上下滑动可以调节屏幕亮度

1.首先，我们需要一个操作屏幕亮度的类。不多说，直接上代码。

package zz.screenlight;

import android.app.Activity;
import android.content.ContentResolver;
import android.net.Uri;
import android.provider.Settings;
import android.provider.Settings.SettingNotFoundException;
import android.util.Log;
import android.view.WindowManager;

public class BrightnessTools {
	

	/** 判断是否开启了自动亮度调节 */

	public static boolean isAutoBrightness(ContentResolver aContentResolver) {

		boolean automicBrightness = false;

		try {

			automicBrightness = Settings.System.getInt(aContentResolver,

			Settings.System.SCREEN_BRIGHTNESS_MODE) == Settings.System.SCREEN_BRIGHTNESS_MODE_AUTOMATIC;

		}

		catch (SettingNotFoundException e)

		{

			e.printStackTrace();

		}

		return automicBrightness;
	}

	/**  获取屏幕的亮度 */

	public static int getScreenBrightness(Activity activity) {

		int nowBrightnessValue = 0;

		ContentResolver resolver = activity.getContentResolver();

		try {

			nowBrightnessValue = android.provider.Settings.System.getInt(
					resolver, Settings.System.SCREEN_BRIGHTNESS);

		}

		catch (Exception e) {

			e.printStackTrace();

		}

		return nowBrightnessValue;
	}

	

	/**  设置亮度 */

	public static void setBrightness(Activity activity, int brightness) {

		// Settings.System.putInt(activity.getContentResolver(),

		// Settings.System.SCREEN_BRIGHTNESS_MODE,

		// Settings.System.SCREEN_BRIGHTNESS_MODE_MANUAL);

		WindowManager.LayoutParams lp = activity.getWindow().getAttributes();

		lp.screenBrightness = Float.valueOf(brightness) * (1f / 255f);
		Log.d("lxy", "set  lp.screenBrightness == " + lp.screenBrightness);

		activity.getWindow().setAttributes(lp);
	}

	

	/**停止自动亮度调节 */

	public static void stopAutoBrightness(Activity activity) {

		Settings.System.putInt(activity.getContentResolver(),

		Settings.System.SCREEN_BRIGHTNESS_MODE,

		Settings.System.SCREEN_BRIGHTNESS_MODE_MANUAL);
	}

	

	/**开启亮度自动调节 */
	

	public static void startAutoBrightness(Activity activity) {

		Settings.System.putInt(activity.getContentResolver(),

		Settings.System.SCREEN_BRIGHTNESS_MODE,

		Settings.System.SCREEN_BRIGHTNESS_MODE_AUTOMATIC);

	}

	

	/** 保存亮度设置状态 */

	public static void saveBrightness(ContentResolver resolver, int brightness) {

		Uri uri = android.provider.Settings.System
				.getUriFor("screen_brightness");

		android.provider.Settings.System.putInt(resolver, "screen_brightness",
				brightness);

		// resolver.registerContentObserver(uri, true, myContentObserver);

		resolver.notifyChange(uri, null);
	}
}

2.把上边这个类直接放到你的utils工具类中即可使用了，他里面包含了获取当前屏幕亮度，设置亮度，等功能。

3.下面是我写的一个小demo

3.1 在activity_main.xml 中定义了几个按钮，可以点击按钮进行相关的设置，并且获取数据。

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:padding="20dp" >

  

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="state"
        android:text="屏幕亮度状态" />
    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="close"
        android:text="关闭自动亮度调节功能" />
    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="open"
        android:text="开启自动亮度调节功能" />
    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="get"
        android:text="获取当前屏幕亮度" />
    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="set"
        android:text="设置屏幕亮度" />
    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="save"
        android:text="保存屏幕亮度" />

</LinearLayout>

3.2.接下来是MainActivity.java中的代码了。

package zz.screenlight;

import android.os.Bundle;
import android.app.Activity;
import android.util.Log;
import android.view.Menu;
import android.view.MotionEvent;
import android.view.View;
import android.widget.Toast;

public class MainActivity extends Activity {

	private float downY;
	private float moveY;
	private int screenBrightness;

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

	// 判断亮度状态
	public void state(View view) {
		boolean autoBrightness = BrightnessTools
				.isAutoBrightness(getContentResolver());
		Toast.makeText(getApplicationContext(), "亮度状态为" + autoBrightness,
				Toast.LENGTH_SHORT).show();
	}

	// 关闭自动亮度调节功能
	public void close(View view) {
		BrightnessTools.stopAutoBrightness(this);
		Toast.makeText(getApplicationContext(), "关闭自动亮度调节功能",
				Toast.LENGTH_SHORT).show();
	}

	// 开启自动亮度调节功能
	public void open(View view) {
		BrightnessTools.startAutoBrightness(this);
		Toast.makeText(getApplicationContext(), "开启自动亮度调节功能",
				Toast.LENGTH_SHORT).show();
	}

	// 获取屏幕亮度
	public void get(View view) {
		int screenBrightness = BrightnessTools.getScreenBrightness(this);
		Toast.makeText(getApplicationContext(), "获取屏幕亮度" + screenBrightness,
				Toast.LENGTH_SHORT).show();
	}

	// 设置屏幕亮度,接着保存屏幕亮度
	public void set(View view) {
		int i = 33;
		BrightnessTools.setBrightness(this, i);
		Toast.makeText(getApplicationContext(), "设置屏幕亮度" + i,
				Toast.LENGTH_SHORT).show();
		BrightnessTools.saveBrightness(getContentResolver(), i);
	}

	// 保存屏幕亮度
	public void save(View view) {
		int brightness = 0;
		BrightnessTools.saveBrightness(getContentResolver(), brightness);
		Toast.makeText(getApplicationContext(), "保存屏幕亮度" + brightness,
				Toast.LENGTH_SHORT).show();
	}

	@Override
	public boolean onTouchEvent(MotionEvent event) {
		switch (event.getAction()) {
		case MotionEvent.ACTION_DOWN:
			downY = event.getY();
			// 获取当前亮度
			screenBrightness = BrightnessTools
					.getScreenBrightness(MainActivity.this);
			break;
		case MotionEvent.ACTION_MOVE:
			moveY = event.getY();
			float disY = moveY - downY;
			int heightPixels = getResources().getDisplayMetrics().heightPixels / 2;
			float percentLight = disY / heightPixels;
			// 亮度偏移量
			int offsetLight = (int) (percentLight * 255);
			Log.i("MainActivity", offsetLight+"");
			// 最终亮度
			int endLight = screenBrightness + offsetLight;
			Log.i("MainActivity", endLight+"");
			
			
			if (endLight >= 0 && endLight <= 255) {
				BrightnessTools.setBrightness(MainActivity.this, endLight);
				BrightnessTools.saveBrightness(getContentResolver(), endLight);
			}
			break;
		case MotionEvent.ACTION_UP:

			break;

		default:
			break;
		}

		return super.onTouchEvent(event);
	}

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

}

上下滑动改变亮度是在onTouchEvent方法中来实现的，主要是通过滑动距离占屏幕高度一半的百分比计算的。至此就可以在屏幕上滑动的时候改变屏幕的亮度了。

3.3 千万记得在清单文件中添加上一个设置的权限，否则会秒退。

<uses-permission android:name="android.permission.WRITE_SETTINGS"/>

4.现在，就可把最先写的类和上下滑动的代码移植到你自己的代码中了，轻松实现滑动改变屏幕亮度。其实也可以设置成左右滑动改变亮度功能，原理相同，这里就不在写了。

上下滑动可以调节屏幕亮度

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