断点续传
异步主类
异步
public class MyAsyncTask1 extends AsyncTask<String,Integer,String> {
private Context context
;
private List
<JavaBean.DataBean> list
;
private ProgressDialog progressDialog
;
private String path
;
private long maxLen
;
private long start
;
public MyAsyncTask1(Context context
, List
<JavaBean.DataBean> list
, String path
) {
this.context
= context
;
this.list
= list
;
this.path
= path
;
progressDialog
=new ProgressDialog(context
);
progressDialog
.setProgressStyle(ProgressDialog
.STYLE_HORIZONTAL
);
progressDialog
.setTitle("正在下载");
progressDialog
.setMessage("拼命为您下载中!!");
}
@Override
protected void onPreExecute() {
super.onPreExecute();
progressDialog
.show();
}
@Override
protected String
doInBackground(String
... strings
) {
try {
URL url
= new URL(strings
[0]);
HttpURLConnection connection
= (HttpURLConnection
) url
.openConnection();
connection
.connect();
if(connection
.getResponseCode()==200) {
maxLen
= connection
.getContentLength();
}
} catch (IOException e
) {
e
.printStackTrace();
}
File file1
= new File(path
);
if (file1
.exists()){
start
=file1
.length();
}else {
start
=0;
}
try {
URL url
= new URL(strings
[0]);
HttpURLConnection connection
= (HttpURLConnection
) url
.openConnection();
connection
.setRequestProperty("Range","bytes="+start
+"-"+maxLen
);;
connection
.connect();
if(connection
.getResponseCode()==206) {
InputStream is
= connection
.getInputStream();
File file3
= new File(path
);
RandomAccessFile rw
= new RandomAccessFile(file3
, "rw");
rw
.seek(start
);
int len
=0;
byte[] b
= new byte[1024];
long curLen
=start
;
while ((len
=is
.read(b
))!=-1){
rw
.write(b
,0,len
);
try {
Thread
.sleep(500);
} catch (InterruptedException e
) {
e
.printStackTrace();
}
curLen
+=len
;
int progress
= (int) ((curLen
*100)/maxLen
);
publishProgress(progress
);
}
}
} catch (IOException e
) {
e
.printStackTrace();
}
return null
;
}
@Override
protected void onProgressUpdate(Integer
... values
) {
super.onProgressUpdate(values
);
progressDialog
.setProgress(values
[0]);
}
@Override
protected void onPostExecute(String s
) {
super.onPostExecute(s
);
if (progressDialog
.getProgress()==100){
progressDialog
.dismiss();
Toast
.makeText(context
, "下载完毕", Toast
.LENGTH_SHORT
).show();
}else {
File file1
= new File(path
);
if (file1
.exists()){
progressDialog
.dismiss();
Toast
.makeText(context
, "已存在", Toast
.LENGTH_SHORT
).show();
}
}
}
}
主类
public class MainActivity extends AppCompatActivity {
private ListView lv1
;
private MyAdapter myAdapter
;
private List
<JavaBean.DataBean> list
= new ArrayList<>();
private Button dian
;
private static final String TAG
= "MainActivity";
private String path
="/storage/emulated/0/Pictures/";
@Override
protected void onCreate(Bundle savedInstanceState
) {
super.onCreate(savedInstanceState
);
setContentView(R
.layout
.activity_main
);
requestPermissions(new String[]{Manifest
.permission
.READ_EXTERNAL_STORAGE
,Manifest
.permission
.WRITE_EXTERNAL_STORAGE
},100);
}
private void initView() {
lv1
= (ListView
) findViewById(R
.id
.lv_1
);
dian
= (Button
) findViewById(R
.id
.dian
);
new MyAsyncTask(MainActivity
.this, list
).execute("http://www.qubaobei.com/ios/cf/dish_list.php?stage_id=1&limit=20&page=1");
dian
.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v
) {
dian
.setVisibility(View
.GONE
);
myAdapter
= new MyAdapter(MainActivity
.this, list
);
Log
.d(TAG
, "onClick: "+list
);
lv1
.setAdapter(myAdapter
);
}
});
lv1
.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView
<?> parent
, View view
, final int position
, long id
) {
AlertDialog
.Builder builder
=new AlertDialog.Builder(MainActivity
.this);
builder
.setTitle("下载吗?老弟");
builder
.setMessage("是否下载图片?");
builder
.setPositiveButton("确认", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog
, int which
) {
new MyAsyncTask1(MainActivity
.this,list
,path
+"第"+position
+"图.jpg").execute(list
.get(position
).getPic());
}
}).setNegativeButton("取消", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog
, int which
) {
}
}).show();
}
});
}
@Override
public void onRequestPermissionsResult(int requestCode
, @NonNull String
[] permissions
, @NonNull int[] grantResults
) {
super.onRequestPermissionsResult(requestCode
, permissions
, grantResults
);
if (requestCode
==100 && grantResults
[0]== PackageManager
.PERMISSION_GRANTED
){
initView();
}else {
finish();
}
}
}
