Intent intent = new Intent();intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK); intent.setClass(getApplicationContext(),FileBrowserActivity.class);startActivity(intent);

AlertDialog.Builder builder = new AlertDialog.Builder(this);builder.setMessage("是否接受文件?").setPositiveButton("是", new DialogInterface.OnClickListener() {                    @Override                    public void onClick(DialogInterface dialog, int which) {                    }                }).setNegativeButton("否", new OnClickListener() {                    @Override                    public void onClick(DialogInterface dialog, int which) {                    }                });
AlertDialog ad = builder.create();//ad.getWindow().setType(WindowManager.LayoutParams.TYPE_SYSTEM_DIALOG); //系统中关机对话框就是这个属性 ad.getWindow().setType(WindowManager.LayoutParams.TYPE_SYSTEM_ALERT);ad.setCanceledOnTouchOutside(false);                                   //点击外面区域不会让dialog消失ad.show();