android - 单击下载按钮时请求许可
问题描述
我正在 Android Studio 中使用 webView 制作应用程序。它只包含图片,所以我的应用程序中还有一个集成的下载按钮。在 android Marshmallow 版本中,您必须请求许可,我在 onCreate 中有一个许可代码,如下所示:
int check = ActivityCompat.checkSelfPermission(this, android.Manifest.permission.WRITE_EXTERNAL_STORAGE);
if (check == PackageManager.PERMISSION_GRANTED) {
//Do something
} else {
requestPermissions(new String[]{android.Manifest.permission.WRITE_EXTERNAL_STORAGE},1024);
}
但它会在应用程序启动时弹出,我想在用户单击下载按钮时弹出它。
我在 html 中的下载按钮如下所示:
<a href="url">Download</a>
应用程序中的下载代码如下所示:
@Override
public boolean shouldOverrideUrlLoading(WebView view, String url) {
if (url.endsWith(".jpg")) {
Uri source = Uri.parse(url);
// Make a new request pointing to the .apk url
DownloadManager.Request request = new DownloadManager.Request(source);
// appears the same in Notification bar while downloading
request.setDescription("Description for the DownloadManager Bar");
request.setTitle("PunjabiDharti.jpg");
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
request.allowScanningByMediaScanner();
request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
}
// save the file in the "Downloads" folder of SDCARD
request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, "PunjabiDharti.jpg");
// get download service and enqueue file
DownloadManager manager = (DownloadManager) getSystemService(Context.DOWNLOAD_SERVICE);
manager.enqueue(request);
用户点击下载按钮时如何弹出请求权限?
解决方案
您可以按如下方式实现:
public class WebViewActivity extends AppCompatActivity {
public static final int DOWNLOAD_REQUEST_CODE= 1024;
@Override
protected void onCreate(final Bundle savedInstanceState) {
...
webView.setWebViewClient(new WebViewClient(){
@Override
public boolean shouldOverrideUrlLoading(WebView view, String url) {
if (url.endsWith(".jpg")) {
int check = ActivityCompat.checkSelfPermission(this,android.Manifest.permission.WRITE_EXTERNAL_STORAGE);
if (check == PackageManager.PERMISSION_GRANTED) {
//DO the download stuff here
} else {
requestPermissions(new String[]{android.Manifest.permission.WRITE_EXTERNAL_STORAGE},DOWNLOAD_REQUEST_CODE);
}
}
}
});
}
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
if(requestCode == DOWNLOAD_REQUEST_CODE && grantResults[0] == PackageManager.PERMISSION_GRANTED){
//DO the download stuff here
}
}
}