动画之渐变

public class MainActivity extends AppCompatActivity {

    private RelativeLayout rl;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        rl = (RelativeLayout) findViewById(R.id.rl);
        donghua(rl);
    }
    public void donghua(View view){
        AlphaAnimation alphaAnimation=new AlphaAnimation(1,0);//1,0代表是从实体转化成透明的
        alphaAnimation.setDuration(5000);//这个是显示的时间
        view.startAnimation(alphaAnimation);
        alphaAnimation.setAnimationListener(new Animation.AnimationListener() {
            @Override
            public void onAnimationStart(Animation animation) {

            }

            @Override
            public void onAnimationEnd(Animation animation) {
                Intent intent=new Intent(MainActivity.this,HomeActivity.class);
                startActivity(intent);
            }

            @Override
            public void onAnimationRepeat(Animation animation) {

            }
        });
    }
}