Android studio 网络下载图片并保存sdcard download 文件夹下_android studio向sd卡内保存图片

第一步在手机中设置存储sdcard权限

第二步AndroidManifest.xml
   <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />

第三步：activity-main.xml
  <SeekBar
        android:id="@+id/seekbar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:progress="50"/>
    <ImageView
        android:id="@+id/image"
        android:layout_width="match_parent"
        android:layout_height="150dp"
        android:scaleType="center"/>

第四步MainActivity.Java

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Environment;
import android.os.Handler;
import android.os.Message;
import android.os.Bundle;
import android.util.Log;
import android.widget.ImageView;
import android.widget.SeekBar;


import androidx.appcompat.app.AppCompatActivity;

import java.io.BufferedInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.net.URLConnection;


public class MainActivity extends AppCompatActivity {

    private SeekBar mSeekBar;
    private  final String urlString = "http://192.168.0.134:280/AA.jpg";
    private ImageView mIV;
    private int fileLength;
    private Bitmap mBitmap;

    public static void saveBitmap(Bitmap bitmap,String path) {
        String savePath;
        File filePic;
        if (Environment.getExternalStorageState().equals(
                Environment.MEDIA_MOUNTED)) {
            savePath = path;
        } else {
            Log.e("tag", "saveBitmap failure : sdcard not mounted");
            return;
        }
        try {
            filePic = new File(savePath);
            if (!filePic.exists()) {
                filePic.getParentFile().mkdirs();
                filePic.createNewFile();
            }
            FileOutputStream fos = new FileOutputStream(filePic);
            bitmap.compress(Bitmap.CompressFormat.JPEG, 100, fos);
            fos.flush();
            fos.close();
        } catch (IOException e) {
            Log.e("tag", "saveBitmap: " + e.getMessage());
            return;
        }
        Log.i("tag", "saveBitmap success: " + filePic.getAbsolutePath());
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mSeekBar = (SeekBar)findViewById(R.id.seekbar);
        mIV = (ImageView)findViewById(R.id.image);
        new Thread(downloadRunn).start();
    }
    private Runnable downloadRunn = new  Runnable(){
        @Override
        public void run() {
            try {
                String filepath="/sdcard/Download/xxxx20200601.jpg";
                URL url = new URL(urlString);
                URLConnection connection = url.openConnection();
                connection.connect();
                fileLength = connection.getContentLength();
                InputStream in = new BufferedInputStream(connection.getInputStream());
                byte[] arr = readStream(in);
                mBitmap = BitmapFactory.decodeByteArray(arr,0,arr.length);
                //测试保护文件函数代码
                saveBitmap(mBitmap,filepath);
                //
                connectHanlder.sendEmptyMessage(0);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    };
    public  byte[] readStream(InputStream in) throws Exception{
        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        byte data[] = new byte[1024];
        long total = 0;
        int count;
        while((count = in.read(data))!=-1){
            total+=count;
            mSeekBar.setProgress((int)(total*100)/fileLength);
            bos.write(data,0,count);
        }
        bos.close();
        in.close();
        return bos.toByteArray();
    }
    private Handler connectHanlder = new Handler() {
        @Override
        public void handleMessage(Message msg) {
            // 更新UI，显示图片
            if (mBitmap != null) {
                mIV.setImageBitmap(mBitmap);// display image
            }
        }
    };
}








1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140