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我在Android應用程序的第一個活動之前引入了啓動屏幕。此初始屏幕使用AsyncTask在第一個活動開始之前下載一些信息。由於這可能需要5秒鐘，我有一個進度條向用戶顯示進度。 AsyncTask按預期啓動，但我能夠顯示啓動畫面的唯一方法是創建一個單獨的線程。如果我不使用單獨的線程，則不顯示splashscreen。該應用只顯示一個空白屏幕，AsyncTask在後臺運行，然後該應用轉移到主要活動。使用AsyncTask的Android Splash屏幕
因此，它的功能工作，但我想啓動AsyncTask沒有產生一個單獨的線程。我有什麼選擇？
我想刪除的部分代碼如下。
new Thread(){
public void run()
{
startDownloadTask(); //kicks off the AsyncTask.
};
}.start();
這是我的代碼。
AppManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.drillexams.android"
android:versionCode="1"
android:versionName="1.0" >
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.MANAGE_ACCOUNTS" />
<uses-permission android:name="android.permission.GET_ACCOUNTS" />
<uses-permission android:name="android.permission.USE_CREDENTIALS" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="19" />
<application
android:allowBackup="true"
android:icon="@drawable/ic_app_icon"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<uses-library android:name="android.test.runner" />
<activity
android:name="com.drillexams.android.WorkInProgressActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name="com.drillexams.android.ExamListActivity">
<intent-filter>
<action android:name="android.intent.action.EXAMSLIST" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
<activity
android:name="com.drillexams.android.SettingsActivity"
android:parentActivityName="com.drillexams.android.ExamListActivity">
<!-- Parent activity meta-data to support API level 7+ -->
<meta-data
android:name="android.support.PARENT_ACTIVITY"
android:value="com.drillexams.android.ExamListActivity" />
</activity>
<activity
android:name="com.drillexams.android.DrillQuestionActivity"
android:parentActivityName="com.drillexams.android.ExamListActivity">
<!-- Parent activity meta-data to support API level 7+ -->
<meta-data
android:name="android.support.PARENT_ACTIVITY"
android:value="com.drillexams.android.ExamListActivity" />
</activity>
</application>
<instrumentation
android:name="android.test.InstrumentationTestRunner"
android:label="Android tests"
android:targetPackage="com.drillexams.android" />
</manifest>
activity_work_in_progress.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".WorkInProgressActivity" >
<ImageView
android:id="@+id/drillExamsLogoImageView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:contentDescription="@string/drill_exams_logo_content_description"
android:src="@drawable/ic_drill_exams_logo" />
<ProgressBar
android:id="@+id/progressBar"
style="?android:attr/progressBarStyleHorizontal"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/drillExamsLogoImageView"
android:layout_centerHorizontal="true"
android:layout_marginTop="20dp" />
</RelativeLayout>
WorkInProgressActivity.java
package com.drillexams.android;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.List;
import java.util.concurrent.ExecutionException;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;
import android.os.SystemClock;
import android.widget.ProgressBar;
import com.actionbarsherlock.app.SherlockActivity;
import com.drillexams.android.service.DrillExamsService;
import com.drillexams.android.sync.util.DownloadExamListHelper;
import com.drillexams.android.util.DrillExamsLogger;
import com.drillexams.model.Exam;
public class WorkInProgressActivity extends SherlockActivity {
ProgressTask task = new ProgressTask();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
DrillExamsLogger.start("WorkInProgressActivity.onCreate");
setContentView(R.layout.activity_work_in_progress);
new Thread(){
public void run()
{
startDownloadTask();
};
}.start();
DrillExamsLogger.end("WorkInProgressActivity.onCreate");
}
public void startDownloadTask() {
DrillExamsLogger.start("WorkInProgressActivity.startDownloadTask");
try {
task.execute(new URL(DrillExamsService.EXAM_URL));
task.get();
} catch (MalformedURLException e) {
DrillExamsLogger.e(e);
} catch (ExecutionException e) {
DrillExamsLogger.e(e);
} catch (InterruptedException e) {
DrillExamsLogger.e(e);
}
DrillExamsLogger.end("WorkInProgressActivity.startDownloadTask");
}
public void stopProgress() {
task.cancel(true);
}
private class ProgressTask extends AsyncTask<URL, Integer, List<Exam>> {
private ProgressBar progressBar;
private String token;
@Override
protected void onPreExecute() {
super.onPreExecute();
progressBar = (ProgressBar)findViewById(R.id.progressBar);
progressBar.bringToFront();
}
protected List<Exam> doInBackground(URL... urls) {
List<Exam> examsList = null;
DrillExamsLogger.start("DownloadExamList.doInBackground");
int start=0;
for(int i=start;i<=100;i+=5){
try {
if(!isCancelled()){
publishProgress(i);
progressBar.setProgress(i);
DrillExamsLogger.v("increment " + i);
SystemClock.sleep(300);
}
} catch (Exception e) {
DrillExamsLogger.e(e);
}
}
return null;
}
protected void onPostExecute(List<Exam> params) {
super.onPostExecute(params);
DrillExamsLogger.start("WorkInProgressActivity.onPostExecute");
Intent intent = new Intent(WorkInProgressActivity.this, ExamListActivity.class);
startActivity(intent);
finish();
DrillExamsLogger.end("WorkInProgressActivity.onPostExecute");
}
}
}
只需調用startDownloadTask（）），也沒有必要從一個獨立的線程啓動它。 – Houcine