使用DownloadManager进行版本更新（兼容7.0）

概述

DownloadManager是Android SDK中封装的下载文件类，可以很方便开发者使用下载文件。其具体看官方APIhttps://developer.android.com/reference/android/app/DownloadManager.html

正文

使用DownloadManager下载

public class DownloadUtils {

private DownloadManager mDownloadManager;
private Context mContext;
private long downloadId;
private String apkName;

public DownloadUtils(Context context) {
mContext = context;
}

public void download(String url, String name) {
final String packageName = "com.android.providers.downloads";
int state = mContext.getPackageManager().getApplicationEnabledSetting(packageName);
//检测下载管理器是否被禁用
if (state == PackageManager.COMPONENT_ENABLED_STATE_DISABLED
|| state == PackageManager.COMPONENT_ENABLED_STATE_DISABLED_USER
|| state == PackageManager.COMPONENT_ENABLED_STATE_DISABLED_UNTIL_USED) {
AlertDialog.Builder builder = new AlertDialog.Builder(mContext).setTitle("温馨提示").setMessage
("系统下载管理器被禁止，需手动打开").setPositiveButton("确定", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
dialog.dismiss();
try {
Intent intent = new Intent(Settings.ACTION_APPLICATION_DETAILS_SETTINGS);
intent.setData(Uri.parse("package:" + packageName));
mContext.startActivity(intent);
} catch (ActivityNotFoundException e) {
Intent intent = new Intent(Settings.ACTION_MANAGE_APPLICATIONS_SETTINGS);
mContext.startActivity(intent);
}
}
}).setNegativeButton("取消", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
dialog.dismiss();
}
});
builder.create().show();
} else {
//正常下载流程
apkName = name;
DownloadManager.Request request = new DownloadManager.Request(Uri.parse(url));
request.setAllowedOverRoaming(false);

//通知栏显示
request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
request.setTitle(AppUtils.getAppName(mContext));
request.setDescription("正在下载中...");
request.setVisibleInDownloadsUi(true);

//设置下载的路径
request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, apkName);

//获取DownloadManager
mDownloadManager = (DownloadManager) mContext.getSystemService(Context.DOWNLOAD_SERVICE);
downloadId = mDownloadManager.enqueue(request);

mContext.registerReceiver(mReceiver, new IntentFilter(DownloadManager.ACTION_DOWNLOAD_COMPLETE));
}
}

private BroadcastReceiver mReceiver = 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();
query.setFilterById(downloadId);
Cursor cursor = mDownloadManager.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:
installAPK();
break;
//下载失败
case DownloadManager.STATUS_FAILED:
Toast.makeText(mContext, "下载失败", Toast.LENGTH_SHORT).show();
break;
}
}
cursor.close();
}

/**
* 7.0兼容
*/
private void installAPK() {
File apkFile =
new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS), apkName);
Intent intent = new Intent(Intent.ACTION_VIEW);
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
Uri apkUri = FileProvider.getUriForFile(mContext, mContext.getPackageName() + ".provider", apkFile);
intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
intent.setDataAndType(apkUri, "application/vnd.android.package-archive");
} else {
intent.setDataAndType(Uri.fromFile(apkFile), "application/vnd.android.package-archive");
}
mContext.startActivity(intent);
}
}

在Manifest中添加使用权限

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

在Manifest中添加7.0私有文件权限

<provider
android:name="android.support.v4.content.FileProvider"
android:authorities="${applicationId}.provider"
android:exported="false"
android:grantUriPermissions="true">
<meta-data
android:name="android.support.FILE_PROVIDER_PATHS"
android:resource="@xml/provider_paths"/>
</provider>

建立xml私有文件权限配置

在res中建立xml文件夹，建立provider_paths.xml文件，文件中：

<?xml version="1.0" encoding="utf-8"?>
<resources xmlns:android="http://schemas.android.com/apk/res/android">
<paths>
<external-path
name="download"
path=""/>
</paths>
</resources>

后记

已兼容7.0私有文件权限问题
对于部分机型默认或者一些原因，下载管理器是被禁用掉的，必须手动开启或者写代码去跳转到设置界面开启，代码中已兼容。