Question

我有一个使用AsyncTask从服务器获取json文件的应用程序，因此显示了进度条。但是在显示进度条和方向更改时，应用程序崩溃显示VIEW NOT ATTACHED错误或HAS LEAKED WINDOW错误。

如何摆脱这些错误？否则，应用程序在AsyncTask上运行正常。

Answer 1

那么在AsyncTask运行时“锁定”屏幕方向呢？！

例如：

setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_NOSENSOR);

从服务器获取JSON文件之前

setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_SENSOR);

执行AsynTask后

。

Answer 2

我最好的猜测来自现有的有限信息：

当您旋转屏幕时，它会根据需要经历onPause（），onStop（）和onDestroy（）的正常活动生命周期过程，因此您必须在其中一个方法中关闭progressDialog

我是怎么做到的：

@Override
protected void onPause()
{
    super.onPause();
    if (mProgressDialog != null)
        mProgressDialog.dismiss();
}

Answer 3

试试这个活动。虽然不是很干净。它可以帮助

<activity android:configChanges="orientation|screenSize" android:name=".activity.MyActivity" ></activity>

Answer 4

尝试我放在一起的这个小黑客...当你尝试各种屏幕更改组合并按下硬件后退键时，运行它并观察logcat信息。然后尝试下面评论中提到的调整并再修补一些。这可以让你避免使用android：configChanges =“orientation | screenSize”，这是不可取的。

这应该使用最小的manifest和layout.xml文件进行构建。如果我以某种方式将其弄糟，请留下评论。

// ********************************************************************
// *** AsynchHack - allows for multiple screen orientation changes, ***
// ***    multiple asynch tasks are started / stopped,progress      ***
// ***    dialogs handled gracefully (no memory leaks / etc).       ***
// ***                                                              ***
// ***    Remove the wrapping comments in the onCreate() function   ***
// ***    to restrict processing to a single asynch instantiation   ***
// ***    screen rotation will dismiss the progress meter, but not  ***
// ***    the task                                                  ***
// ***                                                              ***
// ***    View the logcat to understand the timing of events and    ***
// ***    their interactions                                        ***
// ***                                                              ***
// ********************************************************************

package com.example.AsynchHack;

import android.app.Activity;
import android.app.ProgressDialog;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.widget.TextView;
import java.util.List;

// *** Main activity

public class AsynchHack extends Activity {

    final static String debugClass = "AsynchHack";
    ProgressDialog mProgressDialog;

    // *** standard onCreate()

    public void onCreate(Bundle aSavedInstanceState) {

        super.onCreate(aSavedInstanceState);
        Log.d(debugClass, "onCreate(" + this + ")");
        setContentView(R.layout.layout);

        // As-is, this allows for multiple starts of asynch tasks
        //if (aSavedInstanceState == null) {
        mProgressDialog = new ProgressDialog(this);
        (new AsynchStartup()).execute();
        //}

    }

    // *** demo Asynch task

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

        protected void onPreExecute() {
            Log.d(debugClass,
                  "--- AsynchStartup() onPreExecute  (" + this + ")");
            mProgressDialog.setMessage("Loading please wait..");
            mProgressDialog.show();
        }

        protected Void doInBackground(Void... aInput) {
            Log.d(debugClass,
                  "--- AsynchStartup() doInBackground(" +
                  this + ") *starts*");

            // simulate lengthy processing
            try {
                Thread.sleep(5000);
            }
            catch (InterruptedException aException) { }

            Log.d(debugClass,
                  "--- AsynchStartup() doInBackground(" +
                  this + ") *finishes*");
            return null;
        }

        protected void onProgressUpdate(Void aProgress){
        }

        protected void onPostExecute(Void aOutput) {
            Log.d(debugClass,
                  "--- AsynchStartup() onPostExecute (" + this + ")");

            if (mProgressDialog != null) {
                Log.d(debugClass,
                      "--- AsynchStartup() onPostExecute " +
                      "(Dismissing progress meter)");
                mProgressDialog.dismiss();
                mProgressDialog = null;
            }
            else {
                Log.d(debugClass,
                      "--- AsynchStartup() onPostExecute " +
                      "(Not required to dismiss progress meter)");
            }
        }

    }

    // *** standard onDestroy()

    public void onDestroy() {

        super.onDestroy();
        Log.d(debugClass, "onDestroy(" + this + ")");

        if (mProgressDialog != null) {
            Log.d(debugClass,
                 "onDestroy(Dismissing progress meter)");
            mProgressDialog.dismiss();
            mProgressDialog = null;
        }
        else {
            Log.d(debugClass,
                  "onDestroy(Not required to dismiss progress meter)");
        }

    }

}

Answer 5

尝试使用此

  dialog.setCancelable(false);

应用程序在AsyncTask中显示进度条时崩溃方向更改

5 个答案: