diff --git a/app/src/main/java/me/jj97181818/ch08_multiactivity/MainActivity.java b/app/src/main/java/me/jj97181818/ch08_multiactivity/MainActivity.java
index 495370b..5384aa7 100644
--- a/app/src/main/java/me/jj97181818/ch08_multiactivity/MainActivity.java
+++ b/app/src/main/java/me/jj97181818/ch08_multiactivity/MainActivity.java
@@ -3,23 +3,51 @@ package me.jj97181818.ch08_multiactivity;
 import android.content.Intent;
 import android.support.v7.app.AppCompatActivity;
 import android.os.Bundle;
+import android.support.annotation.Nullable;
 import android.view.View;
+import android.widget.TextView;
 
 public class MainActivity extends AppCompatActivity {
+    TextView tvPath;
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);
+
+        tvPath = findViewById(R.id.tv_path1);
+
+        run(getIntent());
+    }
+
+    private void run(Intent intent) {
+        tvPath.setText(intent.getCharSequenceExtra("path"));
+        if (tvPath.getText().equals("")) {
+            tvPath.setText("1");
+        }
+        else {
+            tvPath.setText(tvPath.getText() + " -> 1");
+        }
     }
 
     public void goBack (View v) {
+        Intent intent = new Intent();
+        intent.putExtra("path", tvPath.getText());
+        setResult(RESULT_OK, intent);
+
         finish();
     }
 
     public void gotoSecondActivity(View v) {
         Intent it = new Intent(this, SecondActivity.class);
-        startActivity(it);
+        it.putExtra("path", tvPath.getText());
+        startActivityForResult(it, 1);
     }
 
+    @Override
+    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
+        super.onActivityResult(requestCode, resultCode, data);
+
+        run(data);
+    }
 }
diff --git a/app/src/main/java/me/jj97181818/ch08_multiactivity/SecondActivity.java b/app/src/main/java/me/jj97181818/ch08_multiactivity/SecondActivity.java
index dd83e55..aad7c4d 100644
--- a/app/src/main/java/me/jj97181818/ch08_multiactivity/SecondActivity.java
+++ b/app/src/main/java/me/jj97181818/ch08_multiactivity/SecondActivity.java
@@ -1,24 +1,48 @@
 package me.jj97181818.ch08_multiactivity;
 
 import android.content.Intent;
+import android.support.annotation.Nullable;
 import android.support.v7.app.AppCompatActivity;
 import android.os.Bundle;
 import android.view.View;
+import android.widget.TextView;
 
 public class SecondActivity extends AppCompatActivity {
+    TextView tvPath;
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_second);
+
+        tvPath = findViewById(R.id.tv_path2);
+
+        run(getIntent());
+    }
+
+    private void run(Intent intent) {
+        tvPath.setText(intent.getCharSequenceExtra("path"));
+        tvPath.setText(tvPath.getText() + " -> 2");
     }
 
     public void goBack (View v) {
+        Intent intent = new Intent();
+        intent.putExtra("path", tvPath.getText());
+        setResult(RESULT_OK, intent);
+
         finish();
     }
 
     public void gotoThirdActivity(View v) {
         Intent it = new Intent(this, ThirdActivity.class);
-        startActivity(it);
+        it.putExtra("path", tvPath.getText());
+        startActivityForResult(it, 2);
+    }
+
+    @Override
+    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
+        super.onActivityResult(requestCode, resultCode, data);
+
+        run(data);
     }
 }
diff --git a/app/src/main/java/me/jj97181818/ch08_multiactivity/ThirdActivity.java b/app/src/main/java/me/jj97181818/ch08_multiactivity/ThirdActivity.java
index 0eacc97..af8944b 100644
--- a/app/src/main/java/me/jj97181818/ch08_multiactivity/ThirdActivity.java
+++ b/app/src/main/java/me/jj97181818/ch08_multiactivity/ThirdActivity.java
@@ -1,24 +1,48 @@
 package me.jj97181818.ch08_multiactivity;
 
