Question

我尝试输入一些代码，但未与手机电池同步例如：我的手机电池电量为72％，但始终显示100％不会上升或下降。此代码不需要任何特殊权限

public class MainActivity extends AppCompatActivity {
    private Context mContext;
    private TextView mViewInfo;
    private TextView mViewPercentage;
    private ProgressBar mProgressBar;
    private int mProgressStatus = 0;

    private BroadcastReceiver mBroadcastReceiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            int scale = intent.getIntExtra(BatteryManager.EXTRA_SCALE, -1);
            mViewInfo.setText("Battery Scale : " + scale);

            int level = intent.getIntExtra(BatteryManager.EXTRA_SCALE, -1);
            mViewInfo.setText(mViewInfo.getText() + "\nBattery Level : " + level);

            float percentage = level/ (float) scale;
            mProgressStatus = (int)((percentage)*100);
            mViewPercentage.setText("" + mProgressStatus + "%");
            mViewInfo.setText(mViewInfo.getText() + "\nPercentage : " + mProgressStatus + "%");
            mProgressBar.setProgress(mProgressStatus);
        }
    };

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        requestWindowFeature(Window.FEATURE_ACTION_BAR);
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mContext = getApplicationContext();
        IntentFilter iFilter = new IntentFilter(Intent.ACTION_BATTERY_CHANGED);
        mContext.registerReceiver(mBroadcastReceiver, iFilter);
        mViewInfo = (TextView) findViewById(R.id.tv_info);
        mViewPercentage = (TextView) findViewById(R.id.tv_percentage);
        mProgressBar = (ProgressBar) findViewById(R.id.pb);
    }
}

我希望我的代码可以与手机电池同步总是说所有100％的假设都是要与电池同步的

Answer 1

您的问题是由这段代码引起的：

int scale = intent.getIntExtra(BatteryManager.EXTRA_SCALE, -1);
mViewInfo.setText("Battery Scale : " + scale);

int level = intent.getIntExtra(BatteryManager.EXTRA_SCALE, -1);
mViewInfo.setText(mViewInfo.getText() + "\nBattery Level : " + level);

float percentage = level/ (float) scale;
mProgressStatus = (int)((percentage)*100);

如果您注意到了，您会发现同时使用intent.getIntExtra(BatteryManager.EXTRA_SCALE, -1)的 scale 和 level 。

这意味着您将获得完全相同的值，所以当您进行level / (float) scale;的计算时，您几乎正在执行NUM / NUM，这将始终等于到1。然后当您执行1 * 100时，它将始终等于100。

您需要做的是更换：

int level = intent.getIntExtra(BatteryManager.EXTRA_SCALE, -1);

具有：

int level = intent.getIntExtra(BatteryManager.EXTRA_LEVEL, -1);

为什么我的代码无法与手机电池同步？

1 个答案: