动态获取权限

1.在manifest中声明需要的权限

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

2.在activity中动态申请权限

   public void getPermission(){
        if (Build.VERSION.SDK_INT>=Build.VERSION_CODES.M){
            if (ContextCompat.checkSelfPermission(this,Manifest.permission.WRITE_EXTERNAL_STORAGE)!= PackageManager.PERMISSION_GRANTED){
                ActivityCompat.requestPermissions(this,new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE},0);
            }else {
                Log.e("tag","已拥有权限");
            }
        }else {
            Log.e("tag","不用动态申请权限");
        }

    }

3.activity 重写onRequestPermissionResult 方法

   @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions,
            @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        if (requestCode == 0){
            if (grantResults[0] == PackageManager.PERMISSION_GRANTED){
                Log.e("tag","获取权限成功");
            }else {
                Log.e("tag","获取权限失败");
            }
        }
    }