前言

每个应用肯定都会涉及到更新apk，这里给大家带来一个利用安卓原生DownloadManager完成apk下载的util，拷贝代码即可使用！

1.Util代码

package com.lytwsw.weatherad.utils;

import android.app.DownloadManager;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.database.Cursor;
import android.net.Uri;
import android.os.Build;
import android.os.Environment;
import android.support.v4.content.FileProvider;
import android.widget.Toast;

import java.io.File;
import java.io.IOException;

/**
 * author: Created by lixiaotong on 2018/10/17
 * e-mail: 516030811@qq.com
 */
public class DownloadUtils {
    //下载器
    private DownloadManager downloadManager;
    private Context mContext;
    //下载的ID
    private long downloadId;
    private String name;
    private String pathstr;

    public DownloadUtils(Context context, String url, String name) {
        this.mContext = context;
        downloadAPK(url, name);
        this.name = name;
    }

    //下载apk
    private void downloadAPK(String url, String name) {
        //创建下载任务
        DownloadManager.Request request = new DownloadManager.Request(Uri.parse(url));
        //移动网络情况下是否允许漫游
        request.setAllowedOverRoaming(false);
        //在通知栏中显示，默认就是显示的
        request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE);
        request.setTitle("通知标题，随意修改");
        request.setDescription("新版***下载中...");
        request.setVisibleInDownloadsUi(true);

        //设置下载的路径
        File file = new File(mContext.getExternalFilesDir(Environment.DIRECTORY_DOWNLOADS), name);
        request.setDestinationUri(Uri.fromFile(file));
        pathstr = file.getAbsolutePath();
        //获取DownloadManager
        if (downloadManager == null)
            downloadManager = (DownloadManager) mContext.getSystemService(Context.DOWNLOAD_SERVICE);
        //将下载请求加入下载队列，加入下载队列后会给该任务返回一个long型的id，通过该id可以取消任务，重启任务、获取下载的文件等等
        if (downloadManager != null) {
            downloadId = downloadManager.enqueue(request);
        }

        //注册广播接收者，监听下载状态
        mContext.registerReceiver(receiver,
                new IntentFilter(DownloadManager.ACTION_DOWNLOAD_COMPLETE));
    }

    //广播监听下载的各个状态
    private BroadcastReceiver receiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            checkStatus();
        }
    };

    //检查下载状态
    private void checkStatus() {
        DownloadManager.Query query = new DownloadManager.Query();
        //通过下载的id查找
        query.setFilterById(downloadId);
        Cursor cursor = downloadManager.query(query);
        if (cursor.moveToFirst()) {
            int status = cursor.getInt(cursor.getColumnIndex(DownloadManager.COLUMN_STATUS));
            switch (status) {
                //下载暂停
                case DownloadManager.STATUS_PAUSED:
                    break;
                //下载延迟
                case DownloadManager.STATUS_PENDING:
                    break;
                //正在下载
                case DownloadManager.STATUS_RUNNING:
                    break;
                //下载完成
                case DownloadManager.STATUS_SUCCESSFUL:
                    //下载完成安装APK
                    installAPK();
                    cursor.close();
                    break;
                //下载失败
                case DownloadManager.STATUS_FAILED:
                    Toast.makeText(mContext, "下载失败", Toast.LENGTH_SHORT).show();
                    cursor.close();
                    mContext.unregisterReceiver(receiver);
                    break;
            }
        }
    }

    private void installAPK() {
        setPermission(pathstr);
        Intent intent = new Intent(Intent.ACTION_VIEW);
        // 由于没有在Activity环境下启动Activity,设置下面的标签
        intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        //Android 7.0以上要使用FileProvider
        if (Build.VERSION.SDK_INT >= 24) {
            File file = (new File(pathstr));
            //参数1 上下文, 参数2 Provider主机地址 和配置文件中保持一致   参数3  共享的文件
            Uri apkUri = FileProvider.getUriForFile(mContext, "com.lxtwsw.weather.fileprovider", file);
            //添加这一句表示对目标应用临时授权该Uri所代表的文件
            intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
            intent.setDataAndType(apkUri, "application/vnd.android.package-archive");
        } else {
            intent.setDataAndType(Uri.fromFile(new File(Environment.DIRECTORY_DOWNLOADS, name)), "application/vnd.android.package-archive");
        }
        mContext.startActivity(intent);
    }

    //修改文件权限
    private void setPermission(String absolutePath) {
        String command = "chmod " + "777" + " " + absolutePath;
        Runtime runtime = Runtime.getRuntime();
        try {
            runtime.exec(command);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

2.在Manifest中，添加provider

注意，放到application里面

  <provider
            android:name="android.support.v4.content.FileProvider"
            android:authorities="com.lxtwsw.weather.fileprovider"
            android:exported="false"
            android:grantUriPermissions="true">
            <meta-data
                android:name="android.support.FILE_PROVIDER_PATHS"
                android:resource="@xml/filepath" />
  </provider>

3.在res目录下新建xml目录，然后创建一个filepath.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <paths>
        <external-path
            name="download"
            path="" />
    </paths>
</resources>

4.Android8.0未知来源权限

在mainfest中添加权限

<uses-permission android:name="android.permission.REQUEST_INSTALL_PACKAGES" />

5.使用

在需要下载apk的地方，直接调用即可

new DownloadUtils(context, appUrl, "***.apk");