在ACTION_DOWN触摸事件中使用Android Timer错误

Question

I have been working on a very simple app. There is only one music file, one play button and nothing much. I am trying to make it so that the music starts playing when the button is clicked but then I'd like to have the user hold down the stop button for 2 seconds until it stops playing and in case the user releases the button within the 2 seconds, the timer should just terminate.

import android.app.ActionBar;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.media.MediaPlayer;
import android.os.Environment;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.MotionEvent;
import android.view.View;
import android.view.Window;
import android.view.WindowManager;
import android.widget.ImageButton;

import java.util.Timer;
import java.util.TimerTask;

import static com.example.appname.R.raw.sound;


public class MainActivity extends ActionBarActivity {

    boolean isPlaying = false;
    ImageButton button;
    MediaPlayer mp;
    Timer timer;

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

        button = (ImageButton) findViewById(R.id.playButton);
        mp = MediaPlayer.create(this, sound);

        button.setOnClickListener(imgButtonHandler);


    }

    View.OnClickListener imgButtonHandler;

    {
        imgButtonHandler = new View.OnClickListener() {

            public void onClick(View v) {
                if (!isPlaying) {
                    mp.start();
                    isPlaying = true;
                    button.setImageResource(R.drawable.stop);
                    button.setOnTouchListener(imgButtonTouchHandler);
                }

            }
        };
    }

    View.OnTouchListener imgButtonTouchHandler;

    {
        imgButtonTouchHandler = new View.OnTouchListener() {

            @Override
            public boolean onTouch(View v, MotionEvent event) {
                switch (event.getAction()) {
                    case MotionEvent.ACTION_DOWN:
                        // PRESSED
                        if (isPlaying) {
                            button.setImageResource(R.drawable.stop_highlighted);
                            timer.schedule(stopMusic(), 2000);

                            return true;
                        } else {
                            return false;
                        }

                    case MotionEvent.ACTION_UP:
                        if (isPlaying) {
                            if (timer != null){
                                timer.cancel();
                                timer = null;
                            }
                            return true;
                        } else {
                            return false;
                        }
                        // RELEASED
                }
                return false;
            }
        };
    }

    public TimerTask stopMusic() {
        mp.reset();
        mp = MediaPlayer.create(MainActivity.this, sound);
        button.setImageResource(R.drawable.play);
        isPlaying = false;
        return null;
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }

}

I am getting this error: java.lang.NullPointerException: Attempt to invoke virtual method 'void java.util.Timer.schedule(java.util.TimerTask, long)' on a null object reference

If I remove the timer and import the stopMusic() method content into the ACTION_UP part - then it works fine, but the I don't have the 2 seconds requirement. It seems like I am unable to do a timer function within the ACTION_DOWN part. Is there a way for me to accomplish this differently? or is something in my code wrong?

Thanks in advance.

Answer 1

You have not initialized Your timer, first correct this error. If then nothing works, come back:

Timer timer;

You have to initialize it:

timer = new Timer();