休息 API Android 应用程序

【问题标题】：Rest API Android Application休息 API Android 应用程序
【发布时间】：2015-04-23 19:21:07
【问题描述】：

我正在创建一个需要使用 HTTP 从 Web API 获取数据的 Android 应用程序。它很可能是在我的应用程序中检索、处理然后更新 TextViews 的 JSON。我正在使用 SQL Server 数据库运行 MVC Web API 应用程序 (localhost)。我想在我的应用程序中检索数据并输出到 TextViews。我一直在关注本教程http://blog.strikeiron.com/bid/73189/Integrate-a-REST-API-into-Android-Application-in-less-than-15-minutes，因为我是 API 调用的新手，并且我不确定在您删除 API URL 后该怎么做。源码如下

fragment2_layout.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:background="#D70B0D"
    android:orientation="vertical" >

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:layout_marginTop="5dp"
        android:text="@string/textView1"
        android:textAppearance="?android:attr/textAppearanceLarge"
        android:textColor="#FFFFFF"
        android:textStyle="bold"/>

    <TextView
        android:id="@+id/txtId"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/txtId"
        android:textAppearance="?android:attr/textAppearanceMedium"
        android:textColor="#FFFFFF"
        android:layout_margin="23dp"/>

    <TextView
        android:id="@+id/txtName"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/txtName"
        android:textAppearance="?android:attr/textAppearanceMedium"
        android:textColor="#FFFFFF"
        android:layout_margin="23dp"/>

    <TextView
        android:id="@+id/txtBirth"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/txtBirth"
        android:textAppearance="?android:attr/textAppearanceMedium" 
        android:textColor="#FFFFFF"
        android:layout_margin="23dp"/>

    <TextView
        android:id="@+id/textView5"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:layout_marginTop="5dp"
        android:text="@string/textView5"
        android:textAppearance="?android:attr/textAppearanceLarge"
        android:textColor="#FFFFFF"
        android:textStyle="bold" />

     <TextView
        android:id="@+id/txtMedHis"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/txtMedHis"
        android:textAppearance="?android:attr/textAppearanceMedium" 
        android:textColor="#FFFFFF"
        android:layout_margin="23dp"/>

     <TextView
        android:id="@+id/txtMed"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/txtMed"
        android:textAppearance="?android:attr/textAppearanceMedium" 
        android:textColor="#FFFFFF"
        android:layout_margin="23dp"/>

     <TextView
        android:id="@+id/txtAler"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/txtAler"
        android:textAppearance="?android:attr/textAppearanceMedium" 
        android:textColor="#FFFFFF"
        android:layout_margin="23dp"/>

</LinearLayout>

Fragment2.java

package ie.itsligo.medication;

import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.Date;

import org.json.JSONObject;

import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

public class Fragment2 extends Fragment {

    public final static String apiURL = "http://localhost:63607/api/person/1";

    TextView txtId;
    TextView txtName;
    TextView txtBirth;
    TextView txtMedHis;
    TextView txtMed;
    TextView txtAler;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {

        View view = inflater.inflate(R.layout.fragment2_layout, container, false);

        return view;
    }

    private class CallAPI extends AsyncTask<String, String, String> {

        @Override
        protected String doInBackground(String... params) {

            String urlString=params[0]; // URL to call
            String resultToDisplay = "";
            InputStream in = null;

            // HTTP Get
            try {

                URL url = new URL(urlString);
                HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
                in = new BufferedInputStream(urlConnection.getInputStream());

                StringBuilder sb = new StringBuilder();

                String line = "";

                 BufferedReader reader = new BufferedReader(new InputStreamReader(urlConnection.getInputStream()));
                        while ((line=reader.readLine())!=null){
                            sb.append(line);
                        }
                        reader.close();
                String result = sb.toString();

                Log.d("result", result);

                JSONObject jsonResult = new JSONObject(result);
                int id = jsonResult.getInt("ID");
                String name = jsonResult.getString("FullName");

                txtId = (TextView) getView().findViewById(R.id.txtId);
                txtName = (TextView) getView().findViewById(R.id.txtName);

