java HTTP 协议下的文件下载

java HTTP 协议下的文件下载

1. 建立HTTP的链接，返回输入流。
2. 读取输入流，写入输出流。


import java.net.*;
import java.io.*;
class demo{
public static void main(String[] args) {
HttpUtils hu = new HttpUtils("http://bizingeinoutetyou.com/bizinkisya/wp-content/uploads/2015/04/kiritanimirei_i04.jpg");
hu.saveImageToDisk();
}
}

class HttpUtils{
// private static String url_path = "http://bizingeinoutetyou.com/bizinkisya/wp-content/uploads/2015/04/kiritanimirei_i04.jpg";
private static String url_path ;
public HttpUtils(String url_path){
this.url_path = url_path;
}

public void saveImageToDisk(){
InputStream inputstream = getInputStream();
FileOutputStream fileoutputstream = null;
byte[] buff = new byte[1024];
int len = 0;
try{
fileoutputstream = new FileOutputStream("test.jpg");
while((len = inputstream.read(buff)) != -1){
fileoutputstream.write(buff,0,len);
}
}catch(Exception e){
e.printStackTrace();
}finally{
if(inputstream != null){
try{
inputstream.close();
}catch(Exception e){
e.printStackTrace();
}
}
if(fileoutputstream != null){
try{
fileoutputstream.close();
}catch(Exception e){
e.printStackTrace();
}
}
}
}


public static InputStream getInputStream(){
InputStream inputstream = null;
HttpURLConnection httpurlconnection = null;
try{
URL url = new URL(url_path);
httpurlconnection = (HttpURLConnection)url.openConnection();
httpurlconnection.setConnectTimeout(3000);
httpurlconnection.setDoInput(true);
httpurlconnection.setRequestMethod("GET");
int responseCode = httpurlconnection.getResponseCode();
if(responseCode == 200){
inputstream = httpurlconnection.getInputStream();
}
System.out.println(url.getFile());
System.out.println(httpurlconnection.getResponseCode());
}catch(MalformedURLException e){
e.printStackTrace();
}catch(IOException e){
e.printStackTrace();
}
return inputstream;
}
}

Android FileWriter,FileReader

Android FileWriter,FileReader

文件的保存位置有要求
   String path ="/data/data/" + this.getPackageName() +"/demo.txt";



import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;

public class MainActivity extends AppCompatActivity  {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        try {
            Test();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    protected void Test() throws IOException {
        final String tag = "testFile";
        String path ="/data/data/" + this.getPackageName() +"/demo.txt";
        FileWriter fileWriter = new FileWriter(path);

        for( int i = 0; i <102; i++){
            fileWriter.write(String.valueOf(i));
        }
        fileWriter.flush();
        fileWriter.close();

        FileReader fileReader = new FileReader(path);
        char[] buf = new char[24];
        int num;
        while(((num = fileReader.read(buf)) != 0)){
            System.out.println("---" + new String(buf,0,num));
        }
        fileReader.close();
    }
}

结果

com.example.java.m1031a I/System.out: ---012345678910111213141516

com.example.java.m1031a I/System.out: ---171819202122232425262728

com.example.java.m1031a I/System.out: ---293031323334353637383940

com.example.java.m1031a I/System.out: ---414243444546474849505152

com.example.java.m1031a I/System.out: ---535455565758596061626364

com.example.java.m1031a I/System.out: ---656667686970717273747576

com.example.java.m1031a I/System.out: ---777879808182838485868788

com.example.java.m1031a I/System.out: ---899091929394959697989910

com.example.java.m1031a I/System.out: ---0101

Sublime Text 利用するプラグイン

Sublime Text 利用するプラグイン

1.    PackageControl 追加
      https://packagecontrol.io/installation#Simple

2.    日本語サポートする IMESupport

3.    SFTP FTPサーバーと接続するため

4.    F5 を押すと日付を入力する insertDate

SublimeAStyleFormatter
is a simple code formatter plugin for Sublime Text 2.
It provides ability to format C, C++, C#, and Java files.

Android應用開發視頻教程

黑马程序员 毕向东 Java基础视频教程
https://www.youtube.com/playlist?list=PLvswSo32Xlu_ctuWa-7-huGYUlsslzVhi


Android應用開發視頻教程
https://www.youtube.com/playlist?list=PLvswSo32Xlu8EVeS2RZvTg30M78WLROkT

Grid View 自定义布局

Grid View 自定义布局

1.   选择 Grid View 的布局位置
2.   自定义Adapter
3.   设置数据




public class MainActivity extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        GridView gv = (GridView) findViewById(R.id.gv);
        gv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                TextView tv = (TextView) view.findViewById(R.id.grid_textview);
                String s = tv.getText().toString();
                Toast.makeText(MainActivity.this, s, Toast.LENGTH_SHORT).show();
            }
        });
        imgAdapter imgadapter = new imgAdapter();
        gv.setAdapter(imgadapter);
    }

    class imgAdapter extends BaseAdapter {
        public int getCount() {
            return mThumbIds.length;
        }

        public Object getItem(int position) {
            return null;
        }

        public long getItemId(int position) {
            return 0;
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            View v = LayoutInflater.from(getApplication()).inflate(R.layout.gridview, null);
            ImageView iv = (ImageView) v.findViewById(R.id.grid_img);
            TextView tv = (TextView) v.findViewById(R.id.grid_textview);
            iv.setImageResource(mThumbIds[position]);
            tv.setText(getString(mThumbIds[position]));
            return v;
        }

        private Integer[] mThumbIds = {
                R.drawable.sample_2, R.drawable.sample_3,
                R.drawable.sample_4, R.drawable.sample_5,
                R.drawable.sample_6, R.drawable.sample_7,
                R.drawable.sample_0, R.drawable.sample_1,
                R.drawable.sample_2, R.drawable.sample_3,
                R.drawable.sample_4, R.drawable.sample_5,
                R.drawable.sample_6, R.drawable.sample_7,
                R.drawable.sample_0, R.drawable.sample_1,
                R.drawable.sample_2, R.drawable.sample_3,
                R.drawable.sample_4, R.drawable.sample_5,
                R.drawable.sample_6, R.drawable.sample_7
        };
    }
}


Activity 布局
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/activity_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.e560.m1026gridview.MainActivity">

    <GridView
        android:id="@+id/gv"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:columnWidth="90dp"
        android:numColumns="auto_fit"
        android:verticalSpacing="10dp"
        android:horizontalSpacing="10dp"
        android:stretchMode="columnWidth"
        android:gravity="center"
        />
</RelativeLayout>


自定义布局
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

        <ImageView
            android:id="@+id/grid_img"
            android:layout_width="400dp"
            android:layout_height="140dp"
            android:background="#CCCCCC" />

        <TextView
            android:id="@+id/grid_textview"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textColor="#FFCCCC"
            android:textSize="20dp" />

</RelativeLayout>

Android 生命周期

Android 生命周期



第一次启动
MainActivity: --1--onCreate
MainActivity: --2--onStart
MainActivity: --3--onResume

跳到其他Activity
MainActivity: --4--onPause
MainActivity: --9--onSaveInstanceState
MainActivity: --5--onStop

返回键返回
MainActivity: --6--onRestart
MainActivity: --2--onStart
MainActivity: --3--onResume

接电话
MainActivity: --4--onPause
MainActivity: --9--onSaveInstanceState  有延迟

挂电话
MainActivity: --3--onResume

按返回键推出到Android界面
MainActivity: --4--onPause
MainActivity: --5--onStop
MainActivity: --7--onDestroy

重新启动
MainActivity: --1--onCreate
MainActivity: --2--onStart
MainActivity: --3--onResume

旋转屏幕
MainActivity: --4--onPause
MainActivity: --9--onSaveInstanceState
MainActivity: --5--onStop
MainActivity: --7--onDestroy
MainActivity: --1--onCreate
MainActivity: --2--onStart
MainActivity: --8--onRestoreInstanceState
MainActivity: --3--onResume

按Home键
MainActivity: --4--onPause
MainActivity: --9--onSaveInstanceState
MainActivity: --5--onStop

按APP图标开启
MainActivity: --6--onRestart
MainActivity: --2--onStart
MainActivity: --3--onResume

按Power键，关屏幕
MainActivity: --4--onPause
MainActivity: --9--onSaveInstanceState
MainActivity: --5--onStop

按Power键，开屏幕
MainActivity: --6--onRestart
MainActivity: --2--onStart
MainActivity: --3--onResume

按方块键
MainActivity: --4--onPause
MainActivity: --9--onSaveInstanceState
MainActivity: --5--onStop

按方块键，重新回到App
MainActivity: --6--onRestart
MainActivity: --2--onStart
MainActivity: --3--onResume



public class MainActivity extends AppCompatActivity {
    private final String TAG = "MainActivity";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Log.i(TAG, "--1--onCreate");

        Button bt = (Button) findViewById(R.id.button);
        bt.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(MainActivity.this, NewActivity.class);
                startActivity(intent);
            }
        });
    }

    @Override
    protected void onStart() {
        super.onStart();
        Log.i(TAG, "--2--onStart");
    }

    @Override
    protected void onResume() {
        super.onResume();
        Log.i(TAG, "--3--onResume");
    }

    @Override
    protected void onPause() {
        super.onPause();
        Log.i(TAG, "--4--onPause");
    }

    @Override
    protected void onStop() {
        super.onStop();
        Log.i(TAG, "--5--onStop");
    }

    @Override
    protected void onRestart() {
        super.onRestart();
        Log.i(TAG, "--6--onRestart");
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        Log.i(TAG, "--7--onDestroy");
    }

    @Override
    protected void onRestoreInstanceState(Bundle savedInstanceState) {
        super.onRestoreInstanceState(savedInstanceState);
        Log.i(TAG, "--8--onRestoreInstanceState");
    }

    @Override
    protected void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        Log.i(TAG,"--9--onSaveInstanceState");
    }
}

ListFragment 和自定义布局Layout

ListFragment 和自定义布局Layout

public class ListFrag extends ListFragment {

    public myadaputer adapter;
    public List<String> data;

    public void setData(List<String> data) {
        this.data = data;
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        adapter = new myadaputer();
        adapter.setDate(getdata());
    }

    public List<String> getdata(){
        Bundle ig = getArguments();
        int size = ig.getInt("size");
        List<String> x = new ArrayList<String>();
        for(int i=0;i< size ;i++) {
            x.add("add" + i);
        }
        return x;
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.listfrag_layout, null);
        setListAdapter(adapter);
        return view;
    }

    @Override
    public void onPause() {
        super.onPause();
    }

    @Override
    public void onListItemClick(ListView l, View v, int position, long id) {
        super.onListItemClick(l, v, position, id);
        Toast.makeText(getActivity(), "onListItemClick", Toast.LENGTH_SHORT).show();
    }

    class myadaputer extends BaseAdapter {
        private List<String> data;
        public void setDate(List<String> data) {
            this.data = data;
        }

        @Override
        public int getCount() {
            return data.size();
        }

        @Override
        public Object getItem(int position) {
            return data.get(position);
    }

        @Override
        public long getItemId(int position) {
            return position;
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            View view = null;
            if(convertView == null){
                view = LayoutInflater.from(getActivity()).inflate(R.layout.listview,null);
            }else{
                view = convertView;
            }
            TextView tv = (TextView) view.findViewById(R.id.textView);
            tv.setText(data.get(position).toString());
            return view;
        }
    }


}