Question

如果我不想在警告对话框中添加按钮，我可以添加警告对话框。但是，当我想添加一个警告对话框，其中包含2个按钮，其中包含onPostExecute＆＃39;当我输入此代码时，它显示红线：

Toast.makeText(this, "Yes", Toast.LENGTH_SHORT).show();

红线显示的错误：

无法解析方法＆＃39; makeText（匿名android.content.DialogInterface.OnClickListener，java.lang.String，int）＆＃39;

我按照此链接中的教程：https://www.youtube.com/watch?v=nW_nvmmxURc

这是我执行帖子中的代码：

@Override
    protected void onPostExecute(String result) {
        if (type.equals("cleck")){
            alertDialog = new AlertDialog.Builder(context).create();
            alertDialog.setTitle("PUV Checker");
            alertDialog.setMessage("Sample");


        }else {
            alertDialog = new AlertDialog.Builder(context).create();
            alertDialog.setTitle("Comment");

        }

        alertDialog.setMessage(result);
        alertDialog.setButton("Yes", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                Toast.makeText(this, "Yes", Toast.LENGTH_SHORT).show();
            }
        });
        alertDialog.show();
    }

注意：我是一个完全的初学者，只是在不同的教程中编写想法

编辑：添加了整个代码

import android.app.Dialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.os.AsyncTask;
import android.support.v7.app.ActionBarActivity;
import android.support.v7.app.AlertDialog;
import android.view.View;
import android.widget.Toast;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLEncoder;

/**
 * Created by Julian on 7/21/2017.
 */

public class BackgroundWorker extends AsyncTask<String,Void, String> {
    String type;
    Context context;
    AlertDialog alertDialog;
    BackgroundWorker (Context ctx){
        context = ctx;

    }

    @Override
    protected String doInBackground(String... params) {

        type = params[0];
        String register_url = "http://10.0.2.2/insert_comment";
        String retrieve_id = "http://10.0.2.2/rizal3.php";
        String report_id = "http://10.0.2.2/rizal4.php";
        if (type.equals("button")) {
            try {
                String id = params[1];
                String comment = params[2];
                String rating = params[3];
                URL url = new URL(register_url);
                HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
                httpURLConnection.setRequestMethod("POST");
                httpURLConnection.setDoOutput(true);
                httpURLConnection.setDoInput(true);
                OutputStream outputStream = httpURLConnection.getOutputStream();
                BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(outputStream, "UTF-8"));
                String post_data = URLEncoder.encode("id", "UTF-8") + "=" + URLEncoder.encode(id, "UTF-8") + "&"
                        + URLEncoder.encode("comment", "UTF-8") + "=" + URLEncoder.encode(comment, "UTF-8") + "&"
                        + URLEncoder.encode("rating", "UTF-8") + "=" + URLEncoder.encode(rating, "UTF-8");
                bufferedWriter.write(post_data);
                bufferedWriter.flush();
                bufferedWriter.close();
                outputStream.close();
                InputStream inputStream = httpURLConnection.getInputStream();
                BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream, "iso-8859-1"));
                String result = "";
                String line = "";
                while ((line = bufferedReader.readLine()) != null) {
                    result += line;
                }
                bufferedReader.close();
                inputStream.close();
                httpURLConnection.disconnect();
                return result;
            } catch (MalformedURLException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }else if(type.equals("cleck")) {
            try {
                String id_ret = params[1];

                URL url = new URL(retrieve_id);
                HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
                httpURLConnection.setRequestMethod("POST");
                httpURLConnection.setDoOutput(true);
                httpURLConnection.setDoInput(true);
                OutputStream outputStream = httpURLConnection.getOutputStream();
                BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(outputStream, "UTF-8"));
                String post_data = URLEncoder.encode("PLATE_NUM", "UTF-8") + "=" + URLEncoder.encode(id_ret, "UTF-8");
                bufferedWriter.write(post_data);
                bufferedWriter.flush();
                bufferedWriter.close();
                outputStream.close();
                InputStream inputStream = httpURLConnection.getInputStream();
                BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream, "iso-8859-1"));
                String result = "";
                String line = "";
                while ((line = bufferedReader.readLine()) != null) {
                    result += line;
                }
                bufferedReader.close();
                inputStream.close();
                httpURLConnection.disconnect();
                return result;
            } catch (MalformedURLException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }
        } else if(type.equals("report")){
                try {
                    String id_ret = params[1];
                    String puv_type = params[2];
                    String report = params[3];

