android 判断是否第一次进入欢迎页

android 判断是否第一次进入欢迎页

package com.example.zsh.rememberpsw_test;

import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.animation.AlphaAnimation;
import android.view.animation.Animation;
import android.widget.RelativeLayout;

public class MainActivity extends AppCompatActivity {

    private Intent intent;
    private SharedPreferences pref;
    //用于判断是否是第一次运行，运行后变为false
    private boolean isFirst = true;

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

        RelativeLayout layoutWelcome = (RelativeLayout) findViewById(R.id.layoutwelcome);
        AlphaAnimation alphaAnimation = new AlphaAnimation(0.1f, 1.0f);
        alphaAnimation.setDuration(3000);
        layoutWelcome.startAnimation(alphaAnimation);
        alphaAnimation.setAnimationListener(new Animation.AnimationListener() {
            @Override
            public void onAnimationStart(Animation animation) {
            }

            @Override
            public void onAnimationRepeat(Animation animation) {
            }

            @Override
            public void onAnimationEnd(Animation animation) {
                judgeIntent();
            }

            private void judgeIntent() {
                pref = getSharedPreferences("isFirst", MODE_PRIVATE);//创建SharedPreferences对象
                isFirst = pref.getBoolean("isFirstIn", true);//如果第一次运行，无isFirstIn值，自动获取第二个参数为默认值
                if (isFirst) {//如果为true，进入if语句
                    intent = new Intent(MainActivity.this, LoginActivity.class);
                    SharedPreferences.Editor editor = pref.edit();
                    editor.putBoolean("isFirstIn", false);//保存isFirstIn值为false
                    editor.commit();//提交数据
                } else {
                    intent = new Intent(MainActivity.this, MainActivity.class);//如果为false，说明程序已经运行过，直接跳转到主页面
                }
                startActivity(intent);
                finish();
            }
        });
    }
}