This post describes how to start a Service and stop a Service on Button click.
Create your layout in activity_main.xml. Add a TextView, a Button and an ImageView.
<?xml version="1.0" encoding="utf-8"?> <androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" tools:context=".MainActivity"> <TextView android:id="@+id/textView1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Hello World!" android:padding="10dp" android:layout_margin="10dp" app:layout_constraintBottom_toBottomOf="parent" app:layout_constraintLeft_toLeftOf="parent" app:layout_constraintRight_toRightOf="parent" app:layout_constraintTop_toTopOf="parent" /> <Button android:id="@+id/button1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="PICK FILE" app:layout_constraintBottom_toTopOf="@+id/textView1" app:layout_constraintEnd_toEndOf="parent" app:layout_constraintStart_toStartOf="parent" app:layout_constraintTop_toTopOf="parent" /> <ImageView android:id="@+id/imageView1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:scaleType="fitCenter" app:layout_constraintBottom_toBottomOf="parent" app:layout_constraintEnd_toEndOf="parent" app:layout_constraintStart_toStartOf="parent" app:layout_constraintTop_toBottomOf="@+id/textView1" tools:srcCompat="@tools:sample/avatars" /> </androidx.constraintlayout.widget.ConstraintLayout>
In MainActivity.java add following code.
package com.example.pickfile; import android.content.Intent; import android.net.Uri; import android.os.Bundle; import android.view.View; import android.widget.Button; import android.widget.ImageView; import android.widget.TextView; import androidx.annotation.Nullable; import androidx.appcompat.app.AppCompatActivity; public class MainActivity extends AppCompatActivity { ImageView image1; TextView text1; public static final int PICK_FILE =99; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); Button button1 = findViewById(R.id.button1); image1 = findViewById(R.id.imageView1); text1 = findViewById(R.id.textView1); button1.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { Intent intent = new Intent(Intent.ACTION_OPEN_DOCUMENT); intent.addCategory(Intent.CATEGORY_OPENABLE); intent.setType("image/*"); startActivityForResult(intent, PICK_FILE); } }); } @Override protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) { super.onActivityResult(requestCode, resultCode, data); if (requestCode == PICK_FILE && resultCode == RESULT_OK){ if (data != null){ Uri uri = data.getData(); image1.setImageURI(uri); text1.setText(uri.toString()); } } } }
Now run the app.
If you want to use the Activity Result APIs (ActivityResultContract and ActivityResultCallback to return an ActivityResultLauncher), use following code in MainActivity.java.
package com.example.pickfile; import android.net.Uri; import android.os.Bundle; import android.view.View; import android.widget.Button; import android.widget.ImageView; import android.widget.TextView; import androidx.activity.result.ActivityResultCallback; import androidx.activity.result.ActivityResultLauncher; import androidx.activity.result.contract.ActivityResultContracts; import androidx.appcompat.app.AppCompatActivity; public class MainActivity extends AppCompatActivity { ImageView image1; TextView text1; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); Button button1 = findViewById(R.id.button1); image1 = findViewById(R.id.imageView1); text1 = findViewById(R.id.textView1); button1.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { mGetContent.launch("image/*"); } }); } ActivityResultLauncher<String> mGetContent = registerForActivityResult(new ActivityResultContracts.GetContent(), new ActivityResultCallback<Uri>() { @Override public void onActivityResult(Uri uri) { image1.setImageURI(uri); text1.setText(uri.toString()); } }); }
Now run the app.