JAVA与服务器php通信

Question

我想写一个非常简单的API。 当我使用 postman API 时有效。 我想创建 Android 应用程序，但我的应用程序崩溃了。为什么？ 错误在哪里

OkHttpClient zapytanie = new OkHttpClient();
                RequestBody requestBody = new FormBody.Builder()
                        .add("login", "some_email")
                        .add("password", "some_password")
                        .build();
                final Request request = new Request.Builder()
                        .header("Content-Type", "application/x-www-form-urlencoded")
                        .url("https://garlic-dragon.000webhostapp.com/registration.php")
                        .post(requestBody)
                        .build();
                try {
                    Response response = zapytanie.newCall(request).execute();
                    Toast.makeText(getApplicationContext(), "This is my success!",
                            Toast.LENGTH_LONG).show();
                } catch (IOException e) {
                    //e.printStackTrace();
                    Toast.makeText(getApplicationContext(), e.toString(),
                            Toast.LENGTH_LONG).show();
                }

2019-12-07 19:32:56.007 28055-28055/com.example.chat E/AndroidRuntime: FATAL EXCEPTION: main Process: com.example.chat, PID: 28055 android.os.NetworkOnMainThreadException at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1513) at java.net.Inet6AddressImpl.lookupHostByName(Inet6AddressImpl.java:117) at java.net.Inet6AddressImpl.lookupAllHostAddr(Inet6AddressImpl.java:105) at java.net.InetAddress.getAllByName(InetAddress.java:1154) at okhttp3.Dns$Companion$SYSTEM$1.lookup(Dns.kt:48) at okhttp3.internal.connection.RouteSelector.resetNextInetSocketAddress(RouteSelector.kt:160) at okhttp3.internal.connection.RouteSelector.nextProxy(RouteSelector.kt:125) at okhttp3.internal.connection.RouteSelector.next(RouteSelector.kt:71) at okhttp3.internal.connection.ExchangeFinder.findConnection(ExchangeFinder.kt:199) at okhttp3.internal.connection.ExchangeFinder.findHealthyConnection(ExchangeFinder.kt:109) at okhttp3.internal.connection.ExchangeFinder.find(ExchangeFinder.kt:77) at okhttp3.internal.connection.Transmitter.newExchange$okhttp(Transmitter.kt:162) at okhttp3.internal.connection.ConnectInterceptor.intercept(ConnectInterceptor.kt:35) at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.kt:112) at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.kt:87) at okhttp3.internal.cache.CacheInterceptor.intercept(CacheInterceptor.kt:82) at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.kt:112) at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.kt:87) at okhttp3.internal.http.BridgeInterceptor.intercept(BridgeInterceptor.kt:84) at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.kt:112) at okhttp3.internal.http.RetryAndFollowUpInterceptor.intercept(RetryAndFollowUpInterceptor.kt:71) at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.kt:112) at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.kt:87) at okhttp3.RealCall.getResponseWithInterceptorChain(RealCall.kt:184) at okhttp3.RealCall.execute(RealCall.kt:66) at com.example.a4.MainActivity$2.onClick(MainActivity.java:78) at android.view.View.performClick(View.java:7339) at android.widget.TextView.performClick(TextView.java:14222) at android.view.View.performClickInternal(View.java:7305) at android.view.View.access$3200(View.java:846) at android.view.View$PerformClick.run(View.java:27787) at android.os.Handler.handleCallback(Handler.java:873) at android.os.Handler.dispatchMessage(Handler.java:99) at android.os.Looper.loop(Looper.java:214) at android.app.ActivityThread.main(ActivityThread.java:7078) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:964)

Answer 1

错误一定是NetworkOnMainThreadException，这是因为您无法在主线程上执行同步HTTP。使用入队不执行 异步运行请求。

     OkHttpClient zapytanie = new OkHttpClient();
     RequestBody requestBody = new FormBody.Builder()
                          .add("login", "some_email")
                          .add("password", "some_password")
                          .build();
     final Request request = new Request.Builder()
                          .header("Content-Type", "application/x-www-form-urlencoded")
                          .url("https://garlic-dragon.000webhostapp.com/registration.php")
                          .post(requestBody)
                          .build();
     try {
          Response response = zapytanie.newCall(request).enqueue(new Callback() {
          @Override
            public void onFailure(Request request, Throwable throwable) {
             // Something went wrong
            }

            @Override public void onResponse(Response response) throws IOException {
                 if (response.isSuccessful()) {
                  // Do what you want to do with the response.
                 } else {
                  // Request not successful
                 }
            }
           });
     } catch (IOException e) {
          //e.printStackTrace();
          Toast.makeText(getApplicationContext(), e.toString(),
           Toast.LENGTH_LONG).show();
     } 

我推荐像 Retrofit 这样的库以便更轻松地调用 API。