Android开发中很多时候是和UI打交道的,有一种方法叫findViewById(),控件少的适合还能承受,多了就有种想罢工的冲动。而且使用这种方法还要进行强制类型转换,于是,如果你的Id名字长点,变量命名长点说不定还要两行。为了解决这种问题我们可以使用注解的方法。
从JDK1.5开始,Java提供了注解的功能,允许开发者定义和使用自己的注解类型,该功能由一个定义注解类型的语法和描述一个注解声明的语法,读取注解的API,一个使用注解修饰的class文件和一个注解处理工具组成。
ButterKnife简介
ButterKnife是一个专注于Android系统的View、Resource、Action注入框架,可以大量减少findViewById以及setOnClickListener代码,可视化一键生成
优势:1、强大的View绑定和Click事件处理功能、简化代码、提升开发效率;
2、方便的处理Adapter里的ViewHolder绑定问题;
3、运行时不会影响APP效率,使用配置方便;
4、代码清晰,可读性强;
深入学习可以参考:http://jakewharton.github.io/butterknife/ 和 https://github.com/JakeWharton/butterknife/
添加依赖
1、在项目的project的build.gredle文件中的dependenies标签下添加
classpath 'com.neenbedankt.gradle.plugins:android-apt:1.8'
2、在module的build.gredle文件中添加
apply plugin: 'android-apt'
3、在module的buile.gredle文件中的dependencies标签中添加
compile 'com.jakewharton:butterknife:8.4.0' apt 'com.jakewharton:butterknife-compiler:8.4.0'
使用
1、控件id注解:@BindView()
package com.dl.ButterKnifeDemo; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.widget.Button; import butterknife.BindView; import butterknife.ButterKnife; public class ButterknifeActivity extends AppCompatActivity { @BindView( R.id.button1 ) public Button button1 ; // 注意:button 的修饰类型不能是:private 或者 static 。 否则会报错:错误: @BindView fields must not be private or static. (com.zyj.wifi.ButterknifeActivity.button1) @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_butterknife); //绑定activity ButterKnife.bind( this ) ; button1.setText( "I am a button "); } }2、多个控件id注解:@BindViews()
package com.dl.ButterKnifeDemo; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.widget.Button; import java.util.List; import butterknife.BindViews; import butterknife.ButterKnife; public class Main2Activity extends AppCompatActivity { @BindViews({ R.id.button1 , R.id.button2 , R.id.button3 }) public List<Button> buttonList ; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main2); ButterKnife.bind(this); buttonList.get( 0 ).setText( "hello 1 "); buttonList.get( 1 ).setText( "hello 2 "); buttonList.get( 2 ).setText( "hello 3 "); } }3、fragment使用
package com.dl.ButterKnifeDemo; import android.os.Bundle; import android.support.v4.app.Fragment; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.Button; import butterknife.BindView; import butterknife.ButterKnife; public class ButterknifeFragment extends Fragment { @BindView( R.id.button1 ) public Button button1 ; @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { View view = inflater.inflate(R.layout.fragment_butterknife, container, false); //绑定fragment ButterKnife.bind( this , view ) ; button1.setText( "I am a button "); return view ; } }4、绑定字符串:@BindString()
package com.dl.ButterKnifeDemo; import android.os.Bundle; import android.support.v7.app.AppCompatActivity; import android.widget.Button; import butterknife.BindString; import butterknife.BindView; import butterknife.ButterKnife; public class ButterknifeActivity extends AppCompatActivity { @BindView( R.id.button1 ) //绑定button 控件 public Button button1 ; @BindString( R.string.app_name ) //绑定string 字符串 String meg; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_butterknife); //绑定activity ButterKnife.bind( this ) ; button1.setText( meg ); } }5、绑定String中array数组
<resources> <string name="app_name">WiFi管家</string> <string-array name="city"> <item>厦门市</item> <item>福州市</item> <item>泉州市</item> <item>漳州市</item> <item>龙岩市</item> </string-array> </resources> package com.dl.ButterKnifeDemo; import android.os.Bundle; import android.support.v7.app.AppCompatActivity; import android.widget.Button; import butterknife.BindArray; import butterknife.BindView; import butterknife.ButterKnife; public class ButterknifeActivity extends AppCompatActivity { @BindView( R.id.button1 ) //绑定button 控件 public Button button1 ; @BindArray(R.array.city ) //绑定string里面array数组 String [] citys ; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_butterknife); //绑定activity ButterKnife.bind( this ) ; button1.setText( citys[0] ); } }6、绑定bitmap资源:@BindBitmap()
package com.dl.ButterKnifeDemo; import android.graphics.Bitmap; import android.os.Bundle; import android.support.v7.app.AppCompatActivity; import android.widget.ImageView; import butterknife.BindBitmap; import butterknife.BindView; import butterknife.ButterKnife; public class ButterknifeActivity extends AppCompatActivity { @BindView( R.id.imageView ) //绑定ImageView 控件 public ImageView imageView ; @BindBitmap( R.mipmap.wifi ) //绑定Bitmap 资源 public Bitmap wifi_bitmap ; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_butterknife); //绑定activity ButterKnife.bind( this ) ; imageView.setImageBitmap( wifi_bitmap ); } }7、绑定一个颜色值:@BindColor()
package com.dl.ButterKnifeDemo; import android.os.Bundle; import android.support.v7.app.AppCompatActivity; import android.widget.Button; import butterknife.BindColor; import butterknife.BindView; import butterknife.ButterKnife; public class ButterknifeActivity extends AppCompatActivity { @BindView( R.id.button1 ) //绑定一个控件 public Button button1 ; @BindColor( R.color.colorAccent ) int black ; //绑定一个颜色值 @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_butterknife); //绑定activity ButterKnife.bind( this ) ; button1.setTextColor( black ); } }8、绑定控件点击事件:@OnClick();绑定控件长按事件:@OnLongClick()
package com.dl.ButterKnifeDemo; import android.os.Bundle; import android.support.v7.app.AppCompatActivity; import android.widget.Toast; import butterknife.ButterKnife; import butterknife.OnClick; import butterknife.OnLongClick; public class ButterknifeActivity extends AppCompatActivity { @OnClick(R.id.button1 ) //给 button1 设置一个点击事件 public void showToast(){ Toast.makeText(this, "is a click", Toast.LENGTH_SHORT).show(); } @OnLongClick( R.id.button1 ) //给 button1 设置一个长按事件 public boolean showToast2(){ Toast.makeText(this, "is a long click", Toast.LENGTH_SHORT).show(); return true ; } @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_butterknife); //绑定activity ButterKnife.bind( this ) ; } }
ButterKnife自动生成插件安装:
在Android Studio中File->Settings->Plugins->搜索Zelezny下载添加即可,使用时,在要导入的Activity或Fragment或ViewHolder的layout代码资源上右键 Generate->Generate ButterKnife Injections,然后出现选择框,选择要导入的即可
插件:https://github.com/avast/android-butterknife-zelezny