六、华为鸿蒙HarmonyOS应用开发之Java开发模式下的不同Page 间实现页面跳转_entry_mainability

不同Page 间导航，实现页面跳转

AbilitySlice作为Page的内部单元，以Action的形式对外暴露，因此可以通过配置Intent的Action导航到目标AbilitySlice。Page间的导航可以使用startAbility()或startAbilityForResult()方法，获得返回结果的回调为onAbilityResult()。在Ability中调用setResult()可以设置返回结果。详细用法可参考根据Operation的其他属性启动应用中的示例。

根据Ability的全称启动应用
通过构造包含BundleName与AbilityName的Operation对象，可以启动一个Ability、并导航到该Ability。示例代码如下：

Intent intent = new Intent();

// 通过Intent中的OperationBuilder类构造operation对象，指定设备标识（空串表示当前设备）、应用包名、Ability名称
Operation operation = new Intent.OperationBuilder()
        .withDeviceId("")
        .withBundleName("com.demoapp")
        .withAbilityName("com.demoapp.FooAbility")
        .build();

// 把operation设置到intent中
intent.setOperation(operation);
startAbility(intent);
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作为处理请求的对象，会在相应的回调方法中接收请求方传递的Intent对象。以导航到另一个Ability为例，导航的目标Ability可以在其onStart()回调的参数中获得Intent对象。

根据Operation的其他属性启动应用
有些场景下，开发者需要在应用中使用其他应用提供的某种能力，而不感知提供该能力的具体是哪一个应用。例如开发者需要通过浏览器打开一个链接，而不关心用户最终选择哪一个浏览器应用，则可以通过Operation的其他属性（除BundleName与AbilityName之外的属性）描述需要的能力。如果设备上存在多个应用提供同种能力，系统则弹出候选列表，由用户选择由哪个应用处理请求。以下示例展示使用Intent跨Ability查询天气信息。

请求方

在Ability中构造Intent以及包含Action的Operation对象，并调用startAbilityForResult()方法发起请求。然后重写onAbilityResult()回调方法，对请求结果进行处理。

private void queryWeather() {
    Intent intent = new Intent();
    Operation operation = new Intent.OperationBuilder()
            .withAction(Intent.ACTION_QUERY_WEATHER)
            .build();
    intent.setOperation(operation);
    startAbilityForResult(intent, REQ_CODE_QUERY_WEATHER);
}

@Override
protected void onAbilityResult(int requestCode, int resultCode, Intent resultData) {
    switch (requestCode) {
        case REQ_CODE_QUERY_WEATHER:
            // Do something with result.
            ...
            return;
        default:
            ...
    }
}
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处理方

1.作为处理请求的对象，首先需要在配置文件中声明对外提供的能力，以便系统据此找到自身并作为候选的请求处理者。

{
    "module": {
        ...
        "abilities": [
            {
                ...
                "skills":[
                    {
                        "actions":[
                            "ability.intent.QUERY_WEATHER"
                        ]
                    }
                ]
                ...
            }
        ]
        ...
    }
    ...
}
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2.在Ability中配置路由以便支持以此action导航到对应的AbilitySlice。

@Override
protected void onStart(Intent intent) {
    ...
    addActionRoute(Intent.ACTION_QUERY_WEATHER, DemoSlice.class.getName());
    ...
}
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3.在Ability中处理请求，并调用setResult()方法暂存返回结果。

@Override
protected void onActive() {
    ...
    Intent resultIntent = new Intent();
    setResult(0, resultIntent);   //0为当前Ability销毁后返回的resultCode。
    ...
}
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//==========================================
实例测试：

1.首先创建Empty Ability（Java）的AbilityJump工程，运行出现如下界面：

2.在MainAbility.java同级别添加NewAbility.java文件，在slice文件夹下添加NewAbilitySlice.java文件，在layout文件夹下添加ability_new.xml文件。

NewAbility.java

package com.example.abilityjump;

import com.example.abilityjump.slice.NewAbilitySlice;
import ohos.aafwk.ability.Ability;
import ohos.aafwk.content.Intent;

public class NewAbility extends Ability {
    @Override
    public void onStart(Intent intent) {
        super.onStart(intent);
        super.setMainRoute(NewAbilitySlice.class.getName());
    }
}
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NewAbilitySlice.java

package com.example.abilityjump.slice;

import com.example.abilityjump.ResourceTable;
import ohos.aafwk.ability.AbilitySlice;
import ohos.aafwk.content.Intent;

public class NewAbilitySlice extends AbilitySlice {
    @Override
    public void onStart(Intent intent) {
        super.onStart(intent);
        super.setUIContent(ResourceTable.Layout_ability_new);
    }

