Android 修改屏幕亮度

一、获取系统Settings 中的亮度
二、修改APP界面屏幕亮度，不会影响其他APP
三、修改系统Settings 中屏幕亮度，影响所有APP
四、完整代码实现

一、获取系统Settings 中的亮度

系统屏幕亮度值在（0~255）之间，获取方法很简单，只需要调用以下方法即可。

/*** 1.获取系统默认屏幕亮度值 屏幕亮度值范围（0-255）* **/private int getScreenBrightness(Context context) {ContentResolver contentResolver = context.getContentResolver();int defVal = 125;return Settings.System.getInt(contentResolver,Settings.System.SCREEN_BRIGHTNESS, defVal);}

修改屏幕亮度包含两种：
1.修改APP界面屏幕亮度，不会影响其他APP。
2.修改系统 Settings 中屏幕亮度，影响所有APP.

二，修改APP界面屏幕亮度，不会影响其他APP

修改自身 APP 亮度很简单，只需要在Activity OnCreate 方法调用如下代码即可。

/*** 2.设置 APP界面屏幕亮度值方法* **/private void setAppScreenBrightness(int birghtessValue) {Window window = getWindow();WindowManager.LayoutParams lp = window.getAttributes();lp.screenBrightness = birghtessValue / 255.0f;window.setAttributes(lp);}

三、修改系统Settings 中屏幕亮度，影响所有APP

修改系统 Settings 中的屏幕亮度，由于会影响到所有APP，需要申请修改Settings 的权限<uses-permission * android:name=“android.permission.WRITE_SETTINGS”/>，同时需要取消光感自动调节屏幕亮度的功能，设置为手动调节模式，否则光感传感器会随着光照强度的变化修改系统屏幕亮度，并且非系统签名的APP，需要用户手动授权后才可以修改背光亮度。
关闭光感，设置手动调节背光模式实现方法如下：

/*** 3.关闭光感，设置手动调节背光模式* * SCREEN_BRIGHTNESS_MODE_AUTOMATIC 自动调节屏幕亮度模式值为1* * SCREEN_BRIGHTNESS_MODE_MANUAL 手动调节屏幕亮度模式值为0* **/public void setScreenManualMode(Context context) {ContentResolver contentResolver = context.getContentResolver();try {int mode = Settings.System.getInt(contentResolver,Settings.System.SCREEN_BRIGHTNESS_MODE);if (mode == Settings.System.SCREEN_BRIGHTNESS_MODE_AUTOMATIC) {Settings.System.putInt(contentResolver,Settings.System.SCREEN_BRIGHTNESS_MODE,Settings.System.SCREEN_BRIGHTNESS_MODE_MANUAL);}} catch (Settings.SettingNotFoundException e) {e.printStackTrace();}}

非系统签名应用，引导用户手动授权修改Settings 权限
非系统签名应用，无法直接修改Settings,需要引导用户手动授权。

/*** 4.非系统签名应用，引导用户手动授权修改Settings 权限* **/private static final int REQUEST_CODE_WRITE_SETTINGS = 1000;private void allowModifySettings() {// Settings.System.canWrite(MainActivity.this)// 检测是否拥有写入系统 Settings 的权限if (!Settings.System.canWrite(MainActivity.this)) {AlertDialog.Builder builder = new AlertDialog.Builder(this,android.R.style.Theme_Material_Light_Dialog_Alert);builder.setTitle("请开启修改屏幕亮度权限");builder.setMessage("请点击允许开启");// 拒绝, 无法修改builder.setNegativeButton("拒绝",new DialogInterface.OnClickListener() {@Overridepublic void onClick(DialogInterface dialog, int which) {Toast.makeText(MainActivity.this,"您已拒绝修系统Setting的屏幕亮度权限", Toast.LENGTH_SHORT).show();}});builder.setPositiveButton("去开启",new DialogInterface.OnClickListener() {@Overridepublic void onClick(DialogInterface dialog, int which) {// 打开允许修改Setting 权限的界面Intent intent = new Intent(Settings.ACTION_MANAGE_WRITE_SETTINGS, Uri.parse("package:"+ getPackageName()));startActivityForResult(intent,REQUEST_CODE_WRITE_SETTINGS);}});builder.setCancelable(false);builder.show();}}@Overrideprotected void onActivityResult(int requestCode, int resultCode, Intent data) {// TODO Auto-generated method stubsuper.onActivityResult(requestCode, resultCode, data);if (requestCode == REQUEST_CODE_WRITE_SETTINGS) {if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {// Settings.System.canWrite方法检测授权结果if (Settings.System.canWrite(getApplicationContext())) {// 5.调用修改Settings屏幕亮度的方法 屏幕亮度值 200ModifySettingsScreenBrightness(MainActivity.this, 200);Toast.makeText(this, "系统屏幕亮度值" + getScreenBrightness(this),Toast.LENGTH_SHORT).show();} else {Toast.makeText(MainActivity.this, "您已拒绝修系统Setting的屏幕亮度权限",Toast.LENGTH_SHORT).show();}}}}

修改Setting 中屏幕亮度值实现
拥有系统签名的应用可以直接调用此方法修改系统屏幕亮度，非系统签名应用，只有用户授权后才可以修改。

/*** 5.修改Setting 中屏幕亮度值* * 修改Setting的值需要动态申请权限 <uses-permission* android:name="android.permission.WRITE_SETTINGS"/>* **/private void ModifySettingsScreenBrightness(Context context,int birghtessValue) {// 首先需要设置为手动调节屏幕亮度模式setScreenManualMode(context);ContentResolver contentResolver = context.getContentResolver();Settings.System.putInt(contentResolver,Settings.System.SCREEN_BRIGHTNESS, birghtessValue);}

四、完整代码实现

完整代码实现如下：

package com.example.test;import android.app.Activity;
import android.app.AlertDialog;
import android.content.ContentResolver;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.net.Uri;
import android.os.Build;
import android.os.Bundle;
import android.provider.Settings;
import android.view.Window;
import android.view.WindowManager;
import android.widget.Toast;public class MainActivity extends Activity {@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);//获取屏幕亮度getScreenBrightness(this);Toast.makeText(this, "系统屏幕亮度值" + getScreenBrightness(this),Toast.LENGTH_SHORT).show();// 设置APP 屏幕亮度后，系统Setting亮度将对此app 不生效setAppScreenBrightness(100);allowModifySettings();setContentView(R.layout.activity_main);}/*** 1.获取系统默认屏幕亮度值 屏幕亮度值范围（0-255）* **/private int getScreenBrightness(Context context) {ContentResolver contentResolver = context.getContentResolver();int defVal = 125;return Settings.System.getInt(contentResolver,Settings.System.SCREEN_BRIGHTNESS, defVal);}/*** 2.设置 APP界面屏幕亮度值方法* **/private void setAppScreenBrightness(int birghtessValue) {Window window = getWindow();WindowManager.LayoutParams lp = window.getAttributes();lp.screenBrightness = birghtessValue / 255.0f;window.setAttributes(lp);}/*** 3.关闭光感，设置手动调节背光模式* * SCREEN_BRIGHTNESS_MODE_AUTOMATIC 自动调节屏幕亮度模式值为1* * SCREEN_BRIGHTNESS_MODE_MANUAL 手动调节屏幕亮度模式值为0* **/public void setScreenManualMode(Context context) {ContentResolver contentResolver = context.getContentResolver();try {int mode = Settings.System.getInt(contentResolver,Settings.System.SCREEN_BRIGHTNESS_MODE);if (mode == Settings.System.SCREEN_BRIGHTNESS_MODE_AUTOMATIC) {Settings.System.putInt(contentResolver,Settings.System.SCREEN_BRIGHTNESS_MODE,Settings.System.SCREEN_BRIGHTNESS_MODE_MANUAL);}} catch (Settings.SettingNotFoundException e) {e.printStackTrace();}}/*** 4.非系统签名应用，引导用户手动授权修改Settings 权限* **/private static final int REQUEST_CODE_WRITE_SETTINGS = 1000;private void allowModifySettings() {// Settings.System.canWrite(MainActivity.this)// 检测是否拥有写入系统 Settings 的权限if (!Settings.System.canWrite(MainActivity.this)) {AlertDialog.Builder builder = new AlertDialog.Builder(this,android.R.style.Theme_Material_Light_Dialog_Alert);builder.setTitle("请开启修改屏幕亮度权限");builder.setMessage("请点击允许开启");// 拒绝, 无法修改builder.setNegativeButton("拒绝",new DialogInterface.OnClickListener() {@Overridepublic void onClick(DialogInterface dialog, int which) {Toast.makeText(MainActivity.this,"您已拒绝修系统Setting的屏幕亮度权限", Toast.LENGTH_SHORT).show();}});builder.setPositiveButton("去开启",new DialogInterface.OnClickListener() {@Overridepublic void onClick(DialogInterface dialog, int which) {// 打开允许修改Setting 权限的界面Intent intent = new Intent(Settings.ACTION_MANAGE_WRITE_SETTINGS, Uri.parse("package:"+ getPackageName()));startActivityForResult(intent,REQUEST_CODE_WRITE_SETTINGS);}});builder.setCancelable(false);builder.show();}}@Overrideprotected void onActivityResult(int requestCode, int resultCode, Intent data) {// TODO Auto-generated method stubsuper.onActivityResult(requestCode, resultCode, data);if (requestCode == REQUEST_CODE_WRITE_SETTINGS) {if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {// Settings.System.canWrite方法检测授权结果if (Settings.System.canWrite(getApplicationContext())) {// 5.调用修改Settings屏幕亮度的方法 屏幕亮度值 200ModifySettingsScreenBrightness(MainActivity.this, 200);Toast.makeText(this, "系统屏幕亮度值" + getScreenBrightness(this),Toast.LENGTH_SHORT).show();} else {Toast.makeText(MainActivity.this, "您已拒绝修系统Setting的屏幕亮度权限",Toast.LENGTH_SHORT).show();}}}}/*** 5.修改Setting 中屏幕亮度值* * 修改Setting的值需要动态申请权限 <uses-permission* android:name="android.permission.WRITE_SETTINGS"/>* **/private void ModifySettingsScreenBrightness(Context context,int birghtessValue) {// 首先需要设置为手动调节屏幕亮度模式setScreenManualMode(context);ContentResolver contentResolver = context.getContentResolver();Settings.System.putInt(contentResolver,Settings.System.SCREEN_BRIGHTNESS, birghtessValue);}
}