handler.postdelayed()在活动onResume()之后自动更改毫秒

handler.postDelayed(Runnable runnable, long delayMillis);

import android.os.Bundle;
import android.os.Handler;
import android.support.v7.app.AppCompatActivity;

public class MainActivity extends AppCompatActivity {
    private Handler handler;

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

        handler = new Handler();
    }

    @Override
    protected void onResume() {
        super.onResume();

        // 在onResume()之后延迟500毫秒执行任务
        handler.postDelayed(new Runnable() {
            @Override
            public void run() {
                // 执行延迟任务的代码
            }
        }, 500);
    }

    @Override
    protected void onPause() {
        super.onPause();

        // 在活动暂停时移除未执行的延迟任务
        handler.removeCallbacksAndMessages(null);
    }
}