How to stop AsyncTask thread in android?

This example demonstrates how do I stop AsynchTask thread in android.

Step 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.

Step 2 − Add the following code to res/layout/activity_main.xml.

<?xml version="1.0" encoding="utf-8"?> <RelativeLayout    xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:layout_height="match_parent"    tools:context=".MainActivity">    <Button       android:id="@+id/btnDo"       android:layout_width="wrap_content"       android:layout_height="wrap_content"       android:layout_above="@id/btnCancel"       android:layout_centerInParent="true"       android:layout_marginBottom="25sp"       android:text="Do AsyncTask" />    <Button       android:id="@+id/btnCancel"       android:layout_width="wrap_content"       android:layout_height="wrap_content"       android:layout_above="@id/textView"       android:layout_centerInParent="true"       android:layout_marginBottom="20dp"       android:text="Cancel" />    <TextView       android:id="@+id/textView"       android:layout_width="match_parent"       android:layout_height="wrap_content"       android:layout_centerInParent="true"       android:textSize="20sp"       android:gravity="center_horizontal" /> </RelativeLayout>

Step 3 − Add the following code to src/MainActivity.java

import android.graphics.Color; import android.os.AsyncTask; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.view.View; import android.widget.Button; import android.widget.TextView; import java.util.ArrayList; import java.util.List; public class MainActivity extends AppCompatActivity {    private Button btnDo, btnCancel;    private TextView textView;    private AsyncTask myTask;    @Override    protected void onCreate(Bundle savedInstanceState) {       super.onCreate(savedInstanceState);       setContentView(R.layout.activity_main);       btnDo = findViewById(R.id.btnDo);       btnCancel = findViewById(R.id.btnCancel);       textView = findViewById(R.id.textView);       btnDo.setOnClickListener(new View.OnClickListener() {          @Override          public void onClick(View v) {             textView.setText("");             myTask = new DownloadTask().execute("Task1",                "Task2", "Task3", "Task4", "Task5");          }       });       btnCancel.setOnClickListener(new View.OnClickListener() {          @Override          public void onClick(View v) {             myTask.cancel(true);          }       });    }    private class DownloadTask extends AsyncTask<String, Integer, List<String>> {       @Override       protected void onPreExecute() {          super.onPreExecute();          textView.setTextColor(Color.BLUE);          textView.setText(textView.getText() + "
 Starting Task....");       }       @Override       protected List<String> doInBackground(String... tasks) {          int count = tasks.length;          List<String> taskList= new ArrayList<>(count);          for(int i =0;i<count;i++){             String currentTask = tasks[i];             taskList.add(currentTask);             try {                Thread.sleep(1000);             } catch (InterruptedException e) {                e.printStackTrace();             }             publishProgress((int) (((i+1) / (float) count) * 100));             if(isCancelled()){                break;             }          }          return taskList;       }       @Override       protected void onCancelled() {          super.onCancelled();          textView.setTextColor(Color.RED);          textView.setText(textView.getText() + "
 Operation is cancelled..");       }       @Override       protected void onProgressUpdate(Integer... progress) {          super.onProgressUpdate(progress);          textView.setText(textView.getText()+ "
 Completed:)" + progress[0] + "%");       }       @Override       protected void onPostExecute(List<String> result) {          super.onPostExecute(result);          textView.setText(textView.getText() + "

 Done....");          for (int i=0;i<result.size();i++){             textView.setText(textView.getText() + "
" +             result.get(i));          }       }    } }

Step 4 − Add the following code to androidManifest.xml

<?xml version="1.0" encoding="utf-8"?> <manifest    xmlns:android="http://schemas.android.com/apk/res/android"    package="app.com.sample">    <application       android:allowBackup="true"       android:icon="@mipmap/ic_launcher"       android:label="@string/app_name"       android:roundIcon="@mipmap/ic_launcher_round"       android:supportsRtl="true"       android:theme="@style/AppTheme">       <activity android:name=".MainActivity">          <intent-filter>             <action                android:name="android.intent.action.MAIN" />             <category                android:name="android.intent.category.LAUNCHER" />          </intent-filter>       </activity>    </application> </manifest>

Let's try to run your application. I assume you have connected your actual Android Mobile device with your computer. To run the app from android studio, open one of your project's activity files and click Run icon from the toolbar. Select your mobile device as an option and then check your mobile device which will display your default screen −