                /*txtId.setText(ID);
                txtName.setText(FullName);*/

            } catch (Exception e) {

                System.out.println(e.getMessage());
                return e.getMessage();

            }

            return resultToDisplay;
        }

        protected void onPostExecute(String result) {

        }

    } // end CallAPI
}

LogCat

02-22 14:17:17.296: D/dalvikvm(19793): GC_CONCURRENT freed 159K, 13% free 10008K/11399K, paused 18ms+7ms, total 93ms
02-22 14:17:17.296: D/dalvikvm(19793): WAIT_FOR_CONCURRENT_GC blocked 17ms
02-22 14:17:17.466: I/Google Maps Android API(19793): Google Play services client version: 6587000
02-22 14:17:17.486: I/Google Maps Android API(19793): Google Play services package version: 6776034
02-22 14:17:17.606: D/dalvikvm(19793): GC_CONCURRENT freed 248K, 13% free 10298K/11783K, paused 13ms+7ms, total 76ms
02-22 14:17:17.606: D/dalvikvm(19793): WAIT_FOR_CONCURRENT_GC blocked 16ms
02-22 14:17:17.776: D/dalvikvm(19793): GC_CONCURRENT freed 163K, 12% free 10704K/12103K, paused 3ms+4ms, total 57ms
02-22 14:17:17.776: D/dalvikvm(19793): WAIT_FOR_CONCURRENT_GC blocked 10ms
02-22 14:17:17.986: D/dalvikvm(19793): GC_FOR_ALLOC freed 384K, 14% free 10988K/12679K, paused 80ms, total 80ms
02-22 14:17:18.127: D/dalvikvm(19793): GC_FOR_ALLOC freed 625K, 16% free 11321K/13447K, paused 75ms, total 76ms
02-22 14:17:18.717: D/dalvikvm(19793): GC_CONCURRENT freed 1004K, 16% free 12429K/14663K, paused 17ms+5ms, total 104ms
02-22 14:17:18.717: D/dalvikvm(19793): WAIT_FOR_CONCURRENT_GC blocked 46ms
02-22 14:17:19.137: D/dalvikvm(19793): GC_CONCURRENT freed 628K, 13% free 12860K/14727K, paused 19ms+6ms, total 111ms
02-22 14:17:19.137: D/dalvikvm(19793): WAIT_FOR_CONCURRENT_GC blocked 66ms
02-22 14:17:19.658: D/dalvikvm(19793): GC_CONCURRENT freed 272K, 10% free 13801K/15303K, paused 19ms+3ms, total 107ms
02-22 14:17:19.658: D/dalvikvm(19793): WAIT_FOR_CONCURRENT_GC blocked 39ms
02-22 14:17:19.798: I/dalvikvm(19793): Could not find method android.content.pm.PackageManager.getPackageInstaller, referenced from method com.google.android.gms.common.ew.c
02-22 14:17:19.798: W/dalvikvm(19793): VFY: unable to resolve virtual method 441: Landroid/content/pm/PackageManager;.getPackageInstaller ()Landroid/content/pm/PackageInstaller;
02-22 14:17:19.798: D/dalvikvm(19793): VFY: replacing opcode 0x6e at 0x000f
02-22 14:17:20.068: D/AbsListView(19793): Get MotionRecognitionManager
02-22 14:17:20.128: W/ActivityThread(19793): ClassLoader.loadClass: The class loader returned by Thread.getContextClassLoader() may fail for processes that host multiple applications. You should explicitly specify a context class loader. For example: Thread.setContextClassLoader(getClass().getClassLoader());
02-22 14:17:20.679: D/dalvikvm(19793): GC_CONCURRENT freed 1390K, 16% free 13958K/16583K, paused 13ms+4ms, total 189ms
02-22 14:17:20.679: D/dalvikvm(19793): WAIT_FOR_CONCURRENT_GC blocked 125ms
02-22 14:17:20.679: D/dalvikvm(19793): WAIT_FOR_CONCURRENT_GC blocked 79ms
02-22 14:17:20.679: D/dalvikvm(19793): WAIT_FOR_CONCURRENT_GC blocked 127ms
02-22 14:17:20.679: D/dalvikvm(19793): WAIT_FOR_CONCURRENT_GC blocked 130ms
02-22 14:17:20.869: D/AndroidRuntime(19793): Shutting down VM
02-22 14:17:20.869: W/dalvikvm(19793): threadid=1: thread exiting with uncaught exception (group=0x40e622a0)
02-22 14:17:20.899: E/AndroidRuntime(19793): FATAL EXCEPTION: main
02-22 14:17:20.899: E/AndroidRuntime(19793): java.lang.NullPointerException
02-22 14:17:20.899: E/AndroidRuntime(19793):    at ie.itsligo.medication.Fragment2.onCreateView(Fragment2.java:39)
02-22 14:17:20.899: E/AndroidRuntime(19793):    at android.support.v4.app.Fragment.performCreateView(Fragment.java:1786)
02-22 14:17:20.899: E/AndroidRuntime(19793):    at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:947)
02-22 14:17:20.899: E/AndroidRuntime(19793):    at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1126)
02-22 14:17:20.899: E/AndroidRuntime(19793):    at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:739)
02-22 14:17:20.899: E/AndroidRuntime(19793):    at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1489)
02-22 14:17:20.899: E/AndroidRuntime(19793):    at android.support.v4.app.FragmentManagerImpl.executePendingTransactions(FragmentManager.java:486)
