网络通信——下载管理器DownloadManager——在通知栏显示下载进度

比眉伴天荒 2024-04-01 08:22 59阅读 0赞

尽管直接使用GET方式也能下载网络文件，但这种方式存在以下缺点：

(1)无法断点续传，一旦中途失败，只能从头开始获取。(2)不是真正意义上的下载操作，没法设置下载参数。(3)下载过程中无法在界面上展示下载状态。

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布局：

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ApkConstant

package com.example.myapplication.constant;
    
    import com.example.myapplication.R;
    
    public class ApkConstant {
        public static String[] NAME_ARRAY = {
                "爱奇艺", "酷狗音乐", "美图秀秀", "微信", "淘宝", "QQ"
        };
        public static String[] PACKAGE_ARRAY = {
                "com.qiyi.video", "com.kugou.android", "com.mt.mtxx.mtxx",
                "com.tencent.mm", "com.taobao.taobao", "com.tencent.mobileqq"
        };
        public static int[] ICON_ARRAY = {
                R.drawable.icon_aiqiyi, R.drawable.icon_kugou, R.drawable.icon_meitu,
                R.drawable.icon_weixin, R.drawable.icon_taobao, R.drawable.icon_qq
        };
        public static String[] URL_ARRAY = {
                "http://103.231.68.98/McDonald/e/6880639/0/0/0/1632195714369/package_800120950.1632195714369&#39",
                "http://103.231.68.98/McDonald/e/6881873/0/0/0/1632195604939/package_10849.1632195604939&#39",
                "http://103.231.68.98/McDonald/e/6884026/0/0/0/1632196015129/package_9290.1632196015129&#39",
                "http://103.231.68.98/McDonald/e/6882606/0/0/0/1632197046375/package_17857.1632197046375&#39",
                "http://103.231.68.98/McDonald/e/6879467/0/0/0/1632194248559/package_1902.1632194248559&#39",
                "http://103.231.68.98/McDonald/e/6883576/0/0/0/1632196869079/package_2092.1632196869079&#39"
        };
    
    }

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DateUtil

package com.example.myapplication.util;
    
    import android.annotation.SuppressLint;
    import android.text.TextUtils;
    
    import java.text.SimpleDateFormat;
    import java.util.Date;
    
    @SuppressLint("SimpleDateFormat")
    public class DateUtil {
        // 获取当前的日期时间
        public static String getNowDateTime() {
            SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMddHHmmss");
            return sdf.format(new Date());
        }
    
        // 获取当前的时间
        public static String getNowTime() {
            SimpleDateFormat sdf = new SimpleDateFormat("HH:mm:ss");
            return sdf.format(new Date());
        }
    
        // 获取当前的时间(精确到毫秒)
        public static String getNowTimeDetail() {
            SimpleDateFormat sdf = new SimpleDateFormat("HH:mm:ss.SSS");
            return sdf.format(new Date());
        }
    
        // 获取指定格式的日期时间
        public static String getNowDateTime(String formatStr) {
            String format = formatStr;
            if (TextUtils.isEmpty(format)) {
                format = "yyyyMMddHHmmss";
            }
            SimpleDateFormat sdf = new SimpleDateFormat(format);
            return sdf.format(new Date());
        }
    
        public static String formatDate(long time) {
            Date date = new Date(time);
            SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
            return sdf.format(date);
        }
    
        // 重新格式化日期字符串
        public static String convertDateString(String strTime) {
            String newTime = strTime;
            try {
                SimpleDateFormat oldFormat = new SimpleDateFormat("yyyyMMddHHmmss");
                Date date = oldFormat.parse(strTime);
                SimpleDateFormat newFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
                newTime = newFormat.format(date);
            } catch (Exception e) {
                e.printStackTrace();
            }
            return newTime;
        }
    
    }

MainActivity

package com.example.myapplication;
    
    import android.annotation.SuppressLint;
    import android.app.DownloadManager;
    import android.app.DownloadManager.Request;
    import android.content.BroadcastReceiver;
    import android.content.Context;
    import android.content.Intent;
    import android.content.IntentFilter;
    import android.net.Uri;
    import android.os.Bundle;
    import android.os.Environment;
    import android.util.Log;
    import android.view.View;
    import android.widget.AdapterView;
    import android.widget.AdapterView.OnItemSelectedListener;
    import android.widget.ArrayAdapter;
    import android.widget.Spinner;
    import android.widget.TextView;
    import androidx.appcompat.app.AppCompatActivity;
    
    import com.example.myapplication.constant.ApkConstant;
    
    import com.example.myapplication.util.DateUtil;
    
    @SuppressLint({
         "SetTextI18n","DefaultLocale"})
    public class MainActivity extends AppCompatActivity
    {
    
        private static final String TAG = "DownloadApkActivity";
        private Spinner sp_apk_url; // 安装包链接的下拉框
        private TextView tv_apk_result;
        private boolean isFirstSelect = true; // 是否首次选择
        private DownloadManager mDownloadManager; // 声明一个下载管理器对象
        private long mDownloadId = 0; // 下载编号
    
        @Override
        protected void onCreate(Bundle savedInstanceState)
        {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
    
            tv_apk_result = findViewById(R.id.tv_apk_result);
    
