调节的关键代码：
WindowManager.LayoutParams layoutParams = getWindow().getAttributes();
layoutParams.screenBrightness = Float.parseFloat(brightNum);
getWindow().setAttributes(layoutParams);
以下是一个例子，包含拖动条控件：
布局文件：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
> <EditText
android:id="@+id/et"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="请输入亮度（0-1）"
/> <Button
android:id="@+id/btn_set"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="设置一下当前亮度"
android:onClick="changeBright"
/> <Button
android:id="@+id/btn_set"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="设置一下当前亮度 [0, 1]"
android:onClick="changeBright2"
/> <Button
android:id="@+id/btn_current"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="10dp"
android:text="获取当前亮度（非自动调节模式生效）"
android:onClick="showCurrentBright"
/> <SeekBar
android:id="@+id/seek_bar"
android:layout_width="match_parent"
android:layout_height="wrap_content" /> <Button android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="设置为自动调节屏幕亮度"
android:onClick="setAutoBright"
/> <Button android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="设置为手动调节屏幕亮度"
android:onClick="setManualBright"
/> <Button android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="获取亮度的模式（与系统设置相关）"
android:onClick="showScreenMode"
/> <Button android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="让手机直接黑屏..."
android:onClick="setNoBright"
/>
</LinearLayout>
Activity：
package com.example.screenBrightnessTest; import android.app.Activity;
import android.content.ContentResolver;
import android.os.Bundle;
import android.provider.Settings;
import android.view.View;
import android.view.WindowManager;
import android.widget.EditText;
import android.widget.SeekBar;
import android.widget.Toast; public class MyActivity extends Activity {
private EditText editText;
private SeekBar seekBar; @Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main); editText = (EditText) findViewById(R.id.et);
seekBar = (SeekBar) findViewById(R.id.seek_bar); //设置滚动条
seekBar.setProgress(getCurrentBrightValue());
seekBar.setMax(255);
seekBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
/**
* 拖动中数值的时候
* @param fromUser 是否是由用户操作的
*/
@Override
public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
if (progress > 3 && fromUser) {//以免太暗
WindowManager.LayoutParams layoutParams = getWindow().getAttributes();
layoutParams.screenBrightness = (float) progress / 255;//因为这个值是[0, 1]范围的
getWindow().setAttributes(layoutParams);
}
} /**
* 当按下的时候
*/
@Override
public void onStartTrackingTouch(SeekBar seekBar) {
System.out.println("com.example.screenBrightnessTest.MyActivity.onStartTrackingTouch");
} /**
*当松开的时候
*/
@Override
public void onStopTrackingTouch(SeekBar seekBar) {
System.out.println("com.example.screenBrightnessTest.MyActivity.onStopTrackingTouch");
}
});
} public void changeBright(View view) {
String brightNum = editText.getText().toString();
WindowManager.LayoutParams layoutParams = getWindow().getAttributes();
layoutParams.screenBrightness = Float.parseFloat(brightNum);
getWindow().setAttributes(layoutParams);
} /**
* 仅当系统的亮度模式是非自动模式的情况下，获取当前屏幕亮度值[0, 255].
* 如果是自动模式，那么该方法获得的值不正确。
*/
private int getCurrentBrightValue() {
int nowBrightnessValue = 0;
ContentResolver resolver = getContentResolver();
try {
nowBrightnessValue = android.provider.Settings.System.getInt(resolver,
Settings.System.SCREEN_BRIGHTNESS, 255);
} catch (Exception e) {
e.printStackTrace();
}
return nowBrightnessValue;
} /**
* 获取当前的亮度
*/
private float getMaxBrightValue2() {
return getWindow().getAttributes().screenBrightness;
} public void showCurrentBright(View view) {
Toast.makeText(this, "当前系统亮度的值为：" + getCurrentBrightValue(), 1).show();
} /**
* 让手机直接黑屏
*/
public void setNoBright(View view) {
getWindow().getAttributes().screenBrightness = 0;
} /**
* 设置当前屏幕亮度的模式
*
* @param paramInt Settings.System.SCREEN_BRIGHTNESS_MODE_AUTOMATIC或者Settings.System.SCREEN_BRIGHTNESS_MODE_MANUAL
*/
private void setScreenMode(int paramInt) {
try {
Settings.System.putInt(getContentResolver(), Settings.System.SCREEN_BRIGHTNESS_MODE, paramInt);
} catch (Exception localException) {
localException.printStackTrace();
}
} /**
* 设置为自动调节亮度
* 如果当前系统的模式不是自动调节模式，那么才会生效
*/
public void setAutoBright(View view) {
setScreenMode(Settings.System.SCREEN_BRIGHTNESS_MODE_AUTOMATIC);
} /**
* 获得当前屏幕亮度的模式
*/
public void showScreenMode(View view) {
int screenMode = 0;
try {
screenMode = Settings.System.getInt(getContentResolver(), Settings.System.SCREEN_BRIGHTNESS_MODE);
switch (screenMode) {
case Settings.System.SCREEN_BRIGHTNESS_MODE_AUTOMATIC:
Toast.makeText(this, "自动亮度模式", 1).show();
break;
default:
Toast.makeText(this, "手动调节亮度", 1).show();
}
} catch (Exception e) {
e.printStackTrace();
}
} public void setManualBright(View view) {
setScreenMode(Settings.System.SCREEN_BRIGHTNESS_MODE_MANUAL);
} public void changeBright2(View view) {
Toast.makeText(this, "亮度值[0, 1] = " + getWindow().getAttributes().screenBrightness, 1).show();
} }