    @Override
    public void onActive() {
        super.onActive();
    }

    @Override
    public void onForeground(Intent intent) {
        super.onForeground(intent);
    }
}
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ability_new.xml

<?xml version="1.0" encoding="utf-8"?>
<DirectionalLayout
    xmlns:ohos="http://schemas.huawei.com/res/ohos"
    ohos:height="match_parent"
    ohos:width="match_parent"
    ohos:alignment="center"
    ohos:orientation="vertical">

    <Text
        ohos:id="$+id:text_new"
        ohos:height="match_content"
        ohos:width="match_content"
        ohos:background_element="$graphic:background_ability_main"
        ohos:layout_alignment="horizontal_center"
        ohos:text="$string:mainability_new"
        ohos:text_size="40vp"
        />

</DirectionalLayout>
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3.在中文string.json添加
{
“name”: “mainability_new”,
“value”: “目标测试”
}

string.json

{
  "string": [
    {
      "name": "entry_MainAbility",
      "value": "entry_MainAbility"
    },
    {
      "name": "mainability_description",
      "value": "Java_Empty Ability"
    },
    {
      "name": "mainability_HelloWorld",
      "value": "你好，世界"
    },
    {
      "name": "mainability_new",
      "value": "目标测试"
    }
  ]
}
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4.在config.json中"abilities"注册NewAbility

config.json

{
  "app": {
    "bundleName": "com.example.abilityjump",
    "vendor": "example",
    "version": {
      "code": 1000000,
      "name": "1.0.0"
    }
  },
  "deviceConfig": {},
  "module": {
    "package": "com.example.abilityjump",
    "name": ".MyApplication",
    "mainAbility": "com.example.abilityjump.MainAbility",
    "deviceType": [
      "phone"
    ],
    "distro": {
      "deliveryWithInstall": true,
      "moduleName": "entry",
      "moduleType": "entry",
      "installationFree": true
    },
    "abilities": [
      {
        "skills": [
          {
            "entities": [
              "entity.system.home"
            ],
            "actions": [
              "action.system.home"
            ]
          }
        ],
        "orientation": "unspecified",
        "name": "com.example.abilityjump.MainAbility",
        "icon": "$media:icon",
        "description": "$string:mainability_description",
        "label": "$string:entry_MainAbility",
        "type": "page",
        "launchType": "standard"
      },
      {
        "skills": [
          {
            "actions": [
              "action.new"
            ]
          }
        ],
        "orientation": "unspecified",
        "name": "com.example.abilityjump.NewAbility",
        "icon": "$media:icon",
        "description": "$string:mainability_description",
        "label": "$string:entry_MainAbility",
        "type": "page",
        "launchType": "standard"
      }
    ]
  }
}
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5.此时编译运行，应该没有错误，还是出现下面效果：

6.设置文本点击事件导航到另外一个Ability页面

参数发送端
MainAbilitySlice.java

package com.example.abilityjump.slice;

import com.example.abilityjump.ResourceTable;
import ohos.aafwk.ability.AbilitySlice;
import ohos.aafwk.content.Intent;
import ohos.aafwk.content.Operation;
import ohos.agp.components.Text;

public class MainAbilitySlice extends AbilitySlice {
    @Override
    public void onStart(Intent intent) {
        super.onStart(intent);
        super.setUIContent(ResourceTable.Layout_ability_main);
        //获取文本对象
        Text text = (Text)findComponentById(ResourceTable.Id_text_helloworld);
        //设置文本的点击事件
        text.setClickedListener(component -> {
            Intent intent1 = new Intent();
            intent1.setParam("data","新页面");
            Operation operation = new Intent.OperationBuilder()
                    .withAction("action.new")
                    .build();
            intent1.setOperation(operation);
            startAbility(intent1);
        });
    }

    @Override
    public void onActive() {
        super.onActive();
    }

    @Override
    public void onForeground(Intent intent) {
        super.onForeground(intent);
    }
}
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参数接收端
NewAbilitySlice.java

package com.example.abilityjump.slice;

import com.example.abilityjump.ResourceTable;
import ohos.aafwk.ability.AbilitySlice;
import ohos.aafwk.content.Intent;
import ohos.agp.components.Text;

public class NewAbilitySlice extends AbilitySlice {
    Text text;
    String oldString;

    @Override
    public void onStart(Intent intent) {
        super.onStart(intent);
        super.setUIContent(ResourceTable.Layout_ability_new);
        //获取文本对象
        Text text = (Text)findComponentById(ResourceTable.Id_text_new);
        oldString = text.getText();
        //设置新文本
        text.setText(oldString + "，" + intent.getStringParam("data"));

    }

    @Override
    public void onActive() {
        super.onActive();
    }

    @Override
    public void onForeground(Intent intent) {
        super.onForeground(intent);
    }
}
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7.运行程序，效果如下：

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