第八次作业

package com.example.qq2;


import android.app.Activity;
import android.content.SharedPreferences;
import android.content.SharedPreferences.Editor;
import android.os.Bundle;
import android.text.TextUtils;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends Activity {
     private EditText madmin;
     private EditText mpassword;
     private Button mlogin;
     private TextView mtextview;
    /* (non-Javadoc)
     * @see android.app.Activity#onCreate(android.os.Bundle)
     */
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        
        setContentView(R.layout.activity_main);
        madmin = (EditText) findViewById(R.id.admin);
        mpassword = (EditText) findViewById(R.id.password);
        mlogin = (Button) findViewById(R.id.login);
        mtextview = (TextView) findViewById(R.id.textview);
        //回显文本
        readData();
        mlogin.setOnClickListener(new View.OnClickListener() {
            
            @Override
            public void onClick(View view) {
                // TODO Auto-generated method stub
                String admin = madmin.getText().toString();
                String password = mpassword.getText().toString();
                if(TextUtils.isEmpty(password)||TextUtils.isEmpty(admin)) {
                   Toast.makeText(MainActivity.this, "请填写正确信息", 0).show();
                   return;
               }
//               保存登录数据  Ctrl+1生成下面的那个方法
               saveData(admin,password);
               /*将数据保存到手机里面-->文件系统-->将"账号#密码"写到文件里面去*/
            }
                
        });
    }
//     回显文本 
    private void readData() {
        // TODO Auto-generated method stub
         SharedPreferences sp= getSharedPreferences("ppinfo", MODE_PRIVATE);
//         defValues  如果找不到对应的值应该怎么办
         String admin = sp.getString("admin","");
         madmin.setText(admin);
         String password = sp.getString("password","");
         mpassword.setText(password);
    }
    private void saveData(String admin, String password) {
         SharedPreferences sp= getSharedPreferences("ppinfo", MODE_PRIVATE);
         Editor edit = sp.edit();
         edit.putString("admin", admin);
         edit.putString("password", password);
//         提交
         edit.commit();
        }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }
}

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#e7e7e7"
    android:orientation="vertical"
    tools:context="com.example.qq2.MainActivity" >
    
   <ImageView
            android:layout_width="80dp"
            android:layout_height="80dp"
            android:layout_gravity="center_horizontal"
            android:layout_marginTop="30dp"
            android:background="@drawable/qq"
             />

    <LinearLayout 
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="horizontal"
    android:layout_marginTop="40dp"
    android:layout_marginLeft="10dp"
    android:layout_marginRight="10dp"
    >
    <TextView 
        android:layout_width="0dp"
        android:layout_height="40dp"
        android:text="账号："
        android:textSize="20dp"
        android:layout_weight="1"/>
    <EditText
        android:id="@+id/admin"
        android:layout_width="0dp"
        android:layout_height="40dp"
        android:hint="账号" 
        android:textSize="20dp"
        android:layout_weight="4"
        android:background="#ffffff"
        />
    </LinearLayout>
    <LinearLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="horizontal"
    android:layout_marginTop="20dp"
    android:layout_marginLeft="10dp"
    android:layout_marginRight="10dp"
   >
    <TextView 
        android:layout_width="0dp"
        android:layout_height="40dp"
        android:text="密码："
        android:textSize="20dp"
        android:layout_weight="1"/>
    <EditText
        android:id="@+id/password"
        android:layout_width="0dp"
        android:layout_height="40dp"
        android:hint="密码" 
        android:textSize="20dp"
        android:layout_weight="4"
        android:background="#ffffff"
        android:inputType="textPassword"
        />
    </LinearLayout>
    <Button 
        android:id="@+id/login"
        android:layout_width="120dp"
        android:layout_height="50dp"
        android:layout_gravity="center_horizontal"
        android:layout_marginTop="20dp"
        android:background="@drawable/bg_selector"
        android:text="登录"/>
    <TextView 
        android:id="@+id/textview"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text=""
        android:layout_gravity="center_horizontal"
        android:layout_marginTop="20dp"
        android:textSize="20dp"
        />
</LinearLayout>