02-22 14:17:20.899: E/AndroidRuntime(19793):    at android.support.v4.app.FragmentPagerAdapter.finishUpdate(FragmentPagerAdapter.java:141)
02-22 14:17:20.899: E/AndroidRuntime(19793):    at android.support.v4.view.ViewPager.populate(ViewPager.java:1073)
02-22 14:17:20.899: E/AndroidRuntime(19793):    at android.support.v4.view.ViewPager.populate(ViewPager.java:919)
02-22 14:17:20.899: E/AndroidRuntime(19793):    at android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1441)
02-22 14:17:20.899: E/AndroidRuntime(19793):    at android.view.View.measure(View.java:15288)
02-22 14:17:20.899: E/AndroidRuntime(19793):    at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4876)
02-22 14:17:20.899: E/AndroidRuntime(19793):    at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1396)
02-22 14:17:20.899: E/AndroidRuntime(19793):    at android.widget.LinearLayout.measureVertical(LinearLayout.java:681)
02-22 14:17:20.899: E/AndroidRuntime(19793):    at android.widget.LinearLayout.onMeasure(LinearLayout.java:574)
02-22 14:17:20.899: E/AndroidRuntime(19793):    at android.view.View.measure(View.java:15288)
02-22 14:17:20.899: E/AndroidRuntime(19793):    at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4876)
02-22 14:17:20.899: E/AndroidRuntime(19793):    at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
02-22 14:17:20.899: E/AndroidRuntime(19793):    at android.view.View.measure(View.java:15288)
02-22 14:17:20.899: E/AndroidRuntime(19793):    at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4876)
02-22 14:17:20.899: E/AndroidRuntime(19793):    at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1396)
02-22 14:17:20.899: E/AndroidRuntime(19793):    at android.widget.LinearLayout.measureVertical(LinearLayout.java:681)
02-22 14:17:20.899: E/AndroidRuntime(19793):    at android.widget.LinearLayout.onMeasure(LinearLayout.java:574)
02-22 14:17:20.899: E/AndroidRuntime(19793):    at android.view.View.measure(View.java:15288)
02-22 14:17:20.899: E/AndroidRuntime(19793):    at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4876)
02-22 14:17:20.899: E/AndroidRuntime(19793):    at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
02-22 14:17:20.899: E/AndroidRuntime(19793):    at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2397)
02-22 14:17:20.899: E/AndroidRuntime(19793):    at android.view.View.measure(View.java:15288)
02-22 14:17:20.899: E/AndroidRuntime(19793):    at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:1974)
02-22 14:17:20.899: E/AndroidRuntime(19793):    at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1217)
02-22 14:17:20.899: E/AndroidRuntime(19793):    at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1390)
02-22 14:17:20.899: E/AndroidRuntime(19793):    at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1113)
02-22 14:17:20.899: E/AndroidRuntime(19793):    at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:4481)
02-22 14:17:20.899: E/AndroidRuntime(19793):    at android.view.Choreographer$CallbackRecord.run(Choreographer.java:725)
02-22 14:17:20.899: E/AndroidRuntime(19793):    at android.view.Choreographer.doCallbacks(Choreographer.java:555)
02-22 14:17:20.899: E/AndroidRuntime(19793):    at android.view.Choreographer.doFrame(Choreographer.java:525)
02-22 14:17:20.899: E/AndroidRuntime(19793):    at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:711)
02-22 14:17:20.899: E/AndroidRuntime(19793):    at android.os.Handler.handleCallback(Handler.java:615)
02-22 14:17:20.899: E/AndroidRuntime(19793):    at android.os.Handler.dispatchMessage(Handler.java:92)
02-22 14:17:20.899: E/AndroidRuntime(19793):    at android.os.Looper.loop(Looper.java:137)
02-22 14:17:20.899: E/AndroidRuntime(19793):    at android.app.ActivityThread.main(ActivityThread.java:4867)
02-22 14:17:20.899: E/AndroidRuntime(19793):    at java.lang.reflect.Method.invokeNative(Native Method)
02-22 14:17:20.899: E/AndroidRuntime(19793):    at java.lang.reflect.Method.invoke(Method.java:511)
02-22 14:17:20.899: E/AndroidRuntime(19793):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1007)
02-22 14:17:20.899: E/AndroidRuntime(19793):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:774)
02-22 14:17:20.899: E/AndroidRuntime(19793):    at dalvik.system.NativeStart.main(Native Method)

