Android应用学习（一）实现activity自动跳转和简单的登录

摘要: Android入门 activity跳转 Android登录

第一册接触Android应用程程序，做了一个简单的登录程序，运行程序后首先进入第一个activity然后4秒后自动跳转到下一个antivity，一个简单的登录界面。

main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<TextView
android:id="@+id/txtuname"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="20dip"
android:layout_marginRight="20dip"
android:textColor="#ff0000"
android:gravity="left"
android:text="用户名:"
/>
<EditText
android:id="@+id/uname"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_marginLeft="20dip"
android:layout_marginRight="20dip"
android:gravity="fill_horizontal"
android:autoText="false"
android:capitalize="none"
android:text="请输入用户名"
/>
<TextView
android:id="@+id/txtpasswd"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="20dip"
android:layout_marginRight="20dip"
android:textColor="#ff0000"
android:gravity="left"
android:text="密码:"
/>
<EditText
android:id="@+id/passwd"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_marginLeft="20dip"
android:layout_marginRight="20dip"
android:gravity="fill_horizontal"
android:autoText="false"
android:password="true"
android:capitalize="none"
android:text="请输入密码"
/>

<Button
android:id="@+id/login"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="登录" />

</LinearLayout>

welcom.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:background="@drawable/welimage"
>

</LinearLayout>

MainActivity.java

package com.test.myapp;

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

public class MainActivity extends Activity {
private Button login;
private EditText uname;
private EditText passwd;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
uname = (EditText)findViewById(R.id.uname);
passwd = (EditText)findViewById(R.id.passwd);
login = (Button)findViewById(R.id.login);
login.setOnClickListener(new OnClickListener(){
public void onClick(View v){
final String str1 = uname.getText().toString();
final String str2 = passwd.getText().toString();
if (str1.equals("username") && str2.equals("passwd"))
{
Intent intent = new Intent(MainActivity.this,NextActivity.class);
startActivity(intent);
}
else
{
Intent intent = new Intent(MainActivity.this,NextActivity.class);
startActivity(intent);
}

}

} );
}

}

NextActivity.java

package com.test.myapp;

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

public class NextActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.next);
}

}

WelcomeActivity.java

public class WelcomeActivity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.welcom);

final Intent main = new Intent(this, MainActivity.class); // 要转向的Activity
Timer timer = new Timer();
TimerTask task = new TimerTask() {
@Override
public void run() {
//WelcomeActivity.this.finish();
// 启动新的Activity
startActivity(main);
}
};
timer.schedule(task, 1000 * 4);//延时

}
}