                    URL url = new URL(report_id);
                    HttpURLConnection httpURLConnection = (HttpURLConnection)url.openConnection();
                    httpURLConnection.setRequestMethod("POST");
                    httpURLConnection.setDoOutput(true);
                    httpURLConnection.setDoInput(true);
                    OutputStream outputStream = httpURLConnection.getOutputStream();
                    BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(outputStream, "UTF-8"));
                    String post_data = URLEncoder.encode("PLATE_NUM","UTF-8")+"="+URLEncoder.encode(id_ret,"UTF-8") + "&"
                            + URLEncoder.encode("PUV_TYPE", "UTF-8") + "=" + URLEncoder.encode(puv_type, "UTF-8") + "&"
                            + URLEncoder.encode("content", "UTF-8") + "=" + URLEncoder.encode(report, "UTF-8");;
                    bufferedWriter.write(post_data);
                    bufferedWriter.flush();
                    bufferedWriter.close();
                    outputStream.close();
                    InputStream inputStream = httpURLConnection.getInputStream();
                    BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream, "iso-8859-1"));
                    String result = "";
                    String line = "";
                    while((line = bufferedReader.readLine())!= null){
                        result += line;
                    }
                    bufferedReader.close();
                    inputStream.close();
                    httpURLConnection.disconnect();
                    return result;
                } catch (MalformedURLException e) {
                    e.printStackTrace();
                } catch (IOException e) {
                    e.printStackTrace();
                }
        }
        return null;
    }
    @Override
    protected void onPreExecute() {

    }


    @Override
    protected void onPostExecute(String result) {
        if (type.equals("cleck")){
            alertDialog = new AlertDialog.Builder(context).create();
            alertDialog.setTitle("PUV Checker");
            alertDialog.setMessage("Sample");


        }else {
            alertDialog = new AlertDialog.Builder(context).create();
            alertDialog.setTitle("Comment");

        }

        alertDialog.setMessage(result);
        alertDialog.setButton("Yes", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {

                Toast.makeText(this, "Yes", Toast.LENGTH_SHORT).show();

            }
        });
        alertDialog.show();
    }

    @Override
    protected void onProgressUpdate(Void... values) {
        super.onProgressUpdate(values);
    }
}

我打电话给后台工作人员：

public void Button(View view) {

        String puv_plate = report_plate.getText().toString();
        String puv_type = report_type.getText().toString();
        String content = report_content.getText().toString();
        String type="report";
        BackgroundWorker backgroundWorker = new BackgroundWorker(Report.this);
        backgroundWorker.execute(type, puv_plate,puv_type,content);
    }

编辑：

使用此行时出现的错误

Toast.makeText(BackgroundWorker.this, "Yes", Toast.LENGTH_SHORT).show();

无法解析方法＆＃39; makeText（rjj.manilapuvtravelcompanion.BackgroundWorker，java.lang.String，int）＆＃39;

编辑：

Report.java中的整个代码（我称之为BackgroundWorker）

package rjj.manilapuvtravelcompanion;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;

public class Report extends AppCompatActivity {

    EditText report_plate, report_type, report_content;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_report);

        report_plate =(EditText)findViewById(R.id.report_plate_num);
        report_type = (EditText)findViewById(R.id.report_puv_type);
        report_content =(EditText)findViewById(R.id.report_content);
    }

    public void Button(View view) {

        String puv_plate = report_plate.getText().toString();
        String puv_type = report_type.getText().toString();
        String content = report_content.getText().toString();
        String type="report";
        BackgroundWorker backgroundWorker = new BackgroundWorker(Report.this);
        backgroundWorker.execute(type, puv_plate,puv_type,content);
    }
}

Answer 1

public static Toast makeText（Context context，CharSequence text，int 持续时间）

您应该传递 context 。

有关应用程序环境的全局信息的接口。这个是一个抽象类，其实现由Android提供系统。

Toast.makeText(context, "Yes", Toast.LENGTH_SHORT).show();

代码

 alertDialog = new AlertDialog.Builder(context).create();
    if (type.equals("cleck"))
    {
       alertDialog.setTitle("PUV Checker");
       alertDialog.setMessage("Sample");
    }
    else
    {
       alertDialog.setTitle("Comment");
       alertDialog.setMessage(result);
    }

 alertDialog.setButton("Yes", new DialogInterface.OnClickListener() 
 {
    @Override
        public void onClick(DialogInterface dialog, int which) 
        {
            Toast.makeText(context, "Yes", Toast.LENGTH_SHORT).show();
        }
        });

    alertDialog.show();

Answer 2

您提供DialogInterface.OnCLickListener引用而不是上下文。这样做

Toast.makeText(getApplicationContext(), "Yes", Toast.LENGTH_SHORT).show();

Answer 3

Toast.makeText(MainActivity.this, "Yes", Toast.LENGTH_SHORT).show();

使用Activity。如果您的代码处于活动状态，则此功能正常。

Answer 4

尝试使用下面而不是传递这个`

Toast.makeText(<YourMainActivity>.this,`...

您也可以使用getApplicationContext（）或getBaseContext（），但不建议使用它们，除非需要应用程序上下文。

如何添加扩展AsyncTask的警报对话框

4 个答案: