一个可以将 json 字符串 直接绑定到 view 上的Android库

android-data-binding

这是一个可以将 json 字符串 直接绑定到 view 上的库， 不用先将 json 转换为 model 类。

github 传送门: https://github.com/gplibs/android-data-binding

1. 安装

gradle:

dependencies {
compile 'com.gplibs:data-binding:1.0.0'
}


---

2. 一个简单的例子

json字符串数据源 json_data_source_binding_json.txt:

{
name: "my name"
}


StringJsonDataSourceBindingActivity:

public class StringJsonDataSourceBindingActivity extends AppCompatActivity { // 将 json 中的 name 字符段绑定到 TextView 的 text 上
@Binding(source = "name", target = "text")
private TextView tvName; @Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_string_json_data_source_binding); tvName = (TextView) findViewById(R.id.tv_name); // 读取json数据
String json = Utils.readText("json_data_source_binding_json.txt");
// 绑定操作
BindingManager.binding(json, this);
}
}


运行结果

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3. 值转换

某些时候数据源的类型可能与 view 的目标字段类型不一致，此时就需要对值进行转换。

json字符串数据源 convert_binding_json.txt:

{
name: "my name",
sex: 1,
head_url: "https://github.com/gplibs/resources/raw/master/sample.jpeg",
is_vip: true
}


定义一个将 boolean 转换为 visibility 的转换器:

class BooleanToVisibilityConverter implements IValueConverter {
@Override
public Object convert(Object sourceValue) {
return ((Boolean) sourceValue) ? View.VISIBLE : View.GONE;
}
}


定义一个将 表示性别的整形值 转换为对应文本的转换器:

class SexToStringConverter implements IValueConverter {
@Override
public Object convert(Object sourceValue) {
return (((Integer) sourceValue) == 0) ? "Female" : "Male";
}
}


定义一个将 url字符串 转换为 bitmap 的转换器:

(为了不阻塞主线程,实现的是一个异步转换器接口 IAsyncValueConverter)

class UrlToBitmapConverter implements IAsyncValueConverter {
@Override
public void convert(final Object sourceValue, final IValueConverterCallback callback) {
Executors.newSingleThreadExecutor().submit(new Runnable() {
@Override
public void run() {
try {
URL url = new URL((String) sourceValue);
callback.run(BitmapFactory.decodeStream(url.openStream()));
} catch (Exception ex) {
ex.printStackTrace();
}
}
});
}
}


ConvertBindingActivity:

public class ConvertBindingActivity extends AppCompatActivity { @Binding(source = "name", target = "text")
private TextView tvName; // 使用转换器将 json 中整形字段 sex 转换为对应文案， 绑定到 TextView 的 text 上
@ConvertBinding(source = "sex", target = "text", converter = SexToStringConverter.class)
private TextView tvSex; // 使用转换器将 json 中布尔字段 is_vip 转换为对应 visibility， 绑定到 TextView 的 visibility 上, 是 vip 才显示
@ConvertBinding(source = "is_vip", target = "visibility", converter = BooleanToVisibilityConverter.class)
private TextView tvVip; // 使用转换器将 json 中布尔字段 head_url 转换为 bitmap， 绑定到 ImageView 的 imageBitmap 上
@ConvertBinding(source = "head_url", target = "imageBitmap", converter = UrlToBitmapConverter.class)
private ImageView ivHead; @Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_convert_binding); tvName = (TextView) findViewById(R.id.tv_name);
tvSex = (TextView) findViewById(R.id.tv_sex);
tvVip = (TextView) findViewById(R.id.tv_vip);
ivHead = (ImageView) findViewById(R.id.iv_head); // 读取json数据
String json = Utils.readText("convert_binding_json.txt");
// 绑定操作
BindingManager.binding(json, this);
}}


运行结果

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4. 将多个字段绑定到同一个 View 的不同属性上

json字符串数据源 multi_binding_json.txt:

{
name: "my name",
is_vip: true,
vip_data: "I am Vip"
}


定义一个将 boolean 转换为 visibility 的转换器:

class BooleanToVisibilityConverter implements IValueConverter {
@Override
public Object convert(Object sourceValue) {
return ((Boolean) sourceValue) ? View.VISIBLE : View.GONE;
}
}


MultiBindingActivity:

public class MultiBindingActivity extends AppCompatActivity { @Binding(source = "name", target = "text")
private TextView tvName; // 将 json 字段 is_vip 绑定到 TextView 的 visibility 上, 是 vip 才显示
// 将 json 字段 vip_data 绑定到 TextView 的 text 上
@ConvertBinding(source = "is_vip", target = "visibility", converter = BooleanToVisibilityConverter.class)
@Binding(source = "vip_data", target = "text")
private TextView tvVip; @Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_multi_binding); tvName = (TextView) findViewById(R.id.tv_name);
tvVip = (TextView) findViewById(R.id.tv_vip); // 读取 json 文本
String json = Utils.readText("multi_binding_json.txt");
// 绑定操作
BindingManager.binding(json, this);
}}


运行结果

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5. 路径绑定

某些 json 有较复杂的数据结构，有子对象 或者 数组; 我们也可以将子对象或者数组中的字段绑定到 View 上;

路径绑定语法中 "." 可以获取子对象; ".[数字索引]" 可以获取数组中某索引处的元素。

json字符串数据源 path_binding_json.txt:

{
name: "my name",
father:
{
name: "my father"
},
children:
[
{
name: "my son"
},
{
name: "my daughter"
}
]
}


PathBindingActivity:

public class PathBindingActivity extends AppCompatActivity { @Binding(source = "name", target = "text")
private TextView tvName; // 将 json 中子对象 father 的 name 字段绑定到 TextView 的 text 上
@Binding(source = "father.name", target = "text")
private TextView tvFatherName; // 将 json 中子对象 children 数组的第0个元素的 name 字段绑定到 TextView 的 text 上
@Binding(source = "children.[0].name", target = "text")
private TextView tvSonName; // 将 json 中子对象 children 数组的第1个元素的 name 字段绑定到 TextView 的 text 上
@Binding(source = "children.[1].name", target = "text")
private TextView tvDaughterName; @Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_path_binding); tvName = (TextView) findViewById(R.id.tv_name);
tvFatherName = (TextView) findViewById(R.id.tv_father_name);
tvSonName = (TextView) findViewById(R.id.tv_son_name);
tvDaughterName = (TextView) findViewById(R.id.tv_daughter_name); // 读取 json 文本
String json = Utils.readText("path_binding_json.txt");
// 绑定操作
BindingManager.binding(json, this);
}}


运行结果

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5. 其他非字符串数据源

除了可以使用 json 字符串作为数据源外，我们也简单支持其他数据源进行绑定。

a. Model类作为数据源， 需实现 ModelSource:

class TestModel extends ModelSource { // @BindingField注解作用为：让框架使用其标注的名称作为绑定中数据源字段名
// GSON 中的 @SerializedName 注解也有同样的效果
@BindingField("name")
public String name = "my name";}


public class ModelSourceActivity extends AppCompatActivity { @Binding(source = "name", target = "text")
private TextView tvName; private Button btnTest; private int index; private TestModel testModel = new TestModel(); @Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_model_source); tvName = (TextView) findViewById(R.id.tv_name);
btnTest = (Button) findViewById(R.id.btn_test); btnTest.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// 修改 ModelSource 的 name 属性, 界面也会一起改变。
testModel.setProperty("name", "new name " + (++index));
}
}); // 绑定操作
BindingManager.binding(testModel, this);
}}


运行结果

b. 数组数据源:

可以使用 "[数字索引]" 语法将某个元素绑定到 View。

public class ArraySourceActivity extends AppCompatActivity { @Binding(source = "[0]", target = "text")
private TextView tvName; @Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_array_source); tvName = (TextView) findViewById(R.id.tv_name); String[] data = new String[] { "item1", "item2", "item3" };
BindingManager.binding(data, this);
}}


c. Collection数据源:

与数组数据源一样

public class CollectionSourceActivity extends AppCompatActivity { @Binding(source = "[1]", target = "text")
private TextView tvName; @Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_collection_source); tvName = (TextView) findViewById(R.id.tv_name); Collection<String> data = new ArrayList<>();
data.add("item1");
data.add("item2");
data.add("item3");
BindingManager.binding(data, this);
}}


d. Map数据源:

只支持 Key 类型为 String 的 Map。

public class MapSourceActivity extends AppCompatActivity { @Binding(source = "key1", target = "text")
private TextView tvName; @Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_map_source); tvName = (TextView) findViewById(R.id.tv_name); Map<String, String> data = new HashMap<>();
data.put("key1", "value1");
BindingManager.binding(data, this);
}}


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6. 各种数据混合时，可以按路径语法绑定指定字段到 View 上

json字符串数据源 mix_binding_json.txt:

{
name: "my name"
}


class MixTestModel extends ModelSource { @BindingField("data")
public Map<String, Collection<String>> data; public MixTestModel() {
data = new HashMap<>();
Collection<String> c = new ArrayList<>();
c.add(Utils.readText("mix_binding_json.txt"));
data.put("my_collection", c);
}}


public class MixDataSourceBindingActivity extends AppCompatActivity { // 将 MixTestModel 的Map数据源字段 "data" 中key为 "my_collection" 的Collection值 中的第 "0" 个json字符串元素 中的 "name" 字段 绑定到 View
@Binding(source = "data.my_collection.[0].name", target = "text")
private TextView tvName; @Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_mix_data_source_binding); tvName = (TextView) findViewById(R.id.tv_name); MixTestModel model = new MixTestModel();
BindingManager.binding(model, this);
}}


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7. 自定义数据源

以下例子为一个符合英文名格式的字符串 转换为 有 "firstName" 和 "lastName" 属性的数据源。

class UserNameAdapter implements IDataSourceAdapter<String> { @Override
public IDataSource getDataSource(String data) {
if (TextUtils.isEmpty(data) || !data.matches("^([a-zA-Z]+\\s)+[a-zA-Z]+$")) {
return null;
}
int i = data.indexOf(" ");
String f = data.substring(0, i);
String l = data.substring(i + 1);
return new IDataSource() {
@Override
public Object getProperty(String propertyName) {
if ("firstName".equals(propertyName)) {
return f;
}
if ("lastName".equals(propertyName)) {
return l;
}
return "";
}
};
} @Override
public Type typeOfData() {
return String.class;
}
}


public class CustomDataSourceAdapterActivity extends AppCompatActivity { @Binding(source = "firstName", target = "text")
private TextView tvFirstName; @Binding(source = "lastName", target = "text")
private TextView tvLastName; @Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_custom_data_source_adapter); BindingManager.registerDataSourceAdapter(new UserNameAdapter()); tvFirstName = (TextView) findViewById(R.id.tv_first_name);
tvLastName = (TextView) findViewById(R.id.tv_last_name); String data = "William Shakespeare";
BindingManager.binding(data, this);
}}


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8. 备注

@Binding(source = "..", target = "text")

绑定时 target 即绑定到 View 的目标属性， 取值按如下规律：

xx.setText(text) | target = "text"

xx.setVisibility(visibility) | target = "visibility"

xx.setBackgroundColor(color) | target = "backgroundColor"

...

以此类推