:50.103: W/WebView(21026): at android.os.Handler.dispatchMessage(Handler.java:102)
03-24 11:47:50.103: W/WebView(21026): at android.os.Looper.loop(Looper.java:137)
03-24 11:47:50.103: W/WebView(21026): at android.os.HandlerThread.run(HandlerThread.java:61)
Thanks for the answer. I edited the function in my Javascript file like this:
谢谢你的回答。我在我的 Javascript 文件中编辑了这个函数，如下所示：
private void test(final String s) {
webView.post(new Runnable() {
public void run() {
webView.loadUrl("javascript:" + s + ";");
}
});
System.out.println("javscript done..");
}
回答by ksasq
The JavaScript method is executed on a background (i.e. non-UI) thread. You need to call all Android View related methods on the UI thread. You can achieve what you need with:
JavaScript 方法在后台（即非 UI）线程上执行。您需要在 UI 线程上调用所有与 Android View 相关的方法。您可以通过以下方式实现您的需求：
mWebView.post(new Runnable() {
@Override
public void run() {
mWebView.loadUrl(...).
}
});
Which will post the task to run on the UI thread.
这将发布在 UI 线程上运行的任务。
回答by CoolMind
In my case nothing was shown in a WebView, so I prefer another way:
就我而言，WebView 中没有显示任何内容，所以我更喜欢另一种方式：
runOnUiThread(new Runnable() {
@Override
public void run() {
final WebView webView = (WebView) findViewById(R.id.map);
webView.loadDataWithBaseURL(...);
}
});
回答by Akhil Ghatiki
This can be come over by using the post method. Please go through below code.
这可以通过使用 post 方法来解决。请通过下面的代码。
m_targetView.post(new Runnable() {
@Override
public void run() {
m_targetView.loadUrl(".....");
}
});
回答by Roman
Javaversion: You must to use Runnableinterface and Post to Handler.
Java版本：您必须使用Runnable接口和 Post to Handler。
webView.post(new Runnable() {
@Override
public void run() {
webView.loadUrl("file:///android_asset/www/index.html");
}
});
Kotlinversion:
科特林版本：
webView.post(new Runnable {
webView.loadUrl("file:///android_asset/www/index.html")
})
