Rxjava做倒计时操作

下面是使用Rxjava做倒计时跳转页面，首先导入依赖：

implementation 'com.squareup.retrofit2:adapter-rxjava2:2.4.0'

implementation 'io.reactivex.rxjava2:rxandroid:2.0.1'

public class MainActivity extends AppCompatActivity {

    private Disposable mDisposable;//用于解除订阅
    private TextView text_time;
    private int time=3;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        text_time = findViewById(R.id.text_time);

        Observable observable = Observable.interval(1, TimeUnit.SECONDS);
        observable.create(new ObservableOnSubscribe<Object>() {
            @Override
            public void subscribe(ObservableEmitter<Object> e) throws Exception {
                e.onNext(01);
            }
        });

        Observer observer = new Observer() {
            @Override
            public void onSubscribe(Disposable d) {
                mDisposable=d;
            }

            @Override
            public void onNext(Object value) {
                time--;
                text_time.setText(time+"s");
                if (time==0){
                    if (mDisposable!=null){
                        mDisposable.dispose();
                    }
                    startActivity(new Intent(MainActivity.this,HomeActivity.class));
                    finish();
                }
            }

            @Override
            public void onError(Throwable e) {

            }

            @Override
            public void onComplete() {

            }
        };
        observable.subscribeOn(Schedulers.io())
                .observeOn(AndroidSchedulers.mainThread())
                .subscribe(observer);
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        if (mDisposable!=null){
            mDisposable.dispose();
        }
    }
}