AndroidStudio——網絡圖片的讀取與保存

SaveImageViewActivity：

public class SaveImageViewActivity extends AppCompatActivity {

    private ImageView img, showImg;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_save_image_view);
        img = (ImageView) findViewById(R.id.img);
        showImg = (ImageView) findViewById(R.id.showImg);
    }

    public void readImg(View v) {
        String path = Environment.getExternalStorageDirectory() + "/1.png";
        //方法1：根據URI 加載圖片
        //showImg.setImageURI(Uri.parse(path));

        /*
        方法2：通過BitmapFactory 的靜態方法decodeFile()
        參數爲圖片路徑
         */
        Bitmap bitmap = BitmapFactory.decodeFile(path);
        showImg.setImageBitmap(bitmap);
        /*
        方法3：通過BitmapFactory 的靜態方法decodeStream()
        參數爲 輸入流 InputStream

        try {
            BitmapFactory.decodeStream(new FileInputStream(path));
            showImg.setImageBitmap(bitmap);
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
       */

    }
    //佈局監聽   參數View v一定要寫
    //保存圖片到SD卡
    public void saveImg(View v) {
        //獲取BitmapDrawable對象
        BitmapDrawable bitmapDrawable = (BitmapDrawable) img.getDrawable();
        Bitmap bitmap = bitmapDrawable.getBitmap();
        /*
        通過Bitmap(位圖)壓縮的方法（compress）保存圖片到SD卡
        參數1:圖片格式（PNG JPEJ WEBP）
        參數2：圖片質量（0-100）
        參數3：輸出流
         */
        //取得SD卡根目錄
        File root = Environment.getExternalStorageDirectory();
        FileOutputStream fos = null;
        try {
            fos = new FileOutputStream(root + "/1.png");
            bitmap.compress(Bitmap.CompressFormat.PNG, 100, fos);

        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } finally {
            if (fos != null) {
                try {
                    fos.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }

    //從網絡獲取圖片
    public void getUrlImg(View v) {
        new GetImg().execute("http://img2.imgtn.bdimg.com/it/u=169341381,1292926655&fm=21&gp=0.jpg");
    }

    public  void saveHttpImg(View v){
        new SaveHttpImg().execute("http://img2.imgtn.bdimg.com/it/u=169341381,1292926655&fm=21&gp=0.jpg");
    }

    public class GetImg extends AsyncTask<String, Void, Bitmap> {

        @Override
        protected Bitmap doInBackground(String... params) {
            HttpURLConnection con = null;
            //拿數據
            InputStream is = null;
            try {
                URL url=new URL(params[0]);
                con= (HttpURLConnection) url.openConnection();
                con.setConnectTimeout(5000);
                con.setReadTimeout(5*1000);
                if (con.getResponseCode()==200){
                    is=con.getInputStream();
                    Bitmap bitmap = BitmapFactory.decodeStream(is);
                    return bitmap;
                }
            } catch (MalformedURLException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }finally {
                if (is!=null){
                    try {
                        is.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
                if (con!=null){
                    con.disconnect();
                }
            }
            return null;
        }

        @Override
        protected void onPostExecute(Bitmap bitmap) {
            super.onPostExecute(bitmap);
            showImg.setImageBitmap(bitmap);
        }
    }

    public class SaveHttpImg extends AsyncTask<String,Void,String>{

        @Override
        protected String doInBackground(String... strings) {
            HttpURLConnection con = null;
            InputStream is = null;
            try {
                URL url = new URL(strings[0]);
                con = (HttpURLConnection) url.openConnection();
                con.setConnectTimeout(5*1000);
                con.setReadTimeout(5*1000);
                File root = Environment.getExternalStorageDirectory();
                FileOutputStream fos = new FileOutputStream(root+"/http.jpg");
                if(con.getResponseCode()==200){
                    is = con.getInputStream();
                    int next=0;
                    byte[] bytes = new byte[1024];
                    while ( (next = is.read(bytes))>0){
                        fos.write(bytes,0,next);
                    }
                    fos.flush();
                    fos.close();
                    return  root+"/http.jpg";
                }
            } catch (MalformedURLException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            } finally {
                if(is!=null){
                    try {
                        is.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
                if(con!=null){
                    con.disconnect();
                }
            }
            return "";
        }

        @Override
        protected void onPostExecute(String s) {
            super.onPostExecute(s);
            if(!s.equals("")){
                Toast.makeText(SaveImageViewActivity.this, "保存路徑:" + s, Toast.LENGTH_SHORT).show();
            }else{
                Toast.makeText(SaveImageViewActivity.this,"保存失敗:",Toast.LENGTH_SHORT).show();
            }
        }
    }

}

activity_save_image_view佈局文件

<?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:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.example.dell.jreduch008.SaveImageViewActivity">

    <ImageView
        android:id="@+id/img"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:src="@mipmap/ic_launcher" />

    <LinearLayout
        android:id="@+id/ll1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@+id/img"
        android:orientation="horizontal">

        <Button
            android:id="@+id/read"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentEnd="true"
            android:layout_alignTop="@+id/save"
            android:layout_weight="1"
            android:onClick="readImg"
            android:text="讀取圖片" />

        <Button
            android:id="@+id/save"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_below="@+id/img"
            android:layout_weight="1"
            android:onClick="saveImg"
            android:text="保存圖片" />
    </LinearLayout>

    <LinearLayout
        android:id="@+id/ll2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@+id/ll1"
        android:orientation="horizontal">

        <Button
            android:id="@+id/readUrl"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_below="@+id/img"
            android:layout_weight="1"
            android:onClick="getUrlImg"
            android:text="獲取網絡圖片"/>

        <Button
            android:id="@+id/saveImg"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_below="@+id/img"
            android:layout_weight="1"
            android:onClick="saveHttpImg"
            android:text="保存網絡圖片"/>
    </LinearLayout>

    <ImageView
        android:id="@+id/showImg"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_alignParentStart="true"
        android:layout_below="@+id/ll2" />
</RelativeLayout>