Android电池级检测问题

Question

我是一个新的用户堆叠溢出，这是我的第一篇文章，如果我做错了什么请随时告诉我，谢谢。

我正在开发一个android应用程序来监控电池的电量和改变屏幕亮度，但是我遇到了一个奇怪的问题，在谷歌上搜索了很多次之后找不到它。

public class SmartBrightnessProcessor extends BroadcastReceiver{

Context mContext;
IntentFilter intentFilter;
ContentResolver contentResolver;

public SmartBrightnessProcessor(Context context){
    this.mContext = context;
    intentFilter = new IntentFilter();
    intentFilter.addAction(Intent.ACTION_BATTERY_CHANGED);
}
public void registerReceiver(){
    mContext.registerReceiver(this, intentFilter);
}
public void unRegisterReceiver(){
    mContext.unregisterReceiver(this);
}
@Override
public void onReceive(Context context, Intent intent){

    contentResolver = context.getContentResolver();

    boolean isEnabled = context.getSharedPreferences("SmartBrightness",
            Context.MODE_PRIVATE).getBoolean("SmartBrightness", false);

    int batteryLevel = intent.getIntExtra(BatteryManager.EXTRA_LEVEL, 0);

    if(isEnabled){
        if(Build.VERSION.SDK_INT >= 23){
            if(Settings.System.canWrite(context)){
                if(batteryLevel >= 70){
                    Settings.System.putInt(contentResolver, Settings.System.SCREEN_BRIGHTNESS, 85);
                }else if(batteryLevel >= 50 && batteryLevel <= 69){
                    Settings.System.putInt(contentResolver, Settings.System.SCREEN_BRIGHTNESS, 70);
                }else if(batteryLevel >= 20 && batteryLevel <= 49){
                    Settings.System.putInt(contentResolver, Settings.System.SCREEN_BRIGHTNESS, 50);
                }else if(batteryLevel >= 10 && batteryLevel <= 19){
                    Settings.System.putInt(contentResolver, Settings.System.SCREEN_BRIGHTNESS, 30);
                }else if(batteryLevel <= 9){
                    Settings.System.putInt(contentResolver, Settings.System.SCREEN_BRIGHTNESS, 10);
                }
            }
        }else{
            if(batteryLevel >= 70){
                Settings.System.putInt(contentResolver, Settings.System.SCREEN_BRIGHTNESS, 85);
            }else if(batteryLevel >= 50 && batteryLevel <= 69){
                Settings.System.putInt(contentResolver, Settings.System.SCREEN_BRIGHTNESS, 70);
            }else if(batteryLevel >= 20 && batteryLevel <= 49){
                Settings.System.putInt(contentResolver, Settings.System.SCREEN_BRIGHTNESS, 50);
            }else if(batteryLevel >= 10 && batteryLevel <= 19){
                Settings.System.putInt(contentResolver, Settings.System.SCREEN_BRIGHTNESS, 30);
            }else if(batteryLevel <= 9){
                Settings.System.putInt(contentResolver, Settings.System.SCREEN_BRIGHTNESS, 10);
            }
        }
    }
}

}

当我在真正的设备上测试它时，上面的代码工作得很好，但是当用户启用这个选项时，我想立即设置屏幕亮度，所以当用户单击按钮时，我使用该代码执行操作。

public class SmartBrightness extends Fragment {

SharedPreferences sharedPreferences;
Context context;
ContentResolver contentResolver;
Intent intent;
int batteryLevel;
Switch aSwitch;

public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState){

    View view = inflater.inflate(R.layout.smart_brightness, container, false);

    context = getActivity().getApplicationContext();

    sharedPreferences = getActivity().getSharedPreferences("SmartBrightness", 0);
    Boolean smartBrightness = sharedPreferences.getBoolean("SmartBrightness", false);

    aSwitch = (Switch)view.findViewById(R.id.switch1);

    aSwitch.setChecked(smartBrightness);

    intent = new Intent();

    contentResolver = context.getContentResolver();

    batteryLevel = intent.getIntExtra(BatteryManager.EXTRA_LEVEL, 0);

