今天大体浏览了stormzhang的博客,学到了很多新知识,最主要的就是ButterKnife注入框架,在此记录一下使用方法。使用它可以简化代码,轻松绑定View和Listener。
Github开源地址:https://github.com/JakeWharton/butterknife
官方介绍:http://jakewharton.github.io/butterknife/
Android Studio 配置
首先在Project级别的build.gradle添加 ‘android-apt’ lugin支持:
buildscript {
repositories {
mavenCentral()
}
dependencies {
//https://github.com/JakeWharton/butterknife
classpath 'com.neenbedankt.gradle.plugins:android-apt:1.8'
}
}
然后在Module级别的build.gradle中应用‘android-apt’ lugin支持,并且添加Butter Knife dependencies:
apply plugin: 'android-apt'
android {
......
}
dependencies {
//https://github.com/JakeWharton/butterknife
//http://jakewharton.github.io/butterknife/
compile 'com.jakewharton:butterknife:8.4.0'
apt 'com.jakewharton:butterknife-compiler:8.4.0'
}
Activity中使用ButterKnife绑定View:
- @BindView()
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...
}
}
Activity中使用ButterKnife绑定Resource:
- @BindBool
- @BindColor
- @BindDimen
- @BindDrawable
- @BindInt
- @BindString
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
// ...
}
Fragment中使用ButterKnife绑定View:
- @BindView()
public class FancyFragment extends Fragment {
@BindView(R.id.button1) Button button1;
@BindView(R.id.button2) Button button2;
@Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fancy_fragment, container, false);
ButterKnife.bind(this, view);
// TODO Use fields...
return view;
}
}
ViewHolder中使用ButterKnife绑定View:
- @BindView()
public class MyAdapter extends BaseAdapter {
@Override public View getView(int position, View view, ViewGroup parent) {
ViewHolder holder;
if (view != null) {
holder = (ViewHolder) view.getTag();
} else {
view = inflater.inflate(R.layout.whatever, parent, false);
holder = new ViewHolder(view);
view.setTag(holder);
}
holder.name.setText("John Doe");
// etc...
return view;
}
static class ViewHolder {
@BindView(R.id.title) TextView name;
@BindView(R.id.job_title) TextView jobTitle;
public ViewHolder(View view) {
ButterKnife.bind(this, view);
}
}
}
其他注入方式
- Bind arbitrary objects using an activity as the view root. If you use a pattern like MVC you can bind the controller using its activity with
ButterKnife.bind(this, activity)
.- Bind a view’s children into fields using
ButterKnife.bind(this)
. If you use<merge>
tags in a layout and inflate in a custom view constructor you can call this immediately after. Alternatively, custom view types inflated from XML can use it in theonFinishInflate()
callback.
View Lists 注入:
@BindViews()
@BindViews({ R.id.first_name, R.id.middle_name, R.id.last_name }) List<EditText> nameViews;
ButterKnife.apply()
ButterKnife.apply(nameViews, DISABLE); ButterKnife.apply(nameViews, ENABLED, false);
Action()
static final ButterKnife.Action<View> DISABLE = new ButterKnife.Action<View>() { @Override public void apply(View view, int index) { view.setEnabled(false); } };
Setter()
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); } };
ButterKnife.apply()
//An Android Property can also be used with the apply method. ButterKnife.apply(nameViews, View.ALPHA, 0.0f);
Listener 注入:
@OnClick()
@OnClick(R.id.submit) public void submit(View view) { // TODO submit data to server... }
@OnClick(R.id.submit) public void submit() { // TODO submit data to server... }
@OnClick(R.id.submit) public void sayHi(Button button) { button.setText("Hello!"); }
@OnClick({ R.id.door1, R.id.door2, R.id.door3 }) public void pickDoor(DoorView door) { if (door.hasPrizeBehind()) { Toast.makeText(this, "You win!", LENGTH_SHORT).show(); } else { Toast.makeText(this, "Try again", LENGTH_SHORT).show(); } }
Reset 注入:
unbinder.unbind()
Fragments have a different view lifecycle than activities. When binding a fragment in
onCreateView
, set the views tonull
inonDestroyView
. Butter Knife returns anUnbinder
instance when you callbind
to do this for you. Call itsunbind
method in the appropriate lifecycle callback.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; } @Override public void onDestroyView() { super.onDestroyView(); unbinder.unbind(); } }
其它注入方式
By default, both
@Bind
and listener bindings are required. An exception will be thrown if the target view cannot be found.To suppress this behavior and create an optional binding, add a
@Nullable
annotation to fields or the@Optional
annotation to methods.Note: Any annotation named
@Nullable
can be used for fields. It is encouraged to use the@Nullable
annotation from Android’s “support-annotations” library.@Nullable @BindView(R.id.might_not_be_there) TextView mightNotBeThere; @Optional @OnClick(R.id.maybe_missing) void onMaybeMissingClicked() { // TODO ... }
MULTI-METHOD LISTENERS
Method annotations whose corresponding listener has multiple callbacks can be used to bind to any one of them. Each annotation has a default callback that it binds to. Specify an alternate using the
callback
parameter.@OnItemSelected(R.id.list_view) void onItemSelected(int position) { // TODO ... } @OnItemSelected(value = R.id.maybe_missing, callback = NOTHING_SELECTED) void onNothingSelected() { // TODO ... }
BONUS
Also included are
findById
methods which simplify code that still has to find views on aView
,Activity
, orDialog
. 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);