简单的intent

第一个界面的布局文件

<?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:orientation="vertical"
    tools:context="com.example.hzx.simple_intent.MainActivity">

    <Button
        android:id="@+id/btn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="跳转到第二个Activity"/>
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="第一个Activity"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</LinearLayout>

第二个界面的布局文件

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.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="com.example.hzx.simple_intent.Main2Activity">

    <TextView
        android:id="@+id/show_text"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:textSize="30sp"
        android:text="Activity2"/>
</android.support.constraint.ConstraintLayout>

第一个Activity

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        Button btn = (Button)findViewById(R.id.btn);

        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String data = "Hello";
                Intent intent = new Intent (MainActivity.this,Main2Activity.class);
                intent.putExtra("extra_data",data);
                startActivity(intent);
            }
        });
    }
}

第二个Activity

public class Main2Activity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main2);

        Intent intent = getIntent();
        String Extra_data = intent.getStringExtra("extra_data");

        TextView text = (TextView)findViewById(R.id.show_text);
        text.setText(Extra_data);


    }
}

效果
当点击按钮时，会跳转到第二个Activity,且传入字符串"Hello"

image.png

第二个Activity，从Intent获取到传入的字符串，显示到TextView中

image.png