ButterKnife:
*
Binding Views using ButterKnife
Binding Views using ButterKnife
suggest changewe can annotate fields with @BindView and a view ID for Butter Knife to find and automatically cast the corresponding view in our layout.
Binding Views
Binding Views in Activity
class ExampleActivity extends Activity {
@BindView(R.id.title) TextView title;
@BindView(R.id.subtitle) TextView subtitle;
@BindView(R.id.footer) TextView footer;
@Override public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.simple_activity);
ButterKnife.bind(this);
// TODO Use fields...
}
}Binding Views in Fragments
public class FancyFragment extends Fragment {
@BindView(R.id.button1) Button button1;
@BindView(R.id.button2) Button button2;
private Unbinder unbinder;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fancy_fragment, container, false);
unbinder = ButterKnife.bind(this, view);
// TODO Use fields...
return view;
}
// in fragments or non activity bindings we need to unbind the binding when view is about to be destroyed
@Override
public void onDestroy() {
super.onDestroy();
unbinder.unbind();
}
}Binding Views in Dialogs
We can use ButterKnife.findById to find views on a View, Activity, or Dialog. It uses generics to infer the return type and automatically performs the cast.
View view = LayoutInflater.from(context).inflate(R.layout.thing, null);
TextView firstName = ButterKnife.findById(view, R.id.first_name);
TextView lastName = ButterKnife.findById(view, R.id.last_name);
ImageView photo = ButterKnife.findById(view, R.id.photo);Binding Views in ViewHolder
static class ViewHolder {
@BindView(R.id.title) TextView name;
@BindView(R.id.job_title) TextView jobTitle;
public ViewHolder(View view) {
ButterKnife.bind(this, view);
}
}Binding Resources
Apart from being useful for binding views, one could also use ButterKnife to bind resources such as those defined within strings.xml, drawables.xml, colors.xml, dimens.xml, etc.
public class ExampleActivity extends Activity {@BindString(R.string.title) String title; @BindDrawable(R.drawable.graphic) Drawable graphic; @BindColor(R.color.red) int red; // int or ColorStateList field @BindDimen(R.dimen.spacer) Float spacer; // int (for pixel size) or float (for exact value) field
@Override public void onCreate(Bundle savedInstanceState) {
// ...
ButterKnife.bind(this);}
}Binding View Lists
You can group multiple views into a List or array. This is very helpful when we need to perform one action on multiple views at once.
@BindViews({ R.id.first_name, R.id.middle_name, R.id.last_name })
List<EditText> nameViews;
//The apply method allows you to act on all the views in a list at once.
ButterKnife.apply(nameViews, DISABLE);
ButterKnife.apply(nameViews, ENABLED, false);//We can use Action and Setter interfaces allow specifying simple behavior.
static final ButterKnife.Action<View> DISABLE = new ButterKnife.Action<View>() {
@Override public void apply(View view, int index) {
view.setEnabled(false);
}
};
static final ButterKnife.Setter<View, Boolean> ENABLED = new ButterKnife.Setter<View, Boolean>() {
@Override public void set(View view, Boolean value, int index) {
view.setEnabled(value);
}
};Optional Bindings
By default, both @Bind and listener bindings are required. An exception is thrown if the target view cannot be found. But if we are not sure if a view will be there or not then we can add a @Nullable annotation to fields or the @Optional annotation to methods to suppress this behavior and create an optional binding.
@Nullable
@BindView(R.id.might_not_be_there) TextView mightNotBeThere;
@Optional
@OnClick(R.id.maybe_missing)
void onMaybeMissingClicked() {
// TODO ...
}
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Table Of Contents
1
Layouts
2
Gradle
5
Intent
10
Exceptions
12
AsyncTask
14
Emulator
17
Service
19
WebView
21
RecyclerView
22
Google Maps
25
Android NDK
27
Camera 2 API
28
ViewPager
29
CardView
31
SQLite
33
ButterKnife
35
Glide
36
Retrofit2
37
Dialog
38
ACRA
39
GreenDAO
42
AlarmManager
43
Fragments
44
Handler
47
Activity
48
Snackbar
53
Toast
54
Interfaces
55
Animators
56
Location
59
Parcelable
60
MediaPlayer
63
Menu
65
Picasso
67
RoboGuice
68
Memory Leaks
70
Volley
71
Widgets
77
Dagger 2
78
Realm
84
ProgressBar
85
Custom Fonts
86
Vibration
89
UI Lifecycle
90
Spinner
95
OkHttp
99
Firebase
102
Facebook SDK
103
Unzip File
108
TextView
109
ListView
111
Loader
116
MVP Architecture
118
Xposed
119
Security
120
PackageManager
121
ImageView
123
Doze Mode
125
SearchView
127
Callback URL
128
Twitter APIs
130
Drawables
131
Colors
132
ConstraintLayout
133
RenderScript
134
Fresco
135
Swipe to Refresh
138
IntentService
139
AdMob
140
Implicit Intents
144
Email Validation
145
Keyboard
146
Button
147
TextInputLayout
148
Bottom Sheets
150
EditText
155
Vk SDK
157
Count Down Timer
159
Otto Event Bus
163
ExoPlayer
165
MediaSession
167
FileProvider
169
XMPP
170
Authenticator
172
AudioManager
173
Job Scheduling
175
OpenCV
177
Threads
178
MediaStore
179
Time Utils
180
Touch Events
181
Fingerprint API
184
ORMLite
185
YouTube API
186
TabLayout
189
ShortcutManager
190
LruCache
191
Using Jenkins CI
192
Zip files
193
Vector Drawables
194
Fastlane
199
FileIO
201
Robolectric
202
Moshi
205
Retrolambda
206
SparseArray
209
Android Things
210
VideoView
211
ViewFlipper
216
Paint
217
AudioTrack
218
ProGuard
220
Java on Android
225
ConstraintSet
226
CleverTap
228
ADB shell
229
Ping ICMP
230
AIDL
231
Using Kotlin
234
Context
238
Bitmap Cache
240
JCodec
241
Design Patterns
242
Okio
244
TensorFlow
245
Game developmen
248
Leak Canary
249
FuseView
253
SpannableString
254
Looper
256
Google Drive API
261
Fastjson
263
Jackson
264
Play Store
267
Smartcard
269
Contributors