Question

代码：

button.setOnClickListener(new View.OnClickListener() {
    public void onClick(View v) {
        // fileReader();

        new xyz().execute();

    }// button
});// button end        

private class xyz extends AsyncTask<Void, Void, Void> {

    private final ProgressDialog dialog = new ProgressDialog(CCActivity3.this);

    protected void onPreExecute() {
        this.dialog.setCancelable(true);
        this.dialog.setMessage("Please Wait...");
        this.dialog.setProgressStyle(ProgressDialog.STYLE_SPINNER);
        this.dialog.setProgress(0);
        this.dialog.setMax(100);
        this.dialog.show();
    }

    // put your code which preload with processDialog  
    private boolean running = true;

    @Override
    protected Void doInBackground(Void... params) {

        // while( running ) {
        fileReader(); //i keep getting error here
        //}

        return null;
    }

    @Override
    protected void onPostExecute(final Void unused) {
        if (this.dialog.isShowing()) {
            this.dialog.dismiss();
        }   
        super.onPostExecute(unused);
        //this.dialog.dismiss();
    }
}

堆栈追踪：

04-10 21:05:05.398: D/skia(30039): purging 270K from font cache [38 entries]
04-10 21:05:05.508: D/dalvikvm(30039): GC_EXPLICIT freed 1828K, 18% free 12468K/15107K, external 7017K/7937K, paused 106ms
04-10 21:06:36.318: D/skia(30039): purging 13K from font cache [2 entries]
04-10 21:06:36.418: D/dalvikvm(30039): GC_EXPLICIT freed 3271K, 39% free 9233K/15107K, external 7017K/7937K, paused 93ms
04-10 21:07:37.208: W/dalvikvm(30039): threadid=9: thread exiting with uncaught exception (group=0x40015568)
04-10 21:07:37.228: E/AndroidRuntime(30039): FATAL EXCEPTION: AsyncTask #1
04-10 21:07:37.228: E/AndroidRuntime(30039): java.lang.RuntimeException: An error occured while executing doInBackground()
04-10 21:07:37.228: E/AndroidRuntime(30039):    at android.os.AsyncTask$3.done(AsyncTask.java:200)
04-10 21:07:37.228: E/AndroidRuntime(30039):    at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:274)
04-10 21:07:37.228: E/AndroidRuntime(30039):    at java.util.concurrent.FutureTask.setException(FutureTask.java:125)
04-10 21:07:37.228: E/AndroidRuntime(30039):    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:308)
04-10 21:07:37.228: E/AndroidRuntime(30039):    at java.util.concurrent.FutureTask.run(FutureTask.java:138)
04-10 21:07:37.228: E/AndroidRuntime(30039):    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1088)
04-10 21:07:37.228: E/AndroidRuntime(30039):    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:581)
04-10 21:07:37.228: E/AndroidRuntime(30039):    at java.lang.Thread.run(Thread.java:1019)
04-10 21:07:37.228: E/AndroidRuntime(30039): Caused by: android.view.ViewRoot$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views.
04-10 21:07:37.228: E/AndroidRuntime(30039):    at android.view.ViewRoot.checkThread(ViewRoot.java:2954)
04-10 21:07:37.228: E/AndroidRuntime(30039):    at android.view.ViewRoot.invalidateChild(ViewRoot.java:644)
04-10 21:07:37.228: E/AndroidRuntime(30039):    at android.view.ViewRoot.invalidateChildInParent(ViewRoot.java:670)
04-10 21:07:37.228: E/AndroidRuntime(30039):    at android.view.ViewGroup.invalidateChild(ViewGroup.java:2533)
