New to coding, app keeps crashing on start up

Question

I'm trying to have a text field and a text view, and set the text view text to whatever is on the the field.

This is my code:

MainActivity.java

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

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        TextView helloMessage = (TextView) findViewById(R.id.hello); //define textView to show the message

        EditText  nameField = (EditText) findViewById(R.id.Name); // Text field to get the name from

        String  getName = nameField.getText().toString(); // set a variable with the text field's value

        helloMessage.setText(getName); // set text on the hello textview to be the name.


    }



}

activity_main.xml:

    <LinearLayout 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"
    android:background="#B388FF"
    android:orientation="vertical"
    tools:context=".MainActivity">


    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:inputType="textPersonName"
        android:ems="10"
        android:id="@+id/Name" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/hello"/>
</LinearLayout>

Thanks in advance for any sort of help!

Answer 1

Brother you need to setContentView(R.layout.activity_main); before finding any other view

Answer 2

您忘记将setContentView(R.layout.activity_main)添加到onCreate()