Александр Дорофеев

MyClass instanceOfMyClass = new MyClass();
 instanceOfMyClass = null;

Xml - файл Layout:

<?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="android.letscoder.xyz.videosolution.MainActivity">

    <VideoView
        android:id="@+id/video_view"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        />
</RelativeLayout>

Код класса Activity:

package android.letscoder.xyz.videosolution;

import android.net.Uri;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.widget.MediaController;
import android.widget.VideoView;

public class MainActivity extends AppCompatActivity {

    VideoView mVideoView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        setupVideoView(mVideoView, "http://techslides.com/demos/sample-videos/small.mp4");
    }

    private void setupVideoView(VideoView videoView, String url) {
        videoView = (VideoView) findViewById(R.id.video_view);
        MediaController controls = new MediaController(this);
        controls.setAnchorView(videoView);
        videoView.setMediaController(controls);
        videoView.setVideoURI(Uri.parse(url));
        videoView.start();
    }

}

Не забудьте прописать permisson в манифесте:

<uses-permission android:name="android.permission.INTERNET"/>

Всё работает:

public class TimerClass extends CountDownTimer {
    public String getCurrentTime() {
        return currentTime;
    }

    private String currentTime;

    public TimerClass(long milliFuture, long interval) {
        super(milliFuture, interval);
    }

    @Override
    public void onTick(long millisUntilFinished) {
        long millis = millisUntilFinished;
        String hhmmss = String.format("%02d:%02d:%02d", TimeUnit.MILLISECONDS.toHours(millis),
                TimeUnit.MILLISECONDS.toMinutes(millis) - TimeUnit.HOURS.toMinutes(TimeUnit.MILLISECONDS.toHours(millis)),
                TimeUnit.MILLISECONDS.toSeconds(millis) - TimeUnit.MINUTES.toSeconds(TimeUnit.MILLISECONDS.toMinutes(millis)));
        currentTime = hhmmss;
    }

    @Override
    public void onFinish() {
        currentTime = "Completed";
    }
}

public class MainActivity extends AppCompatActivity implements View.OnClickListener {

    TextView mTimer;
    Button startButton, pauseButton;
    int timeToEnd = 25000;
    final TimerClass timer = new TimerClass(timeToEnd, 1000);

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

        mTimer = (TextView) findViewById(R.id.tv);
        startButton = (Button) findViewById(R.id.startButton);
        pauseButton = (Button) findViewById(R.id.pauseButton);
        startButton.setOnClickListener(this);
        pauseButton.setOnClickListener(this);
        runTimer();
    }

    @Override
    public void onClick(View v) {

        switch (v.getId()) {
            case R.id.startButton:
                startButton.setOnClickListener(this);
                timer.start();
                break;
            case R.id.pauseButton:
                pauseButton.setOnClickListener(this);
                timer.cancel();
        }
    }

    private void runTimer() {


        final Handler handler = new Handler();
        handler.post(new Runnable() {
            @Override
            public void run() {

                mTimer.setText(timer.getCurrentTime());
                handler.post(this);
            }
        });
    }

}

выложить в Google Play

List lines = Files.readAllLines(Paths.get("res/file.txt"));
//перебираете циклом
for(String s : lines)
{
s = "Бла-бла-бла!"
}
/* Если нужно удалить - для перебора используйте Iterator.
Не забудьте : */ 
Files.write(Paths.get("res/file.txt"), lines);
//иначе результат не запишется