商业转载请联系作者获得授权,非商业转载请注明出处。
目录
一 结合RxBinding
1.1 按钮防抖功能:
1.2 输入框输入实时网络请求步长控制:
1.3 联合/表单判断
1.4 定时器任务
二
2.1 嵌套网络请求
三 防泄漏
3.1 Observable.unsubscribe
3.2 disposable.dispose
3.3 CompositeDisposable
3.4 Rxlifecycle
参考文章:
RxBinding 能够把 Android 平台的兼容包内的 UI 控件变为 Observaber 对象. 可以把 UI 控件的事件当作 RxJava 中的数据流来使用。
依赖如下:
Platform bindings:
implementation 'com.jakewharton.rxbinding3:rxbinding:3.1.0'
AndroidX library bindings:
- implementation 'com.jakewharton.rxbinding3:rxbinding-core:3.1.0'
- implementation 'com.jakewharton.rxbinding3:rxbinding-appcompat:3.1.0'
- implementation 'com.jakewharton.rxbinding3:rxbinding-drawerlayout:3.1.0'
- implementation 'com.jakewharton.rxbinding3:rxbinding-leanback:3.1.0'
- implementation 'com.jakewharton.rxbinding3:rxbinding-recyclerview:3.1.0'
- implementation 'com.jakewharton.rxbinding3:rxbinding-slidingpanelayout:3.1.0'
- implementation 'com.jakewharton.rxbinding3:rxbinding-swiperefreshlayout:3.1.0'
- implementation 'com.jakewharton.rxbinding3:rxbinding-viewpager:3.1.0'
- implementation 'com.jakewharton.rxbinding3:rxbinding-viewpager2:3.1.0'
Google 'material' library bindings:
implementation 'com.jakewharton.rxbinding3:rxbinding-material:3.1.0'
RxBinding 的优点:
进阶案例:
相比之前的定时器或者标志位,来实现的快速点击下的防抖功能,采用RxView可以大大简化代码:
- /**
- * 按钮点击防抖
- */
- RxView.clicks(mBt)
- .throttleFirst(1, TimeUnit.SECONDS)
- .subscribeOn(AndroidSchedulers.mainThread())
- .subscribe(v -> Log.i(TAG, "点击按钮"));
- /**
- * 按钮长按
- */
- RxView.longClicks(mBt)...
很多App都有这种顶部的搜索框,而现有的实现,一般都会在用户进行输入时,用EditText里自带的addTextChangedListener(new TextWatcher()来监听文本变化,进行实时搜索。
- etPriceBegin.addTextChangedListener(new TextWatcher() {
- @Override
- public void onTextChanged(CharSequence s, int start, int before,
- int count) {
- //s:变化后的所有字符
- Toast.makeText(getContext(), "变化:"+s+";"+start+";"+before+";"+count, Toast.LENGTH_SHORT).show();
- Log.i("Seachal:","变化:"+s+";"+start+";"+before+";"+count);
- }
- @Override
- public void beforeTextChanged(CharSequence s, int start, int count,
- int after) {
- //s:变化前的所有字符; start:字符开始的位置; count:变化前的总字节数;after:变化后的字节数
- Toast.makeText(getContext(), "变化前:"+s+";"+start+";"+count+";"+after, Toast.LENGTH_SHORT).show();
- Log.i("Seachal:","变化前:"+s+";"+start+";"+count+";"+after);
- }
- @Override
- public void afterTextChanged(Editable s) {
- //S:变化后的所有字符;start:字符起始的位置;before: 变化之前的总字节数;count:变化后的字节数
- Toast.makeText(getContext(), "变化后:"+s+";", Toast.LENGTH_SHORT).show();
- Log.i("Seachal:","变化后:"+s+";");
- }
- });
但有了RxView后,一切更加方便了起来。下面这个例子里,可以跳过用户的第一次输入不做处理, debounce(1, TimeUnit.SECONDS)又实现了用户在快速删除或者输入时,不会因为每次的实时变化都去进行网络请求或者相关操作,而是在间隔1s后才去进行这些操作。
- ed = findViewById(R.id.ed);
- RxTextView.textChanges(ed)
- .debounce(1, TimeUnit.SECONDS)
- //跳过第1次请求 因为初始输入框的空字符状态
- .skip(1)
- .observeOn(AndroidSchedulers.mainThread())
- .subscribe(new Observer<CharSequence>() {
- @Override
- public void onSubscribe(Disposable d) {
- }
- @Override
- public void onNext(CharSequence charSequence) {
- Log.i(TAG,"收到的字符: " + charSequence.toString());
- }
- @Override
- public void onError(Throwable e) {
- Log.d(TAG, "onError: " + e.getMessage() );
- }
- @Override
- public void onComplete() {
- Log.d(TAG, "onComplete");
- }
- });
- Observable<CharSequence> ObservableName = RxTextView.textChanges(mEtPhone);
- Observable<CharSequence> ObservablePassword = RxTextView.textChanges(mEtPassword);
- Observable.combineLatest(
- ObservableName, ObservablePassword,
- (phone, password) -> {
- return isPhoneValid(phone.toString()) && isPasswordValid(password.toString());
- })
- .subscribe(aBoolean -> {
- mBtLogin.setEnabled(aBoolean);
- // Toast.makeText(getApplicationContext(), "默认的Toast", Toast.LENGTH_SHORT).show();
- });
- //Lambda写法
- Observable.combineLatest(ObservableName, ObservablePassword
- , (phone, password) -> isPhoneValid(phone.toString()) && isPasswordValid(password.toString()))
- .subscribe(mBtLogin::setEnabled);
在我们的登录注册页,少不了一个获得验证码的倒计时定时器,一般开发者都会选择继承CountDownTimer类,神说:太麻烦了!于是有了Rx。下面的代码中,mBt在第一次点击后就处于setEnabled(false)的状态,不可点击。
- private Observable<Boolean> verifyCodeObservable;
- private static int SECOND = 20;
- verifyCodeObservable = RxView.clicks(mBt)
- .throttleFirst(SECOND, TimeUnit.SECONDS) //防止20秒内连续点击,或者只使用doOnNext部分
- .subscribeOn(AndroidSchedulers.mainThread())
- .map(o -> false)
- .doOnNext(mBt::setEnabled);
- verifyCodeObservable.subscribe(s -> {
- Observable.interval(1, TimeUnit.SECONDS, AndroidSchedulers.mainThread())
- .take(SECOND)
- .subscribe(aLong -> {
- RxTextView.text(mBt).accept("剩余" + (SECOND - aLong) + "秒");
- }
- , Throwable::printStackTrace
- , () -> {
- RxTextView.text(mBt).accept("获取验证码");
- RxView.enabled(mBt).accept(true);
- });
- });
- // flatMap
- MyRxView.clicks(btn3)
- .throttleFirst(1000, TimeUnit.MILLISECONDS)
- .observeOn(Schedulers.io())
- .flatMap(new Function<Object, ObservableSource<ProjectBean>>() {
- @Override
- public ObservableSource<ProjectBean> apply(Object o) throws Exception {
- return wanAndroidApi.getProject();
- }
- })
- .flatMap(new Function<ProjectBean, ObservableSource<ProjectBean.DataBean>>() {
- @Override
- public ObservableSource<ProjectBean.DataBean> apply(ProjectBean projectBean) throws Exception {
- return Observable.fromIterable(projectBean.getData());
- }
- })
- .flatMap(new Function<ProjectBean.DataBean, ObservableSource<ProjectItem>>() {
- @Override
- public ObservableSource<ProjectItem> apply(ProjectBean.DataBean dataBean) throws Exception {
- return wanAndroidApi.getProjectItem(1,dataBean.getId());
- }
- })
- .observeOn(AndroidSchedulers.mainThread())
- .subscribe(new Consumer<ProjectItem>() {
- @Override
- public void accept(ProjectItem projectItem) throws Exception {
- Log.i(TAG, "accept: " + projectItem);
- }
- });
- //lambda方式
- // RxView.clicks(btn3)
- // .throttleFirst(1000, TimeUnit.MILLISECONDS)
- // .observeOn(Schedulers.io())
- // .flatMap( o -> wanAndroidApi.getProject())
- // .flatMap(projectBean -> Observable.fromIterable(projectBean.getData()))
- // .flatMap(dataBean -> wanAndroidApi.getProjectItem(1,dataBean.getId()))
- // .observeOn(AndroidSchedulers.mainThread())
- // .subscribe(projectItem -> Log.i(TAG, "projectItem: " + projectItem));
- @Override
- protected void onDestroy() {
- super.onDestroy();
- Observable.unsubscribeOn(AndroidSchedulers.mainThread()); //防止泄露
- }
- @Override
- protected void onDestroy() {
- super.onDestroy();
- if(disposable!=null && !disposable.isDisposed()){
- disposable.dispose();
- }
- }
如果在请求过程中,UI层destroy了怎么办,不及时取消订阅,可能会造成内存泄漏。因此,CompositeDisposable就上场了,它可以对我们订阅的请求进行统一管理。CompositeDisposable的clear方法内部,实际上就会调用Disposable的dispose方法。
大致三步走:
1、在UI层创建的时候(比如onCreate之类的),实例化CompositeDisposable;
2、把subscribe订阅返回的Disposable对象加入管理器;
3、UI销毁时清空订阅的对象。
- private CompositeDisposable mCompositeDisposable;
- // when create UI
- mCompositeDisposable = new CompositeDisposable();
- // when request data
- if (mCompositeDisposable != null && !mCompositeDisposable.isDisposed()) {
- mCompositeDisposable.add(disposable);
- }
- // when destroy UI
- if (mCompositeDisposable != null) {
- mCompositeDisposable.clear(); // clear时网络请求会随即cancel
- mCompositeDisposable = null;
- }
这样我们就可以管理脱缰的网络请求了,相当于将它与UI的生命周期绑定。只要稍稍将上述模板封装一哈,就比较方便了。比如add操作可以封装一个方法,每次网络请求时add一发就好。