 import android.content.Intent;
+import android.support.annotation.Nullable;
 import android.support.v7.app.AppCompatActivity;
 import android.os.Bundle;
 import android.view.View;
+import android.widget.TextView;
 
 public class ThirdActivity extends AppCompatActivity {
+    TextView tvPath;
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_third);
+
+        tvPath = findViewById(R.id.tv_path3);
+
+        run(getIntent());
+    }
+
+    private void run(Intent intent) {
+        tvPath.setText(intent.getCharSequenceExtra("path"));
+        tvPath.setText(tvPath.getText() + " -> 3");
     }
 
     public void goBack (View v) {
+        Intent intent = new Intent();
+        intent.putExtra("path", tvPath.getText());
+        setResult(RESULT_OK, intent);
+
         finish();
     }
 
     public void gotoFirstActivity(View v) {
         Intent it = new Intent(this, MainActivity.class);
-        startActivity(it);
+        it.putExtra("path", tvPath.getText());
+        startActivityForResult(it, 3);
+    }
+
+    @Override
+    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
+        super.onActivityResult(requestCode, resultCode, data);
+
+        run(data);
     }
 }
diff --git a/app/src/main/res/layout/activity_main.xml b/app/src/main/res/layout/activity_main.xml
index b2205e7..3f9f8df 100644
--- a/app/src/main/res/layout/activity_main.xml
+++ b/app/src/main/res/layout/activity_main.xml
@@ -6,24 +6,8 @@
     android:layout_height="match_parent"
     tools:context=".MainActivity">
 
-    <Button
-        android:id="@+id/button"
-        android:layout_width="wrap_content"
-        android:layout_height="wrap_content"
-        android:layout_marginStart="8dp"
-        android:layout_marginTop="8dp"
-        android:layout_marginEnd="8dp"
-        android:layout_marginBottom="8dp"
-        android:onClick="gotoSecondActivity"
-        android:text="開啟活動2"
-        app:layout_constraintBottom_toBottomOf="parent"
-        app:layout_constraintEnd_toEndOf="parent"
-        app:layout_constraintStart_toStartOf="parent"
-        app:layout_constraintTop_toBottomOf="@+id/button5"
-        app:layout_constraintVertical_bias="0.125" />
-
     <TextView
-        android:id="@+id/textView"
+        android:id="@+id/tv_name1"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_marginStart="20dp"
@@ -33,17 +17,45 @@
         app:layout_constraintStart_toStartOf="parent"
         app:layout_constraintTop_toTopOf="parent" />
 
-    <Button
-        android:id="@+id/button5"
+    <TextView
+        android:id="@+id/tv_path1"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_marginStart="8dp"
-        android:layout_marginTop="200dp"
         android:layout_marginEnd="8dp"
+        android:layout_marginBottom="8dp"
+        android:text="TextView"
+        app:layout_constraintBottom_toTopOf="@+id/btn_back1"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toBottomOf="@+id/tv_name1" />
+
+    <Button
+        android:id="@+id/btn_back1"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_marginStart="8dp"
+        android:layout_marginTop="164dp"
+        android:layout_marginEnd="8dp"
+        android:layout_marginBottom="8dp"
         android:onClick="goBack"
         android:text="結束活動1"
+        app:layout_constraintBottom_toTopOf="@+id/btn_start1"
         app:layout_constraintEnd_toEndOf="parent"
         app:layout_constraintStart_toStartOf="parent"
         app:layout_constraintTop_toTopOf="parent" />
 
+    <Button
+        android:id="@+id/btn_start1"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_marginStart="8dp"
+        android:layout_marginEnd="8dp"
+        android:layout_marginBottom="164dp"
+        android:onClick="gotoSecondActivity"
+        android:text="開啟活動2"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent" />
+
 </android.support.constraint.ConstraintLayout>
\ No newline at end of file
diff --git a/app/src/main/res/layout/activity_second.xml b/app/src/main/res/layout/activity_second.xml
index 0907afa..48b9558 100644
--- a/app/src/main/res/layout/activity_second.xml
+++ b/app/src/main/res/layout/activity_second.xml
@@ -6,24 +6,8 @@
     android:layout_height="match_parent"
     tools:context=".SecondActivity">
 
