6.1 页面间跳转
1.认识Intent
Intent是对象之间传递信息的载体。
例如，当一个Ability需要启动另一个Ability时，或者一个AbilitySlice需要导航到另一个AbilitySlice时，可以通过Intent指定启动的目标同时携带相关数据。Intent的构成元素包括Operation与Parameters：

2. 了解AbilitySlice路由配置虽然一个Page可以包含多个AbilitySlice，但是Page进入前台时界面默认只展示一个AbilitySlice。默认展示的AbilitySlice是通过setMainRoute（）方法来指定的。当有多个需要展示的AbilitySlice，可以通过addActionRoute（）方法为MainAbilitySlice以外的AbilitySlice配置路由规则。此时，当其他Page实例期望导航到这些AbilitySlice时，可以通过AbilitySlice之间的跳转，显示出这张页面。

public class MyAbility extends Ability {
    @Override
    public void onStart(Intent intent) {
        super.onStart(intent);
        // set the main route
        setMainRoute(MainSlice.class.getName());
 
        // set the action route
         addActionRoute("action.pay", PaySlice.class.getName());
        addActionRoute("action.scan", ScanSlice.class.getName());
    }
}

addActionRoute（）方法中使用的动作命名，需要在应用配置文件（config.json）中注册：

{
    "module": {
        "abilities": [
            {
                "skills":[
                    {
                        "actions":[
                            "action.pay",
                            "action.scan"
                        ]
                    }
                ]
                ...
            }
        ]
        ...
    }
    ...
}

3. 同一个Page里的AbilitySlice1与AbilitySlice2间的跳转（无参，带参，回值）
1）无参数跳转

@Override
public void onStart(Intent intent) {
    super.onStart(intent);
    super.setUIContent(ResourceTable.Layout_ability_main);

    Text text = (Text)findComponentById(ResourceTable.Id_text_helloworld);
    text.setClickedListener(component->{
        Intent intent1 = new Intent();
        present(new MainAbilitySlice1(),intent1);
    });
}

2）带参数跳转
（1）产生参数端的AbilitySlice

@Override
public void onStart(Intent intent) {
    super.onStart(intent);
    super.setUIContent(ResourceTable.Layout_ability_main);

    Text text = (Text)findComponentById(ResourceTable.Id_text_helloworld);
    text.setClickedListener(component->{
        //有参数跳转
        Intent intent1 = new Intent();
        intent1.setParam("user","钟发发");
        present(new MainAbilitySlice1(),intent1);
    });
}

（2）接收参数端的AbilitySlice

public class MainAbilitySlice1 extends AbilitySlice {
    Text text;
    String oldText;
    @Override
    public void onStart(Intent intent) {
        super.onStart(intent);
        super.setUIContent(ResourceTable.Layout_ability_main1);
        text = (Text) findComponentById(ResourceTable.Id_text_helloworld1);
        if(intent != null){
            String user = intent.getStringParam("user");
            oldText = text.getText();
            text.append("," + user);
        }
    }
    @Override
    protected void onInactive() {
        super.onInactive();
    }
....
}

3）带参数跳转+返回值
（1）参数产生端

public class MainAbilitySlice extends AbilitySlice {
    @Override
    public void onStart(Intent intent) {
        super.onStart(intent);
        super.setUIContent(ResourceTable.Layout_ability_main);

        Text text = (Text)findComponentById(ResourceTable.Id_text_helloworld);
        text.setClickedListener(component->{
            //有参数跳转
            Intent intent1 = new Intent();
            intent1.setParam("user","钟发发");
            presentForResult(new MainAbilitySlice1(),intent1,120);
        });
    }
...
}

（2）参数接收端

public class MainAbilitySlice1 extends AbilitySlice {
    Text text;
    String oldText;
    @Override
    public void onStart(Intent intent) {
        super.onStart(intent);
        super.setUIContent(ResourceTable.Layout_ability_main1);
        text = (Text) findComponentById(ResourceTable.Id_text_helloworld1);
        if(intent != null){
            String user = intent.getStringParam("user");
            oldText = text.getText();
            text.setText(oldText + "," + user);
        }
        //参数接收端在对文字点击
        text.setClickedListener(component -> {
            //1.给跳转来的页面返回值
            Intent intent1 = new Intent();
            intent1.setParam("password","123456");
            setResult(intent1);
            //2.接收本AbilityAlice，自动返回上一页
            terminate();
        });
    }

    @Override
    protected void onInactive() {
        super.onInactive();
        text.setText(oldText);
    }
...
}

（3）回到参数产生端接收返回值

public class MainAbilitySlice extends AbilitySlice {
    Text text;
    @Override
    public void onStart(Intent intent) {
        super.onStart(intent);
        super.setUIContent(ResourceTable.Layout_ability_main);

        text = (Text)findComponentById(ResourceTable.Id_text_helloworld);
        text.setClickedListener(component->{
            //有参数跳转
            Intent intent1 = new Intent();
            intent1.setParam("user","钟发发");
            presentForResult(new MainAbilitySlice1(),intent1,120);
        });
    }

    @Override
    protected void onResult(int requestCode, Intent resultIntent) {
        super.onResult(requestCode, resultIntent);
        if(requestCode==120){
            String password = resultIntent.getStringParam("password");
            text.setText("返回值：" + password);
        }
    }
...
}

4. 不同的Page直接跳转，第一个鸿蒙应用例子写的就是这个，核心代码：

if (button != null) {
    // 为按钮设置点击回调
    button.setClickedListener(new Component.ClickedListener() {
        @Override
        public void onClick(Component component) {
            Intent secondIntent = new Intent();
            // 指定待启动FA的bundleName和abilityName
            Operation operation = new Intent.OperationBuilder()
                    .withDeviceId("")
                    .withBundleName("com.example.myapplication")
                    .withAbilityName("com.example.myapplication.SecondAbility")
                    .build();
            secondIntent.setOperation(operation);
            startAbility(secondIntent); // 通过AbilitySlice的startAbility接口实现启动另一个页面
        }
    });
}

5. Page1的MainAbilitySlice跳转Page2的AbilitySlice1

@Override
public void onStart(Intent intent) {
    super.onStart(intent);
    super.setUIContent(ResourceTable.Layout_ability_main);

    text = (Text)findComponentById(ResourceTable.Id_text_helloworld);
    text.setClickedListener(component->{
        Intent intent1 = new Intent();
        intent1.setAction("abilityslice1");  //关键是配置文件里配置action和Ability里注册路由
        startAbility(intent1);
    });
}