前言:
其实RxJava引起的内存泄漏是我无意中发现了,本来是想了解Retrofit与RxJava相结合中是如何通过适配器模式解决的,结果却发现了RxJava是会引起内存泄漏的,所有想着查找一下资料学习一下如何解决RxJava引起的内存泄漏,就查到了利用Rxlifecycle开源框架可以解决,今天周末就来学习一下如何使用Rxlifecycle。
引用泄漏的背景:
RxJava作为一种响应式编程框架,是目前编程界网红,可谓是家喻户晓,其简洁的编码风格、易用易读的链式方法调用、强大的异步支持等使得RxJava被广泛使用,它通过线程调度器更容易控制和切换线程,如果该工作线程还没执行结束就退出Activity或者Fragment,就会Activity或者Fragment无法释放引起内存泄漏。
什么是Rxlifecycle?
rxlifecycle是trello开发的用于解决RxJava引起的内存泄漏的开源框架。
github地址:https://github.com/trello/RxLifecycle
如何使用Rxlifecycle?
1.)在build.gradle文件中添加引用
compile 'com.trello:rxlifecycle:1.0'
// If you want to bind to Android-specific lifecycles
compile 'com.trello:rxlifecycle-android:1.0'
// If you want pre-written Activities and Fragments you can subclass as providers
compile 'com.trello:rxlifecycle-components:1.0'
// If you want to use Navi for providers
compile 'com.trello:rxlifecycle-navi:1.0'
// If you want to use Kotlin syntax
compile 'com.trello:rxlifecycle-kotlin:1.0'
根据自己的需要添加 我这里使用了如下两个
compile 'com.trello:rxlifecycle:1.0'
compile 'com.trello:rxlifecycle-components:1.0'
2.)根据不同的需要Activity继承RxActivity ,Fragment继承RxFragment
public class MainActivity7 extends RxActivity {
private TextView mTextView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mTextView = (TextView) findViewById(R.id.text);
//模拟内存泄露
testRxJava();
finish();
}
private void testRxJava() {
Observable.create(new Observable.OnSubscribe<String>() {
@Override
public void call(Subscriber<? super String> subscriber) {
int i = 0;
while (i < 1000000000) {
i++;
}
subscriber.onNext(String.valueOf(i));
subscriber.onCompleted();
}
}).compose(this.<String>bindUntilEvent(ActivityEvent.PAUSE))
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(new Action1<String>() {
@Override
public void call(String s) {
mTextView.setText(s);
}
});
}
@Override
protected void onDestroy() {
super.onDestroy();
LApplication.getRefWatcher().watch(this);
}
}
目前支持的Activity/Fragment 结构图
3.)使用bindToLifecycle()的方式
在子类使用Observable中的compose操作符,调用,完成Observable发布的事件和当前的组件绑定,实现生命周期同步。从而实现当前组件生命周期结束时,自动取消对Observable订阅。
Observable.create(new Observable.OnSubscribe<String>() {
@Override
public void call(Subscriber<? super String> subscriber) {
int i = 0;
while (i < 1000000000) {
i++;
}
subscriber.onNext(String.valueOf(i));
subscriber.onCompleted();
}
}).compose(this.<String>bindToLifecycle())
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(new Action1<String>() {
@Override
public void call(String s) {
mTextView.setText(s);
}
});
4.)使用bindUntilEvent()方式
使用ActivityEvent类,其中的CREATE、START、 RESUME、PAUSE、STOP、 DESTROY分别对应生命周期内的方法。使用bindUntilEvent指定在哪个生命周期方法调用时取消订阅。
Observable.create(new Observable.OnSubscribe<String>() {
@Override
public void call(Subscriber<? super String> subscriber) {
int i = 0;
while (i < 1000000000) {
i++;
}
subscriber.onNext(String.valueOf(i));
subscriber.onCompleted();
}
}).compose(this.<String>bindUntilEvent(ActivityEvent.PAUSE))
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(new Action1<String>() {
@Override
public void call(String s) {
mTextView.setText(s);
}
});
5.)自定义一个RxActivity/RxFragment
只需要你想要的Activity实现LifecycleProvider<ActivityEvent>接口就可以了,这里贴出RxActivity的源码仿照它做下修改即可。
public abstract class RxActivity extends Activity implements LifecycleProvider<ActivityEvent> {
private final BehaviorSubject<ActivityEvent> lifecycleSubject = BehaviorSubject.create();
public RxActivity() {
}
@NonNull
@CheckResult
public final Observable<ActivityEvent> lifecycle() {
return this.lifecycleSubject.asObservable();
}
@NonNull
@CheckResult
public final <T> LifecycleTransformer<T> bindUntilEvent(@NonNull ActivityEvent event) {
return RxLifecycle.bindUntilEvent(this.lifecycleSubject, event);
}
@NonNull
@CheckResult
public final <T> LifecycleTransformer<T> bindToLifecycle() {
return RxLifecycleAndroid.bindActivity(this.lifecycleSubject);
}
@CallSuper
protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.lifecycleSubject.onNext(ActivityEvent.CREATE);
}
@CallSuper
protected void onStart() {
super.onStart();
this.lifecycleSubject.onNext(ActivityEvent.START);
}
@CallSuper
protected void onResume() {
super.onResume();
this.lifecycleSubject.onNext(ActivityEvent.RESUME);
}
@CallSuper
protected void onPause() {
this.lifecycleSubject.onNext(ActivityEvent.PAUSE);
super.onPause();
}
@CallSuper
protected void onStop() {
this.lifecycleSubject.onNext(ActivityEvent.STOP);
super.onStop();
}
@CallSuper
protected void onDestroy() {
this.lifecycleSubject.onNext(ActivityEvent.DESTROY);
super.onDestroy();
}
}
总结:
本文总结了通过RxLifeCycle解决RxJava的内存泄漏问题,同时也给我们提了一个警告,再好的框架都有它好的一面也有坏的一面,这时做好技术选型以及规避风险就很重要了。