Java KeyEvent.ACTION_DOWN屬性代碼示例

/**
 * You can call this function yourself to have the scroll view perform
 * scrolling from a key event, just as if the event had been dispatched to
 * it by the view hierarchy.
 *
 * @param event The key event to execute.
 * @return Return true if the event was handled, else false.
 */
public boolean executeKeyEvent(KeyEvent event) {
    boolean handled = false;
    if (event.getAction() == KeyEvent.ACTION_DOWN) {
        switch (event.getKeyCode()) {
            case KeyEvent.KEYCODE_DPAD_LEFT:
                handled = arrowScroll(FOCUS_LEFT);
                break;
            case KeyEvent.KEYCODE_DPAD_RIGHT:
                handled = arrowScroll(FOCUS_RIGHT);
                break;
            case KeyEvent.KEYCODE_TAB:
                if (Build.VERSION.SDK_INT >= 11) {
                    // The focus finder had a bug handling FOCUS_FORWARD and FOCUS_BACKWARD
                    // before Android 3.0. Ignore the tab key on those devices.
                    if (KeyEventCompat.hasNoModifiers(event)) {
                        handled = arrowScroll(FOCUS_FORWARD);
                    } else if (KeyEventCompat.hasModifiers(event, KeyEvent.META_SHIFT_ON)) {
                        handled = arrowScroll(FOCUS_BACKWARD);
                    }
                }
                break;
        }
    }
    return handled;
}
 

public InputConnection createInputConnection(InputConnection base) {
    return base == null ? null : new InputConnectionWrapper(base, true) {

        @Override
        public boolean sendKeyEvent(KeyEvent event) {
            // TODO: this could be improved by working even when we are not empty.
            // The behavior should be 'delete isLast character from mPre'.
            // In that case, we should check also that getSelectionStart() == 0.
            if (!isFirst() && mView.getText().length() == 0 &&
                    event.getAction() == KeyEvent.ACTION_DOWN &&
                    event.getKeyCode() == KeyEvent.KEYCODE_DEL) {
                removeFromChain(mView);
                return false;
            }
            return super.sendKeyEvent(event);
        }
    };
}
 

/**
 * Called to process key events.  You can override this to intercept all
 * key events before they are dispatched to the window.  Be sure to call
 * this implementation for key events that should be handled normally.
 *
 * @param event The key event.
 *
 * @return boolean Return true if this event was consumed.
 */
public boolean dispatchKeyEvent(KeyEvent event) {
    onUserInteraction();

    // Let action bars open menus in response to the menu key prioritized over
    // the window handling it
    final int keyCode = event.getKeyCode();
    if (keyCode == KeyEvent.KEYCODE_MENU &&
            mActionBar != null && mActionBar.onMenuKeyEvent(event)) {
        return true;
    } else if (event.isCtrlPressed() &&
            event.getUnicodeChar(event.getMetaState() & ~KeyEvent.META_CTRL_MASK) == '<') {
        // Capture the Control-< and send focus to the ActionBar
        final int action = event.getAction();
        if (action == KeyEvent.ACTION_DOWN) {
            final ActionBar actionBar = getActionBar();
            if (actionBar != null && actionBar.isShowing() && actionBar.requestFocus()) {
                mEatKeyUpEvent = true;
                return true;
            }
        } else if (action == KeyEvent.ACTION_UP && mEatKeyUpEvent) {
            mEatKeyUpEvent = false;
            return true;
        }
    }

    Window win = getWindow();
    if (win.superDispatchKeyEvent(event)) {
        return true;
    }
    View decor = mDecor;
    if (decor == null) decor = win.getDecorView();
    return event.dispatch(this, decor != null
            ? decor.getKeyDispatcherState() : null, this);
}
 

@Override
public boolean onKey(DialogInterface dialog, int keyCode, KeyEvent event) {
    if (keyCode == KeyEvent.KEYCODE_BACK && event.getAction() == KeyEvent.ACTION_DOWN) {
        finishActivity();
    }
    return false;
}
 

/**
 * Called to process media key events. Any {@link KeyEvent} can be passed but only media key
 * events will be handled.
 *
 * @param event A key event.
 * @return Whether the key event was handled.
 */
public boolean dispatchMediaKeyEvent(KeyEvent event) {
    int keyCode = event.getKeyCode();
    if (player == null || !isHandledMediaKey(keyCode)) {
        return false;
    }
    if (event.getAction() == KeyEvent.ACTION_DOWN) {
        if (keyCode == KeyEvent.KEYCODE_MEDIA_FAST_FORWARD) {
            fastForward();
        } else if (keyCode == KeyEvent.KEYCODE_MEDIA_REWIND) {
            rewind();
        } else if (event.getRepeatCount() == 0) {
            if (player == null) {
                return true;
            }
            switch (keyCode) {
                case KeyEvent.KEYCODE_MEDIA_PLAY_PAUSE:
                    controlDispatcher.dispatchSetPlayWhenReady(player, !player.getPlayWhenReady());
                    break;
                case KeyEvent.KEYCODE_MEDIA_PLAY:
                    controlDispatcher.dispatchSetPlayWhenReady(player, true);
                    break;
                case KeyEvent.KEYCODE_MEDIA_PAUSE:
                    controlDispatcher.dispatchSetPlayWhenReady(player, false);
                    break;
                case KeyEvent.KEYCODE_MEDIA_NEXT:
                    next();
                    break;
                case KeyEvent.KEYCODE_MEDIA_PREVIOUS:
                    previous();
                    break;
                default:
                    break;
            }
        }
    }
    return true;
}
 

