Android笔记——判断程序是否第一次启动

public class Welcome extends Activity {
    private final long SPLASH_LENGTH = 2000;
    Handler handler = new Handler();

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.farst_img);
        
        //定义一个setting记录APP是几次启动！！！
        SharedPreferences setting = getSharedPreferences("com.example.hr_jie", 0);
        Boolean user_first = setting.getBoolean("FIRST", true);
        if (user_first) {// 第一次则跳转到欢迎页面
            setting.edit().putBoolean("FIRST", false).commit();
            tiaozhuanzhu();
        } else {//如果是第二次启动则直接跳转到主页面
            tiaozhuanfu();
        }
    }
    
    public void tiaozhuanzhu(){ 
    handler.postDelayed(new Runnable() {  //使用handler的postDelayed实现延时跳转  
         
            public void run() {    
                Intent intent = new Intent(Welcome.this, Welcome_four.class);    
                startActivity(intent);    
                finish();       
            }    
        }, SPLASH_LENGTH);//2秒后跳转至应用主界面MainActivity  
}
    
    public void tiaozhuanfu(){ 
    handler.postDelayed(new Runnable() {//使用handler的postDelayed实现延时跳转  
         
            public void run() {    
                Intent intent = new Intent(Welcome.this, MainActivity.class);    
                startActivity(intent);    
                finish();       
            }    
        }, SPLASH_LENGTH);//2秒后跳转至应用欢迎界面
}
}