android 右上角菜单不显示出来,Android创建右上角菜单

在app/src/main/res目录下创建一个Android Resource Directory

创建一个 Android Resource Directory

Resource type 选择 menu

在app/src/main/res/menu目录下创建一个Menu resource file

创建一个 Menu resource file

填写菜单的文件名

打开app/src/main/res/menu/menu.xml文件，添加菜单项

在MainActivity中创建菜单

//创建菜单

@Override

public boolean onCreateOptionsMenu(Menu menu) {

getMenuInflater().inflate(R.menu.menu,menu);

return true;

}

//菜单点击事件

@Override

public boolean onOptionsItemSelected(MenuItem item) {

switch (item.getItemId()){

case R.id.id_about_us: //关于

String version = "1.0.190712";

AlertDialog aboutDialog = new AlertDialog.Builder(this).create();

aboutDialog.setTitle("鱼知凡在线学习系统");

aboutDialog.setMessage("当前版本：" + version);

aboutDialog.show();

break;

case R.id.id_scan_some: //扫码

Intent intent = new Intent();

intent.setClass(MainActivity.this, CaptureActivity.class);

intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);

startActivityForResult(intent, REQUEST_CODE_SCAN);

break;

case R.id.id_close_app: //退出

AlertDialog exitDialog = new AlertDialog.Builder(this).create();

exitDialog.setTitle("系统提示");

exitDialog.setMessage("确定要退出吗");

exitDialog.setButton(DialogInterface.BUTTON_POSITIVE, "确定", new DialogInterface.OnClickListener() {

@Override

public void onClick(DialogInterface dialog, int which) {

finish();

}

});

exitDialog.setButton(DialogInterface.BUTTON_NEGATIVE, "取消", new DialogInterface.OnClickListener() {

@Override

public void onClick(DialogInterface dialog, int which) {

Toast.makeText(MainActivity.this, "欢迎回来", Toast.LENGTH_SHORT).show();

}

});

exitDialog.show();

break;

default:

break;

}

return true;

}