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package com.example.myapplication;
import android.os.Bundle;
import android.widget.TextView;
import androidx.appcompat.app.AppCompatActivity;
import android.view.ViewGroup;
import android.widget.LinearLayout;
public class MainActivity extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        TextView textView = new TextView(this);
        textView.setText("Hello World!");
        LinearLayout layout = new LinearLayout(this);
        layout.setLayoutParams(new LinearLayout.LayoutParams(
                ViewGroup.LayoutParams.MATCH_PARENT,
                ViewGroup.LayoutParams.MATCH_PARENT));
        layout.addView(textView);
        setContentView(layout);
    }
}