    aSwitch.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {

        @Override
        public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
            if(isChecked){
                if(Build.VERSION.SDK_INT >= 23){
                    if(!writeSettingsPermissionGranted()){
                        showMissingPermissionDialog();
                        aSwitch.setChecked(false);
                        SharedPreferences.Editor editor = sharedPreferences.edit();
                        editor.putBoolean("SmartBrightness", false);
                        editor.apply();
                    }else{
                        if(batteryLevel >= 70){
                            Settings.System.putInt(contentResolver, Settings.System.SCREEN_BRIGHTNESS, 85);
                        }else if(batteryLevel >= 50 && batteryLevel <= 69){
                            Settings.System.putInt(contentResolver, Settings.System.SCREEN_BRIGHTNESS, 70);
                        }else if(batteryLevel >= 20 && batteryLevel <= 49){
                            Settings.System.putInt(contentResolver, Settings.System.SCREEN_BRIGHTNESS, 50);
                        }else if(batteryLevel >= 10 && batteryLevel <= 19){
                            Settings.System.putInt(contentResolver, Settings.System.SCREEN_BRIGHTNESS, 30);
                        }else if(batteryLevel <= 9){
                            Settings.System.putInt(contentResolver, Settings.System.SCREEN_BRIGHTNESS, 10);
                        }
                        SharedPreferences.Editor editor = sharedPreferences.edit();
                        editor.putBoolean("SmartBrightness", true);
                        editor.apply();
                    }
                }else{
                    if(batteryLevel >= 70){
                        Settings.System.putInt(contentResolver, Settings.System.SCREEN_BRIGHTNESS, 85);
                    }else if(batteryLevel >= 50 && batteryLevel <= 69){
                        Settings.System.putInt(contentResolver, Settings.System.SCREEN_BRIGHTNESS, 70);
                    }else if(batteryLevel >= 20 && batteryLevel <= 49){
                        Settings.System.putInt(contentResolver, Settings.System.SCREEN_BRIGHTNESS, 50);
                    }else if(batteryLevel >= 10 && batteryLevel <= 19){
                        Settings.System.putInt(contentResolver, Settings.System.SCREEN_BRIGHTNESS, 30);
                    }else if(batteryLevel <= 9){
                        Settings.System.putInt(contentResolver, Settings.System.SCREEN_BRIGHTNESS, 10);
                    }
                    SharedPreferences.Editor editor = sharedPreferences.edit();
                    editor.putBoolean("SmartBrightness", true);
                    editor.apply();
                }
            }else{
                SharedPreferences.Editor editor = sharedPreferences.edit();
                editor.putBoolean("SmartBrightness", false);
                editor.apply();
            }
        }
    });

    return view;
}
private void requestWriteSettingsPermission(){
    if(Build.VERSION.SDK_INT >= 23){
        Intent intent = new Intent(android.provider.Settings.ACTION_MANAGE_WRITE_SETTINGS);
        intent.setData(Uri.parse("package:" + context.getPackageName()));
        intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        startActivity(intent);
    }
}
public void showMissingPermissionDialog(){
    final ViewGroup nullParent = null;
    AlertDialog.Builder alertDialog = new AlertDialog.Builder(getActivity());
    LayoutInflater layoutInflater = LayoutInflater.from(getActivity());
    View view = layoutInflater.inflate(R.layout.write_settings_explaination, nullParent);

    alertDialog.setView(view);
    alertDialog.setCancelable(false);
    alertDialog.setPositiveButton("Continue", new DialogInterface.OnClickListener() {
        public void onClick(DialogInterface dialog, int which) {
            requestWriteSettingsPermission();
            dialog.dismiss();
        }
    });
    alertDialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
        public void onClick(DialogInterface dialog, int which) {
            dialog.dismiss();
        }
    });
    alertDialog.show();
}
public boolean writeSettingsPermissionGranted(){
    if(Build.VERSION.SDK_INT >= 23){
        if(android.provider.Settings.System.canWrite(context)){
            return true;
        }
    }
    return false;
}

}

但问题是，当我在真正的设备上测试时，即使我的设备的电池电平也超过了50%。

当我单击按钮时，屏幕亮度将更改为10，这也意味着执行此代码。

Settings.System.putInt(contentResolver, Settings.System.SCREEN_BRIGHTNESS, 10);

我不知道为什么它完美地工作在广播接收器，但不工作的按钮点击。

如果有人有解决这个问题的想法或遇到同样的问题之前请帮助我，谢谢提前。

Answer 1

如果你检查BatteryManager.EXTRA_LEVEL，你会发现它是

包含当前电池级别的整数字段，从0到EXTRA_SCALE。

EXTRA_SCALE是另一个可供您获取的值，我在这里的假设，以及您面临的问题是，这个比例可能是1.0，这意味着20%的电池实际上是.20。

若要正确计算电池百分比，请在0 -> 100比例上使用以下命令

batteryLevel = intent.getIntExtra(BatteryManager.EXTRA_LEVEL, 0);
levelScale = intent.getIntExtra(BatteryManager.EXTRA_SCALE, 0);

double realPercent = (((double)batteryLevel) / levelScale) * 100 ;

编辑

我只是重新阅读了您的代码，对于您看到0作为您的onClick方法的报告百分比并不感到惊讶，您已经写到：

intent = new Intent();
batteryLevel = intent.getIntExtra(...);

在这里，您正在尝试从您刚刚创建的意图中获取数据，而不是包含您正在寻找的数据的数据。

试着改变你的意图，真正得到电池的水平，然后使用我的上述修正，以获得适当的百分比。

Intent batteryIntent = registerReceiver(null, new IntentFilter(Intent.ACTION_BATTERY_CHANGED));