无法在适配器中使用意图

Question

触发时 Intent finish activity 我收到此错误

03-20 11:05:16.991 8566-8566/com.example.jenya1.ebilling E/AndroidRuntime: FATAL EXCEPTION: main
                                                                       Process: com.example.jenya1.ebilling, PID: 8566
                                                                       java.lang.ClassCastException: droidninja.filepicker.FilePickerDelegate cannot be cast to android.app.Activity
                                                                           at com.example.jenya1.ebilling.adapter.MaterialAdapter.onClick(MaterialAdapter.java:142)
                                                                           at com.android.internal.app.AlertController$ButtonHandler.handleMessage(AlertController.java:166)
                                                                           at android.os.Handler.dispatchMessage(Handler.java:105)
                                                                           at android.os.Looper.loop(Looper.java:164)
                                                                           at android.app.ActivityThread.main(ActivityThread.java:6541)
                                                                           at java.lang.reflect.Method.invoke(Native Method)
                                                                           at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240)
                                                                           at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:767)

这一行导致错误

((Activity)mContext).finish();    //error

正在调用应用程序 class

private void loadMaterialRequest() {

    final ProgressBar progressBar = (ProgressBar) findViewById(R.id.progressBar);
    //getting the progressbar

    //making the progressbar visible
    progressBar.setVisibility(View.VISIBLE);

    albumList.clear();

    //creating a string request to send request to the url
    StringRequest stringRequest = new StringRequest(Request.Method.GET, HttpUrl+token+"&type="+type,
            new Response.Listener<String>() {
                @Override
                public void onResponse(String response) {
                    //hiding the progressbar after completion
                    progressBar.setVisibility(View.INVISIBLE);

                    try {
                        //getting the whole json object from the response
                        JSONObject obj = new JSONObject(response);

                        JSONArray heroArray = obj.getJSONArray("response");

                        //now looping through all the elements of the json array
                        for (int i = 0; i < heroArray.length(); i++) {
                            //getting the json object of the particular index inside the array
                            JSONObject heroObject = heroArray.getJSONObject(i);

                            //creating a hero object and giving them the values from json object
                            Material hero = new Material(
                                    heroObject.getInt("Request_id"),
                                    heroObject.getString("Site_name"),
                                    heroObject.getString("User_id"),
                                    heroObject.getString("Item_name"),
                                    heroObject.getString("Quantity"),
                                    heroObject.getString("Country"),
                                    heroObject.getString("Request_date"),
                                    heroObject.getString("Request_status"));

                            //adding the hero to herolist
                            albumList.add(hero);
                        }
                        //Log.e("list", String.valueOf(albumList));
                        //creating custom adapter object
                        adapter = new MaterialAdapter(getApplicationContext(),albumList);

                        //adding the adapter to listview
                        recyclerView.setAdapter(adapter);

                    } catch (JSONException e) {

                        e.printStackTrace();
                    }
                }
            },
            new Response.ErrorListener() {
                @Override
                public void onErrorResponse(VolleyError error) {

                    Log.e("error", String.valueOf(error));

                }
            });

    //creating a request queue
    RequestQueue requestQueue = Volley.newRequestQueue(this);

    //adding the string request to request queue
    requestQueue.add(stringRequest);
}

我正在尝试 Intent 当用户单击警报对话框是按钮时

这是我的适配器class：

import android.app.Activity;
import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.graphics.Color;
import android.graphics.Typeface;
import android.support.v7.widget.CardView;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.TextView;
import android.widget.Toast;

import com.example.jenya1.ebilling.MaterialHistoryActivity;
import com.example.jenya1.ebilling.R;
import com.example.jenya1.ebilling.model.HistoryQuotation;
import com.example.jenya1.ebilling.model.Material;

import java.util.ArrayList;
import java.util.List;

/**
 * Created by Mitesh Makwana on 18/03/18.
 */
public class MaterialAdapter extends RecyclerView.Adapter<MaterialAdapter.MyViewHolder> {

    private Context mContext;
    private List<Material> albumList;
    private List lstfavquoteid;


    String quote_id;
    ArrayList<Integer> arryfavquoteid;

    Typeface tf;
    ArrayList<String> imageserver,imageList;
    int count;

    int status=0;
    private int mExpandedPosition=-1;

    public class MyViewHolder extends RecyclerView.ViewHolder {
    public TextView title,quantity,site,date,note,req_id,status;

    ImageView delete;
    LinearLayout lndetail,lnapprove,lnreject,lnoperation;
    CardView cdview;

    public MyViewHolder(View view) {
        super(view);

        title = (TextView) view.findViewById(R.id.txttitle);
        req_id = (TextView) view.findViewById(R.id.txtreqid);
        quantity = (TextView) view.findViewById(R.id.txtquantity);
        date = (TextView) view.findViewById(R.id.txtdate);
        site = (TextView) view.findViewById(R.id.txtsite);
        note = (TextView) view.findViewById(R.id.txtnotes);
        status = (TextView) view.findViewById(R.id.txtstatus);

        delete=(ImageView)view.findViewById(R.id.imgmdelete);

        lndetail = (LinearLayout) view.findViewById(R.id.lndetails);
        lnapprove = (LinearLayout) view.findViewById(R.id.lnapprove);
        lnreject = (LinearLayout) view.findViewById(R.id.lnreject);
        lnoperation = (LinearLayout) view.findViewById(R.id.lnstatusoperation);
        cdview = (CardView) view.findViewById(R.id.card_view);
    }
    }

    public MaterialAdapter(Context mContext, List<Material> albumList) {
    this.mContext = mContext;
    this.albumList = albumList;
    }

