Android性能優化之利用Rxlifecycle解決RxJava內存泄漏

時間 2019-11-06

標籤 android 性能優化利用 rxlifecycle 解決 rxjava 內存泄漏欄目 Android 简体版

原文原文鏈接

前言：

其實RxJava引發的內存泄漏是我無心中發現了，原本是想了解Retrofit與RxJava相結合中是如何經過適配器模式解決的，結果卻發現了RxJava是會引發內存泄漏的，全部想着查找一下資料學習一下如何解決RxJava引發的內存泄漏，就查到了利用Rxlifecycle開源框架能夠解決，今天週末就來學習一下如何使用Rxlifecycle。android

引用泄漏的背景：

RxJava做爲一種響應式編程框架，是目前編程界網紅，可謂是家喻戶曉，其簡潔的編碼風格、易用易讀的鏈式方法調用、強大的異步支持等使得RxJava被普遍使用，它經過線程調度器更容易控制和切換線程，若是該工做線程還沒執行結束就退出Activity或者Fragment，就會Activity或者Fragment沒法釋放引發內存泄漏。git

什麼是Rxlifecycle？

rxlifecycle是trello開發的用於解決RxJava引發的內存泄漏的開源框架。github

github地址：https://github.com/trello/RxLifecycle編程

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'

根據本身的須要添加我這裏使用了以下兩個框架

 compile 'com.trello:rxlifecycle:1.0'
 compile 'com.trello:rxlifecycle-components:1.0'

2.）根據不一樣的須要Activity繼承RxActivity ，Fragment繼承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);
        //模擬內存泄露
        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 結構圖異步

3.）使用bindToLifecycle()的方式

在子類使用Observable中的compose操做符，調用，完成Observable發佈的事件和當前的組件綁定，實現生命週期同步。從而實現當前組件生命週期結束時，自動取消對Observable訂閱。ide

 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類，其中的CREATE、START、 RESUME、PAUSE、STOP、 DESTROY分別對應生命週期內的方法。使用bindUntilEvent指定在哪一個生命週期方法調用時取消訂閱。學習

      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.）自定義一個RxActivity/RxFragment

只須要你想要的Activity實現LifecycleProvider<ActivityEvent>接口就能夠了，這裏貼出RxActivity的源碼仿照它作下修改便可。gradle

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();
    }
}