android6.0下载路径设置

android6.0下载文件路径设置

最近有很多朋友问我，android6.0下载文件怎样设置文件的保存路径。今天就把android6.0下载文件路径设置总结一下。

在android 6.0以前，你可以只关注外置存储是否挂载即可，并且可以直接在sdcard目录下创建“xxx”文件夹保存下载的文件（例如下载一张图片a.jpg到sdcar“xxx”文件夹下，我们只需要在清单文件中配置对sdcard读写权限，就可以设置下载路径“mnt/sdcard/xxx/a.jpg”）。但是从6.0以后，也就是M系统后，还需要判断是否有读写权限，只有具备这些权限才可以读写外置存储。并且要通过这个方法：Environment.getExternalStorageDirectory（）获取路径：/storage/emulated/0
默认存在，声明权限则可读写（6.0和以后系统还需要向用户申请同意才可以）。
下面直接上代码：
Java代码：

package com.hc.android6.download;
import android.os.Environment;
import android.os.Handler;
import android.os.Message;
import android.os.SystemClock;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.ProgressBar;
import android.widget.Toast;
import org.hpg.weather.download.R;
import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URL;
import java.net.URLConnection;


public class MainActivity extends ActionBarActivity {
private final int TODOWN = 1;
private static final String TAG = "hc";
private File file1;
private int contentLength;
private Handler mhandler = new Handler() {
    @Override
    public void handleMessage(Message msg) {
        switch (msg.what) {
            case TODOWN:
//                设置下载进度条的进度
                if (file1.length() == contentLength) {
                    Toast.makeText(getApplicationContext(), "下载完成", Toast.LENGTH_SHORT).show();
//                        隐藏进度条
                    mprogressBar.setVisibility(View.GONE);
                } else {

                    setmprogressbar();

                }
                break;
        }
    }
};

private void setmprogressbar() {
    mprogressBar.setProgress((int) file1.length());
}

String hcUrl = "http://p1.so.qhmsg.com/t016269623a51ead026.jpg";
private Button button;
private ProgressBar mprogressBar;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    button = (Button) findViewById(R.id.download);
    mprogressBar = (ProgressBar) findViewById(R.id.progressBar);
    button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            new Thread(new Runnable() {
                @Override
                public void run() {
                    download();
                }
            }).start();
        }
    });
}


//下载
private void download() {
    Message message = new Message();
    message.what = TODOWN;
    try {
        URL url = new URL(hcUrl);
        //打开连接
        URLConnection conn = url.openConnection();
        //打开输入流
        InputStream is = conn.getInputStream();
        //获得长度
        contentLength = conn.getContentLength();
        mprogressBar.setMax(contentLength);
        Log.e(TAG, "contentLength = " + contentLength);
        //创建文件夹 HC，在存储卡下
        String dirName = Environment.getExternalStorageDirectory() + "/HC/";
        File file = new File(dirName);
        //不存在创建
        if (!file.exists()) {
            file.mkdir();
        }
        //下载后的文件名
        String fileName = dirName + "hcdown.jpg";
        file1 = new File(fileName);
        if (file1.exists()) {
            file1.delete();
        }
        //创建字节流
        byte[] bs = new byte[1024];
        int len;
        OutputStream os = new FileOutputStream(fileName);
        //写数据
        while ((len = is.read(bs)) != -1) {
            os.write(bs, 0, len);
            mhandler.sendEmptyMessage(TODOWN);
            SystemClock.sleep(100);

        }
        //完成后关闭流
        Log.e(TAG, "download-finish");
        Log.e(TAG, file1.length() + "");
        os.close();
        is.close();
    } catch (Exception e) {
        e.printStackTrace();
    }
}
}

xml布局文件

<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.hc.android6.download.MainActivity">

<Button
    android:layout_marginTop="10dp"
    android:id="@+id/download"
    android:text="开始下载图片"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content" />

<ProgressBar
    android:layout_below="@+id/download"
    android:layout_marginTop="10dp"
    style="?android:attr/progressBarStyleHorizontal"
    android:layout_width="match_parent"
    android:layout_height="5dp"
    android:id="@+id/progressBar" />
</RelativeLayout>