package com.example.admin.sdapplication;import android.Manifest;import android.app.Dialog;import android.content.DialogInterface;import android.content.pm.PackageManager;import android.os.Build;import android.os.Bundle;import android.os.Environment;import android.support.annotation.NonNull;import android.support.v4.app.ActivityCompat;import android.support.v4.content.ContextCompat;import android.support.v7.app.AlertDialog;import android.support.v7.app.AppCompatActivity;import android.util.Log;import android.view.View;import android.widget.Button;import java.io.BufferedReader;import java.io.File;import java.io.FileInputStream;import java.io.FileOutputStream;import java.io.InputStreamReader;public class SdkActivity extends AppCompatActivity implements View.OnClickListener{ private Button btn_write; private Button btn_read; final int REQUEST_WRITE=1;//申請權限的請求碼 @Override protected void onCreate(Bundle savedInstanceState) {  super.onCreate(savedInstanceState);  setContentView(R.layout.activity_sdk);  btn_write= (Button) findViewById(R.id.btn_write);  btn_read= (Button) findViewById(R.id.btn_read);  btn_read.setOnClickListener(this);  btn_write.setOnClickListener(this); } private void showAlert(){  Dialog alertDialog = new AlertDialog.Builder(this).    setTitle("權限說明").    setMessage("我們需要這個權限給你提供存儲服務").    setIcon(R.drawable.ic_launcher).    setPositiveButton("確定", new DialogInterface.OnClickListener() {     @Override     public void onClick(DialogInterface dialog, int which) {      // TODO Auto-generated method stub      //2、申請權限: 參數二：權限的數組；參數三：請求碼      ActivityCompat.requestPermissions(SdkActivity.this,new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE},REQUEST_WRITE);     }    }).    setNegativeButton("取消", new DialogInterface.OnClickListener() {     @Override     public void onClick(DialogInterface dialog, int which) {      // TODO Auto-generated method stub     }    }).    create();  alertDialog.show(); } @Override public void onClick(View view) {  switch (view.getId()){   case R.id.btn_read:    String s= readToSdCard();    Log.i("readTosdCard",s);    break;   case R.id.btn_write:    //判斷是否6.0以上的手機 不是就不用    if(Build.VERSION.SDK_INT>=23){     //判斷是否有這個權限     if(ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE)!=PackageManager.PERMISSION_GRANTED){      //第一請求權限被取消顯示的判斷，一般可以不寫      if (ActivityCompat.shouldShowRequestPermissionRationale(SdkActivity.this,        Manifest.permission.WRITE_EXTERNAL_STORAGE)){       Log.i("readTosdCard","我們需要這個權限給你提供存儲服務");       showAlert();      }else {       //2、申請權限: 參數二：權限的數組；參數三：請求碼       ActivityCompat.requestPermissions(this,new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE},REQUEST_WRITE);      }     }else {      writeToSdCard();     }    } else{     writeToSdCard();    }    break;  } } //寫數據 public void writeToSdCard(){  //1、判斷sd卡是否可用  if(Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){   //sd卡可用   //2、獲取sd卡路徑   File sdFile=Environment.getExternalStorageDirectory();   File path=new File(sdFile,"a.txt");//sd卡下面的a.txt文件 參數 前面 是目錄 后面是文件   try {    FileOutputStream fileOutputStream=new FileOutputStream(path);    fileOutputStream.write("hello".getBytes());   } catch (Exception e) {    e.printStackTrace();   }  } } //讀數據 public String readToSdCard(){  StringBuilder stringBuilder = null;  if(Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){   File sdFile=Environment.getExternalStorageDirectory();   File path=new File(sdFile,"a.txt");   stringBuilder =new StringBuilder();   try {    FileInputStream fileInputStream=new FileInputStream(path);    BufferedReader bufferedReader=new BufferedReader(new InputStreamReader(fileInputStream));    String str;    while ((str=bufferedReader.readLine())!=null){     stringBuilder.append(str);    }   } catch (Exception e) {    e.printStackTrace();   }  }  return stringBuilder.toString(); } //判斷授權的方法 授權成功直接調用寫入方法 這是監聽的回調 //參數 上下文 授權結果的數組 申請授權的數組 @Override public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {  super.onRequestPermissionsResult(requestCode, permissions, grantResults);  if(requestCode==REQUEST_WRITE&&grantResults[0]== PackageManager.PERMISSION_GRANTED){   writeToSdCard();  } }}

//第一請求權限被取消顯示的判斷，一般可以不寫if (ActivityCompat.shouldShowRequestPermissionRationale(SdkActivity.this,  Manifest.permission.WRITE_EXTERNAL_STORAGE)){ Log.i("readTosdCard","我們需要這個權限給你提供存儲服務"); showAlert();}else { //2、申請權限: 參數二：權限的數組；參數三：請求碼 ActivityCompat.requestPermissions(this,new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE},REQUEST_WRITE);}