android示例：一个简单的登陆程序

最近写了个简单的登陆程序，有几点收获：

1.懂得如何在LinearLayout中嵌套LinearLayout，完善布局的行列；

2.用android:layout_weight控制控件的比重；

3.用getText()获取EditText内容；

4.熟悉控件的编写，不用再照着书抄写了=.=

 

代码如下：

LoginActivity.java

import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class LoginActivity extends Activity {
private Button button;
private EditText editText1;
private EditText editText2;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.login);
//加载按钮和文件框等控件
button=(Button)findViewById(R.id.button);
editText1=(EditText)findViewById(R.id.input_account);
editText2=(EditText)findViewById(R.id.input_password);

button.setOnClickListener(new OnClickListener(){
public void onClick(View v){
//获取editText的文本内容，并删去空格
String inputAccount=editText1.getText().toString().trim();
String inputPassword=editText2.getText().toString().trim();
//如果账号密码为"123"就跳转活动
if(inputAccount.equals("123")&& inputPassword.equals("123")) {
Toast.makeText(LoginActivity.this, "账号密码正确，正在登陆中", Toast.LENGTH_SHORT).show();
Intent intent=new Intent(LoginActivity.this,MainActivity.class);
startActivity(intent);
}else {
Toast.makeText(LoginActivity.this, "账号或者密码不正确，请重新输入", Toast.LENGTH_SHORT).show();

}
}
});

}

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

}

LoginActivity.java

 

MainActivity.java

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;

public class MainActivity extends Activity {

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

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

}

MainActivity.java

 

login.xml

<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:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".LoginActivity"
android:orientation="vertical"
>
<LinearLayout
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="wrap_content"
>

<TextView
android:id="@+id/account"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="帐号:"    />

<EditText
android:id="@+id/input_account"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:hint="Input your account"
android:layout_weight="1" >

</EditText>
</LinearLayout>

<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<TextView
android:id="@+id/password"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="密码:"        />
<EditText
android:id="@+id/input_password"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:hint="Input your password"
android:layout_weight="1"      />

</LinearLayout>

<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">

<Button
android:id="@+id/button"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="登陆" />

</LinearLayout>
</LinearLayout>

login.xml

 

activity_main.xml

<RelativeLayout 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:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity" >

<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="登陆成功！撒花~" />

</RelativeLayout>

activity_main.xml

 

在AndroidManifest.xml中注册Activity

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.logindemo"
android:versionCode="1"
android:versionName="1.0" >

<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="17" />

<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name="com.example.logindemo.LoginActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />

<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>

<activity
android:name="com.example.logindemo.MainActivity" >
</activity>
</application>

</manifest>

AndroidManifest.xml

 

运行效果如下：

 

帐号密码均输入“123”，就可以成功登陆了。。开心^_^