使用改进功能从（本地）android资产文件夹获取Json数据
我正在处理一个需要从本地android资产目录访问Json数据的项目。 我可以使用Volley Library从资源文件夹读取json数据，但我想使用Retrofit来做同样的事情。 以下是我的json文件 - myfile.json 。
{
"formules": [
{
"formule": "Linear Motion",
"url": "<html><body>You scored <b>192</b> points. <img src="http://192.168.1.46/shanta_holdings/img/images/project-thumbs/Glasshouse-1.jpg" alt="Smiley face"/></body></html> ",
"des":"Here is a description"
},
{
"formule": "Constant Acceleration Motion",
"url": "<html><body>You scored <b>192</b> points. <img src="http://192.168.1.46/shanta_holdings/img/images/project-thumbs/Glasshouse-1.jpg" alt="Smiley face"/></body></html> ",
"des":"Here is a description"
},
{
"formule": "Projectile Motion",
"url": "<html><body>You scored <b>192</b> points. <img src="http://192.168.1.46/shanta_holdings/img/images/project-thumbs/Glasshouse-1.jpg" alt="Smiley face"/></body></html> ",
"des":"Here is a description"
},
{
"formule": "Force",
"url": "<html><body>You scored <b>192</b> points. <img src="http://192.168.1.46/shanta_holdings/img/images/project-thumbs/Glasshouse-1.jpg" alt="Smiley face"/></body></html> ",
"des":"Here is a description"
},
{
"formule": "Work, Power, Energy",
"url": "<html><body>You scored <b>192</b> points. <img src="http://192.168.1.46/shanta_holdings/img/images/project-thumbs/Glasshouse-1.jpg" alt="Smiley face"/></body></html> ",
"des":"Here is a description"
},
{
"formule": "Rotary Motion",
"url": "<html><body>You scored <b>192</b> points. <img src="http://192.168.1.46/shanta_holdings/img/images/project-thumbs/Glasshouse-1.jpg" alt="Smiley face"/></body></html> ",
"des":"Here is a description"
},
{
"formule": "Harmonic Motion",
"url": "<html><body>You scored <b>192</b> points. <img src="http://192.168.1.46/shanta_holdings/img/images/project-thumbs/Glasshouse-1.jpg" alt="Smiley face"/></body></html> ",
"des":"Here is a description"
},
{
"formule": "Gravity",
"url": "<html><body>You scored <b>192</b> points. <img src="http://192.168.1.46/shanta_holdings/img/images/project-thumbs/Glasshouse-1.jpg" alt="Smiley face"/></body></html> ",
"des":"Here is a description"
},
{
"formule": "Lateral and Longitudinal Waves",
"url": "<html><body>You scored <b>192</b> points. <img src="http://192.168.1.46/shanta_holdings/img/images/project-thumbs/Glasshouse-1.jpg" alt="Smiley face"/></body></html> ",
"des":"Here is a description"
},
{
"formule": "Sound Waves",
"url": "<html><body>You scored <b>192</b> points. <img src="http://192.168.1.46/shanta_holdings/img/images/project-thumbs/Glasshouse-1.jpg" alt="Smiley face"/></body></html> ",
"des":"Here is a description"
},
{
"formule": "Electrostatics",
"url": "<html><body>You scored <b>192</b> points. <img src="http://192.168.1.46/shanta_holdings/img/images/project-thumbs/Glasshouse-1.jpg" alt="Smiley face"/></body></html> ",
"des":"Here is a description"
},
{
"formule": "Direct Current",
"url": "<html><body>You scored <b>192</b> points. <img src="http://192.168.1.46/shanta_holdings/img/images/project-thumbs/Glasshouse-1.jpg" alt="Smiley face"/></body></html> ",
"des":"Here is a description"
},
{
"formule": "Magnetic Field",
"url": "https://www.google.com/",
"des":"Here is a description"
},
{
"formule": "Alternating Current",
"url": "https://www.google.com/",
"des":"Here is a description"
},
{
"formule": "Thermodynamics",
"url": "https://www.google.com/",
"des":"Here is a description"
},
{
"formule": "Hydrogen Atom",
"url": "https://www.google.com/",
"des":"Here is a description"
},
{
"formule": "Optics",
"url": "https://www.google.com/",
"des":"Here is a description"
},
{
"formule": "Modern Physics",
"url": "https://www.google.com/",
"des":"Here is a description"
},
{
"formule": "Hydrostatics",
"url": "https://www.google.com/",
"des":"Here is a description"
},
{
"formule": "Astronomy",
"url": "https://www.google.com/",
"des":"Here is a description"
}
]
}
我搜索了一个星期，但没有得到任何适合的改造解决方案。 我可以使用Retrofit从服务器读取数据。 有什么方法可以使用改造来实现这一要求。
正如Dheerubhai写的Retrofit不用于解析JSON对象。 你可以使用GSON，看到这个线程看看如何使它与Retrofit一起工作，你可以看到这个教程。
您正试图在您的项目中实施存根。
将你的.json文件添加到res / raw / filename.json中
