1/* 2 * Copyright (C) 2011 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 17package android.support.v4.view; 18 19import android.view.ViewConfiguration; 20 21/** 22 * Helper for accessing features in {@link ViewConfiguration} 23 * introduced after API level 4 in a backwards compatible fashion. 24 */ 25public final class ViewConfigurationCompat { 26 /** 27 * Interface for the full API. 28 */ 29 interface ViewConfigurationVersionImpl { 30 public int getScaledPagingTouchSlop(ViewConfiguration config); 31 public boolean hasPermanentMenuKey(ViewConfiguration config); 32 } 33 34 /** 35 * Interface implementation that doesn't use anything about v4 APIs. 36 */ 37 static class BaseViewConfigurationVersionImpl implements ViewConfigurationVersionImpl { 38 @Override 39 public int getScaledPagingTouchSlop(ViewConfiguration config) { 40 return config.getScaledTouchSlop(); 41 } 42 43 @Override 44 public boolean hasPermanentMenuKey(ViewConfiguration config) { 45 // Pre-HC devices will always have a menu button 46 return true; 47 } 48 } 49 50 /** 51 * Interface implementation for devices with at least v8 APIs. 52 */ 53 static class FroyoViewConfigurationVersionImpl extends BaseViewConfigurationVersionImpl { 54 @Override 55 public int getScaledPagingTouchSlop(ViewConfiguration config) { 56 return ViewConfigurationCompatFroyo.getScaledPagingTouchSlop(config); 57 } 58 } 59 60 /** 61 * Interface implementation for devices with at least v11 APIs. 62 */ 63 static class HoneycombViewConfigurationVersionImpl extends FroyoViewConfigurationVersionImpl { 64 @Override 65 public boolean hasPermanentMenuKey(ViewConfiguration config) { 66 // There is no way to check on Honeycomb so we assume false 67 return false; 68 } 69 } 70 71 /** 72 * Interface implementation for devices with at least v14 APIs. 73 */ 74 static class IcsViewConfigurationVersionImpl extends HoneycombViewConfigurationVersionImpl { 75 @Override 76 public boolean hasPermanentMenuKey(ViewConfiguration config) { 77 return ViewConfigurationCompatICS.hasPermanentMenuKey(config); 78 } 79 } 80 81 /** 82 * Select the correct implementation to use for the current platform. 83 */ 84 static final ViewConfigurationVersionImpl IMPL; 85 static { 86 if (android.os.Build.VERSION.SDK_INT >= 14) { 87 IMPL = new IcsViewConfigurationVersionImpl(); 88 } else if (android.os.Build.VERSION.SDK_INT >= 11) { 89 IMPL = new HoneycombViewConfigurationVersionImpl(); 90 } else if (android.os.Build.VERSION.SDK_INT >= 8) { 91 IMPL = new FroyoViewConfigurationVersionImpl(); 92 } else { 93 IMPL = new BaseViewConfigurationVersionImpl(); 94 } 95 } 96 97 // ------------------------------------------------------------------- 98 99 /** 100 * Call {@link ViewConfiguration#getScaledPagingTouchSlop()}. 101 * If running on a pre-{@link android.os.Build.VERSION_CODES#FROYO} device, 102 * returns {@link ViewConfiguration#getScaledTouchSlop()}. 103 */ 104 public static int getScaledPagingTouchSlop(ViewConfiguration config) { 105 return IMPL.getScaledPagingTouchSlop(config); 106 } 107 108 /** 109 * Report if the device has a permanent menu key available to the user, in a backwards 110 * compatible way. 111 */ 112 public static boolean hasPermanentMenuKey(ViewConfiguration config) { 113 return IMPL.hasPermanentMenuKey(config); 114 } 115 116 private ViewConfigurationCompat() {} 117} 118