Java Android studio-在互联网不可用时禁用下载按钮/活动

我在我的应用程序中配置了下载按钮。当我在internet不可用时单击“下载”按钮时，该按钮被单击。当internet可用时，此下载活动开始，并且文件在internet脱机时我单击的次数都不会被下载

当互联网不可用时，我是否可以通过发送消息“检查您的互联网连接”来禁用下载活动

主要活动

public class Download_Activity extends AppCompatActivity {

    FirebaseFirestore downdb;
    RecyclerView downRecyclerView;
    ArrayList<Downloadsmodel> downloadsmodelArrayList=new ArrayList<>();
    DownloadsAdapter downloadsAdapter;


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

        setUpRV();
        setUpFB();
        dataFromFirebase();
    }

    private void dataFromFirebase() {
        downdb.collection("Downloads").get().addOnCompleteListener(new OnCompleteListener<QuerySnapshot>() {
            @Override
            public void onComplete(@NonNull Task<QuerySnapshot> task) {
                for(DocumentSnapshot documentSnapshot: task.getResult()){

                    Downloadsmodel downloadsmodel= new Downloadsmodel(documentSnapshot.getString("name")
                            ,documentSnapshot.getString("link"),documentSnapshot.getString("fileextension"),documentSnapshot.getString("uploaddate"),documentSnapshot.getString("icon"));
                    downloadsmodelArrayList.add(downloadsmodel);
                }
                downloadsAdapter= new DownloadsAdapter(Download_Activity.this,downloadsmodelArrayList);
                downRecyclerView.setAdapter(downloadsAdapter);
            }
        })

                .addOnFailureListener(new OnFailureListener() {
                    @Override
                    public void onFailure(@NonNull Exception e) {
                        Toast.makeText(Download_Activity.this,"Error",  Toast.LENGTH_SHORT).show();
                    }
                });

    }

    private void setUpFB() {
        downdb=FirebaseFirestore.getInstance();
    }

    private void setUpRV() {
        downRecyclerView=findViewById(R.id.drecyclerdownloads);
        downRecyclerView.setHasFixedSize(true);
        downRecyclerView.setLayoutManager(new LinearLayoutManager(this));
    }


}

公共类下载\u活动扩展了AppCompatActivity{
FireBaseFireStoreDownDB；
RecyclerView downRecyclerView；
ArrayList downloadsmodelArrayList=新建ArrayList（）；
下载Sadapter下载Sadapter；
@凌驾
创建时受保护的void（Bundle savedInstanceState）{
super.onCreate（savedInstanceState）；
setContentView（R.layout.activity\u下载）；
setUpRV（）；
setUpFB（）；
dataFromFirebase（）；
}
私有void dataFromFirebase（）{
downdb.collection（“Downloads”）.get（）.addOnCompleteListener（新的OnCompleteListener（）{
@凌驾
未完成的公共void（@NonNull任务）{
对于（DocumentSnapshot DocumentSnapshot:task.getResult（））{
Downloadsmodel Downloadsmodel=newdownloadsmodel（documentSnapshot.getString（“name”）
，documentSnapshot.getString（“链接”）、documentSnapshot.getString（“文件扩展”）、documentSnapshot.getString（“上传日期”）、documentSnapshot.getString（“图标”）；
downloadsmodelArrayList.add（downloadsmodel）；
}
downloadsAdapter=新的downloadsAdapter（下载活动。此为downloadsmodelArrayList）；
setAdapter（downloadsAdapter）；
}
})
.addOnFailureListener（新的OnFailureListener（）{
@凌驾
public void onFailure（@NonNull异常e）{
Toast.makeText（下载活动。此“错误”，Toast.LENGTH\u SHORT.show（）；
}
});
}
私有void setUpFB（）{
downdb=FirebaseFirestore.getInstance（）；
}
私有void setUpRV（）{
downRecyclerView=findViewById（R.id.DrecyclerDownload）；
downRecyclerView.setHasFixedSize（true）；
downRecyclerView.setLayoutManager（新的LinearLayoutManager（this））；
}
}

下载适配器

public class DownloadsAdapter extends RecyclerView.Adapter<Downloadsviewholder> {

    Download_Activity download_activity;
    ArrayList<Downloadsmodel> downloadsmodels;

    public DownloadsAdapter(Download_Activity download_activity, ArrayList<Downloadsmodel> downloadsmodels) {
        this.download_activity = download_activity;
        this.downloadsmodels = downloadsmodels;
    }



