Question

这是新的更新代码，但仍然给我错误“未经授权。您没有此操作的权限”我想知道为什么这个错误谢谢。我已经实施了推荐的答案仍然没有用。

public class TipsActivity extends AppCompatActivity {
    private WebView mWebView;
    private static final int REQUEST_CODE_PERMISSION = 2;
    private static String[] PERMISSIONS_REQ = {
            Manifest.permission.WRITE_EXTERNAL_STORAGE
    };
    private static boolean verifyPermissions(Activity activity) {
        // Check if we have write permission
        int WritePermision = ActivityCompat.checkSelfPermission(activity, Manifest.permission.WRITE_EXTERNAL_STORAGE);
        if (WritePermision != PackageManager.PERMISSION_GRANTED) {
            // We don't have permission so prompt the user
            ActivityCompat.requestPermissions(
                    activity,
                    PERMISSIONS_REQ,
                    REQUEST_CODE_PERMISSION
            );
            return false;
        } else {
            return true;
        }
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_tips);
        mWebView = (WebView) findViewById(R.id.webView7);
        WebSettings webSettings = mWebView.getSettings();
        webSettings.setJavaScriptEnabled(true);
        mWebView.setWebChromeClient(new WebChromeClient());
        mWebView.loadUrl("http://www.example.com");
        mWebView.setWebViewClient(new WebViewClient());
        mWebView.setDownloadListener(new DownloadListener() {

            @Override
            public void onDownloadStart(String url, String userAgent,
                                        String contentDisposition, String mimeType,
                                        long contentLength) {
                if (verifyPermissions(TipsActivity.this)) {
                    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 dm = (DownloadManager) getSystemService(DOWNLOAD_SERVICE);
                    dm.enqueue(request);
                    Toast.makeText(getApplicationContext(), "Downloading File",
                            Toast.LENGTH_LONG).show();
                } else {
//prompt user for permission
                }

            }
        });
    }


    @Override
    public void onBackPressed() {
        if (mWebView.canGoBack()) {
            mWebView.goBack();
        } else {
            super.onBackPressed();
        }
    }

    }

这是新的更新代码，但仍然给我错误“未经授权。您没有此操作的权限”我想知道为什么这个错误谢谢。我已经实施了推荐的答案仍然没有用。

Answer 1

注意！添加在清单中写入外部存储的权限，并获取用户对lolipop api设备后的运行时权限

对于运行时持久性检查此Document Link

您的活动中的

首先将此声明为字段（GLOBAL VARIABLE）

private static final int REQUEST_CODE_PERMISSION = 2;
    private static String[] PERMISSIONS_REQ = {
           Manifest.permission.WRITE_EXTERNAL_STORAGE
    };
private static boolean verifyPermissions(Activity activity) {
        // Check if we have write permission
        int WritePermision = ActivityCompat.checkSelfPermission(activity, Manifest.permission.WRITE_EXTERNAL_STORAGE);
        if (WritePermision != PackageManager.PERMISSION_GRANTED) {
            // We don't have permission so prompt the user
            ActivityCompat.requestPermissions(
                    activity,
                    PERMISSIONS_REQ,
                    REQUEST_CODE_PERMISSION
            );
            return false;
        } else {
            return true;
        }
    }

在您的下载管理器中使用上述方法，有点像

 mwebView.setDownloadListener(new DownloadListener()
       {

      @Override  
       public void onDownloadStart(String url, String userAgent,
            String contentDisposition, String mimeType,
            long contentLength) {
if(verifyPermissions(yourActivity.this)){
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 dm = (DownloadManager) getSystemService(DOWNLOAD_SERVICE);
        dm.enqueue(request);
        Toast.makeText(getApplicationContext(), "Downloading File",
                Toast.LENGTH_LONG).show();
}else{
//prompt user for permission
}

    }});

了解更多支票this

Answer 2

你可以尝试 -

mWebView.setDownloadListener(new DownloadListener() {
    public void onDownloadStart(String url, String userAgent,
                String contentDisposition, String mimetype,
                long contentLength) {
        Intent i = new Intent(Intent.ACTION_VIEW);
        i.setData(Uri.parse(url));
        startActivity(i);
    }
});

如何在webview中下载文档或文件

2 个答案: