Android 如何获取写外部存储的运行时权限？

甚至我也在manifest.xml上添加了权限

package com.example.shery.youtubevideodownloader;

 import android.Manifest;
 import android.app.DownloadManager;
 import android.content.pm.PackageManager;
 import android.net.Uri;
 import android.os.Environment;
 import android.support.v4.app.ActivityCompat;
 import android.support.v4.content.ContextCompat;
 import android.support.v7.app.AppCompatActivity;
 import android.os.Bundle;
 import android.webkit.DownloadListener;
 import android.webkit.WebChromeClient;
 import android.webkit.WebSettings;
 import android.webkit.WebView;
 import android.webkit.WebViewClient;
 import static android.Manifest.permission.WRITE_EXTERNAL_STORAGE;
 import static android.content.pm.PackageManager.*;

 public class MainActivity extends AppCompatActivity {
 private WebView webView;
 String url = "https://svidzdownloader.com/";
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    webView = (WebView)findViewById(R.id.webview);
    webView.setWebViewClient(new WebViewClient());
    webView.loadUrl(url);
    WebSettings webSettings = webView.getSettings();



    webSettings.setJavaScriptEnabled(true);
    webView.setDownloadListener(new DownloadListener() {
        @Override
        public void onDownloadStart(String s, String s1, String s2, String s3, long l) {
            DownloadManager.Request request = new DownloadManager.Request(Uri.parse(url));
            request.allowScanningByMediaScanner();
            request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
            request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS,"Download");
            DownloadManager dm = (DownloadManager)getSystemService(DOWNLOAD_SERVICE);
            dm.enqueue(request);
        }
    });

}

}

我有一个webview应用程序，我想从中下载视频，我在上面的代码中添加了下载功能，所以我添加了清单上的权限，但是 当我按下下载按钮时，我的应用程序崩溃
这是我的日志“没有写入/storage/simulated/0/Download/Download的权限：用户10143和当前进程都没有android.permission.write\u EXTERNAL\u storage”

---

因此，如何获取运行时权限

首先，您必须使用以下代码检查您是否已经拥有该权限：

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

现在，如果权限被授予，那么您必须重写此方法以了解权限的状态

if (ActivityCompat.checkSelfPermission(context, Manifest.permission. WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED){
  //Ask for permission
   ActivityCompat.requestPermissions(context, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE});
}else{
  // Do your work
  webView.setDownloadListener(new DownloadListener() {
    @Override
    public void onDownloadStart(String s, String s1, String s2, String s3, long l) {
        DownloadManager.Request request = new DownloadManager.Request(Uri.parse(url));
        request.allowScanningByMediaScanner();
        request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
        request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS,"Download");
        DownloadManager dm = (DownloadManager)getSystemService(DOWNLOAD_SERVICE);
        dm.enqueue(request);
    }
});
}

---

希望这能有所帮助。

我尝试过搜索吗？是的，我已经搜索过了，但无法理解代码。改进我的代码可能与否重复我提出了我的问题我在这里提到的工作是downlod start方法及其侦听器。我写了一个关于如何在android中请求权限以及如何处理权限的一般回答。因此，如果允许如果我们的工作不是为您编写完整的代码，我们的工作也不是为您做任何事情@AhmedShahryarShery，那么我们应该做什么呢。请做些调查。一个简单的谷歌搜索就能找到你的答案。这两个答案将是下载开始时添加的方法？？

@RequiresApi(api = Build.VERSION_CODES.M)
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
    super.onRequestPermissionsResult(requestCode, permissions, grantResults);
    switch (requestCode) {
        case 100:
            if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
               //Do your work here.
               webView.setDownloadListener(new DownloadListener() {
    @Override
    public void onDownloadStart(String s, String s1, String s2, String s3, long l) {
        DownloadManager.Request request = new DownloadManager.Request(Uri.parse(url));
        request.allowScanningByMediaScanner();
        request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
        request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS,"Download");
        DownloadManager dm = (DownloadManager)getSystemService(DOWNLOAD_SERVICE);
        dm.enqueue(request);
    }
});
            }

    }
}