上面的示例显示了两个Web服务端点（/ some / web / service，/ another / web / service）的本地存根文件以及两个方案 - empty和default（默认存根没有前缀，空存根以“empty_”为前缀） ）。 这些文件的内容通常是JSON。
接下来，我们编写一个自定义的HTTP客户端来从这些本地文件而不是网络中获取。 以下示例从Square的Retrofit库实现Client对象。 如果您对Retrofit不熟悉，则默认的客户端实现为OkClient。 它发出一个标准的HTTP网络请求。 我们正在编写一个自定义客户端来伪造网络请求，并从本地文件而不是网络服务器获取响应数据。
上面的示例显示了两个Web服务端点（/ some / web / service，/ another / web / service）的本地存根文件以及两个方案 - empty和default（默认存根没有前缀，空存根以“empty_”为前缀） ）。 这些文件的内容通常是JSON。
接下来，我们编写一个自定义的HTTP客户端来从这些本地文件而不是网络中获取。 以下示例从Square的Retrofit库实现Client对象。 如果您对Retrofit不熟悉，则默认的客户端实现为OkClient。 它发出一个标准的HTTP网络请求。 我们正在编写一个自定义客户端来伪造网络请求，并从本地文件而不是网络服务器获取响应数据。
public class LocalStubClient implements Client {
private Context context;
private String scenario;
public LocalStubClient(Context context, String scenario) {
this.context = context;
this.scenario = scenario;
}
public LocalStubClient(Context context) {
this.context = context;
}
public void setScenario(String scenario) {
this.scenario = scenario;
}
@Override
public Response execute(Request request) throws IOException {
//get resource id for local file
String fileName = createFilename(request, scenario);
int resourceId = getResourceId(fileName);
if (resourceId == 0) { //fallback to default filename
fileName = createFilename(request, null);
resourceId = getResourceId(fileName);
if (resourceId == 0) {
throw new IOException("Could not find res/raw/" + fileName + ".stub");
}
}
//get input stream & mime for local file
InputStream inputStream = context.getResources().openRawResource(resourceId);
String mimeType = URLConnection.guessContentTypeFromStream(inputStream);
//wrap local stream in retrofit objects
TypedInput body = new TypedInputStream(mimeType, inputStream.available(), inputStream);
Response response = new Response(request.getUrl(), 200, "Stub from res/raw/" + fileName, new ArrayList<Header>(), body);
return response;
}
private String createFilename(Request request, String scenario) throws IOException {
URL requestedUrl = new URL(request.getUrl());
String requestedMethod = request.getMethod();
String prefix = scenario == null ? "" : scenario + "_";
String filename = prefix + requestedMethod + requestedUrl.getPath();
filename = filename.replace("/", "_").replace("-", "_").toLowerCase();
return filename;
}
private int getResourceId(String filename) {
return context.getResources().getIdentifier(filename, "raw", context.getPackageName());
}
private static class TypedInputStream implements TypedInput {
private final String mimeType;
private final long length;
private final InputStream stream;
private TypedInputStream(String mimeType, long length, InputStream stream) {
this.mimeType = mimeType;
this.length = length;
this.stream = stream;
}
@Override
public String mimeType() {
return mimeType;
}
@Override
public long length() {
return length;
}
@Override
public InputStream in() throws IOException {
return stream;
}
}
}
最后，我们检查我们的“后端环境”设置，以确定我们是否应该使用我们的LocalStubClient或默认的OkClient：
RestAdapter.Builder builder = new RestAdapter.Builder();
String selectedBackend = getSharedPreference(R.string.pref_backend, "");
switch (Integer.parseInt(selectedBackend)) {
case R.string.test_server:
case default:
builder.setClient(new OkClient());
builder.setEndpoint("http://test.api.mydomain.com");
break;
case R.string.demo_server:
builder.setClient(new OkClient());
builder.setEndpoint("http://demo.api.mydomain.com");
break;
case R.string.default_local_stubs:
builder.setClient(new LocalStubClient(app));
break;
case R.string.empty_local_stubs:
builder.setClient(new LocalStubClient(app, "empty"));
break;
}
RestAdapter adapter = builder.build();
模拟网络延迟和故障改造还使我们能够模拟网络延迟，变化和故障。 以下是基于我们的第二个Dev设置启用/禁用模拟网络适配器的代码：
RestAdapter.Builder builder = new RestAdapter.Builder();
//...
RestAdapter adapter = builder.build();
if (getSharedPreference(R.string.pref_mock_network, false)) {
MockRestAdapter mockRestAdapter = MockRestAdapter.from(adapter);
mockRestAdapter.setDelay(1000);
mockRestAdapter.setVariancePercentage(50);
mockRestAdapter.setErrorPercentage(10);
return mockRestAdapter.create(serviceType, adapter.create(serviceType));
}
return adapter.create(serviceType)
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