android6.0文件存储权限问题

在Manifest中也要加入权限，不加也会出问题

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

SDFile

package com.chuanxidemo.shaoxin.demo06;

import android.Manifest;
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.os.Environment;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

/**
 * Created by shaoxin on 2017/2/23.
 */

public class SDFile extends AppCompatActivity {
    private Button sdread;
    private Button sdwrite;
    private FileOutputStream outputStream;
    private static int REQUEST_EXTERNAL_STRONGE = 1;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.sdfile);
        sdread = (Button) findViewById(R.id.sdread);
        sdwrite = (Button) findViewById(R.id.sdwrite);
        sdread.setOnClickListener(new MyClick());
        sdwrite.setOnClickListener(new MyClick());

    }
//申请权限的方法包装，与clock 中的if语句的内容作用一样
//    public static void verifyStoragePermissions(Activity activity) {
//
//        if (ContextCompat.checkSelfPermission(activity, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
//            ActivityCompat.requestPermissions(activity, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE, Manifest.permission.READ_EXTERNAL_STORAGE}, REQUEST_EXTERNAL_STRONGE);
//        }//REQUEST_EXTERNAL_STRONGE是自定义个的一个对应码，用来验证请求是否通过
//    }


    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
//根据请求是否通过的返回码进行判断，然后进一步运行程序
        if (grantResults.length > 0 && requestCode == REQUEST_EXTERNAL_STRONGE && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
            writerSD();
        }

    }


    public class MyClick implements View.OnClickListener {

        @Override
        public void onClick(View v) {
            switch (v.getId()) {
                case R.id.sdwrite:
                    //获取SD路径
                    //判断是否有SD卡
                    if (ContextCompat.checkSelfPermission(SDFile.this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
                        ActivityCompat.requestPermissions(SDFile.this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE, Manifest.permission.READ_EXTERNAL_STORAGE}, REQUEST_EXTERNAL_STRONGE);
                    }//REQUEST_EXTERNAL_STRONGE是自定义个的一个对应码，用来验证请求是否通过
                    else {
                        writerSD();
                    }
                    break;
                case R.id.sdread:
                    break;
            }
        }
    }

//封装了数据写入SD卡的方法
    public void writerSD() {
        if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {

        } else {
            Toast.makeText(SDFile.this, "SD卡不存在", Toast.LENGTH_SHORT).show();
        }
        File file = Environment.getExternalStorageDirectory();
        File newfile = new File(file, "1.txt");
        try {
            outputStream = new FileOutputStream(file);
            outputStream.write("123".getBytes());
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (outputStream != null) {
                try {
                    outputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }
}

sdfile.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">
    <Button
        android:id="@+id/sdread"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="读文件" />

    <Button
        android:id="@+id/sdwrite"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="写文件" />
</LinearLayout>