[英]RxAndroid - fix Activity Leak?
我使用相关的build.config和activity_main.xml将事情简化为以下所示的Activity。
问题是,如果您在计数器完成之前按BACK,则LeakCanary会报告活动的泄漏,而让计数器运行到最后则不会。
我知道发生了什么事。 我知道观察者必须在“活动”中创建一个匿名内部类,该类可以幸免onPause()调用,因为如果您观看控制台,您会看到它继续计数。 我知道我目前已经退订,但是进程中的线程仍作为Activity的内部类运行,这是泄漏的标志。 这对我来说也不只是一个虚假的案例,在我的真实应用中,计数应该在方向改变后继续,所以我坚持保留片段中的必要内容,并以相同的泄漏进行计数。 我只是不需要在这里显示它来简化示例。
MainAcivity.java:
package com.otamate.rxactivityleaker;
import android.os.Bundle;
import android.os.SystemClock;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.widget.TextView;
import com.squareup.leakcanary.LeakCanary;
import rx.Observable;
import rx.Subscriber;
import rx.android.schedulers.AndroidSchedulers;
import rx.schedulers.Schedulers;
public class MainActivity extends AppCompatActivity {
private Observable<Long> mObservable;
private Subscriber<Long> mSubscriber;
public TextView mTextView;
public final static int MAX_PROGRESS = 10;
public final static int EMIT_DELAY_MS = 1000;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
LeakCanary.install(getApplication());
setContentView(R.layout.activity_main);
mTextView = (TextView) findViewById(R.id.textView);
mSubscriber = createSubscriber();
mObservable = createObservable();
mObservable.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(mSubscriber);
}
private Observable createObservable() {
return Observable.create (
new Observable.OnSubscribe<Long>() {
@Override
public void call(Subscriber<? super Long> sub) {
for (long i = 1; i < MAX_PROGRESS + 1; i++) {
Log.d("Observable", "Progress: " + i);
sub.onNext(i);
SystemClock.sleep(EMIT_DELAY_MS);
}
sub.onCompleted();
}
}
);
}
private Subscriber createSubscriber() {
return new Subscriber<Long>() {
@Override
public void onNext(Long val) {
Log.d("Subscriber", "Loop " + val);
mTextView.setText("Progress: " + val);
}
@Override
public void onCompleted() {
Log.d("Subscriber", "Completed");
mTextView.setText("Done!");
}
@Override
public void onError(Throwable e) {
Log.d("Subscriber", "Error: " + e);
mTextView.setText("Error!");
}
};
}
@Override
public void onPause() {
super.onPause();
if (mSubscriber != null) {
Log.d("MainActivity", "onPause() Unsubscribed");
mSubscriber.unsubscribe();
}
}
}
这是activity_main.xml:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.otamate.rxactivityleaker.MainActivity">
<TextView
android:id="@+id/textView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Idle" />
</RelativeLayout>
的build.gradle:
apply plugin: 'com.android.application'
android {
compileSdkVersion 23
buildToolsVersion "23.0.2"
defaultConfig {
applicationId "com.otamate.rxactivityleaker"
minSdkVersion 15
targetSdkVersion 23
versionCode 1
versionName "1.0"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
}
dependencies {
compile fileTree(dir: 'libs', include: ['*.jar'])
testCompile 'junit:junit:4.12'
compile 'com.android.support:appcompat-v7:23.1.1'
compile 'com.android.support:appcompat-v7:23.1.1'
compile 'io.reactivex:rxandroid:0.25.0'
debugCompile 'com.squareup.leakcanary:leakcanary-android:1.3.1'
releaseCompile 'com.squareup.leakcanary:leakcanary-android-no-op:1.3.1'
}
Observable.create
使您轻松射击自己的脚 。
您的问题在这里:
private Observable createObservable() {
return Observable.create (
new Observable.OnSubscribe<Long>() {
@Override
public void call(Subscriber<? super Long> sub) {
for (long i = 1; i < MAX_PROGRESS + 1; i++) {
Log.d("Observable", "Progress: " + i);
sub.onNext(i);
SystemClock.sleep(EMIT_DELAY_MS);
}
sub.onCompleted();
}
}
);
}
在创建Observable时,您不会在调用onNext/onCompleted
之前检查Subscriber
是否已取消订阅。 您也没有处理背压。
查看AbstractOnSubscribe,它可以帮助您更轻松地创建Observable
。
编辑: AbstractOnSubscribe
在1.1中已删除,但SyncOnSubscribe可能会起作用。
尝试这个
Subscription subscription;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
LeakCanary.install(getApplication());
setContentView(R.layout.activity_main);
mTextView = (TextView) findViewById(R.id.textView);
mSubscriber = createSubscriber();
mObservable = createObservable();
subscription = mObservable.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(mSubscriber);
}
比onPause()
@Override
public void onPause() {
super.onPause();
if (subscription != null) {
subscription.unsubscribe();
}
}
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