package com.example.bluegrey.myapplication;
import android.graphics.Color;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Gravity;
import android.view.View;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.TextView;
public class FirstActivity extends AppCompatActivity {
TextView textView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
LinearLayout linearLayout=new LinearLayout(this);
linearLayout.setOrientation(LinearLayout.VERTICAL);
linearLayout.setBackgroundColor(Color.GREEN);
setContentView(linearLayout);
Button button = new Button(this);
button.setText("Click me");
linearLayout.addView(button);
LinearLayout.LayoutParams layoutParams=new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT,LinearLayout.LayoutParams.WRAP_CONTENT);
layoutParams.gravity= Gravity.CENTER;
button.setLayoutParams(layoutParams);
final TextView textView=new TextView(this);
textView.setText("hello world!");
textView.setLayoutParams(layoutParams);
linearLayout.addView(textView);
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
textView.setText("I am happy");
}
});
}
}