【问题讨论】：

    标签： android json api http model-view-controller


    【解决方案1】：

    假设你的服务器返回 json

    {
      "id":711,
      "main":"Smoke",
      "description":"smoke",
      "icon":"50n"
}

    所以你需要得到它。

     StringBuilder sb = new StringBuilder(); // for final result
 String line ="";
 BufferedReader reader = new BufferedReader(new InputStreamReader(urlConnection.getInputStream())); // read whatever is returned by server
        while ((line=reader.readLine())!=null){
            sb.append(line); // get response by line and append to StringBulder
        }
        reader.close();
String result = sb.toString(); //this is a response to parse.
Log.d("result", result); // check what is returned by server

    解析来自服务器的响应。

    JSONObject jsonResult = new JSONObject(result);// convert response to JSONObject
String main = jsonResult.getString("main"); // Smoke
int id = jsonResult.getInt("id") // 711 and so on.

    将你的值输出到 TextView

    textView.setText(main);
textView.setText(id);

    【讨论】：

    • StringBuilder 中究竟存储了什么，我不确定其中的值是什么（“someKey”）
    • StringBuilder - 存储 urlConnection 带给你的任何东西，在你的情况下它是 json。放 Log.d("结果", 结果);后字符串结果 = sb.toString();
    • 好的。我对此很陌生，所以我不确定输入什么值（“someKey”）以及如何将数据输出到我的应用程序中的 TextViews。
    • 我更新了 Fragment2.java 我收到一个错误，我将值输出到 TextViews（括号内的值）并且我是否正确连接到 API 似乎有很多未使用代码。
    • Log.d("result", result);给我看看。它在您的控制台中打印什么
    【解决方案2】：

    为了更好的使用

    RetroFit2.0

    或者可以使用更多的托管（POST/GET）

    RetroLet 1.5

    //In your build.gradle
allprojects {
    repositories {
        ...
		maven { url 'https://jitpack.io' }
    }
}


//In your application's build.gradle

    dependencies {
	        implementation 'com.github.Collabalist:RetroLet:1.5'
	}

    【讨论】：

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