首先，你需要先建立两个Activity,这里我们以MainActivtiy ,然后另一个是SecondActivtiy.
MainActivity中设置一个输入框跟一个点击按钮。然后SecondActivity中设置一个Text.
当在MainActivity写了东西之后，点击按钮。SecondActivity的Text就会显示MainActivity那里传送过来的内容。

MainActivty 的Layout:

<LinearLayout 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"
    android:orientation="vertical"
    android:background="#ffffff"
    tools:context=".MainActivity">
    <EditText
        android:id="@+id/edt"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="top"
        android:minLines="3"
        android:maxLines="3"
        android:textColor="#000000"
        android:textSize="20dp"
        android:hint="请输入.."
        android:textColorHint="#707070"/>


<Button
    android:id="@+id/btn"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:text="点击"
    android:textSize="15dp"
    android:textColor="#000000"/>
</LinearLayout>

SecondActivtiy的Layout

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
    android:background="#ffffff"
    tools:context=".SecondActivity">
    <TextView
        android:id="@+id/txt"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textSize="20dp"
        android:textColor="#000000"/>

</LinearLayout>

接下来，是MainActivity的java代码：

public class MainActivity extends AppCompatActivity {

  private Button btn;
  private EditText edt;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        btn = findViewById(R.id.btn);
        edt = findViewById(R.id.edt);
        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String data = edt.getText().toString();
                Intent intent = new Intent(MainActivity.this, SecondActivity.class);
                intent.putExtra("extra_data",data);
                startActivity(intent);


            }
        });



    }

接着是SecondActivity的代码：

public class SecondActivity extends AppCompatActivity {
   private TextView txt1;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_second);
        txt1 = findViewById(R.id.txt);
        Intent intent = getIntent();
        String data = intent.getStringExtra("extra_data");
        txt1.setText(data);

    }
}