android AsyncTask 详细例子（2）

最新推荐文章于 2021-04-06 15:43:03 发布

原创最新推荐文章于 2021-04-06 15:43:03 发布 · 1.7k 阅读

1 ·

CC 4.0 BY-SA版权

android 专栏收录该内容

156 篇文章

订阅专栏

本文介绍了一个Android应用中处理任务超时的方法。通过使用AsyncTask结合Java的Timer和TimerTask，实现了在指定时间内未完成任务则取消任务或者抛出超时异常的功能。此方案适用于需要在后台执行耗时操作并关注其执行时间的应用场景。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

超时处理

001
import java.util.Timer;

002
import java.util.TimerTask;

003
 
004
import android.app.Activity;

005
import android.os.AsyncTask;

006
import android.os.Bundle;

007
import android.widget.Toast;

008
 
009
public class TimeoutTestActivity extends Activity
 {

010
    private final static int TIME_OUT
 = 3 * 1000;

011
    private final static int SLEEP_TIME
 = 2 * 1000;

012
 
013
    @Override

014
    public void onCreate(Bundle
 savedInstanceState) {

015
        super.onCreate(savedInstanceState);

016
        setContentView(R.layout.main);

017
        //new
 TimeOutTask().execute();

018
        new CancelSelfWhenTimeOutTask().execute();

019
    }

020
 
021
    private class CancelSelfWhenTimeOutTask extends AsyncTask<Void,
 Void, Void> {

022
        private boolean done
 = false;

023
 
024
        @Override

025
        protected Void
 doInBackground(Void... params) {

026
            cancelSelfWhenTimeOut();

027
            sleep();

028
            return null;

029
        }

030
 
031
        @Override

032
        protected void onPostExecute(Void
 result) {

033
            super.onPostExecute(result);

034
            Toast.makeText(TimeoutTestActivity.this, "任务完成",
 Toast.LENGTH_SHORT)

035
                    .show();

036
        }

037
 
038
        private void cancelSelfWhenTimeOut()
 {

039
            new Timer().schedule(new TimerTask()
 {

040
 
041
                @Override

042
                public void run()
 {

043
                    if (!done)
 {

044
                        CancelSelfWhenTimeOutTask.this.cancel(true);

045
                    }

046
                }

047
            },
 TIME_OUT);

048
        }

049
 
050
        private void sleep()
 {

051
            try {

052
                Thread.sleep(SLEEP_TIME);

053
                done
 = true;

054
            } catch (InterruptedException
 e) {

055
            }

056
        }

057
    }

058
 
059
    private class TimeOutTask extends AsyncTask<Void,
 Void, Void> {

060
        private boolean done
 = false;

061
        private boolean isTimeOut
 = false;

062
 
063
        @Override

064
        protected Void
 doInBackground(Void... params) {

065
            try {

066
                throwTimeOutException();

067
            } catch (Exception
 e) {

068
                isTimeOut
 = true;

069
            }

070
            sleep();

071
            return null;

072
        }

073
 
074
        @Override

075
        protected void onPostExecute(Void
 result) {

076
            super.onPostExecute(result);

077
            if (isTimeOut)
 {

078
                Toast.makeText(TimeoutTestActivity.this, "任务超时",

079
                        Toast.LENGTH_SHORT).show();

080
            } else {

081
                Toast.makeText(TimeoutTestActivity.this, "任务完成",

082
                        Toast.LENGTH_SHORT).show();

083
            }

084
        }

085
 
086
        private void throwTimeOutException()
 {

087
            new Timer().schedule(new TimerTask()
 {

088
 
089
                @Override

090
                public void run()
 {

091
                    if (!done)
 {

092
                        isTimeOut
 = true;

093
                    }

094
                }

095
            },
 TIME_OUT);

096
        }

097
 
098
        private void sleep()
 {

099
            try {

100
                Thread.sleep(SLEEP_TIME);

101
                done
 = true;

102
            } catch (InterruptedException
 e) {

103
            }

104
        }

105
    }

106
 
107
}