[问答]HarmonyOS如何获取系统内存大小和可用内存？

解决方案Harmony获取内存大小和Android类似的系统。
SystemMemoryInfo systemMemoryInfo = new SystemMemoryInfo();
IAbilityManager iAbilityManager = getAbilityManager();
iAbilityManager.getSystemMemoryInfo(systemMemoryInfo);
systemMemoryInfo.getTotalSysMem(); // 系统内存大小
systemMemoryInfo.getAvailSysMem(); // 可用内存大小
完整示例创建一个名为 SystemMemoryInfo 的 Java 语言项目。修改 MainAbilitySlice
代码如下：
package com.waylau.hmos.systemmemoryinfo.slice;
import com.waylau.hmos.systemmemoryinfo.ResourceTable;
import ohos.aafwk.ability.AbilitySlice;
import ohos.aafwk.ability.SystemMemoryInfo;
import ohos.aafwk.content.Intent;
import ohos.agp.components.Text;
import ohos.app.IAbilityManager;
import ohos.hiviewdfx.HiLog;
import ohos.hiviewdfx.HiLogLabel;
public class MainAbilitySlice extends AbilitySlice {
    private static final String TAG = MainAbilitySlice.class.getSimpleName();
    private static final HiLogLabel LABEL_LOG =
            new HiLogLabel(HiLog.LOG_APP, 0x00001, TAG);
    @Override
    public void onStart(Intent intent) {
        super.onStart(intent);
        super.setUIContent(ResourceTable.Layout_ability_main);
        // 添加点击事件来触发请求
        Text text = (Text) findComponentById(ResourceTable.Id_text_helloworld);
        text.setClickedListener(listener -> this.printSystemMemoryInfo());
    }
    // 打印内存信息
    private void printSystemMemoryInfo() {
        HiLog.info(LABEL_LOG, "Before printSystemMemoryInfo");
        SystemMemoryInfo systemMemoryInfo = new SystemMemoryInfo();
        IAbilityManager iAbilityManager = getAbilityManager();
        iAbilityManager.getSystemMemoryInfo(systemMemoryInfo);
        HiLog.info(LABEL_LOG, "TotalSysMem: %{public}s B", systemMemoryInfo.getTotalSysMem() );
        HiLog.info(LABEL_LOG, "AvailSysMem: %{public}s B", systemMemoryInfo.getAvailSysMem() );
        HiLog.info(LABEL_LOG, "After printSystemMemoryInfo");
    }
    @Override
    public void onActive() {
        super.onActive();
    }
    @Override
    public void onForeground(Intent intent) {
        super.onForeground(intent);
    }

}
上述代码

• 默认对生成文本设置Id_text_设置点击事件，点击调用打印世界的方法信息。
• printSystemMemoryInfo方法使用SystemMemoryInfo、来获取IAbilityManager系统内存大小、可用内存。
  

运行运行应用程序，界面显示如下。点击此处的“Hello World”，触发点击事件。
此时，界面切换到了搜索界面，如下。

日志输入如下：
10-19 17:26:31.555 9566-9566/com.waylau.hmos.systemmemoryinfo I 00001/MainAbilitySlice：在 printSystemMemoryInfo 之前
10-19 17:26:31.556 9566-9566/com.waylau.hmos.systemmemoryinfo I 00001/MainAbilitySlice: TotalSysMem: 8363315200 B
10-19 17:26:31.556 9566-9566/com.waylau.hmos.systemmemoryinfo I 00001/MainAbilitySlice: AvailSysMem: 6595653632 B

10-19 17:26:31.556 9566-9566/com.waylau.hmos.systemmemoryinfo I 00001/MainAbilitySlice：在 printSystemMemoryInfo