下载完成后如何通知

Question

我的 Android 应用中有下载功能。当我下载文件时，它会通过 toast 通知我。我想知道如何在下载完成后收到 toast 通知。我尝试了其他建议，但没有成功找到我预期的结果。

这是下载代码。

webView.setDownloadListener(new DownloadListener() {
            @Override
            public void onDownloadStart(String url, String userAgent, String contentDisposition,
                                        String mimeType, long contentLength) {
                DownloadManager.Request request = new DownloadManager.Request(Uri.parse(url));
                request.setMimeType(mimeType);
                String cookies = CookieManager.getInstance().getCookie(url);
                request.addRequestHeader("cookie",cookies);
                request.addRequestHeader("User-Agent",userAgent);
                request.setDescription("Downloading File");
                request.setTitle(URLUtil.guessFileName(url,contentDisposition,mimeType));
                request.allowScanningByMediaScanner();
                request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
                request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS,
                        URLUtil.guessFileName(url, contentDisposition, mimeType));
                DownloadManager downloadManager = (DownloadManager) getSystemService(DOWNLOAD_SERVICE);
                downloadManager.enqueue(request);
                Toast.makeText(getApplicationContext(), "Downloading File", Toast.LENGTH_SHORT).show();
            }
        });

提前谢谢你。

Answer 1

您可以创建一个Broadcast Receiver 来处理任何已完成下载的文件：

主要活动

public class MainActivity extends AppCompatActivity {

// create an object
OnComplete onComplete ;

@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    WebView webView = null;
    webView.setDownloadListener(new DownloadListener() {
        @Override
        public void onDownloadStart(String url, String userAgent, String contentDisposition,
                                    String mimeType, long contentLength) {
            DownloadManager.Request request = new DownloadManager.Request(Uri.parse(url));
            request.setMimeType(mimeType);
            String cookies = CookieManager.getInstance().getCookie(url);
            request.addRequestHeader("cookie",cookies);
            request.addRequestHeader("User-Agent",userAgent);
            request.setDescription("Downloading File");
            request.setTitle(URLUtil.guessFileName(url,contentDisposition,mimeType));
            request.allowScanningByMediaScanner();
            request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
            request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS,
                    URLUtil.guessFileName(url, contentDisposition, mimeType));
            DownloadManager downloadManager = (DownloadManager) getSystemService(DOWNLOAD_SERVICE);
            downloadManager.enqueue(request);
            Toast.makeText(getApplicationContext(), "Downloading File", Toast.LENGTH_SHORT).show();
        }
    });

    // the broadcast receiver object
    onComplete = new OnComplete();

}

@Override
protected void onResume() {
    super.onResume();
    // to start handling any download that completes
    registerReceiver(onComplete, new IntentFilter(DownloadManager.ACTION_DOWNLOAD_COMPLETE));
}

@Override
protected void onPause() {
    super.onPause();
    // to stop handling download complete when exit app
    unregisterReceiver(onComplete);
}

}

广播接收器（OnComplete）

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;

public class OnComplete extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
    // these codes will run when download completed
    // And you can do some thing
}
}

请不要忘记在Mainfest.xml 的<application/> 标签中添加此内容

<receiver android:name=".OnComplete" />

Answer 2

感谢@a7d.24_ 的回答。

我已经简化了答案，所以我不需要创建新的 Java 类 (OnComplete)，因此不需要将它添加到 Manifest.XML。

我只需在 webView.setDownloadListener 中添加一行代码并在 WebView 类中创建新的 BroadcastReceiver。

 @Override
 protected void onCreate(@Nullable Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);

 ...

        webView.setDownloadListener(new DownloadListener() {
        @Override
        public void onDownloadStart(String url, String userAgent, String contentDisposition,
                                    String mimeType, long contentLength) {
            DownloadManager.Request request = new DownloadManager.Request(Uri.parse(url));
            request.setMimeType(mimeType);
            String cookies = CookieManager.getInstance().getCookie(url);
            request.addRequestHeader("cookie",cookies);
            request.addRequestHeader("User-Agent",userAgent);
            request.setDescription("Downloading File");
            request.setTitle(URLUtil.guessFileName(url,contentDisposition,mimeType));
            request.allowScanningByMediaScanner();
            request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
            request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS,
                    URLUtil.guessFileName(url, contentDisposition, mimeType));
            DownloadManager downloadManager = (DownloadManager) getSystemService(DOWNLOAD_SERVICE);
            //Registering receiver in Download Manager
            registerReceiver(onCompleted, new IntentFilter(DownloadManager.ACTION_DOWNLOAD_COMPLETE));    
            downloadManager.enqueue(request);
            Toast.makeText(getApplicationContext(), "Downloading File", Toast.LENGTH_SHORT).show();
        }
    });

 ...

 BroadcastReceiver onCompleted = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
        Toast.makeText(context.getApplicationContext(), "Download Finish", Toast.LENGTH_SHORT).show();