Android的東西 - 如何保持領導不間斷的指令後mLedGpio.setValue（true）

Question

我完成了這個項目：sample-button 但我需要改變這一點，當我按下按鈕，只是按下按鈕後，再次按鈕。

如何才能做到這一點？

Answer 1

更換下方回調方法刪除裏面onKeyDown重寫方法的代碼，並更改setLedValue這樣：

private void setLedValue(boolean value) { 
    try { 
     mLedGpio.setValue(!mLedGpio.getValue()); 
    } catch (IOException e) { 
     Log.e(TAG, "Error updating GPIO value", e); 
    } 
} 

（您可以更好刪除的onkeydown比的onkeyup美好用戶體驗從用戶體驗的角度來看，改變某些關鍵的東西比在第一次按下時更好一些。）

---

如果你想看到全班改變它看起來像這樣：

public class ButtonActivity extends Activity { 

    private Gpio mLedGpio; 
    private ButtonInputDriver mButtonInputDriver; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     PeripheralManagerService pioService = new PeripheralManagerService(); 
     try { 
      mLedGpio = pioService.openGpio(BoardDefaults.getGPIOForLED()); 
      mLedGpio.setDirection(Gpio.DIRECTION_OUT_INITIALLY_LOW); 

      mButtonInputDriver = new ButtonInputDriver(
        BoardDefaults.getGPIOForButton(), 
        Button.LogicState.PRESSED_WHEN_LOW, 
        KeyEvent.KEYCODE_SPACE); 
      mButtonInputDriver.register(); 
     } catch (IOException e) { 
      throw new IllegalStateException("Error configuring GPIO pins", e); 
     } 
    } 

    @Override 
    public boolean onKeyUp(int keyCode, KeyEvent event) { 
     if (keyCode == KeyEvent.KEYCODE_SPACE) { 
      toggleLedValue(); 
      return true; 
     }  
     return super.onKeyUp(keyCode, event); 
    } 

    /** 
    * Update the value of the LED output. 
    */ 
    private void toggleLedValue() { 
     try { 
      mLedGpio.setValue(!mLedGpio.getValue()); 
     } catch (IOException e) { 
      Log.e(TAG, "Error updating GPIO value", e); 
     } 
    } 

    @Override 
    protected void onDestroy(){ 
     super.onDestroy(); 

     mButtonInputDriver.unregister(); 
     try { 
      mButtonInputDriver.close(); 
     } catch (IOException e) { 
      Log.e(TAG, "Error closing Button driver", e); 
     } 

     try { 
      mLedGpio.close(); 
     } catch (IOException e) { 
      Log.e(TAG, "Error closing LED GPIO", e); 
     } 
    } 
} 

Answer 2

嘗試與ButtonActivity.java

static boolean mToggle ; 
@Override 
    public boolean onKeyDown(int keyCode, KeyEvent event) { 
     if (keyCode == KeyEvent.KEYCODE_SPACE) { 
      // Turn on the LED 
      mToggle = !mToggle; 
      setLedValue(mToggle); 
      return true; 
     } 

     return super.onKeyDown(keyCode, event); 
    } 

    @Override 
    public boolean onKeyUp(int keyCode, KeyEvent event) { 
     if (keyCode == KeyEvent.KEYCODE_SPACE) { 
      // Turn off the LED 
      // setLedValue(false); 
      return true; 
     } 

     return super.onKeyUp(keyCode, event); 
}