Android 调整屏幕亮度

Android屏幕亮度调节分两种：
1.调节当前Activity的亮度，当退出该Activity就可以恢复到系统默认亮度。

Window window = getWindow();WindowManager.LayoutParams mParams = window.getAttributes();//brightness值:0-1mParams.screenBrightness = brightness;window.setAttributes(mParams);

2.调节系统的屏幕亮度，跟Activity无关。

//value 值：0-255Settings.System.putInt(getContentResolver(), Settings.System.SCREEN_BRIGHTNESS, value);  

Demo:

import android.os.Build;import android.os.Bundle;import android.provider.Settings;import android.support.v7.app.AppCompatActivity;import android.util.Log;import android.view.View;import android.view.Window;import android.view.WindowManager;import android.widget.Button;import android.widget.RadioButton;import android.widget.RadioGroup;import android.widget.SeekBar;import android.widget.TextView;import com.example.androidtest.BuildConfig;import com.example.androidtest.R;import butterknife.Bind;import butterknife.ButterKnife;import butterknife.OnClick;public class BrightnessActivity extends AppCompatActivity {    private static final String TAG = "BrightnessActivity";    Window window;    @Bind(R.id.default_Btn)    Button defaultBtn;    @Bind(R.id.max_Btn)    Button maxBtn;    @Bind(R.id.exchange_Sb)    SeekBar exchangeSb;    @Bind(R.id.screen_brightness_Tv)    TextView screenBrightnessTv;    @Bind(R.id.activity_Rb)    RadioButton activityRb;    @Bind(R.id.system_Rb)    RadioButton systemRb;    @Bind(R.id.radio_group)    RadioGroup radioGroup;    private WindowManager.LayoutParams mParams;    private int screenBrightness;    private int screenMode;    private boolean isSystem = false;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_brightness);        ButterKnife.bind(this);        window = getWindow();        getBrightNess();        exchangeSb.setProgress((int) (screenBrightness / 255.0f * 100));        Log.i(TAG, "progress:" + exchangeSb.getProgress());        radioGroup.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {            @Override            public void onCheckedChanged(RadioGroup group, int checkedId) {                switch (checkedId) {                    case R.id.activity_Rb:                        isSystem = false;                        break;                    case R.id.system_Rb:                        isSystem = true;                        break;                }            }        });        exchangeSb.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {            @Override            public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {                if (isSystem) {                    float brightness = progress / 100f * 255;                    setGlobalBrightness((int) brightness);                    screenBrightnessTv.setText("系统亮度：" + (int) brightness);                } else {                    float brightness = progress / 100f;                    setBrightness(brightness);                    screenBrightnessTv.setText("Activity亮度：" + brightness);                }            }            @Override            public void onStartTrackingTouch(SeekBar seekBar) {            }            @Override            public void onStopTrackingTouch(SeekBar seekBar) {            }        });    }    @OnClick({R.id.default_Btn, R.id.max_Btn})    public void onClick(View view) {        switch (view.getId()) {            case R.id.default_Btn:                setBrightness(-1.0f);                getBrightNess();                break;            case R.id.max_Btn:                setBrightness(1.0f);                getBrightNess();                break;        }    }    private void getBrightNess() {        mParams = window.getAttributes();        /**         * 第一次获取这值为-1,表示跟随系统亮度         */        Log.i(TAG, "Attributes:" + mParams.screenBrightness + "");        try {            /**             * 获得当前屏幕亮度的模式             * SCREEN_BRIGHTNESS_MODE_AUTOMATIC=1 为自动调节屏幕亮度             * SCREEN_BRIGHTNESS_MODE_MANUAL=0 为手动调节屏幕亮度             */            screenMode = Settings.System.getInt(getContentResolver(), Settings.System.SCREEN_BRIGHTNESS_MODE);            Log.i(TAG, "screenMode = " + screenMode);            // 获得当前屏幕亮度值 0--255            screenBrightness = Settings.System.getInt(getContentResolver(), Settings.System.SCREEN_BRIGHTNESS);            Log.i(TAG, "Global screenBrightness = " + screenBrightness);        } catch (Settings.SettingNotFoundException e) {            e.printStackTrace();        }    }    /**     * @param brightness:0.0f-1.0f如果为负数表示跟随系统亮度，     *                   单纯window.setAttributes(mParams)不会改变其他Activity的亮度以及系统亮度     *                   --Settings.System.getInt(getContentResolver(), Settings.System.SCREEN_BRIGHTNESS）的值不会变;     */    private void setBrightness(float brightness) {        mParams.screenBrightness = brightness;        window.setAttributes(mParams);    }    /**     * @param mode 1:自动调节亮度，0为手动调节亮度     *             需要 <uses-permission android:name="android.permission.WRITE_SETTINGS" />”权限     */    private void setBrightnessMode(int mode) {        Settings.System.putInt(getContentResolver(), Settings.System.SCREEN_BRIGHTNESS_MODE, mode);    }    /**     * @param brightness 0-255     */    private void setGlobalBrightness(int brightness) {        if (BuildConfig.VERSION_CODE < Build.VERSION_CODES.M) {//6.0系统以下改变系统屏幕亮度需要设置亮度模式为手动调节            setBrightnessMode(0);        }        Settings.System.putInt(getContentResolver(), Settings.System.SCREEN_BRIGHTNESS, brightness);    }}

<?xml version="1.0" encoding="utf-8"?><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:paddingBottom="@dimen/activity_vertical_margin"    android:paddingLeft="@dimen/activity_horizontal_margin"    android:paddingRight="@dimen/activity_horizontal_margin"    android:paddingTop="@dimen/activity_vertical_margin"    tools:context="com.example.androidtest.activity.BrightnessActivity">    <Button        android:id="@+id/default_Btn"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:text="默认亮度（跟随系统）" />    <Button        android:id="@+id/max_Btn"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:text="最大亮度" />    <RadioGroup        android:id="@+id/radio_group"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_marginTop="40dp"        android:orientation="horizontal">        <RadioButton            android:id="@+id/activity_Rb"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:checked="true"            android:text="Activity" />        <RadioButton            android:id="@+id/system_Rb"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:text="系统" />    </RadioGroup>    <SeekBar        android:id="@+id/exchange_Sb"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_marginTop="20dp" />    <TextView        android:id="@+id/screen_brightness_Tv"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_gravity="center"        android:layout_marginTop="40dp"        android:text="亮度" /></LinearLayout>