android仿微信好友列表功能

.android 仿微信好友列表功能详解 Android 仿微信好友列表功能是 Android 开发中常见的功能之一，本文将通过实例代码详细介绍 Android 仿微信好友列表功能的实现。下面是本文的主要内容： 一、项目初始化 在 Android Studio 中创建一个新的项目，然后在 build.gradle 文件中添加以下依赖项： ```groovy compile 'com.android.support:recyclerview-v7:26.0.0-alpha1' compile files('libs/pinyin4j-2.5.0.jar') ``` 其中，pinyin4j-2.5.0.jar 是一个用于中文拼音排序的 jar 包，需要将其复制到项目的 app/libs 文件夹中。 二、Contact 类的实现 Contact 类是用于存储联系人信息的类，包含三个成员变量：mName、mType 和构造函数： ```java public class Contact implements Serializable { private String mName; private int mType; public Contact(String name, int type) { mName = name; mType = type; } public String getmName() { return mName; } public int getmType() { return mType; } } ``` 三、ContactAdapter 的实现 ContactAdapter 是用于适配 RecyclerView 的适配器，包含以下成员变量和方法： ```java public class ContactAdapter extends RecyclerView.Adapter<ContactViewHolder> { private Context mContext; private String[] contactNames; public ContactAdapter(Context context, String[] contactNames) { this.mContext = context; this.contactNames = contactNames; } @Override public ContactViewHolder onCreateViewHolder(ViewGroup parent, int viewType) { View view = LayoutInflater.from(mContext).inflate(R.layout.item_contact, parent, false); return new ContactViewHolder(view); } @Override public void onBindViewHolder(ContactViewHolder holder, int position) { holder.tvContactName.setText(contactNames[position]); } @Override public int getItemCount() { return contactNames.length; } } ``` 四、MainActivity 的实现 MainActivity 是应用程序的主活动，包含以下成员变量和方法： ```java public class MainActivity extends AppCompatActivity { private RecyclerView contactList; private String[] contactNames; private LinearLayoutManager layoutManager; private LetterView letterView; private ContactAdapter adapter; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); contactNames = new String[] {"安然","奥兹","德玛","张三丰", "郭靖", "黄蓉", "黄老邪", "赵敏", "123", "天山童姥", "任我行", "于万亭", "陈家洛", "韦小宝", "$6", "穆人清", "陈圆圆", "郭芙", "郭襄", "穆念慈", "东方不败", "梅超风", "林平之", "林远图", "灭绝师太", "段誉", "鸠摩智"}; contactList = (RecyclerView) findViewById(R.id.contact_list); letterView = (LetterView) findViewById(R.id.letter_view); layoutManager = new LinearLayoutManager(this); adapter = new ContactAdapter(this, contactNames); contactList.setLayoutManager(layoutManager); contactList.addItemDecoration(new DividerItemDecoration(this, DividerItemDecoration.VERTICAL_LIST)); contactList.setAdapter(adapter); letterView.setCharacterListener(new LetterView.CharacterClickListener() { @Override public void clickCharacter(String character) { layoutManager.scrollToPositionWithOffset(adapter.getScrollPosition(character),0); } @Override public void clickArrow() { layoutManager.scrollToPositionWithOffset(0,0); } }); } } ``` 五、LetterView 的实现 LetterView 是用于显示字母索引的视图，包含以下成员变量和方法： ```java public class LetterView extends View { private Paint paint; private String[] letters; public LetterView(Context context) { super(context); init(); } private void init() { paint = new Paint(); letters = new String[] {"A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z"}; } @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); for (int i = 0; i < letters.length; i++) { canvas.drawText(letters[i], 10, 20 + i * 20, paint); } } } ``` 六、总结 本文详细介绍了 Android 仿微信好友列表功能的实现，包括 Contact 类、ContactAdapter 类、MainActivity 类和 LetterView 类的实现。通过阅读本文，读者可以了解 Android 仿微信好友列表功能的实现细节，并掌握相关的技术和知识。