对于MVP架构的项目,CompositeDisposable完全可以封装到Presenter当中。这里就不展开了。
我们可以利用Rxlifecycle来解决内存泄漏问题。
依赖:
- implementation 'com.trello.rxlifecycle3:rxlifecycle:3.1.0'
- // If you want to bind to Android-specific lifecycles
- implementation 'com.trello.rxlifecycle3:rxlifecycle-android:3.1.0'
- // If you want pre-written Activities and Fragments you can subclass as providers
- implementation 'com.trello.rxlifecycle3:rxlifecycle-components:3.1.0'
- // If you want pre-written support preference Fragments you can subclass as providers
- implementation 'com.trello.rxlifecycle3:rxlifecycle-components-preference:3.1.0'
- // If you want to use Android Lifecycle for providers
- implementation 'com.trello.rxlifecycle3:rxlifecycle-android-lifecycle:3.1.0'
- // If you want to use Kotlin syntax
- implementation 'com.trello.rxlifecycle3:rxlifecycle-kotlin:3.1.0'
- // If you want to use Kotlin syntax with Android Lifecycle
- implementation 'com.trello.rxlifecycle3:rxlifecycle-android-lifecycle-kotlin:3.1.0'
- // If you want to use Navi for providers
- // DEPRECATED: Use rxlifecycle-android-lifecycle instead. This will be removed in a future release.
- implementation 'com.trello.rxlifecycle3:rxlifecycle-navi:3.1.0'
You can bind when the lifecycle emits anything:
- myObservable
- .compose(RxLifecycle.bind(lifecycle))
- .subscribe();
Or you can bind to when a specific lifecyle event occurs:
- myObservable
- .compose(RxLifecycle.bindUntilEvent(lifecycle, ActivityEvent.DESTROY))
- .subscribe();
Alternatively, you can let RxLifecycle determine the appropriate time to end the sequence:
- myObservable
- .compose(RxLifecycleAndroid.bindActivity(lifecycle))
- .subscribe();
例子:
- public class RxLifeActivity extends RxAppCompatActivity {
- /**
- * RxLifecycle使用:在当前activity中继承RxAppCompatActivity
- * <p>
- * ActivityEvent:手动设置指定在什么时候取消订阅,下列枚举
- * CREATE,
- * START,
- * RESUME,
- * PAUSE,
- * STOP,
- * DESTROY
- */
- @Override
- protected void onCreate(Bundle savedInstanceState) {
- super.onCreate(savedInstanceState);
- setContentView(R.layout.activity_rx_life);
- Flowable.interval(3, 2, TimeUnit.SECONDS)
- .subscribeOn(Schedulers.io())
- .compose(this.bindUntilEvent(ActivityEvent.PAUSE)) //手动设置在activity onPause的时候取消订阅
- .observeOn(AndroidSchedulers.mainThread())
- .subscribe(aLong -> Log.e("liuqiang", "RxLifeActivityOnCreate:" + aLong));
- }
- @Override
- protected void onStart() {
- super.onStart();
- Flowable.interval(6, 3, TimeUnit.SECONDS)
- //bindToLifecycle的自动取消订阅示例,因为是在onStart的时候调用,所以在onStop的时候自动取消订阅
- .compose(this.bindToLifecycle()) //设置在默认的生命周期中取消订阅
- .subscribeOn(Schedulers.io())
- .observeOn(AndroidSchedulers.mainThread())
- .subscribe(aLong -> Log.e("liuqiang", "RxLifeActivityOnStart:" + aLong));
- }
- }
因为写RxJava系列的文章时进行了很多阅读和参考,因此不分一二三等,将全系列的参考引用统一如下:
RxJava3 Wiki:https://github.com/ReactiveX/RxJava/wiki
RxJava3官方github:https://github.com/ReactiveX/RxJava/wiki/What's-different-in-3.0
ReactiveX文档中文翻译:https://mcxiaoke.gitbooks.io/rxdocs/content/operators/Creating-Observables.html
single:http://reactivex.io/documentation/single.html
操作符系列讲的很好的文章:https://blog.csdn.net/weixin_42046829/article/details/104836592
基础介绍:https://blog.csdn.net/weixin_42046829/article/details/104833751
RxJava3的一些简介:https://juejin.im/post/5d1eeffe6fb9a07f0870b4e8
观察者被观察者入门RxJava的一篇好文章:https://juejin.im/post/580103f20e3dd90057fc3e6d
关于背压一个很好的介绍:https://juejin.im/post/582d413c8ac24700619cceed
RxLifecycle:https://github.com/trello/RxLifecycle
刚哥平台的挺好很全:RxJava2 只看这一篇文章就够了https://juejin.im/post/5b17560e6fb9a01e2862246f
联系客服