Question

ProgressDialog在onPreExecute（）方法中崩溃。

以下是我的代码段：

        public class TestCasesActivity extends Activity {
                super.onCreate(savedInstanceState);
                setContentView(R.layout.activity_testcases);

                xmlHelp = new XmlHelper();

                ConfigParser confParser = new ConfigParser();
                confParser.execute();
            }

            private class ConfigParser extends AsyncTask<Void, Void, Void> {
                private ProgressDialog dialog;

            @Override
            protected void onPreExecute() {
                dialog = new ProgressDialog(TestCasesActivity.this);
                dialog.setMessage("Loading TestCases Configuration...");
                dialog.show();
            }

        @Override
        protected Void doInBackground(Void... params) {
            xmlHelp.getNumberOfNodes();
            return null;
        }

        @Override
        protected void onPostExecute(Void v) {
            dialog.dismiss();
            // Show test cases list here via a ListView
        }
}

请在此处说明可能出现的问题。 logcat打印如下：

07-30 08：13：50.511 20200-20200 /？ E /窗口管理器： android.view.WindowLeaked：Activity com.TestCasesActivity 已经泄露了窗户 com.android.internal.policy.impl.PhoneWindow $ {DecorView 31a83555 最初添加的V.E ..... R ...... D 0,0-1026,348} 在android.view.ViewRootImpl。（ViewRootImpl.java:363）在android.view.WindowManagerGlobal.addView（WindowManagerGlobal.java:262）在android.view.WindowManagerImpl.addView（WindowManagerImpl.java:69）在android.app.Dialog.show（Dialog.java:298） at com.TestCasesActivity $ ConfigParser.onPreExecute（TestCasesActivity.java:41）在android.os.AsyncTask.executeOnExecutor（AsyncTask.java:587）在android.os.AsyncTask.execute（AsyncTask.java:535）在com.TestCasesActivity.onCreate（TestCasesActivity.java:30）在android.app.Activity.performCreate（Activity.java:5984）在android.app.Instrumentation.callActivityOnCreate（Instrumentation.java:1105）在android.app.ActivityThread.performLaunchActivity（ActivityThread.java:2254）在android.app.ActivityThread.handleLaunchActivity（ActivityThread.java:2361）在android.app.ActivityThread.access $ 800（ActivityThread.java:147）在android.app.ActivityThread $ H.handleMessage（ActivityThread.java:1281）在android.os.Handler.dispatchMessage（Handler.java:102）在android.os.Looper.loop（Looper.java:135）在android.app.ActivityThread.main（ActivityThread.java:5232） at java.lang.reflect.Method.invoke（Native Method）在java.lang.reflect.Method.invoke（Method.java:372）在com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run（ZygoteInit.java:904）在com.android.internal.os.ZygoteInit.main（ZygoteInit.java:699）

之前由解析器引起的另一次崩溃：

07-30 08:40:32.651  22982-23154/? E/AndroidRuntime﹕ FATAL EXCEPTION: AsyncTask #1
    Process: com.performance_tool, PID: 22982
    java.lang.RuntimeException: An error occured while executing doInBackground()
            at android.os.AsyncTask$3.done(AsyncTask.java:300)
            at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355)
            at java.util.concurrent.FutureTask.setException(FutureTask.java:222)
            at java.util.concurrent.FutureTask.run(FutureTask.java:242)
            at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
            at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
            at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
            at java.lang.Thread.run(Thread.java:818)
     Caused by: org.w3c.dom.DOMException: Only one root element allowed
            at org.apache.harmony.xml.dom.DocumentImpl.insertChildAt(DocumentImpl.java:421)
            at org.apache.harmony.xml.dom.InnerNodeImpl.appendChild(InnerNodeImpl.java:52)
            at org.apache.harmony.xml.parsers.DocumentBuilderImpl.parse(DocumentBuilderImpl.java:306)
            at org.apache.harmony.xml.parsers.DocumentBuilderImpl.parse(DocumentBuilderImpl.java:128)
            at javax.xml.parsers.DocumentBuilder.parse(DocumentBuilder.java:107)
            at com.XmlHelper.getNumberOfNodes(XmlHelper.java:29)
            at com.TestCasesActivity$ConfigParser.doInBackground(TestCasesActivity.java:46)
            at com.TestCasesActivity$ConfigParser.doInBackground(TestCasesActivity.java:33)
            at android.os.AsyncTask$2.call(AsyncTask.java:288)
            at java.util.concurrent.FutureTask.run(FutureTask.java:237)
            at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
            at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
            at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
            at java.lang.Thread.run(Thread.java:818)

Answer 1

解决方案1： 您应该在onPostExecute中关闭进度对话框。像这样。

protected void onPostExecute(...){
    // dismiss dialog here
    dialog.dismiss();
}

你做了这一步吗？

解决方案2： 如果你在onPostExecute上执行了这一步，但仍然得到错误意味着请查看下面的下一个解决方案，

将你的上下文从onCreate方法传递给AsyncTask，就像这样，

confParser.execute(TestCasesActivity.this);

您的异步任务将如下所示，

    private class ConfigParser extends AsyncTask<Void, Void, Void> {
        private ProgressDialog dialog;
        Context context;

        public ConfigParser(Context context){
        this.context=context;
        }

        @Override
        protected void onPreExecute() {
            dialog = new ProgressDialog(context);
            dialog.setMessage("Loading TestCases Configuration...");
            dialog.show();
        }

       @Override
       protected void onPostExecute(...){
       // dismiss dialog here
       dialog.dismiss();
       }
}

Answer 2

我在我的项目中已经这样做了：

class CreaLista extends AsyncTask<String, Void, Void> {

        private ProgressDialog dialog;
        private IndiceActivity indiceActivity;

        public CreaLista(IndiceActivity indiceActivity) {
            this.indiceActivity = indiceActivity;

            context = indiceActivity;

            dialog = new ProgressDialog(context);
        }



        private Context context;

        protected void onPreExecute() {
            this.dialog.setMessage("Dati in caricamento");
            this.dialog.show();
        }

        @Override
        protected void onPostExecute(final Void success) {

            if (dialog.isShowing()) {
                dialog.dismiss();
            }

onPreExecute（）方法

2 个答案: