【Android开发】不同Activity之间的数据回传实例（一）摘桃子游戏

一、功能介绍

该项目实现的功能主要有：

在首页显示一个按钮点击该按钮跳转到桃园页面
在桃园页面，点击桃子会弹窗显示摘到几个桃子，同时被点击桃子消失，总桃子数+1
点击退出桃园会返回首页，首页桃子数会根据点击的桃子数动态增加

二、代码实现

1. 资源准备

将项目所需要的图片bg.png、monkey.png、btn_peach.png、peach_pic.png 导入程序的drawablehdpi文件夹中（默认情况下程序中没有drawable-hdpi 文件夹，需手动在res 文件夹中创建一个）。

2. 布局文件设计

2.1 主Activity

在layout文件夹中编辑activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">
    <TextView
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:background="#008577"
        android:gravity="center"
        android:text="首页"
        android:textColor="@android:color/white"
        android:textSize="20sp" />
    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@drawable/bg"
        android:gravity="center_vertical">

        <ImageView
            android:id="@+id/iv_monkey"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:src="@drawable/monkey" />

        <Button
            android:id="@+id/btn_peach"
            android:layout_width="80dp"
            android:layout_height="40dp"
            android:layout_marginLeft="30dp"
            android:layout_marginTop="250dp"
            android:layout_toRightOf="@id/iv_monkey"
            android:background="@drawable/btn_peach"
            android:gravity="center"
            android:text="去桃园"
            android:textColor="@android:color/black"
            android:textSize="18sp" />
        <ImageView
            android:id="@+id/iv_peach"
            android:layout_width="45dp"
            android:layout_height="35dp"
            android:layout_below="@+id/btn_peach"
            android:layout_centerHorizontal="true"
            android:layout_marginTop="20dp"
            android:src="@drawable/peach_pic" />
        <TextView
            android:id="@+id/tv_count"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_below="@+id/btn_peach"
            android:layout_marginTop="25dp"
            android:layout_marginLeft="10dp"
            android:layout_toRightOf="@id/iv_peach"
            android:text="摘到0 个"
            android:textColor="@android:color/black"
            android:textSize="20sp" />
    </RelativeLayout>
</LinearLayout>

2.2 辅Activity

在layout文件夹中新增activity_peach.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">
    <TextView
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:background="#008577"
        android:gravity="center"
        android:text="桃园"
        android:textColor="@android:color/white"
        android:textSize="20sp" />
    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@drawable/tree_bg">
        <RelativeLayout
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_centerInParent="true"
            android:layout_marginTop="70dp"
            android:background="@drawable/tree">
            <Button
                android:id="@+id/btn_one"
                android:layout_width="55dp"
                android:layout_height="40dp"
                android:layout_marginLeft="140dp"
                android:layout_marginTop="35dp"
                android:background="@drawable/peach_pic" />

            <Button
                android:id="@+id/btn_two"
                android:layout_width="55dp"
                android:layout_height="40dp"
                android:layout_below="@id/btn_one"
                android:layout_marginLeft="80dp"
                android:layout_marginTop="5dp"
                android:background="@drawable/peach_pic" />
            <Button
                android:id="@+id/btn_three"
                android:layout_width="55dp"
                android:layout_height="40dp"
                android:layout_below="@id/btn_one"
                android:layout_marginLeft="70dp"
                android:layout_marginTop="5dp"
                android:layout_toRightOf="@id/btn_two"
                android:background="@drawable/peach_pic" />
            <Button
                android:id="@+id/btn_four"
                android:layout_width="55dp"
                android:layout_height="40dp"
                android:layout_below="@id/btn_two"
                android:layout_marginLeft="25dp"
                android:layout_marginTop="15dp"
                android:background="@drawable/peach_pic" />
            <Button
                android:id="@+id/btn_five"
                android:layout_width="55dp"
                android:layout_height="40dp"
                android:layout_below="@id/btn_two"
                android:layout_marginLeft="70dp"
                android:layout_marginTop="15dp"
                android:layout_toRightOf="@id/btn_four"
                android:background="@drawable/peach_pic" />

            <Button
                android:id="@+id/btn_six"
                android:layout_width="55dp"
                android:layout_height="40dp"
                android:layout_below="@id/btn_two"
                android:layout_marginLeft="45dp"
                android:layout_marginTop="15dp"
                android:layout_toRightOf="@id/btn_five"
                android:background="@drawable/peach_pic" />
        </RelativeLayout>
        <Button
            android:id="@+id/btn_exit"
            android:layout_width="100dp"
            android:layout_height="40dp"
            android:layout_alignParentRight="true"
            android:layout_alignParentBottom="true"
            android:layout_margin="50dp"
            android:background="@drawable/btn_peach"
            android:text="退出桃园"
            android:gravity="center"
            android:textColor="@android:color/black"
            android:textSize="18sp"/>
    </RelativeLayout>
</LinearLayout>