04-10 21:07:37.228: E/AndroidRuntime(30039):    at android.view.View.invalidate(View.java:5288)
04-10 21:07:37.228: E/AndroidRuntime(30039):    at android.widget.TextView.checkForRelayout(TextView.java:5663)
04-10 21:07:37.228: E/AndroidRuntime(30039):    at android.widget.TextView.setText(TextView.java:2814)
04-10 21:07:37.228: E/AndroidRuntime(30039):    at android.widget.TextView.setText(TextView.java:2682)
04-10 21:07:37.228: E/AndroidRuntime(30039):    at android.widget.TextView.setText(TextView.java:2657)
04-10 21:07:37.228: E/AndroidRuntime(30039):    at dev.android.CCActivity3.fileReader(CCActivity3.java:207)
04-10 21:07:37.228: E/AndroidRuntime(30039):    at dev.android.CCActivity3$xyz.doInBackground(CCActivity3.java:110)
04-10 21:07:37.228: E/AndroidRuntime(30039):    at dev.android.CCActivity3$xyz.doInBackground(CCActivity3.java:1)
04-10 21:07:37.228: E/AndroidRuntime(30039):    at android.os.AsyncTask$2.call(AsyncTask.java:185)
04-10 21:07:37.228: E/AndroidRuntime(30039):    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:306)
04-10 21:07:37.228: E/AndroidRuntime(30039):    ... 4 more
04-10 21:07:37.258: I/Process(30039): Sending signal. PID: 30039 SIG: 9
04-10 21:14:03.819: D/dalvikvm(30687): GC_EXTERNAL_ALLOC freed 109K, 64% free 487K/1347K, external 0K/0K, paused 4ms
04-10 21:14:03.988: D/dalvikvm(30687): GC_EXTERNAL_ALLOC freed 4K, 64% free 491K/1347K, external 1K/513K, paused 14ms
04-10 21:14:04.778: D/dalvikvm(30687): GC_EXTERNAL_ALLOC freed 10K, 61% free 534K/1347K, external 1521K/2013K, paused 12ms
04-10 21:14:04.968: D/dalvikvm(30687): GC_EXTERNAL_ALLOC freed 2K, 61% free 533K/1347K, external 4856K/6064K, paused 10ms
04-10 21:14:27.868: W/IInputConnectionWrapper(30687): getExtractedText on inactive InputConnection
04-10 21:14:27.888: W/IInputConnectionWrapper(30687): getCursorCapsMode on inactive InputConnection
04-10 21:14:27.888: W/IInputConnectionWrapper(30687): getExtractedText on inactive InputConnection
04-10 21:14:27.898: W/IInputConnectionWrapper(30687): performPrivateCommand on inactive InputConnection
04-10 21:14:38.208: D/szipinf(30687): Initializing inflate state
04-10 21:14:38.238: D/szipinf(30687): Initializing zlib to inflate
04-10 21:14:40.628: D/dalvikvm(30687): GC_FOR_MALLOC freed 412K, 24% free 3798K/4995K, external 7079K/7937K, paused 27ms
04-10 21:14:40.808: D/dalvikvm(30687): GC_CONCURRENT freed 405K, 18% free 5440K/6595K, external 7079K/7937K, paused 0ms+4ms
04-10 21:14:41.038: D/dalvikvm(30687): GC_CONCURRENT freed 7K, 10% free 7457K/8259K, external 7079K/7937K, paused 1ms+4ms
04-10 21:14:41.288: D/dalvikvm(30687): GC_CONCURRENT freed 351K, 11% free 9202K/10307K, external 7079K/7937K, paused 1ms+7ms
04-10 21:14:41.488: D/dalvikvm(30687): GC_FOR_MALLOC freed 6K, 7% free 10789K/11587K, external 7079K/7937K, paused 75ms
04-10 21:14:41.758: D/dalvikvm(30687): GC_CONCURRENT freed 522K, 10% free 12363K/13635K, external 7079K/7937K, paused 0ms+9ms
04-10 21:14:42.118: D/dalvikvm(30687): GC_CONCURRENT freed 8K, 6% free 14316K/15107K, external 7079K/7937K, paused 1ms+9ms
04-10 21:15:55.768: D/skia(30687): purging 340K from font cache [47 entries]
04-10 21:15:55.888: D/dalvikvm(30687): GC_EXPLICIT freed 1817K, 17% free 12542K/15107K, external 7079K/7937K, paused 107ms
