Android 仿微信QQ聊天界面

一些IM聊天軟件的展現形式是左右分開的形式。比如說，別人給你發的信息全部靠左顯示，你自己發給別人的信息全部靠右顯示。

而我們的ListView很多時候是顯示同一個布局，其實BaseAdapter中有2個重要的方法在大多數情況下我們並未使用到，一個是public int getViewTypeCount()，顯示ListView中有多少種布局（默認是顯示是1），像微信那樣聊天界面，是有2種布局方式；另外一個getItemViewType()，可以讓不同item條目加載不同的布局,下面就簡單的模擬下微信的聊天界面做法：

MainActivity.java

1. package com.jackie.wechat;
3. import java.util.ArrayList;
4. import java.util.List;
6. import android.app.Activity;
7. import android.os.Bundle;
8. import android.view.LayoutInflater;
9. import android.view.View;
10. import android.view.ViewGroup;
11. import android.widget.BaseAdapter;
12. import android.widget.ListView;
13. import android.widget.TextView;
15. public class MainActivity extends Activity {
16. private ListView mListView;
17. private List persons;
18. private int TYPE_COUNT = 2;
19. private int LEFT = 0;
20. private int RIGHT = 1;
21. private LayoutInflater mInflater;
22. private MyAdapter adapter;
23. @Override
24. protected void onCreate(Bundle savedInstanceState) {
25. super.onCreate(savedInstanceState);
26. setContentView(R.layout.activity_main);
27. mListView = (ListView) findViewById(R.id.listview);
28. mInflater = LayoutInflater.from(this);
29. initData();
30. adapter = new MyAdapter();
31. mListView.setAdapter(adapter);
32. }
33. private void initData() {
34. persons = new ArrayList();
35. for(int i = 0; i < 40; i++){
36. Person person = new Person();
37. person.setAge(i);
38. person.setName("更深的藍");
39. if(i % 2 == 0){
40. person.setType(0);
41. } else {
42. person.setType(1);
43. }
44. persons.add(person);
45. }
46. }
48. private class MyAdapter extends BaseAdapter{
50. @Override
51. public int getCount() {
52. return persons.size();
53. }
55. @Override
56. public Object getItem(int position) {
57. return persons.get(position);
58. }
60. @Override
61. public long getItemId(int position) {
62. return position;
63. }
64. 
    
65. @Override
66. public int getItemViewType(int position) {
67. if(persons.get(position).getType() == 0){
68. return LEFT;
69. }
70. return RIGHT;
71. }
73. @Override
74. public int getViewTypeCount() {
75. return TYPE_COUNT;
76. }
78. @Override
79. public View getView(int position, View convertView, ViewGroup parent) {
80. ViewHolder mHolder;
81. Person person = persons.get(position);
82. if(getItemViewType(position) == LEFT) {
83. if (convertView == null) {
84. mHolder = new ViewHolder();
85. convertView = mInflater.inflate(R.layout.item_left, null);
86. mHolder.tv_username = (TextView) convertView.findViewById(R.id.tv_username);
87. mHolder.tv_age = (TextView) convertView.findViewById(R.id.tv_age);
88. convertView.setTag(mHolder);
89. } else {
90. mHolder = (ViewHolder) convertView.getTag();
91. }
93. mHolder.tv_username.setText(person.getName());
94. mHolder.tv_age.setText(String.valueOf(person.getAge()));
95. } else {
96. if(convertView == null){
97. mHolder = new ViewHolder();
98. convertView = mInflater.inflate(R.layout.item_right, null);
99. mHolder.tv_username = (TextView) convertView.findViewById(R.id.tv_username);
100. mHolder.tv_age = (TextView) convertView.findViewById(R.id.tv_age);
101. convertView.setTag(mHolder);
102. }else{
103. mHolder = (ViewHolder) convertView.getTag();
104. }
105. 
     
106. mHolder.tv_username.setText(person.getName());
107. mHolder.tv_age.setText(String.valueOf(person.getAge()));
108. }
109. return convertView;
110. }
112. private class ViewHolder {
113. TextView tv_username;
114. TextView tv_age;
115. }
116. }
117. } Person.java [java] view plaincopyprint?
     1. package com.jackie.wechat;
     3. public class Person {
     4. private String name;
     5. private int age;
     6. private int type;
     7. public String getName() {
     8. return name;
     9. }
     10. 
         
     11. public void setName(String name) {
     12. this.name = name;
     13. }
     15. public int getAge() {
     16. return age;
     17. }
     19. public void setAge(int age) {
     20. this.age = age;
     21. }
     22. public int getType() {
     23. return type;
     24. }
     25. 
         
     26. public void setType(int type) {
     27. this.type = type;
     28. }
     29. } item_left.xml [html] view plaincopyprint?
         2. android:layout_width="match_parent"
         3. android:layout_height="match_parent"
         4. android:orientation="vertical"
         5. android:background="#ffffff"
         6. >
         7. android:layout_width="fill_parent"
         8. android:layout_height="45dp"
         9. >
         10. android:id="@+id/tv_username"
         11. android:layout_width="wrap_content"
         12. android:layout_height="wrap_content"
         13. android:textSize="16sp"
         14. android:textColor="#123456"
         15. android:layout_centerVertical="true"
         16. android:layout_alignParentLeft="true"
         17. />
         18. android:id="@+id/tv_age"
         19. android:layout_width="wrap_content"
         20. android:layout_height="wrap_content"
         21. android:textSize="16sp"
         22. android:textColor="#123456"
         23. android:layout_centerVertical="true"
         24. android:layout_toRightOf="@id/tv_username"
         25. android:layout_marginLeft="20dp"
         26. />
         28. item_right.xml
             [java] view plaincopyprint?
             2. android:layout_width="match_parent"
             3. android:layout_height="match_parent"
             4. android:orientation="vertical"
             5. android:background="#ffffff"
             6. >
             7. android:layout_width="fill_parent"
             8. android:layout_height="45dp"
             9. >
             10. android:id="@+id/tv_username"
             11. android:layout_width="wrap_content"
             12. android:layout_height="wrap_content"
             13. android:textSize="16sp"
             14. android:textColor="#123456"
             15. android:layout_centerVertical="true"
             16. android:layout_alignParentRight="true"
             17. />
             18. android:id="@+id/tv_age"
             19. android:layout_width="wrap_content"
             20. android:layout_height="wrap_content"
             21. android:textSize="16sp"
             22. android:textColor="#123456"
             23. android:layout_centerVertical="true"
             24. android:layout_toLeftOf="@id/tv_username"
             25. android:layout_marginRight="20dp"
             26. />