Android开发：如何用TextView显示电池充电/USB/AC充电的True/False状态

Hey there! Let's get those three charging status TextViews showing True/False correctly. You've already nailed the battery percentage, so we just need to extend that logic to capture the charging state flags and update your UI. Here's a step-by-step solution tailored to your code:

Key Background #

The system sends a sticky broadcast (Intent.ACTION_BATTERY_CHANGED) with all battery-related info, including charging type. We'll use BatteryManager.EXTRA_PLUGGED to check which charging source is active:

• BATTERY_PLUGGED_NONE (0): Not charging
• BATTERY_PLUGGED_AC (1): Charging via AC adapter
• BATTERY_PLUGGED_USB (2): Charging via USB

Note: This broadcast can't be received via static manifest registration—you need to register it dynamically in your Activity.

Solution Code #

1. Update your MainActivity

Replace your existing Activity code with this (it includes dynamic receiver registration and UI updates):

public class MainActivity extends AppCompatActivity {
    private TextView tvBatteryPercent;
    private TextView tvBatteryCharging;
    private TextView tvUsbCharging;
    private TextView tvAcCharging;
    private BroadcastReceiver batteryReceiver;

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

        // Link TextViews from your layout
        tvBatteryPercent = findViewById(R.id.tv_battery_percent);
        tvBatteryCharging = findViewById(R.id.tv_battery_charging);
        tvUsbCharging = findViewById(R.id.tv_usb_charging);
        tvAcCharging = findViewById(R.id.tv_ac_charging);

        // Create receiver to handle battery updates
        batteryReceiver = new BroadcastReceiver() {
            @Override
            public void onReceive(Context context, Intent intent) {
                // Update battery percentage (your existing logic)
                int level = intent.getIntExtra(BatteryManager.EXTRA_LEVEL, -1);
                int scale = intent.getIntExtra(BatteryManager.EXTRA_SCALE, -1);
                float batteryPercent = level / (float) scale * 100;
                tvBatteryPercent.setText(String.format("%.0f%%", batteryPercent));

                // Get charging source info
                int pluggedStatus = intent.getIntExtra(BatteryManager.EXTRA_PLUGGED, 0);

                // 1. General battery charging status (True if any charging is active)
                boolean isCharging = pluggedStatus != BatteryManager.BATTERY_PLUGGED_NONE;
                tvBatteryCharging.setText(String.valueOf(isCharging));

                // 2. USB charging status
                boolean isUsbCharging = pluggedStatus == BatteryManager.BATTERY_PLUGGED_USB;
                tvUsbCharging.setText(String.valueOf(isUsbCharging));

                // 3. AC charging status
                boolean isAcCharging = pluggedStatus == BatteryManager.BATTERY_PLUGGED_AC;
                tvAcCharging.setText(String.valueOf(isAcCharging));
            }
        };

        // Register the receiver to listen for battery changes
        IntentFilter filter = new IntentFilter(Intent.ACTION_BATTERY_CHANGED);
        registerReceiver(batteryReceiver, filter);
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        // Unregister receiver to avoid memory leaks
        if (batteryReceiver != null) {
            unregisterReceiver(batteryReceiver);
        }
    }
}

2. Update your Layout (if needed)

Make sure your XML layout has the four TextViews with matching IDs:

<!-- Example layout snippet -->
<TextView
    android:id="@+id/tv_battery_charging"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="False"
    android:textSize="18sp"/>

<TextView
    android:id="@+id/tv_usb_charging"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="False"
    android:textSize="18sp"/>

<TextView
    android:id="@+id/tv_ac_charging"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="False"
    android:textSize="18sp"/>

<TextView
    android:id="@+id/tv_battery_percent"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="0%"
    android:textSize="18sp"/>

3. Remove Static Receiver from Manifest

Since we're using dynamic registration, you can delete any static <receiver> entry for your battery receiver in AndroidManifest.xml—it won't work for this broadcast anyway.

How It Works #

• The dynamic receiver listens for every battery state change (including when the app starts, thanks to the sticky broadcast).
• We check pluggedStatus to determine which charging type is active, then set each TextView to "True" or "False" accordingly.
• We unregister the receiver in onDestroy() to prevent memory leaks.

内容的提问来源于stack exchange，提问作者user3215990