[移动开发]Android中Activity各种页面跳转并传值（Activity -＞ Activity）（Activity -＞ Fragment）（Activity -＞ Service)

目录

Activity -> Activity

Activity -> Fragment

Fragment -> Activity?

Activity -> Service

• Activity -> Activity

? ? ? 实现小例子：

? ? ? ? ?从MainActivity跳转并传值到Activity2，之后从Activity2再传值回到MainActivity

activity_main的布局：

 <Button
        android:id="@+id/btn_send"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="传值"
        android:textSize="20sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <TextView
        android:id="@+id/textview_back"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="50dp"
        android:textSize="20sp"
        android:text="默认值"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="1.0"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/btn_send"
        app:layout_constraintVertical_bias="0.0" />

activity2的布局：

 <TextView
        android:id="@+id/text_receive"
        android:layout_width="match_parent"
        android:layout_height="100dp"
        android:gravity="center"
        android:text="默认值"
        android:textSize="30dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="1.0"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.339" />

    <EditText
        android:id="@+id/edit_back"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/text_receive"
        app:layout_constraintVertical_bias="0.2" />

    <Button
        android:id="@+id/btn_back"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="返回值"
        android:textSize="18sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/edit_back" />

MainActivity代码（写有备注）:创建Bundle对象，向其里面加入需要传递的值，注意值的类型，添加完毕之后，由intent将该bundle对象传递即可。?

注意一下，如果另一个activity2返回来用的是setResult（）函数，那么在MainActivity中传值是需要使用?startActivityForResult函数，如果单纯的使用startActivity函数进行跳转，会导致MainActivity中onActivityResult不会执行。

public class MainActivity extends AppCompatActivity implements View.OnClickListener {

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

        //获取控件
        Button button = findViewById(R.id.btn_send);
        textView = findViewById(R.id.textview_back);

        button.setOnClickListener(this);
    }

    //得到传回的数据
    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        switch (resultCode) {
            case 1:
                Bundle bundle_back=data.getExtras();
                String str=bundle_back.getString("b");
                textView.setText(str);
                break;
        }
    }

    //按钮点击事件
    @Override
    public void onClick(View view) {
        switch (view.getId()){
            case R.id.btn_send:
                Bundle bundle = new Bundle();
                bundle.putString("name","玛丽");
                bundle.putInt("age",15);

                Intent intent = new Intent(MainActivity.this,Activity2.class);
                intent.putExtras(bundle);
                startActivityForResult(intent,0);
            break;
        }
    }
}

Activity2代码：在获传递过来值的时候我一直获取为空值，感觉很奇怪，之后发现是有两点导致的

1.被传递到的这个Activity中对Intent的操作，不要写成?Intent intent = new Intent();，这样只是会重新在该页面创建了一个新的对象，而需要写成?Intent intent = getIntent();去获取前面传递的值。

2.对于获取需要传回的content的放置位置也很关键，不可以放在onCreate()函数里面获取，这样会导致只会在初始化的时候执行一次，之后写入数据后是不会再执行的，会导致传回去的值一直为空。

public class Activity2 extends Activity implements View.OnClickListener {
    String name,content;
    int age;
    EditText editText;
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity2);

        //获取控件
        TextView textView = findViewById(R.id.text_receive);
        editText = findViewById(R.id.edit_back);
        Button button = findViewById(R.id.btn_back);

        //接收传来的值并显示
        Intent intent = getIntent();
        name = intent.getStringExtra("name");
        age = intent.getIntExtra("age",-1);

        textView.setText("名字:"+name+",年龄:"+age);



        button.setOnClickListener(this);
    }

    @Override
    public void onClick(View view) {
        switch (view.getId()){
            case R.id.btn_back:
                //返回值
                content = editText.getText().toString().trim();
                Intent intent_back = new Intent(Activity2.this,MainActivity.class);
                intent_back.putExtra("b",content);
                setResult(1,intent_back);
                finish();
            break;
        }
    }
}

执行效果如下：

? ??

• Activity -> Fragment

?实现小例子：

? ??? ?从Activity跳转并传值到Fragment

?activity_main的布局：

<?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=".MainActivity">

    <EditText
        android:id="@+id/edit_input"
        android:layout_width="match_parent"
        android:layout_height="60dp"
        android:layout_margin="10dp"
        android:hint="输入内容" />

    <Button
        android:id="@+id/btn_send"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:layout_margin="10dp"
        android:text="发送"
        android:textSize="30sp" />

    <LinearLayout
        android:id="@+id/contentLayout"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical">

    </LinearLayout>

</LinearLayout>

fragment_test的布局：

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <TextView
        android:id="@+id/tvContent"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:text="默认值"
        android:textSize="25sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>

MainActivity代码（写有备注）：注意需要将fragment与activity进行绑定。

public class MainActivity extends AppCompatActivity {
    private EditText edit_input;
    private Button btn_send;
    private String inputContent;

    private FragmentManager manager;
    private FragmentTransaction transaction;

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

        //获取控件
        edit_input = findViewById(R.id.edit_input);
        btn_send = findViewById(R.id.btn_send);

        //fragment与activity进行绑定
        manager = getSupportFragmentManager();
        transaction = manager.beginTransaction();
        transaction.add(R.id.contentLayout, new FragmentTest());
        transaction.commit();

        //按钮点击事件
        btn_send.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                inputContent = edit_input.getText().toString().trim();
                FragmentTest fragmentTest = new FragmentTest();
                Bundle bundle = new Bundle();
                bundle.putString("content", inputContent);
                fragmentTest.setArguments(bundle);
                manager = getSupportFragmentManager();
                transaction = manager.beginTransaction();
                transaction.replace(R.id.contentLayout, fragmentTest);
                transaction.commit();
            }
        });
    }
}

在从Activity -> Fragment传值中，困扰了我很久，我使用FragmentManager manager = getFragmentManager(); 再使用（transaction为FragmentTransaction的对象）

transaction.add(R.id.contentLayout, new FragmentTest()); 

该句下方会出现红线。最后成功解决使用的方法是FragmentManager manager =getSupportFragmentManager(); 上方导入的为

import androidx.fragment.app.FragmentManager;
import androidx.fragment.app.FragmentTransaction;

具体的原因目前我还是不太了解。

FragmentTest代码:

public class FragmentTest extends Fragment {
    private TextView tvContent;
    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment_test, null);

        tvContent = view.findViewById(R.id.tvContent);

        //获取activity传送过来的值
        Bundle bundle = getArguments();
        if (bundle != null) {
            tvContent.setText(bundle.getString("content"));
        }

        return view;
    }
}

运行结果如图：

• Fragment -> Activity?

??activity_main的布局：

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.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"
    android:id="@+id/contents"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/tv1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="默认值"
        android:textSize="25sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

fragment_test的布局：

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.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">

    <Button
        android:id="@+id/btn_send"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="发送"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <EditText
        android:id="@+id/edit_test"
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:layout_marginTop="88dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/btn_send" />
</androidx.constraintlayout.widget.ConstraintLayout>

MainActivity代码（写有备注）:

public class MainActivity extends Activity implements FragmentTest.CallBackValue {

    private TextView tv1;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        tv1 = (TextView) findViewById(R.id.tv1);

        //activity与fragment进行绑定
        FragmentManager manager = getFragmentManager();
        FragmentTransaction transaction = manager.beginTransaction();
        transaction.add(R.id.contents, new Fragmen1());
        transaction.commit();

    }
    //传递值
    @Override
    public void SendMessageValue(String content) {
        tv1.setText(content);
    }
}

FragmentTest代码:

public class FragmentTest extends Fragment{
    private Button btn1;
    private EditText et1;
    CallBackValue callBackValue;

    //fragment与activity产生关联是回调这个方法
    @Override
    public void onAttach(Activity activity) {
        super.onAttach(activity);
        callBackValue =(CallBackValue) getActivity();
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment_layout1, container, false);

        //获取控件
        btn1 = (Button) view.findViewById(R.id.btn_send);
        et1 = (EditText) view.findViewById(R.id.edit_test);

        //点击事件
        btn1.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                String content = et1.getText().toString().trim();
                callBackValue.SendMessageValue(content);
            }
        });

        return view;
    }
    //定义一个回调接口
    public interface CallBackValue{
        public void SendMessageValue(String content);
    }
}

运行结果截图：

• Activity -> Service

??activity_main的布局如上。

方法一：使Activity实现implements ServiceConnection ，实现onServiceConnected函数。创ServiceTest.Binder的对象，通过这个对象来实现通信传值。

MainActivity代码（写有备注）:?

public class MainActivity extends AppCompatActivity implements ServiceConnection {
    private EditText edit_input;
    private Button btn_send;
    private String inputContent;

    public ServiceTest.Binder binder = null;

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

        //获取控件
        edit_input = findViewById(R.id.edit_input);
        btn_send = findViewById(R.id.btn_send);

        //绑定服务
        Intent intent = new Intent(MainActivity.this,ServiceTest.class);
        bindService(intent,this, Context.BIND_AUTO_CREATE);

        //按钮点击事件
        btn_send.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                inputContent = edit_input.getText().toString().trim();
                //通过 binder 对象来和 Service 进行通信
                if(binder != null)
                binder.sendData(inputContent);
            }
        });
    }

    @Override
    public void onServiceConnected(ComponentName componentName, IBinder iBinder) {
        binder = (ServiceTest.Binder)iBinder;
    }

    @Override
    public void onServiceDisconnected(ComponentName componentName) {

    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        unbindService(this);
    }
}

ServiceTest代码（写有备注）:?

public class ServiceTest extends Service {

    String data;

    public ServiceTest(){

    }

    @Nullable
    @Override
    public IBinder onBind(Intent intent) {
        return new Binder();
    }

    public class Binder extends android.os.Binder{
        public void sendData(String data){
            ServiceTest.this.data = data;
            Toast.makeText(ServiceTest.this, "哈哈哈"+data, Toast.LENGTH_SHORT).show();
        }
    }
}

运行如下：

?方法二：使用Intent,适用于传送少量的数据。

MainActivity代码（写有备注）:?

public class MainActivity extends AppCompatActivity {
    private EditText edit_input;
    private Button btn_send;
    private String inputContent;

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

        //获取控件
        edit_input = findViewById(R.id.edit_input);
        btn_send = findViewById(R.id.btn_send);

        //绑定服务
        Intent intent = new Intent(MainActivity.this,ServiceTest.class);

        //按钮点击事件
        btn_send.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                inputContent = edit_input.getText().toString().trim();
                intent.putExtra("test",inputContent);
                startService(intent);
            }
        });
    }
}

ServiceTest代码（写有备注）:?

public class ServiceTest extends Service {

    String data;

    public ServiceTest(){

    }

    @Nullable
    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        //得到Activity传的数据
        data = intent.getStringExtra("test");
        Toast.makeText(ServiceTest.this, "传过来的数据"+data, Toast.LENGTH_SHORT).show();
        return super.onStartCommand(intent, flags, startId);

    }
}

运行截图：