-    <Button
-        android:id="@+id/button2"
-        android:layout_width="wrap_content"
-        android:layout_height="wrap_content"
-        android:layout_marginStart="8dp"
-        android:layout_marginTop="8dp"
-        android:layout_marginEnd="8dp"
-        android:layout_marginBottom="8dp"
-        android:onClick="goBack"
-        android:text="回到活動1"
-        app:layout_constraintBottom_toTopOf="@+id/button3"
-        app:layout_constraintEnd_toEndOf="parent"
-        app:layout_constraintStart_toStartOf="parent"
-        app:layout_constraintTop_toTopOf="parent"
-        app:layout_constraintVertical_bias="0.848" />
-
     <TextView
-        android:id="@+id/textView2"
+        android:id="@+id/tv_name2"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_marginStart="20dp"
@@ -33,8 +17,35 @@
         app:layout_constraintStart_toStartOf="parent"
         app:layout_constraintTop_toTopOf="parent" />
 
+    <TextView
+        android:id="@+id/tv_path2"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_marginStart="8dp"
+        android:layout_marginEnd="8dp"
+        android:text="TextView"
+        app:layout_constraintBottom_toTopOf="@+id/btn_back2"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toBottomOf="@+id/tv_name2" />
+
     <Button
-        android:id="@+id/button3"
+        android:id="@+id/btn_back2"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_marginStart="8dp"
+        android:layout_marginTop="164dp"
+        android:layout_marginEnd="8dp"
+        android:layout_marginBottom="8dp"
+        android:onClick="goBack"
+        android:text="回到活動1"
+        app:layout_constraintBottom_toTopOf="@+id/btn_start2"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toTopOf="parent" />
+
+    <Button
+        android:id="@+id/btn_start2"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_marginStart="8dp"
diff --git a/app/src/main/res/layout/activity_third.xml b/app/src/main/res/layout/activity_third.xml
index 5fcb228..206425d 100644
--- a/app/src/main/res/layout/activity_third.xml
+++ b/app/src/main/res/layout/activity_third.xml
@@ -7,7 +7,7 @@
     tools:context=".ThirdActivity">
 
     <TextView
-        android:id="@+id/textView3"
+        android:id="@+id/tv_name3"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_marginStart="20dp"
@@ -17,28 +17,40 @@
         app:layout_constraintStart_toStartOf="parent"
         app:layout_constraintTop_toTopOf="parent" />
 
-    <Button
-        android:id="@+id/button4"
+    <TextView
+        android:id="@+id/tv_path3"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_marginStart="8dp"
-        android:layout_marginTop="88dp"
+        android:layout_marginEnd="8dp"
+        android:text="TextView"
+        app:layout_constraintBottom_toTopOf="@+id/btn_back3"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toBottomOf="@+id/tv_name3" />
+
+    <Button
+        android:id="@+id/btn_back3"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_marginStart="8dp"
+        android:layout_marginTop="164dp"
         android:layout_marginEnd="8dp"
         android:layout_marginBottom="8dp"
         android:onClick="goBack"
         android:text="回到活動2"
-        app:layout_constraintBottom_toTopOf="@+id/button6"
+        app:layout_constraintBottom_toTopOf="@+id/btn_start3"
         app:layout_constraintEnd_toEndOf="parent"
         app:layout_constraintStart_toStartOf="parent"
         app:layout_constraintTop_toTopOf="parent" />
 
     <Button
-        android:id="@+id/button6"
+        android:id="@+id/btn_start3"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_marginStart="8dp"
         android:layout_marginEnd="8dp"
-        android:layout_marginBottom="163dp"
+        android:layout_marginBottom="164dp"
         android:onClick="gotoFirstActivity"
         android:text="開啟活動1"
         app:layout_constraintBottom_toBottomOf="parent"