Android Studio学习路程

Posted 2021-03-10 mashuxia

今天学习怎样调用互联网的API，下面是一些代码：

  1 package com.example.hp.app3;
  2 
  3 /*
  4 学会调用互联网API（公共的）
  5  */
  6 
  7 import android.os.Bundle;
  8 import android.os.Handler;
  9 import android.os.Message;
 10 import android.support.v7.app.ActionBarActivity;
 11 import android.util.Log;
 12 import android.view.View;
 13 import android.widget.TextView;
 14 
 15 import java.io.BufferedReader;
 16 import java.io.InputStream;
 17 import java.io.InputStreamReader;
 18 import java.net.HttpURLConnection;
 19 import java.net.URL;
 20 
 21 public class MainActivity extends ActionBarActivity implements View.OnClickListener {
 22     private  int GET_DATA_SUCCESS = 101;//获取信息成功的标志
 23     private TextView mTvShow;
 24     private BufferedReader bufferedreader;
 25     private InputStream inputstream;
 26     private StringBuilder stringBuilder;
 27     private HttpURLConnection connection;
 28 
 29     //多线程传输数据  Handler
 30     Handler mHandler = new Handler(new Handler.Callback() {
 31         @Override
 32         public boolean handleMessage(Message message) {
 33             if(message.what==GET_DATA_SUCCESS){
 34              String data = message.getData().getString("data");
 35                 Log.i("MainActivity",data);
 36                 mTvShow.setText(data);
 37             }
 38             return false;
 39         }
 40     });
 41 
 42     @Override
 43     protected void onCreate(Bundle savedInstanceState) {
 44         super.onCreate(savedInstanceState);
 45         setContentView(R.layout.activity_main);
 46 
 47         //初始化控件
 48         initUI();
 49         //初始化数据
 50         initData();
 51     }
 52 
 53     private void initUI() {
 54         //获取文本框
 55        mTvShow = (TextView) findViewById(R.id.tv_show);
 56         //获取按钮
 57         findViewById(R.id.btn).setOnClickListener(this);
 58     }
 59 
 60     @Override
 61     public void onClick(View view) {
 62         //初始化数据
 63         initData();
 64     }
 65 
 66     private void initData() {
 67         //请求网络（创建一个主线程，否则数据太多过不来）
 68         new Thread(new Runnable() {
 69 
 70             @Override
 71             public void run() {
 72                 //定义一个方法，从服务器获取数据。
 73                 String data = getDataFromServer();
 74                 //创建信息对象
 75                 Message message = Message.obtain();
 76                 Bundle bundle = new Bundle();
 77                 bundle.putString("data",data);
 78                 message.setData(bundle);
 79                 //设置一个标志：
 80                 message.what = GET_DATA_SUCCESS;
 81 
 82                 //向主线程发信息
 83                 mHandler.sendMessage(message);
 84             }
 85 
 86         }).start();
 87     }
 88     //从服务器获取数据
 89     private String getDataFromServer() {
 90         try{
 91             //1.创建一个URL
 92             URL url = new URL("https://v1.hitokoto.cn/?c=f&encode=text");
 93             //2.打开链接
 94             connection = (HttpURLConnection) url.openConnection();
 95             //3.判断并处理结果
 96             if(connection.getResponseCode()==200){
 97                 //获取链接的输入流
 98               inputstream = connection.getInputStream();
 99                 
100               //判断读取的数据
101                 bufferedreader = new BufferedReader(new InputStreamReader(inputstream));
102                 stringBuilder=new StringBuilder();
103                 for(String line = "";(line=bufferedreader.readLine())!=null;){
104                     stringBuilder.append(line);
105                 }
106                 return stringBuilder.toString();
107             }
108 
109         }catch(Exception e){
110             e.printStackTrace();
111         }finally {
112             try{
113                if(inputstream!=null)inputstream.close();
114                 if(bufferedreader!=null)bufferedreader.close();
115                 if(connection!=null)connection.disconnect();
116             }catch(Exception e){
117                 e.printStackTrace();
118             }
119         }
120 
121         return "";
122 
123     }
124 }

 1 <?xml version="1.0" encoding="utf-8"?>
 2 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
 3     xmlns:tools="http://schemas.android.com/tools"
 4     android:layout_width="match_parent"
 5     android:layout_height="match_parent"
 6     android:paddingBottom="@dimen/activity_vertical_margin"
 7     android:paddingLeft="@dimen/activity_horizontal_margin"
 8     android:paddingRight="@dimen/activity_horizontal_margin"
 9     android:paddingTop="@dimen/activity_vertical_margin"
10     tools:context="com.example.hp.app3.MainActivity">
11 
12     <TextView
13         android:id="@+id/tv_show"
14         android:textSize="16dp"
15         android:background="@android:color/holo_blue_bright"
16         android:layout_width="wrap_content"
17         android:layout_height="wrap_content"
18         android:text="Hello World!" />
19 
20     <Button
21         android:id="@+id/btn"
22         android:text="                              刷新数据"
23         android:textSize="20dp"
24         android:layout_width="match_parent"
25         android:layout_height="40dp"
26         android:layout_centerVertical="true"
27         android:layout_alignParentLeft="true"
28         android:layout_alignParentStart="true" />
29 </RelativeLayout>

 1 <?xml version="1.0" encoding="utf-8"?>
 2 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
 3     package="com.example.hp.app3">
 4     
 5     //需要添加：
 6    <uses-permission android:name="android.permission.INTERNET">
 7 
 8    </uses-permission>
 9 
10     <application
11         android:allowBackup="true"
12         android:icon="@mipmap/ic_launcher"
13         android:label="@string/app_name"
14         android:supportsRtl="true"
15         android:theme="@style/AppTheme">
16         <activity android:name=".MainActivity">
17             <intent-filter>
18                 <action android:name="android.intent.action.MAIN" />
19 
20                 <category android:name="android.intent.category.LAUNCHER" />
21             </intent-filter>
22         </activity>
23     </application>
24 
25 </manifest>