04-10 21:16:42.368: D/skia(30687): purging 13K from font cache [2 entries]
04-10 21:16:42.478: D/dalvikvm(30687): GC_EXPLICIT freed 1038K, 24% free 11524K/15107K, external 7079K/7937K, paused 102ms
04-10 21:18:28.688: D/skia(30687): purging 13K from font cache [2 entries]
04-10 21:18:28.788: D/dalvikvm(30687): GC_EXPLICIT freed 6921K, 70% free 4646K/15107K, external 7079K/7937K, paused 91ms
04-10 21:18:33.758: W/dalvikvm(30687): threadid=9: thread exiting with uncaught exception (group=0x40015568)
04-10 21:18:33.768: E/AndroidRuntime(30687): FATAL EXCEPTION: AsyncTask #1
04-10 21:18:33.768: E/AndroidRuntime(30687): java.lang.RuntimeException: An error occured while executing doInBackground()
04-10 21:18:33.768: E/AndroidRuntime(30687):    at android.os.AsyncTask$3.done(AsyncTask.java:200)
04-10 21:18:33.768: E/AndroidRuntime(30687):    at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:274)
04-10 21:18:33.768: E/AndroidRuntime(30687):    at java.util.concurrent.FutureTask.setException(FutureTask.java:125)
04-10 21:18:33.768: E/AndroidRuntime(30687):    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:308)
04-10 21:18:33.768: E/AndroidRuntime(30687):    at java.util.concurrent.FutureTask.run(FutureTask.java:138)
04-10 21:18:33.768: E/AndroidRuntime(30687):    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1088)
04-10 21:18:33.768: E/AndroidRuntime(30687):    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:581)
04-10 21:18:33.768: E/AndroidRuntime(30687):    at java.lang.Thread.run(Thread.java:1019)
04-10 21:18:33.768: E/AndroidRuntime(30687): Caused by: android.view.ViewRoot$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views.
04-10 21:18:33.768: E/AndroidRuntime(30687):    at android.view.ViewRoot.checkThread(ViewRoot.java:2954)
04-10 21:18:33.768: E/AndroidRuntime(30687):    at android.view.ViewRoot.invalidateChild(ViewRoot.java:644)
04-10 21:18:33.768: E/AndroidRuntime(30687):    at android.view.ViewRoot.invalidateChildInParent(ViewRoot.java:670)
04-10 21:18:33.768: E/AndroidRuntime(30687):    at android.view.ViewGroup.invalidateChild(ViewGroup.java:2533)
04-10 21:18:33.768: E/AndroidRuntime(30687):    at android.view.View.invalidate(View.java:5288)
04-10 21:18:33.768: E/AndroidRuntime(30687):    at android.widget.TextView.checkForRelayout(TextView.java:5663)
04-10 21:18:33.768: E/AndroidRuntime(30687):    at android.widget.TextView.setText(TextView.java:2814)
04-10 21:18:33.768: E/AndroidRuntime(30687):    at android.widget.TextView.setText(TextView.java:2682)
04-10 21:18:33.768: E/AndroidRuntime(30687):    at android.widget.TextView.setText(TextView.java:2657)
04-10 21:18:33.768: E/AndroidRuntime(30687):    at dev.android.CCActivity3.fileReader(CCActivity3.java:207)
04-10 21:18:33.768: E/AndroidRuntime(30687):    at dev.android.CCActivity3$xyz.doInBackground(CCActivity3.java:110)//file reader
04-10 21:18:33.768: E/AndroidRuntime(30687):    at dev.android.CCActivity3$xyz.doInBackground(CCActivity3.java:1)
04-10 21:18:33.768: E/AndroidRuntime(30687):    at android.os.AsyncTask$2.call(AsyncTask.java:185)
04-10 21:18:33.768: E/AndroidRuntime(30687):    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:306)
04-10 21:18:33.768: E/AndroidRuntime(30687):    ... 4 more

