学步园

package com.example.timing;

import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.os.PowerManager;
import android.os.PowerManager.WakeLock;

public class TimingActivity extends Activity {
	PowerManager manager = null;
	WakeLock lock = null;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_timing);
		manager = (PowerManager) this.getSystemService(Context.POWER_SERVICE);
		lock = manager.newWakeLock(PowerManager.SCREEN_DIM_WAKE_LOCK, "mylock");
		// PARTIAL_WAKE_LOCK :保持CPU 运转，屏幕和键盘灯有可能是关闭的。
		// SCREEN_DIM_WAKE_LOCK ：保持CPU 运转，允许保持屏幕显示但有可能是灰的，允许关闭键盘灯
		// SCREEN_BRIGHT_WAKE_LOCK ：保持CPU 运转，允许保持屏幕高亮显示，允许关闭键盘灯
		// FULL_WAKE_LOCK ：保持CPU 运转，保持屏幕高亮显示，键盘灯也保持亮度
	}

	@Override
	protected void onPause() {
		super.onPause();
		lock.release();// 关闭长亮
	}

	@Override
	protected void onResume() {
		super.onResume();
		lock.acquire();// 打开长亮
	}
}

或者直接在onCreate()里，不用权限getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);