实现应用前后台切换的监听
面向接口编程：
public interface BackgroundForegroundDelegate {
void onBackground();
void onForeground();
}
让 Application 实现这个接口。
App.class
public class App extends Application implements BackgroundForegroundDelegate {
private static App sApp;
public static App getInstance() {
return sApp;
}
private BackgroundForegroundHandler mBackgroundForegroundHandler;
private boolean mIsBackground = true;
@Override
public void onCreate() {
super.onCreate();
sApp = this;
mBackgroundForegroundHandler = new BackgroundForegroundHandler(this);
registerLifecycleHandler();
}
private void registerLifecycleHandler() {
registerActivityLifecycleCallbacks();
registerComponentCallbacks();
}
private void unregisterLifecycleHandler() {
unregisterActivityLifecycleCallbacks();
unregisterComponentCallbacks();
}
public void registerActivityLifecycleCallbacks() {
synchronized (sApp) {
registerActivityLifecycleCallbacks(mBackgroundForegroundHandler);
}
}
public void unregisterActivityLifecycleCallbacks() {
synchronized (sApp) {
unregisterActivityLifecycleCallbacks(mBackgroundForegroundHandler);
}
}
public void registerComponentCallbacks() {
synchronized (mBackgroundForegroundHandler) {
this.registerComponentCallbacks(mBackgroundForegroundHandler);
}
}
public void unregisterComponentCallbacks() {
synchronized (mBackgroundForegroundHandler) {
this.unregisterComponentCallbacks(mBackgroundForegroundHandler);
}
}
@Override
public void onBackground() {
if (mIsBackground) {
return;
}
mIsBackground = true;
// do something
}
@Override
public void onForeground() {
if (mIsBackground) {
mIsBackground = false;
// do something
}
}
}
BackgroundForegroundHandler.class 用于捕获 Foreground 和 Background 的监听，这个类在 Applicatin 中初始化。
public class BackgroundForegroundHandler implements Application.ActivityLifecycleCallbacks, ComponentCallbacks2 {
private static final String TAG = BackgroundForegroundHandler.class.getSimpleName();
private BackgroundForegroundDelegate mDelegate;
public BackgroundForegroundHandler(BackgroundForegroundDelegate delegate) {
mDelegate = delegate;
}
@Override
public void onActivityCreated(Activity activity, Bundle savedInstanceState) {
}
@Override
public void onActivityStarted(Activity activity) {
}
@Override
public void onActivityResumed(Activity activity) {
Log.d(TAG, "onActivityResumed: ");
mDelegate.onForeground();
}
@Override
public void onActivityPaused(Activity activity) {
}
@Override
public void onActivityStopped(Activity activity) {
}
@Override
public void onActivitySaveInstanceState(Activity activity, Bundle outState) {
}
@Override
public void onActivityDestroyed(Activity activity) {
}
@Override
public void onTrimMemory(int level) {
if (level == ComponentCallbacks2.TRIM_MEMORY_UI_HIDDEN) {
mDelegate.onBackground();
}
}
@Override
public void onConfigurationChanged(Configuration newConfig) {
}
@Override
public void onLowMemory() {
}
}
使用 onTrimMemory 实现 Background 监听
使用方法参考：https://www.jianshu.com/p/9e19f48c90ee
public void registerComponentCallbacks() {
synchronized (mTrimMemoryCallback) {
this.registerComponentCallbacks(mTrimMemoryCallback);
}
}
public void unregisterComponentCallbacks() {
synchronized (mTrimMemoryCallback) {
this.unregisterComponentCallbacks(mTrimMemoryCallback);
}
}
public ComponentCallbacks2 mTrimMemoryCallback = new ComponentCallbacks2() {
@Override
public void onConfigurationChanged(Configuration newConfig) {
}
@Override
public void onLowMemory() {
}
@Override
public void onTrimMemory(int level) {
if (level == ComponentCallbacks2.TRIM_MEMORY_UI_HIDDEN) {
App.getInstance().onBackground();
}
}
};
利用 Application.ActivityLifecycleCallbacks 实现 Foreground 监听 （推荐）
一个类实现 Application.ActivityLifecycleCallbacks 接口，在 Application 中注册。
就能获取 Activiyt onResume 的监听。
利用 BaseActivity 实现 Foreground 监听（不推荐）
BaseActivity.class
@Override
protected void onResume() {
super.onResume();
App.getInstance().onForeground();
}
使用 Android Android Architecture Components 实现
。。。
