DavyJones的博客

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Retrofit2的基本使用

添加Retrofit2和butterknife等依赖

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// build.gradle
buildscript {
    repositories {
       mavenCentral()
    }
    dependencies {
        classpath 'com.neenbedankt.gradle.plugins:android-apt:1.8'
    }
}

// app/build.gradle
apply plugin: 'com.neenbedankt.android-apt'
dependencies {
      compile 'io.reactivex:rxjava:1.1.0'
      compile 'io.reactivex:rxandroid:1.1.0'
      compile 'com.squareup.retrofit2:retrofit:2.0.2'
      compile 'com.squareup.retrofit2:converter-gson:2.0.2'
      compile 'com.squareup.retrofit2:adapter-rxjava:2.0.2'
      compile 'com.squareup.okhttp3:logging-interceptor:3.2.0'  

      compile 'com.jakewharton:butterknife:8.0.1'
      apt 'com.jakewharton:butterknife-compiler:8.0.1'
}

IpEntity.java

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public class IpEntity {
    /**
     * code : 0
     * data : {"country":"美国","country_id":"US","area":"","area_id":"","region":"","region_id":"","city":"","city_id":"","county":"","county_id":"","isp":"","isp_id":"","ip":"63.223.108.42"}
     */
    private int code;
    private DataBean data;
    // getter and setter ...
}
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public class DataBean {
    private String country;
    private String country_id;
    private String area;
    private String area_id;
    private String region;
    private String region_id;
    private String city;
    private String city_id;
    private String county;
    private String county_id;
    private String isp;
    private String isp_id;
    private String ip;
    // getter and setter ...
}

MainActivity.java

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   public class MainActivity extends AppCompatActivity {
       @BindView(R.id.search)
       Button button;
       @BindView(R.id.ip_info)
       TextView ipInfo;

       @Override
       protected void onCreate(Bundle savedInstanceState) {
           super.onCreate(savedInstanceState);
           setContentView(R.layout.activity_main);
           ButterKnife.bind(this);
       }

       @OnClick(R.id.search)
       public void getIpInfo(){

       }
   }

   activity_main.xml

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<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Search Ip"
        android:id="@+id/search"
        android:layout_alignParentRight="true"
        android:layout_alignParentLeft="true" />

    <TextView
        android:text="Hello World!"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/ip_info"/>
</LinearLayout>

AndroidManefest.xml添加网络权限

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<uses-permission android:name="android.permission.INTERNET"></uses-permission>

定义API接口,已淘宝IP查询为例

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import retrofit2.Call;
import retrofit2.http.GET;
import retrofit2.http.Query;

public interface IpService {
    @GET("service/getIpInfo.php")
    Call<IpEntity> searchIp(@Query("ip") String ip);
}

实现接口API 并添加HttpLoggingInterceptor记录请求

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import okhttp3.OkHttpClient;
import okhttp3.logging.HttpLoggingInterceptor;
import retrofit2.Retrofit;
import retrofit2.converter.gson.GsonConverterFactory;

public class ServiceGenerator {
    public static final String API_BASE_URL = "http://ip.taobao.com";
    private static final OkHttpClient.Builder httpClient = new OkHttpClient.Builder();
    private static Retrofit.Builder builder =
            new Retrofit.Builder()
                    .baseUrl(API_BASE_URL)
                    .addConverterFactory(GsonConverterFactory.create());

    public static <S> S createService(Class<S> serviceClass) {
        HttpLoggingInterceptor interceptor = new HttpLoggingInterceptor();
        interceptor.setLevel(HttpLoggingInterceptor.Level.BASIC);
        httpClient.addInterceptor(interceptor);

        Retrofit retrofit = builder.client(httpClient.build()).build();
        return retrofit.create(serviceClass);
    }
}

调用查询IP

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@OnClick(R.id.search)
public void getIpInfo() {
    final IpService ipService = ServiceGenerator.createService(IpService.class);
    ipService.searchIp("63.223.108.42").enqueue(new Callback<IpEntity>() {
        @Override
        public void onResponse(Call<IpEntity> call, Response<IpEntity> response) {
            ipInfo.setText(response.body().toString());
        }

        @Override
        public void onFailure(Call<IpEntity> call, Throwable t) {
            ipInfo.setText(t.toString());
        }
    });
}

结果：

D/OkHttp (31286): –> GET http://ip.taobao.com/service/getIpInfo.php?ip=63.223.108.42 http/1.1
D/OkHttp (31286): <– 200 OK http://ip.taobao.com/service/getIpInfo.php?ip=63.223.108.42 (210ms, unknown-length body)

Post方式

提交表单，使用@FormUrlEncoded

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@FormUrlEncoded
@POST("/service/getIpInfo.php")
Observable<IpEntity> searchIp(@Field("ip") String ip);
//或者
@FormUrlEncoded
@POST("/service/getIpInfo.php")
Observable<IpEntity> searchIp(@FieldMap Map<String,String> ip);

RxJava使用

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private static Retrofit.Builder builder =
        new Retrofit.Builder()
                .baseUrl(API_BASE_URL)
                .addCallAdapterFactory(RxJavaCallAdapterFactory.create())
                .addConverterFactory(GsonConverterFactory.create());

在ServiceGenerator为添加 .addCallAdapterFactory(RxJavaCallAdapterFactory.create())

修改ApiService

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public interface IpService {
    @GET("/service/getIpInfo.php")
    Observable<IpEntity> searchIp(@Query("ip") String ip);
}

修改调用方式

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ipService.searchIp("63.223.108.42")
        .subscribeOn(Schedulers.io())
        .unsubscribeOn(Schedulers.io())
        .observeOn(AndroidSchedulers.mainThread())
        .subscribe(new Subscriber<IpEntity>() {
    @Override
    public void onCompleted() {
        Toast.makeText(MainActivity.this, "get Ip address!", Toast.LENGTH_LONG).show();
    }

    @Override
    public void onError(Throwable e) {
        ipInfo.setText(e.toString());
    }

    @Override
    public void onNext(IpEntity ipEntity) {
        ipInfo.setText(ipEntity.toString());
    }
});

发表于 更新于

Android视图系统事件的传递过程中，有个重要的对象MotionEvent。当我们在屏幕上按下，滑动，离开时，系统就会生成一系列包含了我们操作信息的MotionEvent对象。 MotionEvent对象里面包含了很多信息，包括操作的坐标，类型等。

MotionEvent对象包含了2个重要概念是指针索引和指针ID。

指针索引(PointerIndex)： 当我们用多个手指在屏幕操作时，系统会将每一个手指抽象成一个”指针”。每个指针都有一个索引。从0开始。这个索引分配给对应的手指之后，值是会随着手指数量的增减而改变的。如果同时有2根手指在屏幕上，第一根手指指针索引为0，第二根为1，如果第一根手指离开屏幕，第二根的指针索引变为0，因为此刻屏幕上只有1根手指

指针ID(PointerId)：指针ID唯一标识一根手指，这个值和索引不一样，是不会变的。

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