    @NonNull
    @Override
    public Downloadsviewholder onCreateViewHolder(@NonNull ViewGroup parent, int i) {
        LayoutInflater layoutInflater = LayoutInflater.from(download_activity.getBaseContext());
        View view = layoutInflater.inflate(R.layout.downloads_elements,null,false);
        return new Downloadsviewholder(view);
    }

    @Override
    public void onBindViewHolder(@NonNull final Downloadsviewholder downloadsviewholder, final int i) {
        downloadsviewholder.dName.setText(downloadsmodels.get(i).getName());
        downloadsviewholder.dUploaddate.setText(downloadsmodels.get(i).getUploaddate());
        downloadsviewholder.dExtension.setText(downloadsmodels.get(i).getFileextension());
        Picasso.get().load(downloadsmodels.get(i).getIcon()).into(downloadsviewholder.dIcon);
        downloadsviewholder.dButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                dowloadFile(downloadsviewholder.dName.getContext(),downloadsmodels.get(i).getName(),downloadsmodels.get(i).getFileextension()
                        ,DIRECTORY_DOWNLOADS,downloadsmodels.get(i).getLink());

            }
        });

    }

    public void dowloadFile (Context context,String filename, String fileextension, String destinationdirectory, String url){

        DownloadManager downloadManager=(DownloadManager) context.getSystemService(context.DOWNLOAD_SERVICE);
        Uri uri=Uri.parse(url);
        DownloadManager.Request request=new DownloadManager.Request(uri);
        request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
        request.setDestinationInExternalFilesDir(context, destinationdirectory, filename+fileextension);
        downloadManager.enqueue(request);

    }


    @Override
    public int getItemCount() {
        return downloadsmodels.size();
    }
}

公共类下载适配器扩展了RecyclerView.Adapter{
下载活动下载活动；
ArrayList下载模型；
公共下载适配器（下载活动下载活动，ArrayList downloadsmodels）{
this.download\u activity=下载\u activity；
this.downloadsmodels=downloadsmodels；
}
@非空
@凌驾
公开下载ViewHolder onCreateViewHolder（@NonNull ViewGroup父级，int i）{
LayoutInflater LayoutInflater=LayoutInflater.from（下载_activity.getBaseContext（））；
View=LayoutFlater.inflate（R.layout.downloads\u元素，null，false）；
返回新下载的viewholder（视图）；
}
@凌驾
public void onBindViewHolder（@NonNull final Downloadsviewholder Downloadsviewholder，final int i）{
downloadsviewholder.dName.setText（downloadsmodels.get（i.getName（））；
downloadsviewholder.dUploaddate.setText（downloadsmodels.get（i.getUploaddate（））；
downloadsviewholder.dExtension.setText（downloadsmodels.get（i.getFileextension（））；
Picasso.get（）.load（downloadsmodels.get（i.getIcon（））.into（downloadsviewholder.dIcon）；
下载viewholder.dButton.setOnClickListener（新视图.OnClickListener（）{
@凌驾
公共void onClick（视图）{
dowloadFile（downloadsviewholder.dName.getContext（），downloadsmodels.get（i）.getName（），downloadsmodels.get（i）.getFileextension（）
，目录_下载，下载models.get（i.getLink（））；
}
});
}
public void dowloadFile（上下文上下文、字符串文件名、字符串文件扩展名、字符串目标目录、字符串url）{
下载管理器下载管理器=（下载管理器）context.getSystemService（context.DOWNLOAD\u服务）；
Uri=Uri.parse（url）；
DownloadManager.Request=新的DownloadManager.Request（uri）；
request.setNotificationVisibility（DownloadManager.request.VISIBILITY\u VISIBLE\u NOTIFY\u完成）；
setdestinationnexternalfilesdir（上下文、destinationdirectory、文件名+文件扩展名）；
downloadManager.enqueue（请求）；
}
@凌驾
public int getItemCount（）{
返回下载的模型.size（）；
}
}

使用此功能检查互联网连接

   protected boolean isInternetConnected() {
        ConnectivityManager cm = (ConnectivityManager)getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo netInfo = cm.getActiveNetworkInfo();
        if (netInfo != null && netInfo.isConnectedOrConnecting()) {
            return true;
        } else {
            return false;
        }
    }

在您的

BindViewHolder中

如下使用：

   downloadsviewholder.dButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                     if(isInternetConnected()){

               dowloadFile(downloadsviewholder.dName.getContext(),downloadsmodels.get(i).getName(),downloadsmodels.get(i).getFileextension()
                        ,DIRECTORY_DOWNLOADS,downloadsmodels.get(i).getLink());
               } else {

                    //Change your button color so it looks like disable if you want 
                }

            }
        });