2.3 其他资源文件

主题文件themes.xml

<resources xmlns:tools="http://schemas.android.com/tools">
    <!-- Base application theme. -->
    <style name="Theme.PickPeach" parent="Theme.MaterialComponents.DayNight.DarkActionBar.Bridge">
        <!-- Primary brand color. -->
        <item name="colorPrimary">@color/colorPrimary</item>
        <item name="colorPrimaryVariant">@color/colorPrimaryDark</item>
        <item name="colorOnPrimary">@color/white</item>
        <!-- Secondary brand color. -->
        <item name="colorSecondary">@color/teal_200</item>
        <item name="colorSecondaryVariant">@color/teal_700</item>
        <item name="colorOnSecondary">@color/black</item>
        <!-- Status bar color. -->
        <item name="android:statusBarColor" tools:targetApi="l">?attr/colorPrimaryVariant</item>
        <!-- Customize your theme here. -->
    </style>
    <style name="MyCustomTheme" parent="Theme.AppCompat.Light.NoActionBar">
        <!-- Primary brand color. -->
        <item name="colorPrimary">@color/colorPrimary</item>
        <item name="colorPrimaryVariant">@color/colorPrimaryDark</item>
        <item name="colorOnPrimary">@color/white</item>
        <!-- Secondary brand color. -->
        <item name="colorSecondary">@color/teal_200</item>
        <item name="colorSecondaryVariant">@color/teal_700</item>
        <item name="colorOnSecondary">@color/black</item>
        <!-- Status bar color. -->
        <item name="android:statusBarColor" tools:targetApi="l">?attr/colorPrimaryVariant</item>
        <!-- Customize your theme here. -->
    </style>
</resources>

3. 实现逻辑功能

3.0 全局配置文件

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.hzj.pickpeach">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/MyCustomTheme">
        <activity
            android:name=".MainActivity"
            android:exported="true">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity
            android:name=".PeachActivity"
            android:exported="true">
        </activity>
    </application>

</manifest>

3.1 首页功能

在MainActivity 中实现“去桃园”按钮的点击事件，当点击按钮时程序跳转到桃园摘桃的界面。同时，还需要接收桃园界面回传过来的桃子个数。

public class MainActivity extends AppCompatActivity {
    private Button btn_peach;
    private TextView tv_count;
    private int totalCount = 0;

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

    private void init() {
        btn_peach = findViewById(R.id.btn_peach);
        tv_count = findViewById(R.id.tv_count);
        //为按钮设置点击事件监听器
        btn_peach.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                //设置意图对象，实现界面跳转
                Intent intent = new Intent(MainActivity.this, PeachActivity.class);
                startActivityForResult(intent, 1);
//                startActivity(intent);
            }
        });
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        //判断请求码和返回码是否正确
        if (requestCode==1 && requestCode==1) {
            //获取回传的数据
            int count = data.getIntExtra("count", 0);;
            totalCount = totalCount + count;
            tv_count.setText("摘到" + totalCount + "个");
        }
    }
}

3.2 桃园界面的摘桃效果

点击桃子实现摘桃效果，同时全局桃子数动态变化，点击退出桃园，返回首页，同时更新首页桃子数。

public class PeachActivity extends AppCompatActivity implements View.OnClickListener {

    private Button btn_one, btn_two, btn_three, btn_four, btn_five, btn_six, btn_exit;
    private int count = 0;//桃子个数

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

    private void init() {
        btn_one = findViewById(R.id.btn_one);
        btn_two = findViewById(R.id.btn_two);
        btn_three = findViewById(R.id.btn_three);
        btn_four = findViewById(R.id.btn_four);
        btn_five = findViewById(R.id.btn_five);
        btn_six = findViewById(R.id.btn_six);
        btn_exit = findViewById(R.id.btn_exit);
        btn_one.setOnClickListener(this);
        btn_two.setOnClickListener(this);
        btn_three.setOnClickListener(this);
        btn_four.setOnClickListener(this);
        btn_five.setOnClickListener(this);
        btn_six.setOnClickListener(this);
        btn_exit.setOnClickListener(this);
    }

    @Override
    public void onClick(View view) {
        switch (view.getId()) {
            case R.id.btn_one: //第一个桃子的点击事件
                info(btn_one);
                break;
            case R.id.btn_two: //第二个桃子的点击事件
                info(btn_two);
                break;
            case R.id.btn_three: //第三个桃子的点击事件
                info(btn_three);
                break;
            case R.id.btn_four: //第四个桃子的点击事件
                info(btn_four);
                break;
            case R.id.btn_five: //第五个桃子的点击事件
                info(btn_five);
                break;
            case R.id.btn_six: //第六个桃子的点击事件
                info(btn_six);
                break;
            case R.id.btn_exit: //“退出桃园”按钮的点击事件
                returnData();
                break;
            default:
                throw new IllegalStateException("Unexpected value: " + view.getId());
        }
    }

    /**
     * 按钮的点击事件处理
     */
    private void info(Button btn) {
        //桃子个数加1
        count++;
        //被摘掉的桃子设置为隐藏不可见
        btn.setVisibility(View.INVISIBLE);
        Toast.makeText(PeachActivity.this, "摘到" + count + "个桃子",
                Toast.LENGTH_LONG).show();
    }

    /**
     * 将数据回传到上个界面
     */
    private void returnData() {
        //设置意图对象，将摘桃子的个数回传给首页界面
        Intent intent = new Intent();
        intent.putExtra("count", count);
        //返回码标识
        setResult(1, intent);
        //销毁本界面
        PeachActivity.this.finish();
    }

    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        //当点击设备返回键时，调用数据回传方法，返回首页界面
        if (keyCode == KeyEvent.KEYCODE_BACK && event.getRepeatCount() == 0) {
            returnData();
        }
        return false;
    }
}