Michael Kolb | 8872c23 | 2013-01-29 10:33:22 -0800 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2008 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | package com.android.camera; |
| 18 | |
| 19 | import android.content.Context; |
| 20 | import android.util.AttributeSet; |
| 21 | import android.view.MotionEvent; |
| 22 | import android.view.View; |
| 23 | import android.widget.ImageView; |
| 24 | |
| 25 | /** |
| 26 | * A button designed to be used for the on-screen shutter button. |
| 27 | * It's currently an {@code ImageView} that can call a delegate when the |
| 28 | * pressed state changes. |
| 29 | */ |
| 30 | public class ShutterButton extends ImageView { |
| 31 | |
| 32 | private boolean mTouchEnabled = true; |
| 33 | |
| 34 | /** |
| 35 | * A callback to be invoked when a ShutterButton's pressed state changes. |
| 36 | */ |
| 37 | public interface OnShutterButtonListener { |
| 38 | /** |
| 39 | * Called when a ShutterButton has been pressed. |
| 40 | * |
| 41 | * @param pressed The ShutterButton that was pressed. |
| 42 | */ |
| 43 | void onShutterButtonFocus(boolean pressed); |
| 44 | void onShutterButtonClick(); |
| 45 | } |
| 46 | |
| 47 | private OnShutterButtonListener mListener; |
| 48 | private boolean mOldPressed; |
| 49 | |
| 50 | public ShutterButton(Context context, AttributeSet attrs) { |
| 51 | super(context, attrs); |
| 52 | } |
| 53 | |
| 54 | public void setOnShutterButtonListener(OnShutterButtonListener listener) { |
| 55 | mListener = listener; |
| 56 | } |
| 57 | |
| 58 | @Override |
| 59 | public boolean dispatchTouchEvent(MotionEvent m) { |
| 60 | if (mTouchEnabled) { |
| 61 | return super.dispatchTouchEvent(m); |
| 62 | } else { |
| 63 | return false; |
| 64 | } |
| 65 | } |
| 66 | |
| 67 | public void enableTouch(boolean enable) { |
| 68 | mTouchEnabled = enable; |
| 69 | } |
| 70 | |
| 71 | /** |
| 72 | * Hook into the drawable state changing to get changes to isPressed -- the |
| 73 | * onPressed listener doesn't always get called when the pressed state |
| 74 | * changes. |
| 75 | */ |
| 76 | @Override |
| 77 | protected void drawableStateChanged() { |
| 78 | super.drawableStateChanged(); |
| 79 | final boolean pressed = isPressed(); |
| 80 | if (pressed != mOldPressed) { |
| 81 | if (!pressed) { |
| 82 | // When pressing the physical camera button the sequence of |
| 83 | // events is: |
| 84 | // focus pressed, optional camera pressed, focus released. |
| 85 | // We want to emulate this sequence of events with the shutter |
| 86 | // button. When clicking using a trackball button, the view |
| 87 | // system changes the drawable state before posting click |
| 88 | // notification, so the sequence of events is: |
| 89 | // pressed(true), optional click, pressed(false) |
| 90 | // When clicking using touch events, the view system changes the |
| 91 | // drawable state after posting click notification, so the |
| 92 | // sequence of events is: |
| 93 | // pressed(true), pressed(false), optional click |
| 94 | // Since we're emulating the physical camera button, we want to |
| 95 | // have the same order of events. So we want the optional click |
| 96 | // callback to be delivered before the pressed(false) callback. |
| 97 | // |
| 98 | // To do this, we delay the posting of the pressed(false) event |
| 99 | // slightly by pushing it on the event queue. This moves it |
| 100 | // after the optional click notification, so our client always |
| 101 | // sees events in this sequence: |
| 102 | // pressed(true), optional click, pressed(false) |
| 103 | post(new Runnable() { |
| 104 | @Override |
| 105 | public void run() { |
| 106 | callShutterButtonFocus(pressed); |
| 107 | } |
| 108 | }); |
| 109 | } else { |
| 110 | callShutterButtonFocus(pressed); |
| 111 | } |
| 112 | mOldPressed = pressed; |
| 113 | } |
| 114 | } |
| 115 | |
| 116 | private void callShutterButtonFocus(boolean pressed) { |
| 117 | if (mListener != null) { |
| 118 | mListener.onShutterButtonFocus(pressed); |
| 119 | } |
| 120 | } |
| 121 | |
| 122 | @Override |
| 123 | public boolean performClick() { |
| 124 | boolean result = super.performClick(); |
| 125 | if (mListener != null && getVisibility() == View.VISIBLE) { |
| 126 | mListener.onShutterButtonClick(); |
| 127 | } |
| 128 | return result; |
| 129 | } |
Michael Kolb | 8872c23 | 2013-01-29 10:33:22 -0800 | [diff] [blame] | 130 | } |