public class MainActivity extends AppCompatActivity {

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        //1. 创建http客户端

        OkHttpClient okHttpClient = new OkHttpClient();

        //2. 创建请求

        Request request = new Request.Builder()

                .get() //get请求

                .url("http://www.baidu.com")

                .build();

        //3. 发起请求

         //同步的请求,耗时操作不推荐使用

         // okHttpClient.newCall().execute();

        //异步请求

        okHttpClient.newCall(request).enqueue(new MyCallback());

    }

    private  class MyCallback implements Callback {

        //失败 ,回调方法在子线程中

        @Override

        public void onFailure(Call call, IOException e) {

            //            Toast.makeText(MainActivity.this,"网络请求失败",Toast.LENGTH_SHORT).show();

            showToastInAnyThread("网络请求失败");

        }

        //成功回调 ,回调方法在子线程中

        @Override

        public void onResponse(Call call, Response response) throws IOException {

            String text = response.body().string();

            showToastInAnyThread(text);

        }

    }

    public void showToastInAnyThread(final String text){

        runOnUiThread(new Runnable() {

            @Override

            public void run() {

                Toast.makeText(MainActivity.this,text,Toast.LENGTH_SHORT).show();

            }

        });

    }

}