    @Override
    public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    View itemView = LayoutInflater.from(parent.getContext())
            .inflate(R.layout.raw_material_history, parent, false);

    return new MyViewHolder(itemView);
    }

    @Override
    public void onBindViewHolder(final MyViewHolder holder, final int position) {

    arryfavquoteid = new ArrayList<Integer>();
    imageserver = new ArrayList<String>();

    tf = Typeface.createFromAsset(mContext.getAssets(), "fonts/HKNova-Medium.ttf");
    holder.title.setTypeface(tf);
    holder.req_id.setTypeface(tf);
    holder.quantity.setTypeface(tf);
    holder.date.setTypeface(tf);
    holder.site.setTypeface(tf);
    holder.note.setTypeface(tf);

    final Material album = albumList.get(position);

    holder.title.setText(album.getItem_name());
    holder.req_id.setText("#"+album.getId());
    holder.quantity.setText(album.getQuantity());
    holder.site.setText(album.getSite_id());

    String  input = album.getRequest_date();
    input = input.replace(" ", "\n");
    holder.date.setText(input);
    holder.note.setText("Notes : "+album.getCountry());

    holder.delete.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
//                Toast.makeText(mContext, "Delete...", Toast.LENGTH_SHORT).show();
            AlertDialog.Builder alert = new AlertDialog.Builder(
                    view.getContext());
            alert.setTitle("Alert!!");
            alert.setMessage("Are you sure to delete record");
            alert.setPositiveButton("YES", new DialogInterface.OnClickListener() {

                @Override
                public void onClick(DialogInterface dialog, int which) {
                    MaterialHistoryActivity.deleterequest(mContext,album.getId());

                    notifyDataSetChanged();

                    Intent i=new Intent(mContext,MaterialHistoryActivity.class);
                    mContext.startActivity(i);
                    ((Activity)mContext).finish();    //error

                    dialog.dismiss();

                }
            });
            alert.setNegativeButton("NO", new DialogInterface.OnClickListener() {

                @Override
                public void onClick(DialogInterface dialog, int which) {
                    dialog.dismiss();
                }
            });

            alert.show();
        }
    });
    if (mExpandedPosition == position) {

        if(album.getRequest_status().equals("1"))
        {
            holder.status.setText("Approved");
            holder.status.setVisibility(View.VISIBLE);
            holder.status.setTextColor(Color.GREEN);
            holder.lnoperation.setVisibility(View.GONE);
        }else if(album.getRequest_status().equals("2"))
        {
            holder.status.setText("Rejected");
            holder.status.setVisibility(View.VISIBLE);
            holder.status.setTextColor(Color.RED);
            holder.lnoperation.setVisibility(View.GONE);
        }
        else
        {
            holder.status.setVisibility(View.GONE);
            holder.lnoperation.setVisibility(View.VISIBLE);
        }

        //creating an animation
        Animation slideDown = AnimationUtils.loadAnimation(mContext, R.anim.slide_down);

        //toggling visibility
        holder.lndetail.setVisibility(View.VISIBLE);

        //adding sliding effect
        holder.lndetail.startAnimation(slideDown);
    }
    else
    {
        holder.lndetail.setVisibility(View.GONE);
    }

    holder.cdview.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {

            //getting the position of the item to expand it
            mExpandedPosition = position;

            //reloding the list
            notifyDataSetChanged();
        }
    });


    holder.lnapprove.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
//                Toast.makeText(mContext, "Approve...", Toast.LENGTH_SHORT).show();
            MaterialHistoryActivity.materialpermission(mContext,album.getId(),1);
        }
    });

    holder.lnreject.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
//                Toast.makeText(mContext, "Reject...", Toast.LENGTH_SHORT).show();
            MaterialHistoryActivity.materialpermission(mContext,album.getId(),2);

        }
    });

    }

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

非常感谢任何帮助。

Answer 1

您传递的是应用程序上下文，而不是适配器中的 Activity 上下文。

getApplicationContext(); 无论你经过哪里，它都会传递这个或 ActivityName.this。

由于您试图将您传递的上下文（应用程序不是您认为的 Activity）转换为具有

的 Activity

(Activity) 你得到这个异常是因为你不能将 Application 转换为 Activity 因为 Application 不是 Activity.

的 sub-class

Answer 2

让我们看看：

((Activity)mContext).finish();

日志说 mContext 是一种 FilePickerDelegate。因此，请检查您的 Adapter init 函数。我认为您将上下文作为 "this" 传递，但 "this" 引用 FilePickerDelegate。所以将其更改为 YourActivity.this（使用 activity）或 getActivity（在片段中）

Answer 3

在您的适配器中使用 Activity 而不是上下文。由于 Activity 可以转换为上下文，但上下文不能转换为 activity.

Activity avtivity;

public MaterialAdapter(Activity activity, List<Material> albumList) {
this.activity = activity;
this.albumList = albumList;
}

在你的调用中 activity 当你初始化你的适配器时，像下面这样调用这个适配器。

new MaterialAdapter(<your calling activity>.this, yourList);

Answer 4

view.getContext().startActivity(new Intent(mContext, MaterialHistoryActivity.class));

无法在适配器中使用意图

Unable to use intent in adapter

android

adapter

android-intent

android-activity