（三一）HarmonyOS Design 的性能优化：方法与实践案例 原创

<!-- 优化前：多层嵌套布局 -->                <NestedScrollView                    xmlns:ohos="http://schemas.huawei.com/res/ohos"                    ohos:height="match_parent"                    ohos:width="match_parent">                    <DirectionalLayout                        ohos:height="wrap_content"                        ohos:width="match_parent">                        <Text                            ohos:height="wrap_content"                            ohos:width="wrap_content"                            ohos:text="示例文本"/>                    </DirectionalLayout>                </NestedScrollView>                                 <!-- 优化后：扁平化布局 -->                <DirectionalLayout                    xmlns:ohos="http://schemas.huawei.com/res/ohos"                    ohos:height="match_parent"                    ohos:width="match_parent">                    <Text                        ohos:height="wrap_content"                        ohos:width="wrap_content"                        ohos:text="示例文本"/>                </DirectionalLayout>
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<ConstraintLayout                    xmlns:ohos="http://schemas.huawei.com/res/ohos"                    ohos:height="match_parent"                    ohos:width="match_parent">                    <Text                        ohos:id="$+id:text1"                        ohos:height="wrap_content"                        ohos:width="wrap_content"                        ohos:text="文本1"                        ohos:top_toTopOf="parent"                        ohos:left_toLeftOf="parent"/>                    <Text                        ohos:id="$+id:text2"                        ohos:height="wrap_content"                        ohos:width="wrap_content"                        ohos:text="文本2"                        ohos:top_toBottomOf="$id:text1"                        ohos:left_toLeftOf="parent"/>                </ConstraintLayout>
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// 示例：加载压缩后的图片                import ohos.agp.components.element.PixelMapElement;                import ohos.agp.window.dialog.ToastDialog;                import ohos.data.orm.OrmContext;                import ohos.data.rdb.RdbStore;                import ohos.data.rdb.StoreConfig;                import ohos.media.image.PixelMap;                import ohos.media.image.common.PixelFormat;                import ohos.media.image.common.Size;                import ohos.rpc.RemoteException;                                 public class ImageOptimizationExample {                    public void loadCompressedImage() {                        try {                            // 加载压缩后的图片资源                            PixelMap pixelMap = PixelMap.create(new Size(100, 100), PixelFormat.ARGB_8888);                            PixelMapElement pixelMapElement = new PixelMapElement(pixelMap);                            // 将图片设置到界面元素上                            // 例如：imageView.setImageElement(pixelMapElement);                        } catch (RemoteException e) {                            new ToastDialog(getContext())                                   .setText("图片加载失败：" + e.getMessage())                                   .show();                        }                    }                }
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import ohos.aafwk.ability.AbilitySlice;                import ohos.agp.components.Text;                import ohos.eventhandler.EventHandler;                import ohos.eventhandler.EventHandler;                import ohos.eventhandler.EventRunner;                                 public class AsyncLoadingExample extends AbilitySlice {                    private Text textView;                                     @Override                    public void onStart(ohos.aafwk.content.Intent intent) {                        super.onStart(intent);                        super.setUIContent(ResourceTable.Layout_ability_main);                                         textView = (Text) findComponentById(ResourceTable.Id_text);                                         // 开启异步线程加载数据                        new Thread(new Runnable() {                            @Override                            public void run() {                                // 模拟耗时操作                                try {                                    Thread.sleep(2000);                                    final String data = "异步加载的数据";                                                     // 使用Handler将结果传递到主线程更新UI                                    EventHandler mainHandler = new EventHandler(EventRunner.getMainEventRunner());                                    mainHandler.postTask(new Runnable() {                                        @Override                                        public void run() {                                            textView.setText(data);                                        }                                    });                                } catch (InterruptedException e) {                                    e.printStackTrace();                                }                            }                        }).start();                    }                }
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// 优化前：频繁创建对象                for (int i = 0; i < 100; i++) {                    String str = new String("示例字符串");                    // 处理字符串                }                                 // 优化后：复用对象                String str;                for (int i = 0; i < 100; i++) {                    str = "示例字符串";                    // 处理字符串                }
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