MainActivity.java

package jp.mixi.sample.res.drawable;

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

import android.app.Activity;
import android.graphics.drawable.ClipDrawable;
import android.graphics.drawable.Drawable;
import android.graphics.drawable.ScaleDrawable;
import android.graphics.drawable.TransitionDrawable;
import android.os.Bundle;
import android.os.Handler;

public class MainActivity extends Activity {
    private static final int TRANSITION_DURATION = 5000;
    private static final long TIMER_TASK_PERIOD = 1000L;
    private static final int TIMER_TASK_DELAY = 0;

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

        final Handler handler = new Handler();
        final Timer timer = new Timer();

        // 5秒ごとにレベルを変更するタスク
        final Drawable levelListDrawable = findViewById(R.id.LevelListButton).getBackground();
        timer.scheduleAtFixedRate(
                new TimerTask() {
                    @Override
                    public void run() {
                        final int level = levelListDrawable.getLevel();
                        handler.post(new Runnable() {
                            @Override
                            public void run() {
                                if (level == 0) {
                                    levelListDrawable.setLevel(1);
                                } else {
                                    levelListDrawable.setLevel(0);
                                }
                            }
                        });
                    }
                },
                TIMER_TASK_DELAY, TIMER_TASK_PERIOD);

        // クロスフェードを開始する
        final TransitionDrawable transition = (TransitionDrawable) findViewById(R.id.TransitionView).getBackground();
        transition.startTransition(TRANSITION_DURATION);

        // 5秒ごとにレベルを変更し、クリップの範囲を変化させるタスク
        final ClipDrawable clipDrawable = (ClipDrawable) findViewById(R.id.ClipView).getBackground();
        timer.scheduleAtFixedRate(
                new TimerTask() {
                    @Override
                    public void run() {
                        handler.post(new Runnable() {
                            @Override
                            public void run() {
                                clipDrawable.setLevel(clipDrawable.getLevel() + 1000);
                            }
                        });
                    }
                },
                TIMER_TASK_DELAY, TIMER_TASK_PERIOD);

        // スケールのレベルを変更する
        ScaleDrawable scale = (ScaleDrawable) findViewById(R.id.ScaleView).getBackground();
        scale.setLevel(1);
    }
}