summaryrefslogtreecommitdiff
path: root/java/com/android/dialer/common/FragmentUtils.java
blob: aa4441eebc31a84b853fc6a680a746bf8176bc42 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
/*
 * Copyright (C) 2016 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License
 */

package com.android.dialer.common;

import android.support.annotation.CheckResult;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.annotation.VisibleForTesting;
import android.support.v4.app.Fragment;
import com.android.dialer.main.MainActivityPeer;

/** Utility methods for working with Fragments */
public class FragmentUtils {

  private static Object parentForTesting;

  @VisibleForTesting(otherwise = VisibleForTesting.NONE)
  public static void setParentForTesting(Object parentForTesting) {
    FragmentUtils.parentForTesting = parentForTesting;
  }

  /**
   * Returns an instance of the {@code callbackInterface} that is defined in the parent of the
   * {@code fragment}, or null if no such call back can be found.
   */
  @CheckResult(suggest = "#checkParent(Fragment, Class)}")
  @Nullable
  public static <T> T getParent(@NonNull Fragment fragment, @NonNull Class<T> callbackInterface) {
    if (callbackInterface.isInstance(parentForTesting)) {
      @SuppressWarnings("unchecked") // Casts are checked using runtime methods
      T parent = (T) parentForTesting;
      return parent;
    }

    Fragment parentFragment = fragment.getParentFragment();
    if (callbackInterface.isInstance(parentFragment)) {
      @SuppressWarnings("unchecked") // Casts are checked using runtime methods
      T parent = (T) parentFragment;
      return parent;
    } else if (callbackInterface.isInstance(fragment.getActivity())) {
      @SuppressWarnings("unchecked") // Casts are checked using runtime methods
      T parent = (T) fragment.getActivity();
      return parent;
    } else if (fragment.getActivity() instanceof FragmentUtilListener) {
      @SuppressWarnings("unchecked") // Casts are checked using runtime methods
      T parent = ((FragmentUtilListener) fragment.getActivity()).getImpl(callbackInterface);
      return parent;
    } else if (fragment.getActivity() instanceof MainActivityPeer.PeerSupplier) {
      MainActivityPeer peer = ((MainActivityPeer.PeerSupplier) fragment.getActivity()).getPeer();
      if (peer instanceof FragmentUtilListener) {
        return ((FragmentUtilListener) peer).getImpl(callbackInterface);
      }
    }
    return null;
  }

  /**
   * Returns an instance of the {@code callbackInterface} that is defined in the parent of the
   * {@code fragment}, or null if no such call back can be found.
   */
  @CheckResult(suggest = "#checkParent(Fragment, Class)}")
  @Nullable
  public static <T> T getParent(
      @NonNull android.app.Fragment fragment, @NonNull Class<T> callbackInterface) {
    if (callbackInterface.isInstance(parentForTesting)) {
      @SuppressWarnings("unchecked") // Casts are checked using runtime methods
      T parent = (T) parentForTesting;
      return parent;
    }

    android.app.Fragment parentFragment = fragment.getParentFragment();
    if (callbackInterface.isInstance(parentFragment)) {
      @SuppressWarnings("unchecked") // Casts are checked using runtime methods
      T parent = (T) parentFragment;
      return parent;
    } else if (callbackInterface.isInstance(fragment.getActivity())) {
      @SuppressWarnings("unchecked") // Casts are checked using runtime methods
      T parent = (T) fragment.getActivity();
      return parent;
    } else if (fragment.getActivity() instanceof FragmentUtilListener) {
      @SuppressWarnings("unchecked") // Casts are checked using runtime methods
      T parent = ((FragmentUtilListener) fragment.getActivity()).getImpl(callbackInterface);
      return parent;
    } else if (fragment.getActivity() instanceof MainActivityPeer.PeerSupplier) {
      MainActivityPeer peer = ((MainActivityPeer.PeerSupplier) fragment.getActivity()).getPeer();
      if (peer instanceof FragmentUtilListener) {
        return ((FragmentUtilListener) peer).getImpl(callbackInterface);
      }
    }
    return null;
  }

  /** Returns the parent or throws. Should perform check elsewhere(e.g. onAttach, newInstance). */
  @NonNull
  public static <T> T getParentUnsafe(
      @NonNull Fragment fragment, @NonNull Class<T> callbackInterface) {
    return Assert.isNotNull(getParent(fragment, callbackInterface));
  }

  /**
   * Version of {@link #getParentUnsafe(Fragment, Class)} which supports {@link
   * android.app.Fragment}.
   */
  @NonNull
  public static <T> T getParentUnsafe(
      @NonNull android.app.Fragment fragment, @NonNull Class<T> callbackInterface) {
    return Assert.isNotNull(getParent(fragment, callbackInterface));
  }

  /**
   * Ensures fragment has a parent that implements the corresponding interface
   *
   * @param frag The Fragment whose parents are to be checked
   * @param callbackInterface The interface class that a parent should implement
   * @throws IllegalStateException if no parents are found that implement callbackInterface
   */
  public static void checkParent(@NonNull Fragment frag, @NonNull Class<?> callbackInterface)
      throws IllegalStateException {
    if (parentForTesting != null) {
      return;
    }
    if (FragmentUtils.getParent(frag, callbackInterface) == null) {
      String parent =
          frag.getParentFragment() == null
              ? frag.getActivity().getClass().getName()
              : frag.getParentFragment().getClass().getName();
      throw new IllegalStateException(
          frag.getClass().getName()
              + " must be added to a parent"
              + " that implements "
              + callbackInterface.getName()
              + ". Instead found "
              + parent);
    }
  }

  /** Useful interface for activities that don't want to implement arbitrary listeners. */
  public interface FragmentUtilListener {

    /** Returns an implementation of T if parent has one, otherwise null. */
    @Nullable
    <T> T getImpl(Class<T> callbackInterface);
  }
}