欢迎界面的使用（小组项目）

第一步：先画布局

<?xml version="1.0" encoding="utf-8"?>
<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"
    tools:context="com.example.zyl.t3.MainActivity">

    <ImageView
        android:scaleType="fitXY"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@drawable/b"
        android:layout_alignParentTop="true"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true" />

</RelativeLayout>

第二步：Java部分

public class MainActivity extends AppCompatActivity {

    private final int SPLASH_DISPLAY_LENGHT = 3000; // 延迟3秒

    private SharedPreferences preferences;
    private SharedPreferences.Editor editor;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        preferences = getSharedPreferences("phone", Context.MODE_PRIVATE);
        new Handler().postDelayed(new Runnable() {

            @Override
            public void run() {
                if (preferences.getBoolean("firststart", true)) {
                    editor = preferences.edit();
                    //将登录标志位设置为false，下次登录时不在显示首次登录界面
                    editor.putBoolean("firststart", false);
                    editor.commit();
                    //实现跳转
                    Intent intent=new Intent();
                    intent.setClass(MainActivity.this,Register.class);
                    MainActivity.this.startActivity(intent);
                    MainActivity.this.finish();
                }else{
                    Intent intent=new Intent();
                    intent.setClass(MainActivity.this,Register.class);
                    MainActivity.this.startActivity(intent);
                    MainActivity.this.finish();

                }

            }
        },SPLASH_DISPLAY_LENGHT);
    }


}