Application的onLowMemory从Android API 34开始系统不再触发，从API 35开始废弃

Android的Application的onLowMemory()是在ComponentCallbacks定义实现，源代码链接 https://android.googlesource.com/platform/frameworks/base/+/master/core/java/android/content/ComponentCallbacks.java ：

java 复制代码

package android.content;

import android.annotation.NonNull;
import android.content.res.Configuration;

/**
 * The set of callback APIs that are common to all application components
 * ({@link android.app.Activity}, {@link android.app.Service},
 * {@link ContentProvider}, and {@link android.app.Application}).
 *
 * <p class="note"><strong>Note:</strong> You should also implement the {@link
 * ComponentCallbacks2} interface, which provides the {@link
 * ComponentCallbacks2#onTrimMemory} callback to help your app manage its memory usage more
 * effectively.</p>
 */
public interface ComponentCallbacks {
    /**
     * Called by the system when the device configuration changes while your
     * component is running.  Note that, unlike activities, other components
     * are never restarted when a configuration changes: they must always deal
     * with the results of the change, such as by re-retrieving resources.
     *
     * <p>At the time that this function has been called, your Resources
     * object will have been updated to return resource values matching the
     * new configuration.
     *
     * <p>For more information, read <a href="{@docRoot}guide/topics/resources/runtime-changes.html"
     * >Handling Runtime Changes</a>.
     *
     * @param newConfig The new device configuration.
     */
    void onConfigurationChanged(@NonNull Configuration newConfig);

    /**
     * This is called when the overall system is running low on memory, and
     * actively running processes should trim their memory usage.  While
     * the exact point at which this will be called is not defined, generally
     * it will happen when all background process have been killed.
     * That is, before reaching the point of killing processes hosting
     * service and foreground UI that we would like to avoid killing.
     *
     * @deprecated Since API level 14 this is superseded by
     *             {@link ComponentCallbacks2#onTrimMemory}.
     *             Since API level 34 this is never called.
     *             Apps targeting API level 34 and above may provide an empty implementation.
     */
    @Deprecated
    void onLowMemory();
}

关于onLowMemory()，Android系统源代码这么说：

* @deprecated Since API level 14 this is superseded by

* {@link ComponentCallbacks2#onTrimMemory}.

* Since API level 34 this is never called.

* Apps targeting API level 34 and above may provide an empty

从 API 34开始，该方法过时了，不再被触发回调。

Android官方链接说明：

https://developer.android.com/reference/android/content/ComponentCallbacks#onLowMemory()

从API 35开始，废弃。此后这里是一个空实现。

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