java - 调整屏幕亮度时出现 WRITE_SETTINGS 权限的 SecurityException

Question

应用程序中间有一个按钮，可以在亮度之间切换，但是现在，如果按钮被单击两次，并且我尝试再次单击它，它就不再起作用了。有谁知道如何在第二次单击按钮后将屏幕亮度设置为单击按钮之前的状态。总体而言，单击按钮时应用程序会不断收到错误日志。如果有人能解决这个问题，请提前致谢!这是错误日志:

W/System.err: java.lang.SecurityException: com.example.kenert.allinoneapp was not granted  this permission: android.permission.WRITE_SETTINGS.
W/System.err:     at android.os.Parcel.readException(Parcel.java:1684)
W/System.err:     at android.database.DatabaseUtils.readExceptionFromParcel(DatabaseUtils.java:183)
W/System.err:     at android.database.DatabaseUtils.readExceptionFromParcel(DatabaseUtils.java:135)
W/System.err:     at android.content.ContentProviderProxy.call(ContentProviderNative.java:646)
W/System.err:     at android.provider.Settings$NameValueCache.putStringForUser(Settings.java:1595)
W/System.err:     at android.provider.Settings$System.putStringForUser(Settings.java:1966)
W/System.err:     at android.provider.Settings$System.putIntForUser(Settings.java:2071)
W/System.err:     at android.provider.Settings$System.putInt(Settings.java:2065)
W/System.err:     at com.example.kenert.allinoneapp.ScreenFlashlight$override.turnBrightnessOff(ScreenFlashlight.java:60)
W/System.err:     at com.example.kenert.allinoneapp.ScreenFlashlight$override.screenFlashButtonClicked(ScreenFlashlight.java:28)
W/System.err:     at com.example.kenert.allinoneapp.ScreenFlashlight$override.access$dispatch(ScreenFlashlight.java)
W/System.err:     at com.example.kenert.allinoneapp.ScreenFlashlight.screenFlashButtonClicked(ScreenFlashlight.java:0)
W/System.err:     at java.lang.reflect.Method.invoke(Native Method)
W/System.err:     at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288)
W/System.err:     at android.view.View.performClick(View.java:5637)
W/System.err:     at android.view.View$PerformClick.run(View.java:22429)
W/System.err:     at android.os.Handler.handleCallback(Handler.java:751)
W/System.err:     at android.os.Handler.dispatchMessage(Handler.java:95)
W/System.err:     at android.os.Looper.loop(Looper.java:154)
W/System.err:     at android.app.ActivityThread.main(ActivityThread.java:6119)
W/System.err:     at java.lang.reflect.Method.invoke(Native Method)
W/System.err:     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
W/System.err:     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)

这是该类的代码:

import android.content.Intent;
import android.provider.Settings;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.view.WindowManager;
import android.widget.ImageButton;

public class ScreenFlashlight extends AppCompatActivity {
private boolean brightnessOnOff;
private ImageButton screenFlashOnOffButton;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_screen_flashlight);
    screenFlashOnOffButton = (ImageButton) findViewById(R.id.screenFlashOnOffButton);
    brightnessOnOff = false;


}
public void screenFlashButtonClicked(View view) {
    try {
        if (brightnessOnOff) {

            turnBrightnessOff();
        } else{
                brightnessOnOff = true;
            turnBrightnessOn();
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
}



private void turnBrightnessOn() {
    try {
        screenFlashOnOffButton.setImageResource(R.drawable.screenonbutton);
        Settings.System.putInt(getContentResolver(), Settings.System.SCREEN_BRIGHTNESS_MODE, Settings.System.SCREEN_BRIGHTNESS_MODE_MANUAL);
        Settings.System.putInt(getContentResolver(), Settings.System.SCREEN_BRIGHTNESS_MODE, 255);
        //Screen refresh to add brightness
        int brightness = Settings.System.getInt(getContentResolver(), Settings.System.SCREEN_BRIGHTNESS_MODE);
        WindowManager.LayoutParams lp = getWindow().getAttributes();
        lp.screenBrightness = (float) brightness / 255;
        getWindow().setAttributes(lp);


    } catch (Exception e) {
        e.printStackTrace();
    }
}

private void turnBrightnessOff() {
    try {
        screenFlashOnOffButton.setImageResource(R.drawable.screenoffbutton);
        Settings.System.putInt(getContentResolver(), Settings.System.SCREEN_BRIGHTNESS_MODE, Settings.System.SCREEN_BRIGHTNESS_MODE_MANUAL);
        Settings.System.putInt(getContentResolver(), Settings.System.SCREEN_BRIGHTNESS_MODE, 100);
        //Refresh screen
        int brightnesss = Settings.System.getInt(getContentResolver(), Settings.System.SCREEN_BRIGHTNESS_MODE);
        WindowManager.LayoutParams lpp = getWindow().getAttributes();
        lpp.screenBrightness = (float) brightnesss/100;
        getWindow().setAttributes(lpp);
    } catch (Exception e) {
        e.printStackTrace();
    }
}

Answer 1

我用这个:

   public void onClick(View arg0) {
      int curBrightnessValue=android.provider.Settings.System.getInt(
      getContentResolver(),android.provider.Settings.System.SCREEN_BRIGHTNESS);
      int SysBackLightValue = curBrightnessValue-25;
      android.provider.Settings.System.putInt(getContentResolver(),
      android.provider.Settings.System.SCREEN_BRIGHTNESS,
      SysBackLightValue);
}

不要忘记许可:

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