目录

WindowListenerNotOff

Window为当前窗口实例，是窗口管理器管理的基本单元，其中存在一些.on()和.off()接口，用于监听窗口状态、尺寸、键盘及规避区等变化，在.on()方法使用完毕后，需及时调用对应的.off()方法注销监听，避免导致内存泄漏。

调用.on()监听接口后，只要存在对应的.off()调用（即取消全部或部分监听），不产生告警；仅当代码中不存在任何.off()调用时，才产生告警。

规则配置

// rules.json
{
  "rules": {
    "arkts": {
      "ResourceLeak": [
        {
          "ruleId": "WindowListenerNotOff",
          "severity": "error",
          "skip": false
        }
      ]
    }
  }
}

正例

import window from '@ohos.window';
import UIAbility from '@ohos.app.ability.UIAbility';

/**
 * 正例：正确释放资源
 */
export default class TestRelease extends UIAbility {
    private onAvoidAreaChange = (): void => {
        console.log('avoidAreaChange');
    };
    private onWindowSizeChange = (): void => {
        console.log('windowSizeChange');
    };
    onWindowStageCreate(windowStage: window.WindowStage): void {
        windowStage.getMainWindow().then((win: window.Window) => {
            win.on('avoidAreaChange', this.onAvoidAreaChange);
            win.on('windowSizeChange', this.onWindowSizeChange);
        });
    }
    onWindowStageWillDestroy(windowStage: window.WindowStage): void {
        windowStage.getMainWindow().then((win: window.Window) => {
            win.off('avoidAreaChange', this.onAvoidAreaChange);
            win.off('windowSizeChange');
        });
    }
}

反例

import window from '@ohos.window';
import UIAbility from '@ohos.app.ability.UIAbility';

/**
 * 反例：未释放资源
 */
export class TestNotRelease extends UIAbility {
    private onAvoidAreaChange = (): void => {
        console.log('avoidAreaChange');
    };
    private onWindowSizeChange = (): void => {
        console.log('windowSizeChange');
    };
    onWindowStageCreate(windowStage: window.WindowStage): void {
        windowStage.getMainWindow().then((win: window.Window) => {
            win.on('avoidAreaChange', this.onAvoidAreaChange); // leak
            win.on('windowSizeChange', () => { // leak, can not off with lambda
                console.log('windowSizeChange');
            });
        });
    }
    onWindowStageWillDestroy(windowStage: window.WindowStage): void {
        windowStage.getMainWindow().then((win: window.Window) => {
            win.off('windowSizeChange', () => {
                console.log('windowSizeChange');
            });
        });
    }
}

Code Scanner代码检查规则的配置指导请参考1.6.3 代码检查工具（codescanner）