Android数据存储：获取网络图片把图片保存到SD卡中并从SDk卡中读取（通过Bitmap方法）

来源：互联网发布：小程序 video.js 编辑：程序博客网时间：2024/05/29 07:43
1、把从布局中获得的图片保存到SD卡中，并把图片在从SD卡中读取出来
2、从网络上获取一张图片的地址，把图片保存到SD卡中，并把网络图片读取出来
程序代码：
package com.example.administrator.jreduch08;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.graphics.drawable.BitmapDrawable;import android.os.AsyncTask;import android.os.Bundle;import android.os.Environment;import android.support.v7.app.AppCompatActivity;import android.view.View;import android.widget.ImageView;import android.widget.Toast;import java.io.File;import java.io.FileOutputStream;import java.io.IOException;import java.io.InputStream;import java.net.HttpURLConnection;import java.net.MalformedURLException;import java.net.URL;public class SaveImageViewToSdActivity extends AppCompatActivity {    private ImageView img;    private ImageView showImg;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_save_image_view_to_sd);        img = (ImageView) findViewById(R.id.img);        showImg = (ImageView) findViewById(R.id.showImg);    }//从网络获取图片    public void getUrlImg(View view) {        new GetImg().execute("http://www.ichong123.com/files/2016/8/11/44/7.jpg");    }    //保存网络图片（边读边写，同时进行）    public void saveUrlImg(View view){        new SaveHttpImg().execute("http://www.ichong123.com/files/2016/8/11/134/8.jpg");    }    public class SaveHttpImg extends AsyncTask<String,Void,String>{        @Override        protected String doInBackground(String... strings) {            HttpURLConnection con = null;//访问网络            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");                /*http 响应吗                 * 200：成功                 * 404：未找到                 * 500：发生错误                 */                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 "";        }        // onPostExecute在UI线程中执行命令        @Override        protected void onPostExecute(String  s) {            super.onPostExecute(s);            if(!s.equals("")){                Toast.makeText(SaveImageViewToSdActivity.this,"保存路径",Toast.LENGTH_SHORT).show();            }else{                Toast.makeText(SaveImageViewToSdActivity.this,"保存路径失败",Toast.LENGTH_SHORT).show();            }        }        } //读取图片    public void readImg(View view) {        String path = Environment.getExternalStorageDirectory() + "/img.png";        //方法一：根据URI加载图片        // showImg.setImageURI(Uri.parse(path));        //方法二：通过BitmapFactory的静态方法decodeFile（）参数为图片路径        Bitmap bitmap = BitmapFactory.decodeFile(path);        showImg.setImageBitmap(bitmap);        /*//方法三：通过BitmapFactory的静态方法decodeFile（）参数为输入流 Inputstream        try {            BitmapFactory.decodeStream(new FileInputStream(path));        } catch (FileNotFoundException e) {            e.printStackTrace();        }*/    }//保存图片    public void saveImg(View view) {        BitmapDrawable bitmapDrawable = (BitmapDrawable) img.getDrawable();        //得到图片        Bitmap bitmap = bitmapDrawable.getBitmap();        /*通过Bitmap(位图）压缩的方法（compress）保存图片到SD卡       参数1：图片格式（ PNG JPEG WEBP）       参数2：图片质量（1-100）       参数3：输出流        * */        String statu = Environment.getExternalStorageState();        if (!statu.equals(Environment.MEDIA_MOUNTED)) {            Toast.makeText(getBaseContext(), "SD卡未就绪", Toast.LENGTH_SHORT).show();            return;        }        File file = Environment.getExternalStorageDirectory();        FileOutputStream fos = null;        try {            fos = new FileOutputStream(file.getCanonicalPath() + "/img.png");            bitmap.compress(Bitmap.CompressFormat.PNG, 100, fos);            Toast.makeText(getBaseContext(), "保存成功", Toast.LENGTH_SHORT).show();        } catch (IOException e) {            e.printStackTrace();        } finally {            if (fos != null) {                try {                    fos.close();                    fos.flush();                } catch (IOException e) {                    e.printStackTrace();                }            }        }    }    public class GetImg extends AsyncTask<String, Void, Bitmap> {        @Override        protected Bitmap doInBackground(String... strings) {            HttpURLConnection con = null;//访问网络            InputStream is = null;            Bitmap bitmap = null;            try {                URL url = new URL(strings[0]);                con = (HttpURLConnection) url.openConnection();                con.setConnectTimeout(5 * 1000);                con.setReadTimeout(5 * 1000);                /*http 响应吗                 * 200：成功                 * 404：未找到                 * 500：发生错误                 */                if (con.getResponseCode() == 200) {                    is = con.getInputStream();                    bitmap = BitmapFactory.decodeStream(is);                    return bitmap;                }            } catch (MalformedURLException e) {                e.printStackTrace();            } catch (IOException e) {                e.printStackTrace();            } finally {                try {                    is.close();                } catch (IOException e) {                    e.printStackTrace();                }                if (con != null) {                    con.disconnect();                }            }            return null;        }        // onPostExecute在UI线程中执行命令        @Override        protected void onPostExecute(Bitmap bitmap) {            super.onPostExecute(bitmap);            showImg.setImageBitmap(bitmap);        }    }}
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