我的应用程序有点滞后，所以我决定在应用程序加载时放入进度条微调器。进度条旋转约6分钟后，我的代码显示错误。它会在fileReader（）上抛出一个错误，有时它会永远旋转。 FileReader（）是另一个类文件，它是代码的核心。如果您希望看到此课程，请点击here 请帮我。我很感激。

Answer 1

问题是您正在尝试从doInBackground方法更改UI。根本原因可能是您的FileReader班级display.setText(fg);。当您在doInBackground时，无法对Acticity's用户界面进行更改。您需要使用AsyncTask的publishProgress和onProgressUpdate方法来实现这一目标。

Answer 2

this.dialog.dismiss();可以从if语句中删除，只要onPostExecute运行时对话框就会自动关闭。

编辑：我的代码建议：

在启动AsyncTask的类中：

            ProgressDialog progressDialog = new ProgressDialog(getActivity());
            progressDialog.setMessage("Logging in...");
            LoginTask loginTask = new LoginTask((Polling) getActivity(), progressDialog);
            loginTask.execute();

AsyncTask本身：

public class LoginTask extends AsyncTask<String, Void, Integer> {

private ProgressDialog progressDialog;
private Polling activity; 
 public LoginTask(Polling activity, ProgressDialog progressDialog)
{
    this.activity = activity;
    this.progressDialog = progressDialog;
}

@Override
protected void onPreExecute()
{
    progressDialog.show();
}

protected Integer doInBackground(String... arg0) {
    EditText userName = (EditText)activity.findViewById(R.id.emailEditText);
    EditText passwordEdit = (EditText)activity.findViewById(R.id.passEditText);
    String email = userName.getText().toString();
    String password = passwordEdit.getText().toString();
    UserFunctions userFunction = new UserFunctions();
    JSONObject json = userFunction.loginUser(email, password);

    // check for login response
    try {
        if (json.getString(KEY_SUCCESS) != null) {
            String res = json.getString(KEY_SUCCESS);

            if(Integer.parseInt(res) == 1){
                //whole bunch of extra code!
                responseCode = 1;
                // Close Login Screen
                //finish();

            }else{
                responseCode = 0;
                // Error in login
            }
        }

    } catch (NullPointerException e) {
        e.printStackTrace();

    }
    catch (JSONException e) {
        e.printStackTrace();
    }

    return responseCode;
}

@Override
protected void onPostExecute(Integer responseCode)
{
    EditText userName = (EditText)activity.findViewById(R.id.emailEditText);
    EditText passwordEdit = (EditText)activity.findViewById(R.id.passEditText);

    if (responseCode == 1) {
        progressDialog.dismiss();
        activity.loginReport(responseCode);
        userName.setText("");
        passwordEdit.setText("");
        //shared prefences, store name

    }
    if (responseCode == 0) {
        progressDialog.dismiss();
        activity.loginReport(responseCode);

    }
}

}

只需按照progressDialog进行操作即可。它在启动任务的主类中启动，传递给AsyncTask。然后，当AsyncTask构造时，progressDialog被存储为AsyncTask中的字段。然后，在preExecute中，我们显示（）progressDialog。然后，根据doInBackground的结果，我们向onPostExecute发送1或0。那一个或零告诉onPostExecute做什么，在我的代码中解析对话框，但是然后在主类中运行不同的方法。希望这有助于您将类似的任务与自己的任务进行比较。

Answer 3

runOnUiThread(new Runnable() {
@Override
public void run() {
// TODO Auto-generated method stub
if (this.dialog.isShowing()) {
this.dialog.dismiss();
}
});

在doInBackground（）的catch块中使用上面的代码。

进度条无限旋转

3 个答案: