文件下载思路
1.首先获取手机或者设备目录
2.创建一个新的目录
3.往新建目录写数据流
4.关闭流
下载.gif
首先获取根目录 创建新目录 （代码在下面复制）
image.png
image.png
getExternalFilesDir(Environment.DIRECTORY_DOWNLOADS).getAbsolutePath();
private void downLoad(String urlAddress,String downAdress) {
try {
File file = new File(downAdress+"/downAPK");
Log.i(TAG, "file path: "+file.getAbsolutePath());
if (!file.exists()){
file.mkdirs();
Log.i(TAG, "file path on create ");
}
}catch (Exception ex){
}
}
以上走完我们查看log，发现已经创建成功。我们在模拟器上查下位置！
image.png
image.png
接下来就是写IO流的一些操作
private void downLoad(String urlAddress, String downAdress) {
try {
HttpURLConnection coon = (HttpURLConnection) new URL(urlAddress).openConnection();
coon.setConnectTimeout(6000);
String fileAddress = coon.getURL().getFile();
String fileName = fileAddress.substring(fileAddress.lastIndexOf(File.separatorChar) + 1);
File file = new File(downAdress );
if (!file.exists()) {
file.mkdirs();
Log.i(TAG, "file path on create ");
}
file = new File(file+fileName);
if (!file.exists()){
file.delete();
}
InputStream is = coon.getInputStream();
FileOutputStream fos = new FileOutputStream(file);
BufferedInputStream bis = new BufferedInputStream(is);
byte[] bytes = new byte[1024];
int size;
int len = 0;
while ((size = bis.read(bytes)) != -1) {
len += size;
fos.write(bytes, 0, size);
Log.i(TAG, "下载进度: " + len * 100 / coon.getContentLength() + "%");
Message mg = Message.obtain();
mg.obj =len * 100 / coon.getContentLength();
downHandler.sendMessage(mg);
}
fos.close();
bis.close();
is.close();
} catch (Exception ex) {
ex.printStackTrace();
}
}
下载部分全部代码如下
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.test.filedownload">
<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.READ_SETTINGS" />
<uses-permission android:name="android.permission.WRITE_SETTINGS" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
<application
android:usesCleartextTraffic="true"
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:roundIcon="@mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context=".MainActivity">
<Button
android:id="@+id/bt_download"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:onClick="btOnClick"
android:text="文件下载" />
<Button
android:id="@+id/bt_pause"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:onClick="btOnClick"
android:text="暂停" />
<Button
android:id="@+id/bt_goon"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:onClick="btOnClick"
android:text="继续下载" />
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<ProgressBar
android:id="@+id/pb"
style="@style/Widget.AppCompat.ProgressBar.Horizontal"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginRight="20dp"
android:layout_toLeftOf="@id/tv_jindu" />
<TextView
android:id="@+id/tv_jindu"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:text="20%" />
</RelativeLayout>
</LinearLayout>
package com.test.filedownload;
import android.os.Bundle;
import android.os.Environment;
import android.os.Handler;
import android.os.Message;
import android.util.Log;
import android.view.View;
import android.widget.ProgressBar;
import android.widget.TextView;
import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
public class MainActivity extends AppCompatActivity {
private ProgressBar pb;
private TextView tvJindu;
private static String TAG = "main";
private Handler downHandler = new Handler(){
@Override
public void handleMessage(@NonNull Message msg) {
super.handleMessage(msg);
int str= (int) msg.obj;
pb.setProgress(str);
tvJindu.setText(str+"%");
}
};
private String absolutePath;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initView();
absolutePath = getExternalFilesDir(Environment.DIRECTORY_DOWNLOADS).getAbsolutePath();
String rootFilePath = getRootFilePath();
Log.i(TAG, "onCreate: "+ absolutePath);
Log.i(TAG, "onCreate: "+rootFilePath);
}
public void btOnClick(View view) {
switch (view.getId()){
case R.id.bt_download:
new DownLoadThread(absolutePath,downHandler).start();
break;
case R.id.bt_pause:
break;
case R.id.bt_goon:
break;
}
}
private void initView() {
pb = (ProgressBar) findViewById(R.id.pb);
tvJindu = (TextView) findViewById(R.id.tv_jindu);
}
//找到手机中内置存储卡的根目录
public static String getRootFilePath() {
/***
* getExternalStorageDirectory() 返回主共享/外部存储目录
* getAbsolutePath() 返回此文件的绝对路径
* getDataDirectory() 返回用户数据目录
*/
if (hasSDCard()) {
return Environment.getExternalStorageDirectory().getAbsolutePath() + "";
} else {
return Environment.getDataDirectory().getAbsolutePath() + "/data";
}
}
//上面需要判断用的方法
public static boolean hasSDCard() {
/***
* Environment 提供对环境变量的访问。
* getExternalStorageState() 返回主共享/外部存储介质的当前状态。
* Environment.MEDIA_MOUNTED mounted 安装
*/
String status = Environment.getExternalStorageState();
Log.i(TAG, "status---->>: " + status);
if (!status.equals(Environment.MEDIA_MOUNTED)) {
return false;
}
return true;
}
}
package com.test.filedownload;
import android.os.Looper;
import android.os.Message;
import android.util.Log;
import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import android.os.Handler;
public class DownLoadThread extends Thread {
// private String urlAddress = "http://192.168.0.110/ChaoyangHygiene.apk";
private String urlAddress = "http://192.168.1.12/ChaoyangHygiene.apk";//这个地址你换成自己的就行
private String downAddress;
private Handler downHandler;
private String TAG = "down";
public DownLoadThread(String downAdress, Handler downHandler) {
this.downAddress = downAdress;
this.downHandler = downHandler;
}
@Override
public void run() {
super.run();
downLoad(urlAddress, downAddress);
}
private void downLoad(String urlAddress, String downAdress) {
try {
HttpURLConnection coon = (HttpURLConnection) new URL(urlAddress).openConnection();
coon.setConnectTimeout(6000);
String fileAddress = coon.getURL().getFile();
String fileName = fileAddress.substring(fileAddress.lastIndexOf(File.separatorChar) + 1);
File file = new File(downAdress );
if (!file.exists()) {
file.mkdirs();
Log.i(TAG, "file path on create ");
}
file = new File(file+fileName);
if (!file.exists()){
file.delete();
}
InputStream is = coon.getInputStream();
FileOutputStream fos = new FileOutputStream(file);
BufferedInputStream bis = new BufferedInputStream(is);
byte[] bytes = new byte[1024];
int size;
int len = 0;
while ((size = bis.read(bytes)) != -1) {
len += size;
fos.write(bytes, 0, size);
Log.i(TAG, "下载进度: " + len * 100 / coon.getContentLength() + "%");
Message mg = Message.obtain();
mg.obj =len * 100 / coon.getContentLength();
downHandler.sendMessage(mg);
}
fos.close();
bis.close();
is.close();
} catch (Exception ex) {
ex.printStackTrace();
}
}
}
网友评论