Android EditText 获得输入焦点 以及requestfocus()失效的问题

package com.example.hfs.requestfocusdemo;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity implements View.OnClickListener {


    private EditText mUserName,mPassWord;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        initView();

    }

    private void initView() {
        mUserName= (EditText) this.findViewById(R.id.et_username);
        mPassWord= (EditText) this.findViewById(R.id.et_password);

        mPassWord.setOnClickListener(this);
    }

    @Override
    public void onClick(View view) {
        if (!"123456".equals(mPassWord.getText().toString())){
            Toast.makeText(this,"密码错误,请重新输入",Toast.LENGTH_SHORT).show();
            mPassWord.requestFocus();
        }else{
            startActivity(new Intent(this,MainActivity.class));
            Toast.makeText(this,"登陆成功",Toast.LENGTH_SHORT).show();
            finish();
        }
    }
}

mPassWord.postDelayed(new Runnable() {  
　　@Override  
　　public void run() {  
　　　　mPassWord.requestFocus();  
　　}  
}, 500);