            // 从系统服务中获取下载管理器
            mDownloadManager = (DownloadManager) getSystemService(Context.DOWNLOAD_SERVICE);
    
            initApkSpinner(); // 初始化安装包链接的下拉框
        }
    
        // 初始化安装包链接的下拉框
        private void initApkSpinner()
        {
            ArrayAdapter<String> apkUrlAdapter = new ArrayAdapter<String>(this, R.layout.item_select, ApkConstant.NAME_ARRAY);
    
            sp_apk_url = findViewById(R.id.sp_apk_url);
    
            sp_apk_url.setPrompt("请选择要下载的安装包");
    
            sp_apk_url.setAdapter(apkUrlAdapter);
    
            sp_apk_url.setOnItemSelectedListener(new ApkUrlSelectedListener());
    
            sp_apk_url.setSelection(0);
        }
    
        class ApkUrlSelectedListener implements OnItemSelectedListener
        {
            public void onItemSelected(AdapterView<?> arg0, View arg1, int arg2, long arg3)
            {
    
                if (isFirstSelect)      // 刚打开页面时不需要执行下载动作
                {
    
                    isFirstSelect = false;
                    return;
                }
                startDownload(arg2); // 开始下载指定序号的apk文件
            }
    
            public void onNothingSelected(AdapterView<?> arg0) {}
        }
    
        // 开始下载指定序号的apk文件
        private void startDownload(int pos)
        {
    
            tv_apk_result.setText("正在下载" + ApkConstant.NAME_ARRAY[pos] + "的安装包，请到通知栏查看下载进度");
    
            Uri uri = Uri.parse(ApkConstant.URL_ARRAY[pos]); // 根据下载地址构建一个Uri对象
    
            Request down = new Request(uri); // 创建一个下载请求对象，指定从哪里下载文件
    
            down.setTitle(ApkConstant.NAME_ARRAY[pos] + "下载信息"); // 设置任务标题
    
            down.setDescription(ApkConstant.NAME_ARRAY[pos] + "安装包正在下载"); // 设置任务描述
    
            // 设置允许下载的网络类型
            down.setAllowedNetworkTypes(Request.NETWORK_MOBILE | Request.NETWORK_WIFI);
    
            // 设置通知栏在下载进行时与完成后都可见
            down.setNotificationVisibility(Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
    
            // 设置下载文件在私有目录的保存路径。从Android10开始，只有保存到公共目录的才会在系统下载页面显示，保存到私有目录的不在系统下载页面显示
            down.setDestinationInExternalFilesDir(this, Environment.DIRECTORY_DOWNLOADS, pos + ".apk");
    
            // 设置下载文件在公共目录的保存路径。保存到公共目录需要申请存储卡的读写权限
            //down.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, pos + ".apk");
            mDownloadId = mDownloadManager.enqueue(down); // 把下载请求对象加入到下载队列
        }
    
        // 定义一个下载完成的广播接收器。用于接收下载完成事件
        private class DownloadCompleteReceiver extends BroadcastReceiver
        {
    
            @Override
            public void onReceive(Context context, Intent intent)
            {
    
                if (intent.getAction().equals(DownloadManager.ACTION_DOWNLOAD_COMPLETE))   // 下载完毕
                {
    
                    // 从意图中解包获得下载编号
                    long downId = intent.getLongExtra(DownloadManager.EXTRA_DOWNLOAD_ID, -1);
    
                    Log.d(TAG, "下载完成 id : " + downId + ", mDownloadId=" + mDownloadId);
    
                    tv_apk_result.setVisibility(View.VISIBLE);
    
                    String desc = String.format("%s 编号%d的下载任务已完成", DateUtil.getNowTime(), downId);
    
                    tv_apk_result.setText(desc); // 显示下载任务的完成描述
                }
            }
        }
    
        // 定义一个通知栏点击的广播接收器。用于接收下载通知栏的点击事件，在下载过程中有效，下载完成后失效
        private class NotificationClickReceiver extends BroadcastReceiver
        {
    
            @Override
            public void onReceive(Context context, Intent intent)
            {
    
                if (intent.getAction().equals(DownloadManager.ACTION_NOTIFICATION_CLICKED))  // 点击了通知栏
                {
                    // 从意图中解包获得被点击通知的下载编号
                    long[] downIds = intent.getLongArrayExtra(DownloadManager.EXTRA_NOTIFICATION_CLICK_DOWNLOAD_IDS);
    
                    for (long downId : downIds)
                    {
    
                        Log.d(TAG, "点击通知 id : " + downId + ", mDownloadId=" + mDownloadId);
    
                        if (downId == mDownloadId)   // 找到当前的下载任务
                        {
                            String desc = String.format("%s 点击了编号%d的下载通知", DateUtil.getNowTime(), downId);
    
                            tv_apk_result.setText(desc); // 显示下载任务的点击描述
                        }
                    }
                }
            }
        }
    
        private DownloadCompleteReceiver completeReceiver; // 声明一个下载完成的广播接收器
    
        private NotificationClickReceiver clickReceiver; // 声明一个通知栏点击的广播接收器
    
        @Override
        public void onStart()
        {
    
            super.onStart();
    
    
            completeReceiver = new DownloadCompleteReceiver(); // 创建一个下载完成的广播接收器
    
            // 注册接收器，注册之后才能正常接收广播
            registerReceiver(completeReceiver, new IntentFilter(DownloadManager.ACTION_DOWNLOAD_COMPLETE));
    
            clickReceiver = new NotificationClickReceiver(); // 创建一个通知栏点击的广播接收器
    
            // 注册接收器，注册之后才能正常接收广播
            registerReceiver(clickReceiver, new IntentFilter(DownloadManager.ACTION_NOTIFICATION_CLICKED));
        }
    
        @Override
        public void onStop()
        {
    
            super.onStop();
    
    
            unregisterReceiver(completeReceiver); // 注销下载完成的广播接收器
    
            unregisterReceiver(clickReceiver); // 注销通知栏点击的广播接收器
        }
    
    }

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