@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
	if (keyCode == KeyEvent.KEYCODE_BACK
			&& event.getAction() == KeyEvent.ACTION_DOWN) {
		close();
		return true;
	}
	return super.onKeyDown(keyCode, event);
}
 

@Override
public boolean dispatchKeyEvent(KeyEvent event) {
    boolean retVal = super.dispatchKeyEvent(event);
    if (retVal && mUrlHasFocus && mUrlFocusedWithoutAnimations
            && event.getAction() == KeyEvent.ACTION_DOWN && event.isPrintingKey()
            && event.hasNoModifiers()) {
        handleUrlFocusAnimation(mUrlHasFocus);
    }
    return retVal;
}
 

@Override
public boolean dispatchKeyEvent(KeyEvent event) {
  int action = event.getAction();
  int keyCode = event.getKeyCode();
  if (keyCode == KeyEvent.KEYCODE_VOLUME_DOWN) {
    if (action == KeyEvent.ACTION_DOWN) {
      ((AndroidCompatibility) Compatibility.get()).modifier = true;
    } else if (action == KeyEvent.ACTION_UP) {
      ((AndroidCompatibility) Compatibility.get()).modifier = false;
    }
  }
  return super.dispatchKeyEvent(event);
}
 

@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
    if (KeyEvent.KEYCODE_BACK == keyCode && event.getAction() == KeyEvent.ACTION_DOWN) {
        if ((System.currentTimeMillis() - mKeyTime) > 2000) {
            mKeyTime = System.currentTimeMillis();
            Toast.makeText(getApplicationContext(), "確定要離開嗎？", Toast.LENGTH_SHORT).show();
        } else {
            finish();
            System.exit(0);
        }
        return true;
    }
    return super.onKeyDown(keyCode, event);
}
 

@Override
public boolean dispatchKeyEvent(KeyEvent event) {
    if (event.getKeyCode() == KeyEvent.KEYCODE_BACK) {
        if (event.getAction() == KeyEvent.ACTION_DOWN && event.getRepeatCount() == 0) {
            this.exitApp();
        }
        return true;
    }
    return super.dispatchKeyEvent(event);
}
 

@Override
public boolean sendKeyEvent(KeyEvent event) {
    if (keyboardListener != null) {
        if (event.getAction() == KeyEvent.ACTION_DOWN
                && event.getKeyCode() == KeyEvent.KEYCODE_DEL) { // Backspace key
            keyboardListener.onKeyboardBackspace();
        }
    }
    return super.sendKeyEvent(event);
}
 

@Override
public boolean onKey(View v, int keyCode, KeyEvent event) {
	if (event.getAction() == KeyEvent.ACTION_DOWN) {
		if (event.isShiftPressed()) {//處理*#等鍵
			return false;
		}
		if (keyCode >= KeyEvent.KEYCODE_0 && keyCode <= KeyEvent.KEYCODE_9) {//隻處理數字
			if (result.size() < pswLength) {
				result.add(keyCode - 7);
				invalidate();
				FinishInput();
			}
			return true;
		}
		if (keyCode == KeyEvent.KEYCODE_DEL) {
			if (!result.isEmpty()) {//不為空時，刪除最後一個數字
				saveResult = result.size();
				result.remove(result.size() - 1);
				invalidate();
			}
			return true;
		}
		if (keyCode == KeyEvent.KEYCODE_ENTER) {
			FinishInput();
			return true;
		}
	}
	return false;
}
 

@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
	if (keyCode == KeyEvent.KEYCODE_BACK && event.getAction() == KeyEvent.ACTION_DOWN) {
		if ((System.currentTimeMillis() - exitTime) > 2000) {
			Toast.makeText(getApplicationContext(), "再按一次退出程序", Toast.LENGTH_SHORT).show();
			exitTime = System.currentTimeMillis();
		} else {
			finish();
			System.exit(0);
		}
		return true;
	}
	return super.onKeyDown(keyCode, event);
}
 

@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
    if (event.getAction() == KeyEvent.ACTION_DOWN) {
        if (keyCode == KeyEvent.KEYCODE_BACK) {
            if (getBinding().webView.canGoBack()) {
                getBinding().webView.goBack();
            } else {
                finish();
            }
            return true;
        }
    }
    return super.onKeyDown(keyCode, event);
}
 

static final boolean checkDoubleKeyEvent(KeyEvent event, View view) {
    if (DEBUG_ENABLED) {
        log.debug("dispatchKeyEvent " + mLastTouchTime + " " + event);
    }

    if (event.getAction() == KeyEvent.ACTION_DOWN && event.getKeyCode() == KeyEvent.KEYCODE_ENTER) {
        if (mLastTouchTime != DEFAULT_TOUCH_TIMESTAMP && (SystemClock.elapsedRealtime() - mLastTouchTime) < TOUCH_COOL_DOWN_TIME) {
            log.warn("too many key events " + view + " " + KeyEvent.ACTION_DOWN);
            return true;
        }
        mLastTouchTime = SystemClock.elapsedRealtime();
    }

    return false;
}